JP2000249905A - Electronic image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic image pickup device whose constitution is simple and which is constituted so that an infinite position is extremely accurately measured. SOLUTION: In an infinite-point adjustment mode in which a lens position is controlled so that a photographing lens 2 is focused on an infinite-point object, a lens driving mechanism 3 is controlled so that the contrast of the output of an imaging device 8 becomes the maximum. Besides, the lens position from an restoring and abutting position being one end of the movable range of the lens 2 is stored in an EEPROM 24 as the infinite-point position. In a mode other than the infinite-point adjustment mode, the driving amount of the driving mechanism 3 is controlled by a system controller 1 based on the output of a range-finding circuit 14 and the infinite-point position stored in the EEPROM 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic imaging device for performing a photographing operation using a solid-state imaging device.

[0002]

2. Description of the Related Art Conventionally, there are various known camera systems for performing a photographing operation using a solid-state image sensor, and various automatic focus detection devices applied to such a camera system have been proposed. The present applicant also discloses Japanese Patent Application Laid-Open No. 63-2569.
In JP-A-31, using a photoelectric collimator, an error in the dimensions of a lens frame part and an fc error caused by an assembly error are measured and stored in an EEPROM, and a lens extension amount corresponding to a subject distance when a lens is driven. And an automatic focus detection device that determines the amount of movement of the lens in consideration of the fc error.

In general, a non-TTL automatic focus camera detects a distance to a subject based on a triangulation method. Then, the extension amount of the photographing lens is calculated based on the distance data, and the lens is driven. Based on the position where the lens is focused on the subject at the infinite position ∞, how much should the projecting amount be extended from this reference position in order to focus on the subject at the measured distance? Is shown. The reference position (infinity position) at which the subject at the infinity position is in focus is located at a position extended by a predetermined amount from the position where the lens is most advanced (stopper of the lens frame).

Incidentally, the infinite position may be different for each lens due to a dimensional error of members constituting the lens and an assembly error. Further, in the case of a zoom lens, the reference position also differs depending on the focal length. In order to cope with such a situation, conventionally, a camera taking the following measures has been proposed.

That is, first, an infinite position is measured by each camera, and the measurement result is stored as infinite position information in a nonvolatile memory of the camera. Then, when focusing on the subject, the lens is once moved so as to be most retracted. Next, there has been proposed a camera which determines a moving amount of a lens based on infinite position information based on a moving amount of a lens according to a subject distance and moves the lens according to the moving amount.

A so-called silver halide camera having an infinite position measuring means as described below has also been proposed.

That is, a collimator is used to project a light beam from an object at an infinite distance to a photographic lens, and temporarily detects a contrast of an image formed by the photographic lens on a film surface of the camera. To place. Then, after the photographing lens is fully retracted, a position where the contrast becomes maximum is detected from the output of the sensor while the photographing lens is extended, and the amount of extension at this time is used as infinity position information. Cameras have been proposed.

[0008]

By the way, in an electronic still camera, there is no need to load a film, so that there is no rear lid. Therefore, a sensor for detecting the contrast cannot be temporarily attached. An imaging device such as a CCD is mounted at a position corresponding to the film surface. Therefore, it has been difficult to measure the infinite position by the same method as the above-mentioned silver halide camera.

The present invention has been made in view of such a problem, and an object of the present invention is to provide an electronic image pickup apparatus which measures an infinite position with a very simple configuration and extremely high accuracy.

[0010]

According to a first aspect of the present invention, there is provided an electronic image pickup apparatus having a photographing lens and an image pickup element and outputting subject image data. A distance measuring means for measuring a distance from the electronic imaging device to a subject; a lens driving means for driving the focusing of the photographing lens; and a lens position detecting means for detecting a current position in a movable range of the photographing lens. A mode setting means for setting an operation mode of the electronic imaging apparatus, including an infinity adjustment mode for defining a lens position corresponding to infinity so that the photographing lens focuses on an object at infinity; A storage means for storing at least position information relating to focus adjustment of the photographing lens; and the mode setting means, wherein when the apparatus is in the infinity adjustment mode, the image pickup device The lens driving means is controlled so that the output contrast is maximized, and the lens position from a position with a revolving contact, which is one end of the movable range of the photographing lens, is stored in the storage means as an infinity position, and the infinity is stored in the storage means. In a mode other than the far adjustment mode, there is provided control means for controlling a driving amount of the lens driving means based on an output of the distance measuring means and the infinity position stored in the storage means. It is characterized by the following.

[0011] In order to achieve the above object, a second aspect of the present invention is provided.
In the electronic imaging device, the photographing lens is a zoom lens in the first electronic imaging device, and the infinity position is stored for each focal length value.

[0012] In order to achieve the above object, a third aspect of the present invention is provided.
An electronic imaging device according to the first aspect, wherein the distance measuring device has an optical axis different from the optical axis of the photographing lens in the first electronic imaging device.

In order to achieve the above object, a fourth aspect of the present invention is provided.
The electronic imaging device of the first electronic imaging device further includes a communication terminal to which an external device can be connected, and the mode control means sets the infinity adjustment mode according to only a command from the external device. It is characterized by performing.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of an electronic camera according to a first embodiment of the present invention.

The electronic camera of the present embodiment includes a system controller 1 that controls the entire electronic camera, and appropriately controls the operation of each unit described later. The system controller 1 is constituted by a CPU. On the front surface of the camera body, a photographic lens 2 for receiving subject light is provided movably by a lens driving mechanism 3. The lens drive mechanism 3 includes a motor serving as a drive source and a sensor for detecting the amount of movement of the lens (all of which will be described in detail later), all of which are controlled by the system controller 1 via the lens control circuit 4. Controlled.

