JPH06181530A - Solid-state image pickup camera - Google Patents

Abstract

(57) [Abstract] [Purpose] The image quality is good, and the cost is low not only for the imaging zoom lens but also for the circuit scale. An image pickup zoom lens formed by concentrating distortion aberration only on a part of the image pickup position, a detection means for detecting the image pickup position of the image pickup zoom lens, and an image pickup position of the image pickup zoom lens at the time of image pickup are distorted. When it is detected by the detection means that the position is within a large aberration, the geometric distortion of the image generated by the imaging zoom lens is geometrically transformed into the image data of the solid-state imaging device 10. Correction means 9, 11, 12, 16 for correcting by reading out based on

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a solid-state image pickup camera using a solid-state image pickup element as a photoelectric conversion element such as a still video.

[0002]

2. Description of the Related Art Conventionally, in this type of solid-state image pickup camera, aberration correction of an image pickup zoom lens used, in particular, aberration causing geometric deformation (that is, distortion aberration) and signal chromatic aberration have been severely corrected.

In the case of a camera using an image pickup tube, it is possible to electrically correct the aberration generated in the image pickup zoom lens by controlling the trajectory of deflection of the electron beam of the image pickup tube.

[0004]

However, in the solid-state image pickup camera, the geometrical distortion generated in the image pickup lens is read by the pixel signal of the solid-state image pickup element along with the geometrical deformation and interpolated. Although a method of correcting aberration has been proposed, if a zoom lens is used as the image pickup lens, if aberration correction is performed at each image pickup position by signal processing, a huge amount of calculation and calculation time will be required for signal processing. , And a large-scale signal processing circuit is required,
At present, it has been studied only in a very limited number of fields such as those for broadcasting stations that require high-quality images, and it was not general.

As described above, in a solid-state image pickup camera using a conventional zoom lens, it is difficult to easily perform this kind of correction at a low cost, so that the image pickup zoom lens itself does not require correction. Therefore, there has been a problem of cost increase due to the increase in size, the number of lenses, the increase in weight, and the use of special glass.

Next, another problem to be solved by the invention will be described.

Conventionally, in Japanese Unexamined Patent Publication No. 2-252375, aberration correction is performed by reading a geometric distortion generated in an image pickup lens as a pixel signal of a solid-state image pickup element along with the geometrical deformation and interpolating the pixel signal. Is configured to do.

However, in the above-mentioned conventional example, when a zoom lens is used as the image pickup lens, if the geometric distortion is always corrected by the same method even during zooming, the correction cannot catch up with the zooming, and the output is output. It has a problem that the image becomes unnatural.

Further, it is possible to make the output image natural by limiting the zoom speed, but if this is done, a new problem arises that the zooming time is delayed.

(Object of the Invention) A first object of the present invention is to provide a solid-state image pickup camera which has a good image quality and can be made inexpensive in terms of the circuit scale as well as the image pickup zoom lens. That is.

A second object of the present invention is to provide a solid-state image pickup camera capable of increasing the zoom speed and making the output image natural.

[0012]

SUMMARY OF THE INVENTION According to the present invention, an imaging zoom lens formed by concentrating distortion aberration only in a part of the imaging position, a detection means for detecting the imaging position of the imaging zoom lens, When it is detected by the detection means that the image pickup position of the image pickup zoom lens is in a position with large distortion,
Correcting means for correcting the geometrical distortion of the image generated by the imaging zoom lens by reading out the image data of the solid-state imaging device based on the geometrical deformation is provided, and a part of the distortion aberration is imaged during the optical design. When the imaging zoom lens is formed only at the position and the imaging position of the imaging zoom lens at the time of shooting is within the distortion, the geometric distortion of the image caused by the imaging zoom lens is The image data of the solid-state imaging device is read out along the geometrical deformation to correct the distortion.

Further, according to the present invention, during the zooming operation,
Providing a control means for switching the correction of the geometrical distortion between when the zooming operation is not performed and not performing the correction operation of the geometrical distortion during the zooming operation,
A geometric distortion correction operation is performed using the zooming speed information.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the illustrated embodiments.

FIG. 1 is a diagram showing the optical performances of an image pickup zoom lens and a general image pickup zoom lens according to the first embodiment of the present invention.

FIG. 1 (b) shows distortion aberration of a general zoom lens, in which the wide-angle side is largely on the negative side,
Distortion aberration occurs on the positive side on the telephoto side.

In order to design a zoom lens while satisfying the conditions of small size, light weight and compactness, it is very difficult to reduce the distortion aberration at both wide angle and telephoto ends. It is designed to distribute the distortion aberration amounts at the telephoto end so that they are almost the same amount. Therefore, the absolute amount of distortion does not become small. However, it can be seen that the portion where the distortion is large is near the wide-angle end and the telephoto end, and the middle band changes almost monotonically, and the aberration is not so large.

