JPH06129906A - Camera photometer - Google Patents

Abstract

(57) [Summary] [Purpose] In a photometric device for a camera, even if at least a region with a small photometric output occurs among a plurality of photometric regions, it is possible to calculate an appropriate exposure value without performing photometry again. The purpose is to [Structure] Divide into multiple photometric areas and measure each
Photometric means for detecting information on the brightness of each area, grouping means for grouping a part or all of the plurality of photometric areas based on the information on the brightness of each area, and the part or all Group information detection means for detecting information on the brightness of all areas in the group, information on the brightness of each area, and information on the brightness of all areas in the group. Exposure calculation means for calculating an appropriate exposure value based on the above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photometric device for a camera.

[0002]

2. Description of the Related Art Heretofore, there are known many photometric devices for cameras which divide a photometric area into a plurality of photometric areas and perform photometry, detect the information on the brightness of each area by the photometry, and calculate an exposure value. For example, there is one described in JP-A 1-217428. This device divides the photographic screen into a matrix and photometers each area, and detects information about the brightness of each area, that is, the photometric information (photometric output value) of each area and obtains an appropriate exposure value. It is a thing.

[0003]

However, the above photometric device has the following problems. At least one of the photometric outputs obtained for each region from multiple photometric regions always contains a noise component.The cause of this noise component is the dark current of the light receiving element or the photometric circuit. It is possible that noise is generated,
The magnitude of noise is determined by the temperature of the light receiving element, the power supply voltage, etc., and is not related to the brightness of the subject.

There is no problem if the noise component is negligibly small with respect to the above-mentioned one photometric output, but since the magnitude of the noise component is unrelated to the brightness of the subject as described above, the subject becomes dark. Then, when the photometric output becomes small, the noise component becomes relatively large, and as a result, the photometric error from a plurality of photometric regions becomes large. Therefore, there arises a problem that an appropriate exposure value cannot be obtained.

Therefore, when the above-mentioned noise component is large during the photometric output, it is considered that the photometric error is large, and it is necessary to take measures such as invalidating the photometric output in that area in advance. If you take measures, you will not be able to obtain the photometric value of the low-brightness part of the screen, you will not be able to obtain an appropriate exposure value at the exposure calculation stage, and you will have to re-meter the low-brightness part only. was there.

Further, in the case where a storage type photoelectric conversion element is used as the light receiving element, if the setting of the storage time is inappropriate, the photometric output of a part of the area becomes small as in the above case and the other part of the photoelectric conversion element becomes smaller. There is a problem in that an appropriate photometric value cannot be obtained due to a large photometric error between the area and the area. Therefore, in view of the above problems, an object of the present invention is to make it possible to calculate an appropriate exposure value without performing photometry again even if at least a region with a small photometric output occurs in the plurality of photometric regions. .

[0007]

In order to achieve the above object, the present invention is based on FIG. 1, and is divided into a plurality of photometric regions, the respective photometry is performed, and photometric means for detecting information on the brightness of each region ( 12), and grouping means (13) for grouping a part or all of the plurality of photometric areas based on the information on the brightness of each area, and grouping by the grouping means (13) Group information detection means (14) for detecting information on the brightness of all areas in the group for the part or all of the photometric areas, information on the brightness of the areas, and all of the groups. Exposure calculation means (15) for calculating an appropriate exposure value based on the information on the brightness of the area;
Equipped with.

[0008]

According to the present invention, as in the prior art, even in a scene in which photometry cannot be performed on the low luminance side of the subject, or in a scene in which the photometric error is large and the luminance value of the entire subject cannot be calculated, FIG. A grouping means (13) discriminates areas having a small photometric output based on the information on the brightness of each area detected by the inside photometric means (12) and groups the areas. A group information detecting means (14) detects information on the brightness of all the areas in the group for the above-mentioned group, and information on the brightness of each area and the brightness of all the areas in the group. The exposure calculation means (15) calculates an appropriate exposure value based on the information. Therefore, it is not necessary to perform photometry again, and labor can be saved.

[0009]

FIG. 2 is a block diagram showing the internal optical system of a single-lens reflex camera. In this figure, the light flux that has passed through the taking lens 1 passes through the quick return mirror 2, the diffusion screen 3, the condenser lens 4, the penta prism 5 and the eyepiece lens 6 and reaches the naked eye of the photographer. On the other hand, a part of the light flux diffused by the diffusing screen 3 is received by the light receiving element 9 through the condenser lens 4, the penta prism 5, the photometric prism 7, and the photometric lens 8.

The light receiving element 9 is a storage type photoelectric conversion element such as a CCD sensor, and as shown on the left side in FIG. 3, a light receiving and storage section 91, a transfer section 92, and a voltage conversion section 9 are provided.
3, the storage gate unit 94, and the timing circuit 95 form the light receiving element 9. In the light receiving and accumulating portion 91, light receiving segments are arranged in a plurality of photometric regions divided into a matrix of 20 rows and 12 columns as shown in FIG. 4, and the charges generated in the respective segments are arranged. Is received by the received light storage unit 91.

In FIG. 3, a timing circuit 95 is for receiving a master clock from the clock generation circuit 19 and creating various timing pulses necessary for the transfer of charges, and according to the timing pulse. The transfer unit 92 transfers the accumulated charge of the light receiving and accumulating unit 91 to the voltage converting unit 93 pixel by pixel. The voltage converter 93
Converts the charge sent from the transfer unit 92 into a voltage signal for each pixel and outputs the voltage signal to the A / D conversion circuit 20.

The storage gate unit 94 is a storage time setting unit 18
Is a gate for instructing the light receiving and accumulating portion 91 to start and end the charge accumulation in accordance with the signal from the light receiving and accumulating portion 91, and the light receiving and accumulating portion 91 executes the start and the end of the charge accumulation. The accumulation time setting unit 18 calculates the optimum accumulation time at the next accumulation based on the information from the brightness calculation unit 21 and the exposure calculation unit 24, and adjusts the accumulated charge amount.