A lens shutter 5 is provided behind the taking lens 2.
Is disposed, and further behind the CCD through a filter 7.
8 are provided. The lens shutter 5 has the functions of an aperture and a shutter, and controls the amount of light incident on the CCD 8 disposed behind. The lens shutter 5 is controlled by the system controller 1 via a shutter control circuit 6. A filter 7 having two functions is arranged near the CCD 8. The first function is to cut off infrared rays and guide only visible light to the CCD 8, and the second function is to function as an optical low-pass filter.

A distance measuring sensor 11 is provided near the photographing lens 2. The distance measuring sensor 11 is a sensor for detecting a distance to a subject, and includes a pair of separator lenses 12 and a pair of line sensors 13 arranged to face the separator lenses 12. The line sensor 13 is controlled by a distance measuring circuit 14.
That is, the distance measurement circuit 14 inputs data of the subject image formed on the line sensor 13 and calculates the distance to the subject.

The output of the distance measuring circuit 14 is connected to the system controller 1, which inputs data relating to the distance to the object, and captures the image so that the image of the object formed by the imaging lens 2 is formed on the CCD 8. The position of the lens 2 is controlled.

A photometric circuit 15 is provided near the distance measuring sensor 11 to measure the luminance of the subject. The system controller 1 determines the integration time of the CCD 8 and the lens shutter 5 based on the luminance data input from the photometric circuit 15.
Determine the aperture value.

The system controller 1 is connected to an operation display circuit 21 for displaying operation mode information and exposure information of the camera, and an operation switch 22 for causing the camera system to execute a desired operation by the user.
The operation switch 22 includes a plurality of switches. On the other hand, a test terminal 23 used when executing the test mode is connected to the system controller 1. The terminal 23 is normally in an OPEN state. Then, by short-circuiting the terminal 23, parameters necessary for the focus adjustment operation can be measured. Further, an EEPROM 24 of a nonvolatile memory is connected to the system controller 1 and stores control parameters necessary for controlling the system.

An image data controller 31 is connected to the system controller 1. The image data controller 31 is constituted by a so-called DSP, and controls the CCD 8 via a timing pulse generation circuit 32.
Correction and processing of image data input from the CCD 8 are executed based on a command from the system controller 1. The timing pulse generating circuit 32 outputs a pulse signal necessary for driving the CCD 8 to the CCD 8 and also outputs the pulse signal to the A / D converter 33.

The output terminal of the CCD 8 is an A / D converter 33
Connected to. The A / D converter 33 performs a CCD operation based on the pulse signal from the timing pulse generation circuit 32.
An analog signal corresponding to the subject image output by 8 is converted into digital data and output to the image data controller 31.

The image data controller 31 stores the digital data in a DRAM 34 connected to the image data controller 31. The DRAM 34 is used as storage means for temporarily storing image data before processing or data conversion into a predetermined format.

On the other hand, an image data recording medium 36 is connected to the image data controller 31 via an image compression circuit 35. The image compression circuit 35 is the DRAM
Compression and conversion of the image data stored in, for example, JP
This is a circuit for performing EG processing. The image data converted by the image compression circuit 35 is stored in the image data recording medium 36. In this embodiment, the image data recording medium 36 is a hard disk,
Assume a flash memory, floppy disk, etc.

Further, an image display circuit 39 is connected to the image data controller 31 via a D / A converter 37 and an encoder circuit 38. This image display circuit 3
Reference numeral 9 denotes a circuit for displaying image data picked up by the CCD 8, and generally includes a color liquid crystal display element. The image data controller 31 converts the image data on the DRAM 34 into an analog signal by the D / A converter 37 and outputs the analog signal to the encoder circuit 38. The encoder circuit 38 converts the analog signal into an image signal required for driving the image display circuit 39, for example, an NTSC signal.

Next, the photographing lens 2 and the lens driving mechanism 3 will be described in detail with reference to FIGS.

FIG. 2 is an external perspective view of a main part showing a photographing lens and a lens driving mechanism in the electronic camera according to the first embodiment. FIG. 3 is a photographing lens, a lens driving mechanism and a camera in the electronic camera. It is principal part sectional drawing which showed a part of main body.

As shown in FIG. 2, the photographing lens 2 is held in a focusing frame 52,
A focusing frame gear 53 is integrally provided at one end of the second frame 2, and engages with a power transmission mechanism 46 described later. further,
A helicoid 54 is formed on the outer periphery of the focusing frame 52.

The lens driving mechanism 3 for driving the photographing lens 2 includes a motor 41 as a driving source and this motor 41
A power transmission mechanism 46 comprising a pinion gear 42 provided on the output shaft of
And a rotating slit 47 arranged coaxially with the gear 43 and rotating at the same rotational speed, and a photo interrupter 48 for the rotating slit 47.

The power transmission mechanism 46 meshes with the focusing frame gear 53 at the last stage. As a result, the torque of the motor 41 is transmitted to the focusing frame gear 53 via the power transmission mechanism 46. As a result,
The focusing frame 52 rotates.

The pulse signal output from the photointerrupter 48 is input to the system controller 1 via the lens control circuit 4, and the system controller 1 counts the pulse signal to obtain a photographing lens. 2 is detected.