Therefore, in the first embodiment,
As shown in FIG. 1A, the optical design is designed to concentrate the distortion aberration only on a part of the photographing position. Specifically, as described above, the amount of distortion is substantially the same at the wide-angle end and the telephoto end, and the distortion at the intermediate focal length changes monotonically.

Then, when the image pickup position of the image pickup zoom lens is detected at the time of photographing and it is determined that the image pickup position is near the image pickup position in which the distortion aberration stored in the storage unit is large, the image pickup zoom lens causes the image pickup zoom lens. The geometrical distortion of the image is interpolated by reading out the image data of the solid-state imaging device along the geometrical deformation to correct the aberration and obtain an image quality without distortion.

That is, in the first embodiment, the imaging position for correcting the distortion aberration is assumed in advance,
When designing in consideration of this at the time of optical design, as will be described later, only when the image pickup position of the zoom lens being photographed at the time of photographing is detected and correction is necessary (in this embodiment, near the wide angle end and the telephoto end) Distortion aberration correction is performed only) By using pixel data of multiple rows, each pixel signal of a scanning line having a geometrical deformation is calculated, and the aberration generated by the imaging zoom lens is corrected to make it relatively inexpensive. Even if a lens is used, excellent image quality can be obtained.

FIG. 2 is a block diagram showing the schematic arrangement of a solid-state image pickup camera equipped with an image pickup zoom lens having the above optical performance.

Reference numeral 1 is a photoelectric conversion portion of the CCD 10 which is a solid-state image sensor (image sensor), and 2 is an example of an image pattern, which is formed on the photoelectric conversion portion 1. 3 is CCD
10 is a storage unit, 4 is a charge pattern, and 5 is a shift register.

The CCD 10 is formed by the photoelectric conversion unit 1, the storage unit 3, and the shift register 5 described above.

Reference numeral 17 denotes a signal from the CCD 10 which will be described later in C.
A switch for distributing in accordance with a command from the PU 16, 6 is an amplifier, 7 is a sample hold (S / H) circuit, and 8 is an analog / digital (A / D) converter. A line memory 9 has a capacity for storing the output from the CCD 10 for several lines.

Reference numeral 11 denotes an address storage circuit, which pre-stores address information for reading from the line memory 9 into two types, one for the wide-angle end and one for the telephoto end. Distortion aberration correction amount information) is transmitted (address information is output). Reference numeral 16 denotes a CPU that controls the progress of this system, and based on the current focal length information of the image pickup zoom lens, gives ON / OFF information to the switch 17 (SW1) as to whether or not to perform the distortion aberration correction operation, and corrects the distortion aberration. When the operation is performed, the distortion aberration correction amount information at the wide angle end or the telephoto end is selected via the address storage circuit 11 and the data is sent to the line memory 9.

Reference numeral 12 is an interpolation circuit, 13 is a video signal processing circuit, 14 is a synchronizing signal adding circuit, and 15 is a video signal output from the video signal processing circuit 13.

Although the operation of each circuit described above is controlled by the timing control circuit, the control circuit, control signals and the like are omitted for simplicity.

FIG. 3 is a mechanism diagram showing the image pickup zoom lens and the focal length detection section of the solid-state image pickup camera.

In FIG. 3, reference numeral 71 is a first lens group (focus lens) for focus adjustment, 72 is a second lens group (variator lens) having a zooming action, and 73 is a third lens group (compensator lens) for correcting the focus position. ), 7
Reference numeral 4 denotes a fourth group lens having an image forming function, and these constitute an imaging zoom lens.

Reference numeral 75 is a position detector for detecting the position of the variator lens 72 having a zooming action, and reference numeral 76 is a focal length calculated from the position information (position information of the variator lens 72) from the position detector 75. It is a focal length detection circuit for transmitting focal length information.

FIG. 4 is a flowchart showing the operation of the solid-state image pickup camera according to the first embodiment of the present invention, which will be described below. [Step 91] The shooting operation is started. [Step 92] The focal length information is detected through the focal position detection circuit 76 to obtain the current focal length information. [Step 93] It is determined whether the focal length information is within a predetermined distortion correction range near the wide-angle end or near the telephoto end. If it is within the distortion aberration correction range, the process proceeds to step 94, and if not, the process proceeds to step 95. [Step 94] Since the focal length information of the current imaging zoom lens (specifically, the variator lens 72) is within the distortion correction range, the variable SW1 is turned on. As a result, the switch SW1 is turned on and the signal from the CCD 10 is connected to the amplifier 6 side. [Step 95] Since the current focal length information of the imaging zoom lens is out of the distortion correction range, the variable SW1 is set to O.
Set to FF. As a result, the switch SW1 is turned off and the signal from the CCD 10 is directly connected to the video signal processing circuit 13 side. [Step 96] Whether the variable SW1 is ON or OFF is determined. If ON, the process proceeds to step 97, and if OFF, the process proceeds to step 98. [Step 97] Here, from the amplifier 6 to the interpolation circuit 12
The distortion aberration correction circuit formed by the above is operated, and the distortion aberration correction is performed based on the signal from the CCD 10 and the address information from the address storage circuit 11 (details of the operation in each circuit will be described later). Then, the process proceeds to step 98. [Step 98] The video signal processing circuit 13 is operated to generate a video signal based on the distortion aberration correction circuit or the signal from the CCD 10 and output the video signal. [Step 99] It is determined whether or not the zoom mechanism is operated, and if the zoom mechanism is operated,
Since there is a possibility that the focal length has changed from the previous state by operating during the above-described calculation, the process returns to step 92, where the focal length information is newly detected again, and the operations after step 93 are performed. On the other hand, if the zoom mechanism is not operated, the focal length has not changed, so the processing returns to step 96,
The operations after step 96 are performed.