The A / D conversion circuit 20 converts the voltage signal from the light receiving element 9 into a numerical signal that can be recognized by a computer as conversion into photometric information, and this numerical signal is A / D.
It is output to the brightness calculation unit 21 by the D conversion circuit 20. The brightness calculation unit 21 receives the correction value calculated by the correction data calculation unit 26 based on the information from the in-lens ROM 17, the accumulation time t input from the accumulation time setting unit 18, and the signal from the A / D conversion circuit 20. Using and, the brightness value BV (h,
v) is calculated according to the formula of Formula 1.

[0014]

[Equation 1]

V (h, v) is a numerical signal output from the A / D converter 20, and is an area of the h-th column from the left and the v-th row from the bottom among the plurality of photometric areas in FIG. The photometric output value of Eq. 1 and the logarithm with the base 2 on the right side of the expression 1 is used for conversion into the brightness value based on the apex method, and the brightness value BV (h, v ) Units are (E
V) or (BV).

In the equation (1), k (h, v) is a correction value calculated by the correction data calculation unit 26 based on the information from the in-lens ROM 17 as described above, and is R in the lens.
It is a unique correction value obtained for each photometric area from the open aperture value, the exit pupil position, the vignetting information, etc. input from the OM 17, and is obtained in advance by experiment or simulation in correspondence with each photometric area. is there.

The above-mentioned A / D conversion circuit 20 constitutes a photometric unit for outputting photometric information for each region from the plurality of photometric regions together with the light receiving element 9 including each of the components 91 to 95. The photometric unit and the above-described brightness calculation unit 21 constitute the photometric unit 12 in FIG. The group creating unit 22 in FIG. 3 serves as the grouping unit 13 in FIG. This is for grouping areas, and a method of grouping will be described later. The group luminance calculation unit 23 is a group information detection unit in FIG. 1 for detecting information on the brightness of all areas in the group. Specifically, the group luminance calculation unit 23 inputs information on the group from the group creation unit 22. Then, based on the information of the accumulation time setting unit 18 and the correction data calculation unit 26, the brightness value of each group is calculated.

The exposure calculation section 24 performs an exposure calculation based on each of the brightness values calculated by the brightness calculation section 21 and the brightness value of each group calculated by the group brightness calculation section 23 to obtain an appropriate exposure value. calculate. The method of exposure calculation will also be described later. Further, the exposure control unit 25 calculates the aperture value and shutter speed value for proper exposure based on the signal from the exposure calculation unit 24, and when a release button (not shown) is pressed, the mirror 2 is flipped up and the aperture 10 is opened.
The shutter 11 is controlled according to the appropriate exposure value, and the exposure control is performed.

A photometric counting unit 27 located above the storage time setting unit 18 in the figure is for counting photometry, and a memory unit 28 has a storage time setting unit 18 and A / A. It is for storing the photometric output value obtained by the conversion of the D conversion circuit 20 and the brightness value calculated by the brightness calculation unit 21. Further, the signal synthesizing unit 29 connected to the memory unit 28 is for synthesizing the above-described photometric output values stored in the memory unit 28, and the synthesizing thereof will also be described later.

Next, the necessity of adjusting the storage time of the light receiving element 9 by the storage time setting unit 18 will be described. Generally, the photometric range required for the photometric device of a camera is EV0
~ EV20, ie 20E in dynamic range
It is about V. However, the current CCD has a dynamic range of only about 10 EV. So CC
Therefore, it is necessary to adjust the storage time of D to set the required photometric range to the optimum level including the main subject.

Specifically, the brightness value in the object scene is EV0 to EV0.
With the EV 20, the illuminance on the surface of the light receiving element is about 0.01 Lx to 10000 Lx when the standard taking lens is mounted in the optical system in FIG. The sensitivity of the light receiving element is about 20V / lx · S, and the saturation output is about 2V.
Therefore, when the storage time is 10 μSec, the photometric range is about EV10 to EV20, and the storage time is 10 m.
When it is Sec, the photometric range is EV0 to EV10.

That is, the storage time of the light receiving element is set to 10 μS.
By operating in the range of ec to 10 mSec, the EV0 to E which is the photometric range required for the photometric device of the camera for the first time.
The dynamic range of V20 can be realized. For the above-mentioned reason, when photometry is performed using the CCD, the photometry range for one photometry is limited to the range of 10 EV, but the dynamic range of the silver salt film is 10 EV.
Since it is smaller than the above, no problem occurs.

5 and 6 show the photometric means 12 in FIG.
It is a simulation of the state of the photometric output value output from, which shows that the photometric output value is output for each region according to the clock pulse. In FIG. 5, it is assumed that subjects having the same brightness exist in each photometric area, and the photometric output includes a noise component as shown by the dotted line. This noise component is generated from a photometric circuit or the like, and its average value is 0 with or without some periodicity.
Is close to. As shown in FIG. 5, when the subject is bright, the ratio of the noise component to the photometric output is small, so there is no problem in calculating the brightness value.

Further, the brightness value is 2 as shown in the equation (1).
Since the logarithm is taken as the base, for example, the photometric output is 1
In the case of 024, the photometric output of a subject that is 1 EV dark is 512 from the brightness value. Therefore, the photometric output is 5
Even if it changes from 12 to 1024, the brightness value is 1E
Since only V has changed, the fluctuation due to noise as shown in FIG. 5 does not pose a problem at the time of conversion into a luminance value.

As in FIG. 5, FIG. 6 shows the case where the subject having the same brightness exists in each photometric region, but shows the case where the subject has low brightness. Even if the subject becomes dark, the magnitude of the noise component is determined by the photometric circuit, and therefore remains the same as in FIG. The state at this time is shown in FIG. As described above, when the proportion of the noise component in the photometric output is large, the photometric output varies due to the influence of the noise component even if the luminance components of the photometric outputs are equal, which causes a photometric error.