As shown in FIG. 3, the taking lens 2 (focusing frame 52) and the lens driving mechanism 3 are disposed in a mirror frame 56 which is integrally fixed to a part 55 of the camera body. At the front end of the lens frame 56, a fixed frame 57 is fixedly provided at its flange. A helicoid 57 a is formed on the inner peripheral surface of the frame portion of the fixed frame 57, and fits with the helicoid 54 provided on the focusing frame 52.

As described above, the focusing frame 52 is engaged with the fixed frame 57 and is included in the lens frame 56. On the other hand, the lens driving mechanism 3, ie, the motor 41, the power transmission mechanism 46, etc. It is arranged in a space formed between the lens frame 56 and the lens frame 56.

With such a configuration of the focusing frame 52 and the lens driving mechanism 3, when the motor 41 is rotated in the same direction by a CCW direction signal (in accordance with an instruction from the system controller 1), the focusing frame 52 is fixed to the fixed frame 5.
7 to be unreeled. The movement by this extension is performed at the rear end 53b of the focusing frame gear 53.
And until the rear end face 57b of the fixed frame 57 abuts.

On the other hand, when the focusing frame 52 is rotated in the same direction by the CW direction signal, the focusing frame 52 moves so as to be retracted with respect to the fixed frame 57. Movement by this renormalization,
This is possible until the rear end face 53a of the focusing frame gear 53 and the part 55a of the camera body come into contact with each other.

Next, a main routine executed by the system controller 1 will be described with reference to FIG.

When a power switch which is one of the operation switches 22 is turned on, power is supplied to the system and the system controller 1 starts operating. First, the system controller 1 performs an initial setting (step S100). That is, the initialization of each circuit connected to the memory, the I / O port, and the system controller 1 (CPU), the activation operation of the image data controller 31 (DSP), and the like.

Next, the system controller 1 checks the test terminals 23 (step S101). If the test terminal 23 is in the open state in step S101, the process proceeds to step S103 to perform a normal operation. On the other hand, if the test terminal 23 is in the closed state, the infinite focal position of the photographing lens is measured. That is, step S1
From 01, the process proceeds to step S102 to execute a subroutine "infinite position measurement".

This subroutine is executed in a camera manufacturing process, a camera repair center, or the like, and ordinary users do not use this subroutine. Therefore, the existence of the test terminal 23 is not disclosed to the user. If it is difficult to provide the dedicated test terminal 23, an operation switch operated by a user may be used. However, to prevent users from executing subroutines,
In a special combination, it is necessary to execute a subroutine only when a switch is operated.

In step S 103, the system controller 1 inputs luminance information of the subject from the photometric circuit 15. Then, based on the luminance information, the lens shutter 5
The aperture value is determined at the time of shutter time necessary for controlling the shutter speed.

Next, the system controller 1 outputs data indicating the operation state of the camera, shutter speed, aperture value, etc. to the operation display circuit 21 (step S104), and then detects the state of the release switch (step S10).
5). Here, when the release switch is on, the process proceeds to step S108, and when the release switch is off, the process proceeds to step S106.

In step S106, the system controller 1 detects the state of the power switch. Here, if the power switch is off, the operation of the camera system must be stopped. Therefore, step S1
From step 06, the process proceeds to step S107, and after the processing for system down is executed, the operation is stopped. On the other hand, if the power switch is on, the process moves to step S103 to continue operation as a camera.

In step S108, the system controller 1 outputs a ranging start command to the ranging circuit 14. Then, the distance measurement circuit 14 performs an integration operation of the line sensor 13 incorporated in the distance measurement sensor 11. When the integration operation is completed, the distance measuring circuit 14 outputs an end signal to the system controller 1.

In step S109, the system controller 1 waits until the end signal is detected. When the end signal from the distance measuring circuit 14 is input, the process proceeds to step S110, and the data of the line sensor 13 is input. For example, as shown in FIG.
Is assumed to have three ranging areas in the photographing area. In the drawing, the first, second, and third ranging areas are defined from the right side. The second ranging area of the three ranging areas is located at the center of the shooting area, and the first ranging area and the third ranging area are located at the center of the shooting area.
The ranging area is located away from the center.

Next, the system controller 1 determines the distances between the objects existing in the three areas and the respective distances in step S.
The calculation is performed based on the data input in step 110 (step S111). Next, one data is selected from the three distance data calculated in step S111 (step S111).
112). Although various methods have been proposed for this selection method, they are not directly related to the gist of the present invention, and thus description thereof will be omitted.

Next, in step S113, the system controller 1 reads out the infinite position data corresponding to the distance measuring area selected in step S112 from the EEPROM 24. Table 1 shows an example of infinite position data corresponding to the distance measurement area.

[0048]

[Table 1] In addition, the EEPROM 24 stores infinite position data in correspondence with the distance measurement area and the address. This infinite position data is determined by a subroutine "infinite position measurement". For example, when the third ranging area is selected, Pf
c is 94 pulses (* 1).

In the next step S114, the system controller 1 sends the feed-out data corresponding to the subject distance data to the selected distance measurement area to the EEPROM 2.
Read from # 4. Table 2 shows an example of the correspondence between subject distance data and payout data.

[0050]

[Table 2] Note that Table 2 includes two payout data. One is the second
This is data corresponding to the distance measurement area, and the other one is data corresponding to the first distance measurement area and the third distance measurement area.