Moreover, since the brightness value is logarithmic as in FIG. 5, there is a difference of 1 EV between the case where the photometric output is 8 and the case where the photometric output is 4, as shown in FIG. 6 (a). In the case of FIG. 5, the data was increased by 512 and was 1 EV, but FIG.
In this case, the data increases by 4 and becomes 1 EV. Therefore, if only the noise component is converted into the luminance value, a considerable error occurs and the reliability becomes poor.

Conventionally, photometry is impossible at a point where the photometric output becomes small to some extent where the noise component cannot be ignored, but as already explained, when the average value of the noise component is taken, that value is canceled out and becomes almost zero. Therefore,
By averaging the photometric outputs, the noise components are canceled out as shown in FIG. 6B, and it becomes possible to extract only the luminance value component, and the luminance value can be calculated from the minute photometric output that was impossible to meter. It is possible, and there is no need to repeat photometry.

In this case, since the photometric values themselves are also averaged, the averaged data becomes the average luminance value of those photometric areas. Therefore, when the photometric output is large, the brightness value is calculated for each photometric area, and when the photometric output is small, the brightness value is calculated for each group by grouping, and the number of photometric areas can be calculated. It is possible to obtain a brightness value with a small error even for a low-brightness subject that cannot be metered in the past while ensuring the brightness.

FIG. 7 is a flow chart showing the operation of the microcomputer when the storage time setting unit 18 and each of the components 20 to 29 in FIG. 3 are constituted by one microcomputer. explain. “K” shown in step 101 indicates the number of times of photometry in the flowchart, and here, the photometry count unit 27 in FIG. 3 sets “k” to the initial value “1”. When k = 1, the first photometry is shown, and when k ≠ 1, the second or more photometry is shown.

In step 102, the photometric count k is "1".
The photometric counting section 27 determines whether or not it is, and if it is the first time, the process proceeds to step 103, or if it is the second time or more, the process proceeds to step 109. In step 103, the photometry counting unit 27 sets the photometry count k to “0”.
, And the process proceeds to the next step 104, and the accumulation time setting unit 18 sets the accumulation time t to “t1”. This "t
“1” is a predetermined value, t1 = 10 μSec, and the photometric range is EV10 to EV20.

Proceeding to step 105, the above-mentioned setting unit 1
During the accumulation time t1 (= 10 μSec) set by 8, photometry is performed, that is, according to the output of the light receiving element 9,
The A / D conversion circuit 20 converts each pixel into a numerical signal (photometric output value: V (h, v)), and the brightness calculation unit 21 also uses the predetermined correction value k (h, v) and the above-described photometric measurement. Output value V (h,
v) and the accumulation time t1 are used to calculate the respective brightness values BV (h, v) according to the equation of Formula 1. The memory unit 28 is A /
The 240 photometric output values from the D conversion circuit 20 and the 240 brightness values calculated by the brightness calculation unit 21 are stored.

In step 106, the accumulation time setting unit 18 sets the accumulation time t to "t2". This "t
2 ”is a predetermined value, t2 = 10 mSec, and the photometric range is EV0 to EV10. Step 10
7, the photometry is performed during the accumulation time t2 by the setting unit 18 as in step 105, and in parallel with the photometry, the memory unit 28 also stores 240 photometric output values and luminance values.

Proceeding to step 108, step 105
And the above-mentioned photometric output values stored in step 107 are taken out by the signal synthesizing unit 29 and synthesized, and the accumulation time t
Is EV10 to EV20 when t1 is t1, and EV0 to EV10 when the accumulation time t is t2.
Therefore, based on these two photometric results, the photometric output values are combined corresponding to the dynamic range of the photometric range from EV0 to EV20.

More specifically, the 240 photometric output values obtained in step 105 are searched, and for the area of EV 10 or less, the photometric output value of the same area at the accumulation time t2, that is, step 107. The photometric output value of the same area in the above is taken as the photometric result, and for the area other than that, the photometric output value of the same area at the accumulation time t1, that is, the photometric output value of the same area in step 105 is taken as the photometric result. At this time, in order to correct the difference in output due to the difference in storage time, log (t2 /
t1) / log2 shall be added.

In step 102, when the number of photometry is two or more, the process proceeds to step 109, the accumulation time setting unit 18 reads the accumulation time t from the memory unit 28,
Set that value to the accumulation time. Here, the memory unit 28
The accumulation time t read from is calculated in step 114 based on the previous photometric value, and the method of calculating t will be described later.

In step 110, photometry is performed during the accumulation time of the set, that is, in the same manner as described above, the A / D conversion circuit 20 outputs a numerical signal for each pixel according to the output of the light receiving element 9. (Photometric output value: V (h, v))
The brightness calculation unit 21 also uses the predetermined correction value k (h, v), the above-described photometric output value V (h, v), and the accumulation time t1 in accordance with the expression of Equation 1 to calculate each brightness value BV (h, v). To calculate.
At the same time, the memory unit 28 also stores 240 photometric output values and brightness values.

At the next step 111, the group creating section 22 retrieves the photometric output value of each area from the output of the A / D conversion circuit 20, and the photometric output is considered to have low brightness and a large photometric error. Pick up areas and try to group them together. The method of creating a group will also be described later. Proceeding to step 112, the group brightness calculation unit 23 calculates the brightness values of the above-described grouped groups, and a method of calculating the group brightness value will also be described later.

In step 113, the exposure calculator 24 calculates an appropriate exposure value BVans on the basis of the calculated luminance value, and a method of obtaining BVans will also be described later. In step 114, the accumulation time setting unit 18 calculates the accumulation time t for the next photometry, and the time t is stored in the memory unit 2.
8 memorize. The method of calculating the accumulation time t will also be described later.

In step 115, it is determined whether or not a release button (not shown) is fully pressed. If not yet, the process returns to step 102 to perform photometry in the same manner as described above, or to fully press the button. , The process proceeds to the next step 116, and the appropriate exposure value BVans obtained in step 113
Based on the above, the exposure control unit 25 drives the diaphragm member 10 and the shutter 11 to perform exposure control.

FIG. 8 is a subroutine flow chart for the group creating section 22 to perform the grouping process based on step 111 in FIG. 7. The grouping process will be described with reference to this flow chart. Step 20
“G (h, v)” in 1 indicates the photometric area at the (h, v) address in the h-th column from the left side and the v-th row from the lower side in FIG. 4, and here, in all the photometric areas Initialize by substituting "0". “0” indicates that the photometric area at the address (h, v) does not belong to the group.

"GN (h, v)" in step 202
Is an integer type variable indicating that the photometric area at address (h, v) belongs to any group, and here, "0" is assigned to all the photometric areas for initialization. "0"
Indicates that it does not belong to any group. Step two
“FLG (i)” in 03 is a logical variable indicating whether or not the group having the group number i has been merged with another group, and is initialized by substituting “0” into the variable. "0" means that the group with the group number i has been combined with another group, and the combination of groups will also be described later. If it exists independently of other groups, "1" is substituted. Incidentally, i is an integer type variable representing the count number of the group, and FLG (i) is a matrix type variable having a maximum of i = h × v / 2 elements.

In step 204, the photometric areas in the first column from the left and the first row from the bottom in FIG. 4 are designated,
Initialization is performed by substituting "1" for "h", "1" for "v", and "0" for the group number i of the photometric region (1,1). In step 205,
The output (photometric output value) of the A / D conversion circuit 20 determines whether or not the photometric output value V (h, v) at the address of the photometric area (h, v) is smaller than the predetermined value "3". When the value is smaller than the predetermined value “3”, it is considered that the photometric error is large due to noise, and the photometric areas at the address (h, v) are grouped. Substitute "1" for "G (h, v)". This "1" is
This indicates that the photometric areas at the address (h, v) are grouped.

When the photometric output value V (h, v) of the same area exceeds the predetermined value "3", the photometric area is not grouped and the group attribute "G (h, v) = 0". , ”And the process proceeds from step 205 to step 214. After substituting "1" in step 206 described above, the process proceeds to the next step 207, and it is determined whether or not the photometric area at the address (h, v) is the first row from the lower side in FIG. . If yes, then go to step 208; otherwise, go to step 211.

In step 208, it is determined whether or not the same area is the first column from the left side in FIG. 4, and if so, the process proceeds to step 209, and if not, the process proceeds to step 210. In step 209, since the group in the photometric area at the address (1, 1) is the first group, the group updating process described below is executed, and then the process proceeds to step 214.

In step 210, 1 from the bottom in FIG.
The group determination 1 to be described later is executed for the photometric area at the address (h> 1,1) that is not the first column from the left side in the row. When the determination 1 is completed, the process proceeds to step 214. In step 211, the photometric area at the address (h, v) is
It is determined whether or not it is the first column from the left side in FIG. 4, and if so, the process proceeds to step 212, and if not, the process proceeds to step 213.

In step 212, 1 from the left side in FIG.
The group determination 2 described below is executed for the photometric area at the address (1, v> 1) in the first row but not in the first row from the bottom. When the determination 2 is completed, the process proceeds to step 214. In step 213, the group determination 3 to be described later is executed for the photometric area at the address (h> 1, v> 1) on the second column from the left side and the second row on the lower side in FIG. . Even after the determination 3, the process proceeds to step 214.

In step 214, it is determined whether or not the photometric area at the address (h, v) is the 20th column from the left side. If yes, the process proceeds to step 215, and if not, step 216. Proceed to. In step 215, “1” is added to the above-mentioned column h and step 20 is executed.
Returning to step 5, after that, the process of grouping necessity is executed in the same manner as described above with respect to the photometric area on the immediate right.

In step 214 above, for example,
When the photometric region is the v-th row from the bottom and the 10th column from the left, the process moves to the region from the left-hand to the 11th column in step 215, and the process returns to step 205, from the V-th row from the bottom to the left. For the area of the 11th column, the grouping necessity process is executed as in step 205 and subsequent steps.

In step 216, it is determined whether or not the photometric area at the address (h, v) is on the 12th line from the lower side. If not, the routine proceeds to step 217, where the above-mentioned V line is displayed. Add "1" to (v <12), then
The first column from the left and the above added v + 1 from the bottom
The grouping necessity process is executed for the region of the row in the same manner as in step 205 and subsequent steps described above.

In step 216, when the target area is the 12th row from the bottom, it indicates that the grouping necessity check is completed for all the photometric areas in FIG. At that time, the process returns to the flowchart of FIG. 7 and proceeds to step 112 in the figure. FIG. 9 is a subroutine flowchart for the group creation unit 22 in FIG. 3 to perform the group update process based on step 209 in FIG. 8, and the update process will be described using this flowchart.

In step 301, 1 is added to the integer type variable "i" indicating the number of counts of the group, and the process proceeds to the next step 302, in which the variable "FL" indicating the success or failure of the group combination.
Set “1” to “G (i)”. Further step 30
In step 3, the group number “1” is assigned to the variable “GN (h, v)” indicating the current group name of the photometric area. After that, the process returns to step 214 in FIG. 8 and operates as described above.

FIG. 10 is a subroutine flowchart for the above-mentioned group creating section 22 to perform the processing of the group discrimination 1 based on step 210 in FIG. 8, and as described above, the first line from the bottom side. The processing for performing the group discrimination 1 is performed on the photometric areas (h> 1, 1) on the second and subsequent columns from the left side. The processing of the group discrimination 1 will be described based on the flowchart.

In step 401, it is detected whether or not the photometric region to the left of the photometric region to the left belongs to the group, that is, whether G (h-1, v) = 1. Step 2 in FIG. 8 in the previous grouping necessity check
According to 06, if the photometric areas at the address (h-1, v) are grouped, the process proceeds to step 403, or if not, the process proceeds to step 402.