As shown in FIG. 5, the second distance measuring area is located at the center of the photographing area, and the first distance measuring area and the third distance measuring area are located far from the center. In general, the image formed by the photographing lens is best at the center of the photographing area. The image at the periphery of the shooting area is degraded from the image at the center due to the aberration of the lens. In order to prevent the image from deteriorating due to this aberration, it is desirable to set the position of the taking lens according to the position of the subject image on the taking area. Therefore, Table 2 includes data corresponding to the second ranging area and data corresponding to the first and third ranging areas.

It should be noted that the first and third distance measuring areas are arranged symmetrically with respect to the second distance measuring area, so that the first and third distance measuring areas may be the same data. become. If the lenses constituting the taking lens have no eccentricity, the amounts of aberration of the lenses in the first and third ranging areas are the same, and therefore, the extension data is the same. The extension data can be determined by simulation once the design of the photographing lens is determined. In the simulation, based on the position of the photographing lens that focuses on the subject at the infinite position, it is calculated how much the photographing lens should be extended to focus on the subject at a finite distance. Table 2 shows a value obtained by converting the calculated value into the number of pulse signals generated by the photo interrupter.

It should be noted that even if the lens is slightly decentered and there is a difference between the extension data of the first and third distance measurement areas, the infinite position data is stored in the first distance measurement area, the second distance measurement area, and the third distance measurement area.
Since the measurement is performed in each of the distance measurement areas, it is possible to cancel each other. The extension data is stored in correspondence with the address of the EEPROM 24 based on the distance measurement area and the distance data.

Assuming that the subject distance data in the third distance measurement area is 4.0 (m), the extension data is 170
It becomes a pulse (* 2). When the distance data is not shown in Table 2, the distance data may be calculated from the neighboring data. For example, if the distance data is 4.5 (m), the distance data can be obtained by linear interpolation from the 5.6 (m) extended data and the 4.0 (m) extended data.

Returning to FIG. 4, in step S115, the system controller 1 uses the infinite position data (Pfc) and the feed data (PL) to output total feed data (Px).
Ask for. By adding these two data, total payout data can be obtained.

Thereafter, the system controller 1 outputs a drive signal for rotating the motor 41 in the CW direction to the lens control circuit 4 (step S116). Thereby, the focusing frame 52 starts moving in the retraction direction. Then, the portion 53 of the focusing frame gear 53
a until the motor 55 a comes into contact with the camera body 55a.
Keeps rotating. If the motor 41 is rotating, the photo interrupter 48 continues to output a pulse signal. When the part 53a and the part 55a come into contact with each other and the motor 41 stops, the pulse signal disappears.

Next, the system controller 1 proceeds to step S
At 117, the process waits until the pulse signal is detected and the pulse signal disappears. Here, when the pulse signal disappears, the process shifts to step S118 to output a brake signal to the lens control circuit 4. As a result, the motor 41 stops. At this time, the focusing frame 52 is stopped at the most retracted position. Then, the focusing frame 52 is set with reference to the most sunk position.
Is advanced by the total advance data (Px) calculated in step S115, the subject image from the photographing lens 2 is formed on the image sensor 8 (CCD).

Thereafter, the system controller 1 outputs a drive signal for rotating the motor 41 in the CCW direction to the lens control circuit 4 (step S119). This causes the focusing frame 52 to start moving in the feeding direction.

Further, the system controller 1 waits until the number of pulses generated by the photo interrupter 48 becomes equal to the predetermined value Px (step S120). When the count value of the number of pulses reaches the predetermined value Px, the process proceeds from step S120 to step S121. Step S
At 121, the system controller 1 outputs a brake signal to the lens control circuit 4 to stop the motor 41.

Thereafter, the system controller 1 opens the sector of the lens shutter 5 based on the aperture value determined in step S103 (step S122). Further, a control signal is sent to the image data controller 31 in order to integrate the image sensor 8 at the shutter time determined in step S103 (step S123). When the integration of the image sensor 8 is completed, the system controller 1 closes the sector of the lens shutter 5 (step S12).
4).

Next, the system controller 1 proceeds to step S
At 125, the image data controller 31 (DS
P) is instructed to take in image data from the image sensor 8. Further, an instruction is given to compress the captured image data and store it in the image data storage medium (step S126).

After that, the system controller 1 outputs a drive signal for rotating the motor 41 in the CW direction to the lens control circuit 4 (step S127). Thereby, the focusing frame 52 starts moving in the retraction direction. Further, the system controller 1 waits until the number of pulses generated by the photo interrupter 48 becomes equal to PL (step S128). When the count value of the number of pulses reaches PL, the process proceeds to step S129. In step S129, a brake signal is output to the lens control circuit 4 to stop the motor 41.

Further, if there is no backlash generated by the helicoid 54 and the power transmission mechanism 46, the system controller 1 stops the photographing lens 2 at a position where the infinite object is focused by the operations of steps S127, S128 and S129. . Thereafter, the process returns to step S103 to continue the operation.

Next, the subroutine "infinite position measurement" of step S102 will be described with reference to the flowchart shown in FIG.

This subroutine performs a process of measuring how much the photographing lens 2 can be extended from the reference position, that is, the position where the focusing frame 52 is most retracted, to form an image of an object at an infinite position on the image sensor 8. .

In executing the subroutine, the camera is mounted on a measuring jig as shown in FIG. The measuring jig has a chart as a temporary subject, and the chart is illuminated by a light source. Also,
This chart exists at the focal position of the collimator men. Therefore, looking at the chart through the collimator lens is equivalent to the chart being at an infinite position.

When the subroutine is called in step S102 (see FIG. 4), the system controller 1 first moves the taking lens 2 to the reference position. In the flowchart of FIG.
0, S201, and S202 correspond to this operation, and the operations in steps S200, S201, and S202 are the same as steps S116, S117, and S1 described above.
18 (see FIG. 4), and the description is omitted here.

When the setting to the reference position is completed, the system controller 1 moves to step S203 and instructs the shutter control circuit 6 to open the sector of the lens shutter 5. The aperture value at this time is an open value. By setting the aperture value to an open value, the contrast of the subject image is increased, and the image formation position can be easily detected.

Next, the system controller 1 proceeds to step S
At 204, a control signal is sent to the image data controller 31 to integrate the image sensor at a predetermined shutter time. When the integration operation of the image sensor is completed in step S204, the sector of the lens shutter 5 is closed in step S205.

The system controller 1 determines in step S20
In step S207, the image data controller 31 is instructed to take in image data from the image pickup device, and step S207
Output position information of the distance measurement area (focus area) to the image data controller 31. Accordingly, the image data controller 31 calculates the contrast value from the image data corresponding to the three distance measurement areas,
Store it in AM34.

FIG. 8 is an explanatory diagram showing an area of a pixel for performing a contrast operation with the image pickup device 8. The calculation of the contrast value is performed based on, for example, the following equation.

[0072] Here, Sadd indicates the address of the memory where the data of the first pixel in the pixel area is stored, and Eadd indicates the address of the memory where the data of the last pixel of the pixel area is stored. Xi is an output value of each pixel constituting the image sensor.

When the contrast calculation of the image data controller 31 is completed in step S207, the system controller 1 determines in step S208 whether the number of operations has reached a predetermined number (Nx).
If the number of operations is not Nx, the process proceeds to step S209.

In step S209, the system controller 1 controls the lens control circuit 4 to
A drive signal for rotating in the CW direction is output. Thus, the focusing frame 52 starts moving in the feeding direction. Thereafter, in step S210, the process waits until the number of pulse signals generated by the photo interrupter 48 becomes equal to the predetermined value PΔ. And the pulse count value is P
When Δ is reached, the process moves from step S210 to step S211. In step S211, the motor 41 is braked to instruct each unit to stop the movement of the taking lens 2. Then, the process returns to step S203 to perform the contrast calculation from the output of the image sensor 8 again.

The operation of obtaining the contrast value and the operation of extending the photographing lens 2 by a predetermined amount are repeated until the number reaches Nx (step S208). Number of operations is Nx
Is reached, the process moves from step S208 to step S212. In step S212, the system controller 1 inputs the contrast value calculated based on the image data from the image data controller 31.

FIG. 9 is a diagram showing an example in which the number of operations is plotted on the horizontal axis and the contrast value is plotted on the vertical axis, and the contrast value obtained from the output of the image pickup device 8 is plotted.

After acquiring the contrast value in step S212, the system controller 1 determines in what number of operations the contrast value has reached the maximum in step S213. The number of operations at the time when the contrast value is the maximum is multiplied by PΔ, and the calculation result becomes infinite position data (Pfc).

Now, as shown in FIG. 9, it is assumed that the contrast value with respect to the first distance measurement area becomes maximum at the time of the tenth operation. Assuming that PΔ is 10 pulses, the infinite position data for the first ranging area is 100 (10
The 10th pulse). That is, if the lens is extended 100 pulses from the position where the photographing lens 2 is most advanced,
A subject at an infinite position forms an image on the image sensor 8.

Similarly, in the case of the second ranging area, as shown in FIG. 9, since the contrast value becomes maximum at the time of the eighth operation, P.DELTA. Obtaining infinite position data results in 80 pulses.

When the maximum value of the contrast value is between the ninth and tenth times as in the third ranging area shown in FIG. 9, the maximum value can be calculated by the following method. That is, as shown in FIG. 10, first, the left side of the peak of the curve showing the contrast characteristic is linearly approximated (linear line 1) using the eighth and ninth contrast values C8 and C9. Similarly, the 10th and 11th contrast values C1
Straight line approximation of the right curve using 0 and C11 (Line 2)
I do. Then, the maximum value of the contrast can be known by finding the intersection of the two straight lines. If the obtained value is, for example, the value of 9.4 times, the infinite position data of the third ranging area is 94 pulses under the same conditions as above.

As described above, the infinite position data for the above three distance measurement areas is summarized in Table 1.

Returning to FIG. 6, the above-described infinite position data is stored in the EEPROM 24 in step S214. Incidentally, the number of operations of the contrast detection operation (Nx)
And the lens extension amount (PΔ) are parameters such as the optical characteristics of the taking lens 2, the conversion ratio when converting the number of times of the motor 41 to the movement of the taking lens 2, and the dimensional variation of the focusing frame 52 supporting the taking lens 2. It is necessary to determine in consideration of. These parameters are difficult to determine uniformly and unexpected changes are conceivable. In consideration of these circumstances, in the present embodiment, the number of operations (Nx) and the amount of lens extension (PΔ) are E
The parameters are stored in the EPROM 24. As a result, an optimum value can be set as needed.

As described above, according to the electronic camera of the above embodiment, the measurement data at the infinite position is obtained by using the image sensor actually used for photographing, so that highly accurate measurement data can be obtained. it can. In addition, the same type of measurement in a silver halide camera required a sensor for contrast detection, but this was replaced with an image sensor, so the jig required for measurement could be extremely simplified, contributing to cost reduction. I do.

Next, a second embodiment of the present invention will be described. FIG. 11 is a block diagram showing a configuration of an electronic camera according to the second embodiment of the present invention and an external computer connected to the electronic camera. In the range shown in the block diagram of the electronic camera according to the first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted.