In step 402, the group updating process is executed for the photometric area at the address (h, v), that is, the above-mentioned photometric area, in the same manner as in the flowchart of FIG. (H-1,
Since the photometric area at the address v) and the photometric area at the address (h, v) on the right of the address are adjacent to each other, the group numbers of the adjacent areas are made equal by the formula of the equation (2). I will let you. After that, step 214 in FIG.
Proceed to and operate as before.

[0055]

[Equation 2]

FIG. 11 is a subroutine flow chart for the above-mentioned group creation section 22 to carry out the processing of the group discrimination 2 based on step 212 in FIG. 8, and as described above, the second and subsequent rows from the lower side. In addition, the process for performing the group determination 2 is performed on the photometric area (1, v> 1) on the first column from the left side. The processing of the group discrimination 2 will be described based on the flowchart.

In step 501, it is detected whether or not the photometric region immediately below the photometric region belongs to the group, that is, whether G (h, v-1) = 1. In the previous check of necessity of grouping, step 20 in FIG.
According to 6, if the photometric areas at the address (h, v-1) are grouped, the process proceeds to step 503, or if they are not grouped, the process proceeds to step 502.

In step 502, the group updating process is executed for the photometric area at the address (h, v), that is, the above-mentioned photometric area, in the same manner as in the flowchart of FIG. (H, v-
1) Since the photometric area at the address and the photometric area at the address (h, v), which is one above the address, are adjacent to each other, the respective group numbers are assigned to the areas adjacent to each other by the formula (3). Try to make them equal. After that, step 21 in FIG.
Proceed to step 4 and operate as before.

[0059]

[Equation 3]

FIG. 12 is a subroutine flow chart for the above-mentioned group creating section 22 to perform the processing of the group discrimination 3 based on step 213 in FIG. 8, and as described above, the second and subsequent rows from the lower side. In addition, the processing for performing the group determination 3 is performed on the photometric areas (h> 1, v> 1) on the second and subsequent columns from the left side. The processing of the group discrimination 3 will be described based on the flowchart.

In step 601, it is determined whether or not the photometric area to the left of the photometric area belongs to the group, that is, G (h-1, v) = 1. If not, step 602 If it belongs, go to step 605. In step 602, it is determined whether or not the photometric area immediately below is in the group, that is, G (h,
v-1) = 1 is determined, and if it does not belong, the process proceeds to step 603, and if it does, the process proceeds to step 60.
Go to 4.

In step 603, the above-mentioned step 60 is executed.
Since the conditions of 1 and step 602 are denied, it indicates that the photometering areas to the left and one below are not included in the group. At this time, the above-described photometric areas are similar to those in the flowchart of FIG. The group update process is executed. After that, the process proceeds to step 214 in FIG. 8 and operates as described above.

In step 604, step 601 is negative and step 602 is positive, so
The photometric area to the left of the one does not belong to the group, but it indicates that the photometric area one level below belongs to the group. In this case, the photometric area at address (h, v) and the one below ( h, v
-1) Since the photometric area at the address is adjacent to each other, the adjacent group numbers are made equal to each other by the equation (3). After that, the process proceeds to step 214 in FIG. 8 and operates as described above.

In step 605, similarly to step 602, it is determined whether or not the next lower photometric area belongs to the group, that is, G (h, v-1) = 1, and if not, it is determined. When it belongs to step 606, it proceeds to step 607. In step 606, since step 601 is affirmative and step 605 is negative, it is indicated that the photometric area one level below does not belong to the group, but the photometric area on the left side belongs to the group. Indicates that the photometric area at the address (h, v) and the photometric area at the address (h-1,1) on the left are adjacent to each other. Make the group numbers of the same. After that, the routine proceeds to step 214 in FIG. 8 and operates as described above.

If the above-mentioned step 605 is affirmed, the affirmative result of step 601 indicates that the photometering areas to the left and one below are belonging to the group. At this time,
Proceeding to step 607, the group number to which the photometric area on the left side belongs is made equal to the group number of the photometric area at the address (h, v) according to the equation (2). The process proceeds to the next step 608, and it is determined whether or not the respective group numbers of the photometric region on the left side and the photometric region one below are equal, that is, whether the formula of Formula 4 is satisfied.

[0066]

[Equation 4]

The reason for performing this judgment processing is shown in FIG.
Will be specifically described. Now, let us consider a case in which, for example, a subject having a substantially U-shape is present in the object scene, and the photometric region in the shaded portion belongs to the group as shown in FIG. In the present embodiment, since scanning is performed from the area of h = 1, v = 1 to the right, when the area of h = 5, v = 4 is reached, it is determined that the area belongs to the group and a new one is added. A group number is given, and when the next area of h = 9 and v = 4 is reached, it is determined that the group belongs to another group, and another group number is given.

That is, h = 5, v = 4 subject and h =
9 and the subject of v = 4 are connected at the upper part and are actually the same subject (those in the same group), but h
= 9, v = 9, it is the first time it becomes clear when it reaches the area, and it is counted as a different group until then. Therefore, when h = 9 and v = 9 are reached and it is found that this is the case (the formula 4 is negated), it is necessary to combine the groups and correct the group number.

If the equation (4) is satisfied, it is not necessary to correct the group number. Therefore, from step 608,
After the group discrimination processing is completed, step 214 in FIG.
Or if the expression of Equation 4 is not satisfied, the process proceeds from step 608 to step 609 to perform the group merging process, the number of groups is reduced by the process, and the group number of the region to disappear. Is substituted into the variable DEL in accordance with the equation of Expression 5.

[0070]

[Equation 5]

In step 610, the group number correction processing is performed, that is, the area (x, y) having the same group number as the group number GN (h, n-1) of the area (h, v-1). ) Group number GN (x, y),
The area scanned up to now is traced back to GN (h,
The group number is the same as that of v). After the rewriting process, the process proceeds to step 611, and the variable F indicating that the group with the group number DEL has disappeared
Substituting "0" into LG (DEL), the equation at this time is expressed by Equation 6
Shown in.