The electronic camera of the second embodiment has a zoom lens mechanism, and in this point, the configuration thereof is largely different from that of the electronic camera of the first embodiment. The second embodiment will be described below mainly on the differences from the first embodiment.

As shown in FIG. 11, the electronic camera according to the second embodiment includes a system controller 1 for controlling the entire electronic camera as in the first embodiment.
The operation of each unit described below is appropriately controlled. The electronic camera includes a zoom lens mechanism, and includes a focusing lens 100 for adjusting a focus and a variator 101 for adjusting a focal length. Further focusing lens 100
As a focus adjustment mechanism 102 for controlling the position of the lens, a motor for driving the lens, a mechanism for converting the rotational force of the motor into a movement of the lens, a sensor for detecting the movement of the lens, etc. Are also not shown), and a mechanism similar to that of the first embodiment is provided.

The variator 10 serves as a focal length adjusting mechanism 103 for controlling the position of the variator 101.
1 and a mechanism for converting the rotational force of the motor. A zoom encoder 104 is provided near the variator 101 so as to detect the position of the variator 101. The system controller 1 sets the taking lens to a desired focal length by controlling the position of the variator 101 based on the output of the zoom encoder 104.

The motor for driving the focusing lens 100 and the motor for driving the variator 101 (both not shown) are both controlled by the lens control circuit 105.

On the other hand, the electronic camera of this embodiment is provided with a communication interface 106 for connection to an external control device, for example, a personal computer 200 or the like. The communication interface 106 enables the electronic camera and the external control device 200 to communicate with each other.

The electronic camera has a distance measuring circuit 107 for measuring the distance to the subject. The distance measuring circuit 107 is controlled by the system controller 1. The distance measuring circuit 107 includes an infrared light emitting diode 109, a light projecting lens 111, a light receiving lens 110, and a PSD. The light emitted from the infrared light emitting diode 109 is projected on the subject through the light projecting lens 111. The light reflected by the subject passes through the light receiving lens 110 to the PSD 1
08. The system controller 1 calculates the distance to the subject by detecting the image forming position of the PSD 108 via the distance measuring circuit 107.

The other configuration is the same as that of the first embodiment, and the description is omitted here.

Next, the main operation of the second embodiment will be described with reference to FIG.
This will be described with reference to the flowchart shown in FIG.

First, when a power switch, one of the operation switches 22, is turned on, power is supplied to the electronic camera system, and the system controller 1 starts operating. The system controller 1 first initializes a memory I / O port and a circuit connected to the system controller 1 (step S300).

Next, the system controller 1 communicates with the external control device 200 via the communication interface circuit 106.
It is determined whether there is a communication request from the (personal computer) (step S301). Here, the external control device 2
If there is a communication request from 00, the flow shifts to step S302 to execute a subroutine "test mode". If there is no communication request, the flow shifts to step S303.

In step S303, the system controller 1 determines the focal length of the taking lens system based on the output of the zoom encoder 104. In step S304, luminance information of the subject is input from the photometric circuit 15. An aperture value is set at a shutter time necessary for controlling the lens shutter 5 in consideration of the luminance information and the sensitivity of the image sensor 8. In step S305, the shutter time, the aperture value,
The focal length and the like of the photographing lens system are output to the operation display circuit 21.

Next, the system controller 1 proceeds to step S
At 306, the state of the zoom-up switch, which is one of the operation switches 22, is detected. If the zoom-up switch is on, the process moves to step S307. In this step S307, the variator 1
01 is driven to change the focal length of the taking lens system to the Tele side, and then the flow shifts to step S303.

On the other hand, if the zoom-up switch is off in step S306, the system controller 1 proceeds to step S308 to detect the state of the zoom-down switch, one of the operation switches. If the zoom-down switch is on, the process moves to step S309. This step S309
Then, the variator 101 is driven to change the focal length of the photographing lens system to the Wide side, and then the process proceeds to step S303.

On the other hand, if the zoom-down switch is off in step S308, the system controller 1 proceeds to step S310 to detect the state of the release switch, one of the operation switches. If the release switch is on, the process proceeds to step S313, and if the release switch is off, the process proceeds to step S31.
Move to 1.

The system controller 1 determines in step S31
At 1, the state of the power switch is detected. Here, when the power switch is off, the operation of the electronic camera system must be stopped. Therefore, the system controller 1 proceeds from step S311 to step S3.
After proceeding to 312 to execute processing for system down, the system controller 1 (CPU) stops operation. On the other hand, if the power switch is on in step S311, the system controller 1 proceeds to step S303 to continue the operation of the system.

The system controller 1 determines in step S3
When the process proceeds from step 10 to step S313, the distance measuring circuit 107
Outputs the distance measurement command to Accordingly, the distance measuring circuit 107 causes the infrared light emitting diode 109 to emit light, and detects where the emitted light has returned on the PSD 108. In step S314, a subject distance is calculated based on the light receiving position on the PSD 8, and in step S315, infinite position data corresponding to the focal length of the photographing lens system is converted into EEPROM.
Read from M24.

Table 3 is an example showing the correspondence between the focal length and the infinite position data.

[Table 3] When the focal length of the taking lens system is changed, the mechanism that constitutes the taking lens system is also displaced. With this displacement, the infinite position data is also displaced. Also, the aberration of the taking lens system changes with the change of the focal length. This change in aberration also affects the infinite position data. Therefore, infinite position data according to the focal length is required.

In this embodiment, the EEPROM 24
Stores infinite position data in correspondence with the focal length and the address. This data is measured in the subroutine "test mode". If the focal length of the taking lens is 80 (mm), Pfc is 92 pulses (*
3).

Next, in step S316, the system controller 1 reads out the extension data corresponding to the focal length of the photographing lens system and the subject distance from the EEPROM.

Table 4 is an example showing the feed data.

[Table 4] If the subject distance is 4.0 (m), the PL is 190 pulses (* 4).

Next, the system controller 1 proceeds to step S
At 317, the infinite position data (Pfc) and the feeding data (PL) are added to obtain the total feeding data (Px).
Ask for. This results in 282 pulses. That is,
Position the taking lens system at the reference position (focusing lens 100
After moving to the position where has been re-established the most, the object image is formed on the image sensor 8 if 282 pulses are advanced.

The operation after step S317 is the same as the operation steps S116 to S129 (see FIG. 6) in the first embodiment, and a description thereof will be omitted.

Next, the subroutine "test mode" processing in step S302 will be described with reference to the flowchart shown in FIG.

When the subroutine "test mode" is called in step S302, that is, when a communication request from the external control device (personal computer) 200 is met, the system controller 1 responds to a command from the personal computer 200. A predetermined operation is performed based on this.

First, the system controller 1 inputs data indicating the operation mode output from the personal computer 200 from the communication interface circuit 106 (step S400). Next, in step S401, the system controller 1 determines whether or not the operation mode is the infinite position measurement mode. If the current mode is the infinite position measurement mode, the process proceeds to step S403; otherwise, another test mode is executed (step S4).
02).

In step S403, the system controller 1 inputs measurement conditions from the personal computer 200. Here, the focal length (fx) is the focal length of the taking lens system set when measuring the infinite position.

In the infinite position data shown in Table 3, the focal length of the photographing lens system is divided into four regions, and one infinite position data is used as a representative value in each region. Therefore, the focal length representing each area is set to the focal length (f
x). For example, assuming that the central value of each area is fx, if measurement is performed on an area of 25 to 50 (mm), 3
8 (mm). The number of operations (Nx) and the amount of lens movement (PΔ) are the parameters already described in the description of the first embodiment.

The aperture value is an aperture value set for the lens shutter 5 when performing a measurement operation, and is generally set to an open value. In the case of a zoom lens, the aberration also changes according to the change in the focal length. Therefore, it is not optimal to measure with an open value as shown in the first embodiment.

After step S403, the system controller 1 drives the variator 101 so that the fx input in step S404 matches the output of the zoom encoder 104. Next, step S405,
In S406 and S407, the focusing lens 1
00 is driven to the reference position (the most retracted position).
This operation is performed in steps S116, S117,
Since it is the same as S118 (see FIG. 4), the description is omitted.

Next, the system controller 1 proceeds to step S
At 408, the sector of the lens shutter 5 is opened until the specified aperture value (Ax) is reached. And step S40
At 9, a control signal is sent to an image data controller 31 (DSP) to integrate the image sensor 8 at a predetermined shutter time. When the integration operation of the image sensor 8 is completed, the sector of the lens shutter 5 is closed in step S410.

Further, the system controller 1 instructs the image data controller 31 to take in image data from the image pickup device 8 in step S411. Then, in step S412, the image data controller 3
Image data for the personal computer 200
To be forwarded to. Thus, the image data controller 31 outputs image data to the personal computer 200 through the communication interface circuit 106.

In the next step S413, the system controller 1 sets the predetermined number of times (N
Determine if x) has been reached. Here, the predetermined number (Nx)
If the distance has not been reached, the designated lens movement amount (P
The focus lens 100 is extended by Δ). This operation is performed in steps S414, S415, and S416, but steps S209, S210, and S
211 (see FIG. 6).

After that, when the feeding operation is completed, the system controller 1 shifts to step S408 to fetch image data again and continues the operation.

The operation of taking in the image data and extending the lens is continued until the number of times reaches a predetermined number (Nx). When the predetermined number reaches Nx, the process shifts from step S413 to S417A. This step S
In 417A, the system controller 1 waits until an operation end code is input from the personal computer 200.

Based on the image data output to the personal computer 200 during the operations of steps S408 to S416, the personal computer 200 calculates the contrast value (in the first embodiment, the role of the calculation is in the first embodiment). The image data controller 31 performs the calculation, and the calculation of the payout position at which the contrast value becomes the maximum (in the first embodiment, the calculation operation is performed by the system controller 1). When the calculation is completed, the personal computer 2
00 outputs an operation end code to the system controller 1.

In this step S417A, the system controller 1 waits until this operation end code is detected. When the code is input, step S417 is performed.
Then, the personal computer 200 inputs infinite position data (Pfc). This infinite position data is stored in the EEPROM 24 in step S418.

The system controller 1 proceeds to the next step S
At 419, it is determined whether the personal computer 200 has output a measurement end command. If the end command has not been input, the process proceeds to step S403 to continue the measurement operation. On the other hand, when the end command is input, the process returns to the main routine.

In order to measure the infinite position data shown in Table 4, it is necessary to execute the operations of steps S403 to S419 four times.

In the electronic camera of the first embodiment described above, the calculations required to determine these infinite position data are performed by the processor in the electronic camera, that is, the system controller (CPU) 1 and the image data controller (DS).
P) 31 and so on. In the electronic camera system according to the second embodiment, these calculations are performed by the personal computer 200. Therefore, when the number of infinite position data to be determined is large or when the number of image data of the image sensor is large. For example, even when a larger computing capacity is required, the measuring time can be greatly reduced.