[0072]

[Equation 6]

After step 611, the process proceeds to step 214 in FIG. 8 and operates in the same manner as described above. FIG. 13 is a flowchart showing a process for the group brightness calculation unit 23 in FIG. 3 to calculate the brightness value for each group based on step 112 in FIG. 7, and will be described based on the flowchart.

At step 701, a variable gr representing the number of effective groups is set to "0", and the routine proceeds to the next step 702, where it is judged whether or not the count number i of the group is greater than zero. If i = 0, there is no group, so the processing is terminated and step 1 in FIG.
13 or if the group exists,
The process proceeds from step 702 to step 703, and “j” is set to “1”.

In step 704, it is determined whether or not the group valid flag FLG (j) is "1". If so, the process proceeds to step 705, and if not, the process skips to step 709. Then, the above-mentioned flag FL
It is determined whether G (j) is equal to the group count number i. In step 705, the number of regions GNO belonging to the group j is counted, which is the number of regions where GN (x, y) = j for each region (x, y). In step 706, the number of areas G is set as described above.
It is determined whether or not NO is larger than “2”. GNO is 2
In the following cases, the number of regions in the group is small, so the effect of averaging is small, and since it is small as a subject, it is considered to be less important as a subject.
Disable grouping, then step 709
It works by skipping to.

When the number of regions GNO is larger than "2", the process proceeds from step 706 to the next step 707, 1 is added to the number of effective groups "gr", and the process proceeds to step 708 to further group average brightness value BVG of j
Calculate (j). The calculation method is the average value Vav of the photometric output values V (h, v) of the photometric regions belonging to the group.
The average value kave of e and the correction value k (x, y) may be substituted into each of V (h, v) and k (h, v) in the equation (1). At this time, as a method of obtaining Vave and kave, it is possible to simply take the average as in the equations (7) and (8).
When a region with a small correction value k (x, y) is weighted and averaged as in the formula, the region with a small correction value has a more accurate luminance value because of its higher reliability as a photometric value. can get.

[0077]

[Equation 7]

[0078]

[Equation 8]

[0079]

[Equation 9]

When the equation (9) is applied as the average photometric value, the correction value k is also weighted and averaged as in the equation (10) according to the weighting of Vave.

[0081]

[Equation 10]

Here, the symbol Σ indicates that all the elements belonging to the group are added, and Gnum indicates the number of areas belonging to the group. Also, kmax
Is the correction value k (x, y) in the area belonging to the group.
Indicates the maximum value of. If the optimum value for the entire grouped areas is newly calculated as the correction value k, a more accurate brightness value can be obtained. In addition, if the memory and computing capacity of the microcomputer are not sufficient, some grouping patterns are determined in advance and the optimum value of the correction value k for that group is stored, and the closest value is selected from those groups. You may refer to the value of such a group.

After the average brightness value BVG (j) of the group j shown in step 708 is calculated, the process proceeds to the next step 709, and it is determined whether or not “j = i”. If not, the process proceeds to step 710, "1" is added to "j" and the process returns to step 704, or "j =
If it is “i”, the calculation of the brightness value according to the flowchart of FIG. 13 is completed, and the process proceeds to step 113 in FIG. 7.

FIG. 15 is a subroutine flow chart showing a process for the exposure calculation unit 23 in FIG. 3 to perform the exposure calculation based on step 113 in FIG. 7, and the calculation process will be described with reference to the flow chart. . Step 8
In 01, in response to the output of the brightness calculation unit 21, for 240 brightness values having a brightness value exceeding 16.3 EV, the data is replaced with 16.3 EV. This is because when an object having an ultra-high brightness exceeding 16.3 EV such as the sun is included in the object, those objects are strongly affected and the effect is minimized.

In step 802, it is determined whether or not each of the 240 luminance values is 16.3 EV or more,
If so, the process proceeds to step 803, and as a proper exposure value, as shown in the equation (11), "16.
The value of "3" is detected.

[0086]

[Equation 11]

When the result of step 802 is negative, at least one of the brightness values is 16.
If it is smaller than 3 EV, the process proceeds to step 804, where BVmax, BVmin, BVh, BVl, and BV are output according to the outputs of the brightness calculation unit 21 and the group calculation unit 23.
Each of m and BVcw is calculated. The method of obtaining these variables is as follows.

BVmax gives the highest brightness among 240 brightness values, and does not exceed 16.3. BVmin gives the lowest luminance of the 240 luminance values, and BVh is the average value of the luminance values of the 24 regions from the high luminance side. BVl is the average value of the brightness values of 24 areas from the low brightness side, but when gr ≠ 0, that is, when a group is created, the brightness when the number of areas including the areas forming the group exceeds 24 Use the average value.

Further, BVm is an average value of all 240 luminance values, and BVcw is a photometric area BV (m, n).
The average value of the brightness values of 36 regions of 8 ≦ m ≦ 13 and 4 ≦ n ≦ 9. As described above, when calculating BVh and BVl, the average value of 24 areas was taken, but it is not limited to 24 areas, and it may be larger or smaller than this. Similarly, BVcw is not limited to the average value of 36 areas, but may be an output near the center of the object scene.

When all the calculations in step 804 are completed, the process proceeds to step 805, where "BVmax-BVmi
It is determined whether or not n <2 is satisfied. If so, the difference between the maximum luminance value and the minimum luminance value is small, so it is considered that the scene is extremely flat, and even if the photometric value of any area is selected, there is almost no change. Therefore, the process proceeds to step 806. Then, the photometric value of the central region having high reliability is calculated as the proper exposure value BVans by the equation (12). After that, the process returns to the flowchart in FIG. 7 and proceeds to step 114.