[Appendix] According to the embodiment of the present invention as described in detail above, the following configuration can be obtained. (1) In an electronic image sensor capable of capturing image data of a subject using the image sensor, a photographing lens, a distance measuring means for measuring a distance to the subject, and a focus adjustment of the photographing lens are performed. A lens driving unit for performing, based on image data from the imaging device, a unit for detecting a position where the photographing lens is to be set in a storage for focusing on a subject at infinity, and outputting this position information; Means for outputting the amount of movement of the photographing lens based on the output of the distance measuring means, position information output from the position information output means,
Based on the movement amount output from the movement amount output means,
An electronic imaging apparatus comprising: a control unit that controls the lens driving unit.

(2) The electronic imaging apparatus according to (1), wherein the position information output means detects a contrast of image data corresponding to a distance measuring area of the distance measuring means.

(3) The electronic image pickup apparatus according to (1), wherein the position information output means determines position information based on a contact position where the photographing lens is most advanced.

[0127]

As described above, according to the present invention, it is possible to provide an electronic image pickup apparatus that can measure an infinite position with a simple configuration and extremely high accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an electronic camera according to a first embodiment of the present invention.

FIG. 2 is an external perspective view of a main part showing a taking lens and a lens driving mechanism in the electronic camera of the first embodiment.

FIG. 3 is a cross-sectional view of a principal part showing a part of a photographing lens, a lens driving mechanism, and a camera body in the electronic camera of the first embodiment.

FIG. 4 is a flowchart illustrating a main routine executed by a system controller in the electronic camera according to the first embodiment.

FIG. 5 illustrates a first example of the electronic camera according to the first embodiment.
FIG. 10 is an explanatory diagram showing a positional relationship between a third ranging area and a third ranging area.

FIG. 6 is a flowchart showing a subroutine “infinite position measurement” in the electronic camera of the first embodiment.

FIG. 7 is an explanatory diagram showing a measurement jig used for executing a subroutine “infinite position measurement” in the electronic camera of the first embodiment.

FIG. 8 is an explanatory diagram showing an image sensor and an area of a pixel for performing a contrast operation in the electronic camera of the first embodiment.

FIG. 9 is a diagram showing an example in which the number of operations in the electronic camera according to the first embodiment is plotted on the horizontal axis, and the contrast value is plotted on the vertical axis, with the contrast value obtained from the output of the image sensor taken as the vertical axis.

FIG. 10 is a diagram illustrating a method of obtaining an approximate value of a maximum contrast value in a third ranging area shown in FIG. 9;

FIG. 11 is a block diagram illustrating a configuration of an electronic camera according to a second embodiment of the present invention and an external computer connected to the electronic camera.

FIG. 12 is a flowchart showing a main routine executed by a system controller in the electronic camera according to the second embodiment.

FIG. 13 is a flowchart showing a subroutine “test mode” in the electronic camera of the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... System controller 2 ... Photographing lens 3 ... Lens drive mechanism 4 ... Lens control circuit 5 ... Lens shutter 6 ... Shutter control circuit 8 ... Image sensor 11 ... Distance measuring sensor 12 ... Separator lens 14 ... Distance measuring circuit 15 ... Photometric circuit 21 ... Operation display circuit 22 ... Operation switch 23 ... Test terminal 24 ... EEPROM 31 ... Image data controller 32 ... Timing pulse generation circuit 33 ... A / D converter 34 ... DRAM 35 ... Image compression circuit 36 ... Image data recording medium 37 ... D / A converter 38 ... Encoder circuit 39 ... Image display circuit

Continued on the front page F term (reference) 2H051 AA01 BB07 BB08 CA04 CB19 CD05 CD13 CE02 CE24 DA11 DA39 EB02 EB05 EC01 FA03 FA15 FA76 GB11 5C022 AA13 AB02 AB12 AB17 AB27 AB66 AC03 AC11 AC31 AC32 AC42 AC52 AC54 AC55 AC56 AC69 AC74

Claims (4)

[Claims] 1. An electronic image pickup apparatus having a photographing lens and an image pickup device and outputting subject image data, a distance measuring means for measuring a distance from the electronic image pickup apparatus to a subject, and a focus of the photographing lens. Lens driving means for performing alignment driving; lens position detecting means for detecting a current position in the movable range of the photographing lens; and a lens position corresponding to infinity so that the photographing lens is focused on an object at infinity. A mode setting means for setting an operation mode of the electronic imaging apparatus, a storage means for storing at least positional information relating to focusing of the taking lens, and the mode setting means, When the device is in the infinity adjustment mode, the lens driving unit is controlled so that the contrast of the output of the image sensor becomes maximum. In both cases, the lens position from the repositioning contact position, which is one end of the movable range of the photographing lens, is stored in the storage means as an infinity position, and in a mode other than the infinity adjustment mode, Control means for controlling a driving amount of the lens driving means based on an output and the infinity position stored in the storage means. 2. The electronic imaging apparatus according to claim 1, wherein the photographing lens is a zoom lens, and the infinity position is stored for each focal length value. 3. The electronic imaging apparatus according to claim 1, wherein the distance measuring device has an optical axis different from an optical axis of the photographing lens. 4. An electronic apparatus according to claim 1, further comprising a communication terminal to which an external device can be connected, wherein said mode control means sets said infinity adjustment mode in accordance with a command from said external device. Imaging device.