[0091]

[Equation 12]

Further, the above "BVmax-BVmin <2".
If is not established, the process proceeds to step 807,
It is determined whether "BVh-BVl <2" is established. If so, the difference between the high-luminance region and the low-luminance region is small, so it is considered that the scene is almost flat, and the process proceeds to step 808, and an appropriate exposure value is calculated by the equation (13). . After that, the process returns to the flowchart in FIG. 7 and proceeds to step 114.

[0093]

[Equation 13]

When the above "BVh-BVl <2" is not established, the routine proceeds to step 809, where "BVm-B".
Vcw> 2 "is established. When the condition is satisfied, the central brightness value is smaller than the average brightness value, and the central part is darker than the surroundings, so it can be regarded as backlight. At this time, proceed to step 810,
A proper exposure value is calculated by the mathematical formula 14. After that,
Returning to the flowchart in FIG. 7, step 114
Proceed to.

[0095]

[Equation 14]

When the above-mentioned "BVm-BVcw>2" is not established, the routine proceeds to step 811, where "BVcw-B".
Vm> 2 "is established. When the condition is satisfied, the brightness value in the central part is larger than the average brightness value, and the central part is brighter than the surroundings, so that it can be considered that the scene is in the spotlight. At this time, the process proceeds to step 812, and the appropriate exposure value is calculated by the formula of Expression 15. After that, the process returns to the flowchart in FIG. 7 and proceeds to step 114.

[0097]

[Equation 15]

When the above "BVcw-BVm>2" is not established, the routine proceeds to step 813, where "BVh-B
It is determined whether or not Vm <0.5 "is established. If so, the difference between the high-brightness region and the average brightness value is small, so it can be regarded as a scene in which a small dark subject exists in the screen. In this case, step 8
Proceeding to step 14, the proper exposure value is calculated by the equation (16). After that, the process returns to the flowchart in FIG. 7 and proceeds to step 114.

[0099]

[Equation 16]

When the above "BVh-BVm <0.5" is not established, the routine proceeds to step 815, where "BVm-BVm <0.5".
-BVl <0.5 "is determined. If so, the difference between the low-brightness area and the average brightness value is small, and therefore the scene is considered to have a small bright subject in the screen. In this case, step 81
Proceeding to step 6, the proper exposure value is calculated by the equation (17). After that, the process returns to the flowchart in FIG. 7 and proceeds to step 114.

[0101]

[Equation 17]

When the above "BVm-BVl <0.5" is not established, steps 805, 807, 809,
Since it does not satisfy the conditions of 811, 813 and 815 and does not apply to any of the above scenes, it is considered to be a so-called general scene. At this time, the process proceeds to step 817 and the formula 18 is used. , Calculate an appropriate exposure value. After that, the process returns to the flowchart in FIG. 7 and proceeds to step 114.

[0103]

[Equation 18]

FIG. 16 is a subroutine flow chart showing a process for the storage time setting section 18 in FIG. 3 to calculate the next optimum storage time t based on step 114 in FIG. The calculation of the accumulation time t will be described. In step 901, “BVmax
-BVmin <10 "is determined. If so, it is considered that all 240 photometric output values are within the photometric dynamic range of one time, and the process proceeds to step 902, and the next photometric reference level BVt is calculated by the equation (19). .

[0105]

[Formula 19]

BVt is a luminance value that gives a photometric value that is exactly 1/2 of the saturation level of the photometric output when photometry is performed for a certain storage time. For example, when the photometric range is EV10 to EV20, BVt = 15.
In step 901 described above, "BVmax-BVmin <1
If "0" is not established, it means that there is data above the photometric upper limit value or below the photometric lower limit value in the previous photometry, and the process proceeds to step 903, where the high brightness photometric limit data of the previous photometry is set. Count the number Nmax.

After the counting, the process proceeds to the next step 904, the number Nmin of the low brightness photometric limit data in the previous photometry is counted, and the process proceeds to step 905 to determine the photometric reference level BVt in the previous photometry. It is calculated according to the formula of 20. Here, t indicates the accumulation time in the previous photometry.

[0108]

[Equation 20]

For example, when t = 0.01 seconds, BVt =
It becomes 5. After calculating the above-mentioned reference level BVt, the routine proceeds to step 906, where the next photometric reference level BVt is
It is calculated in accordance with the equation of Expression 21 using the previous photometric reference level.

[0110]

[Equation 21]

In this equation, when Nmax is larger than Nmin, there is a large amount of high-brightness photometry limit data, so that the next photometry reference level works in the direction of increasing from the previous time, and conversely N
When min is greater than Nmax, the amount of low-luminance photometric limit data is large, so that the next photometric reference level works in a direction lower than that of the previous time. Where Nmax-Nmin is 1/10
Although the level shift amount is optimized by setting the above, it is not limited to 1/10, and each optimized value may be used.

In step 907, it is determined whether or not the next photometric reference level BVt is greater than 15, as shown in the equation (22).

[0113]

[Equation 22]

If this is the case, since the photometric reference level has exceeded the photometric upper limit, the routine proceeds to step 908, where the next photometric reference level BVt is set to the photometric upper limit "1".
5 ", and the photometric range at this time is EV10 to EV2
It becomes 0. After step 908, the process proceeds to step 911. When the next photometric reference level BVt is less than 15 in step 907, step 909
23, it is determined whether or not the next photometric reference level BVt is less than 5, as shown in the equation (23).

[0115]

[Equation 23]

If this is the case, since the photometric reference level has exceeded the photometric lower limit, the routine proceeds to step 910, and the next photometric reference level BVt is set to the photometric lower limit "5". Metering range is EV0 to EV1
It becomes 0. After step 910, the process proceeds to step 911. If the next photometric reference level BVt is greater than 5 in step 909, the process proceeds to step 911.

At step 911, the next storage time t is detected from the reference level BVt obtained at step 906, step 908 or step 910 by the formula 24, and the time t is stored in a predetermined address of the memory. .

[0118]

[Equation 24]

Here, the ^ mark represents a power. After storing the time t described above, the process returns to the flowchart of FIG. 7 and proceeds to step 115, and thereafter, the same operation as described above is performed. According to the above-described embodiment, the photometric unit including the light receiving element 9 including each of the components 91 to 95 in FIG. 3 and the A / D conversion circuit 20 and the brightness calculation unit 21 allow the photometric unit 12 in FIG. As described above, the photometric unit 12 may be only the photometric unit itself in the present invention, and in a camera such as a lens shutter camera that calculates an appropriate exposure value by the photometric output of the photometric unit. It is also possible to operate as follows.

Based on the photometric output of each area by the photometric section, the above-mentioned grouping means 13 picks up areas having a small photometric output to group them, and the group information detecting means 14 measures the photometry in group units from all areas within the group. The exposure value may be detected, and the exposure calculation unit 15 may calculate an appropriate exposure value based on the output value of each group and the photometric output value of each area.

[0121]

As described above, according to the present invention, since the photometric output is small, the photometric areas which cannot be photometered or are very difficult are discriminated and the areas are grouped, and the brightness of all the areas in the group is determined. Since it is configured to detect information related to depth, it is not necessary to perform photometry again even in a scene where the photometry of the entire subject could not be performed with one photometry in the past due to the large photometric difference in the scene. It is possible to obtain the photometric value of.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to the claims of the present invention.

FIG. 2 is a diagram showing an internal optical system of a single-lens reflex camera.

FIG. 3 is a block diagram showing a configuration of a photometric device provided in a single-lens reflex camera according to the embodiment of the present invention.

FIG. 4 is a plan view of a photometric area according to an embodiment of the present invention.

5 is a diagram showing a state of a photometric output value output by the photometric means 12 in FIG. 1 when a subject is bright.

6 is a photometric unit 1 in FIG. 1 when the subject is dark.
FIG. 3 is a diagram showing a state of a photometric output value output by No. 2.

7 is a storage time setting unit 18 and each component 20 in FIG.
31 is a flowchart showing the operation of the microcomputer when each of the to 29 is configured by one microcomputer.

FIG. 8 is a subroutine flowchart when the group creating unit 22 groups the above-described photometric areas based on step 111 in FIG. 7.

FIG. 9 is a subroutine flowchart when the group creation unit 22 performs a group update process based on step 209 in FIG.

FIG. 10 is a subroutine flowchart when the group creation unit 22 performs the processing of the group discrimination 1 based on step 210 in FIG.

FIG. 11 is a subroutine flowchart when the group creation unit 22 performs the processing of the group discrimination 2 based on step 212 in FIG.

FIG. 12 is a subroutine flow chart when the group creation unit 22 performs the processing of the group discrimination 3 based on step 213 in FIG.

FIG. 13 is a subroutine flowchart when the group luminance calculation unit 23 calculates the luminance value for each group based on step 112 in FIG. 7.

FIG. 14 is a diagram showing a state in which the photometric areas in the shaded area are grouped.

15 is a subroutine flowchart for the exposure calculation unit 24 to calculate an appropriate exposure value based on step 113 in FIG. 7.

FIG. 16 is a subroutine flowchart for the storage time setting unit 18 to calculate the next storage time t based on step 114 in FIG. 7.

[Explanation of symbols]

1 shooting lens, 2 quick return mirror, 3
Diffusing screen 4 Condenser lens, 5 Penta prism, 6
Eyepiece 7 Photometric prism, 8 Photometric lens, 9 Light receiving element, 10 Aperture 11 Shutter, 12 Photometric means, 13 Grouping means 14 Group information detecting means, 15 Exposure computing means 17 In-lens ROM, 18 Storage time setting section 19 Clock generation circuit, 20 A / D converter, 2
1 brightness calculation unit 22 group creation unit, 23 group brightness calculation unit,
24 exposure calculation unit 25 exposure control unit, 26 correction data calculation unit, 27
Photometric counting section 28 Memory section, 29 Signal combining section, 91 Light receiving and accumulating section 92 Transfer section, 93 Voltage converting section, 94 Accumulating gate 95 Timing circuit

Claims (6)

[Claims] 1. A photometric unit that divides into a plurality of photometric regions and each performs photometry to detect information regarding the brightness of each region, and one of the plurality of photometric regions based on the information regarding the brightness of each region. Grouping means for grouping all or all parts, and group information detection for detecting information on the brightness of all areas in the group for the partial or all photometric areas grouped by the grouping means Means, and exposure calculation means for calculating an appropriate exposure value on the basis of information on the brightness of each area and information on the brightness of all areas in the group, Photometric device. 2. The photometric unit includes a photometric unit that outputs photometric information for each area from the plurality of photometric areas, and a brightness calculation unit that calculates each brightness value in accordance with the photometric information. The grouping means groups a part or all of the plurality of photometric areas based on the respective photometric information, and the group information detecting means is a group from the part or all of the photometric areas. 2. A unit brightness value is calculated, and further, the exposure calculation means calculates an appropriate exposure value based on each of the brightness values and the group unit brightness value. Camera photometric device. 3. The photometric device for a camera according to claim 2, wherein regions of the plurality of photometric regions where the output of the photometric information is small are grouped by the grouping unit. 4. The photometric device for a camera according to claim 2, wherein the grouping unit groups adjacent photometric areas in which the photometric areas are adjacent to each other. 5. The brightness calculating section has a predetermined correction value for each of the plurality of photometric areas, and the brightness calculating section determines the same area based on the predetermined correction value corresponding to one photometric area. Of the photometric information is corrected to calculate a luminance value, and the group information detecting means calculates the luminance value by weighting a region having a small correction value among the photometric regions in the group. The photometric device for a camera according to claim 2. 6. The one group is invalidated when the number of photometric regions belonging to one group grouped by the grouping unit does not reach a predetermined number. Photometric device for the described camera.