FIG. 5 is a schematic diagram for explaining the operation of the image pickup zoom lens.

In FIG. 5, 21 is the object plane, and 22
Is an example of an object. Reference numeral 23 denotes an image pickup zoom lens including the lens groups shown in FIG. 24 is the image plane, 2
5 is an image.

The object 22 on the object plane 21 is imaged on the image plane 24 by the imaging zoom lens 23 and becomes an image 25.
The CCD 10 which is a solid-state image sensor has an image 25
Will be arranged on the image plane 24 for photoelectric conversion. The image pickup zoom lens 23 has distortion (hereinafter, referred to as distortion) set to be larger than a normal allowable value, and therefore the image 25 is distorted as compared with the object 22 as illustrated.

However, in lens design, as is well known, if a certain aberration value is allowed to be larger, correction of other aberrations becomes easier, and the image pickup zoom lens 23 is downsized, the number of lenses is reduced, and inexpensive glass is used. The use of materials can be promoted.

In FIG. 2, an image pattern 2 corresponding to the image 25 formed by the image pickup zoom lens 23 is formed on the photoelectric conversion unit 1 of the CD 10. The CCD 10 shown in this embodiment is a frame transfer type. That is, the image pattern 2 photoelectrically converted by the photoelectric conversion unit 1 is transferred to the storage unit 3 as the charge pattern 4. The charge pattern 4 is read out row by row by the shift register 5.

FIG. 6 is a schematic diagram showing the relationship between the image and the pixels of the CCD.

In FIG. 6, 31 is a pixel of the CCD 10,
Reference numerals 32 ₁ , 32 ₂ , and 32 ₃ are first, second, and third scanning lines, respectively.

The first to third scanning lines 321 _to 323 shows the first three scanning lines, but those should be originally linear, has a curve for the distortion. That is, the shapes of these curves are the curved shapes themselves caused by the distortion when the horizontal line on the object plane 21 of the imaging zoom lens 23 is imaged on the image plane 24.

The charge pattern is read out row by row or pixel by pixel in the row. Of the pixels 31, the lower right pixel is read first, then the pixels in the left diagram are read, and one row is sequentially read first. Then 1
Pixel signals in the upper row are read out from the rightmost pixel. The same applies to the third and subsequent lines.

In FIG. 2, the pixel signal read from the shift register 5 of the CCD 10 is directly sent to the video signal processing circuit 13 when the switch SW1 is OFF, as described above.

On the other hand, when the switch SW1 is ON, it is output to the distortion correction circuit. That is, after being amplified by the amplifier 6, it is held by the S / H 7, and then A /
It is digitized by the D converter 8 and sent to the line memory 9. And it is stored here. This line memory 9
The signals for several rows of the CCD 10 are stored in the CCD before the reading is started. This is because the pixel signal is read out according to the curved scanning line, and this scanning line extends over several rows of pixels.

From the focal length information of the image pickup zoom lens 23, the type of data required for distortion aberration correction is sent from the CPU 16 to the address storage circuit 11, and the address storage circuit 11 reads out the shape data of the designated scanning line. Address information for reading the pixel signal in the line memory 9 is generated. The scan line shape data may be a form in which the scan line is directly sampled, or an appropriate relationship approximation is performed.
It may be in the form of the coefficient. The scanning line shape data corresponding to these lens states are obtained at the time of designing the imaging zoom lens or at the time of optical measurement after the trial manufacture.

Since the pixel positions obtained by the CCD 10 generally do not coincide with each other, the pixel position of the curved scanning line requires interpolation processing. Therefore, data for several pixels is read from the line memory 9 and sent to the interpolation circuit 12, where the value of one pixel on the scanning line is calculated.

Here, the capacity of the line memory 9 is determined as follows.

FIG. 7 shows the relationship between the pixels of the line memory 9 and the scanning lines.

In FIG. 7, reference numeral 41 denotes a pixel of the line memory 9, which corresponds to the pixel 31 of the CCD 10 on a one-to-one basis. 42 is the most curved scan line. That is, it extends over the most pixel rows of the line memory 9 among the scanning lines. Reference numeral 43 is a scan line next to the most curved scan line 42. 44 and 45 are the most curved scanning lines 4 respectively
2 and the pixel of the next scanning line 43. It is necessary to calculate the pixel data value at the position of the pixel 44 of the most curved scanning line 42 and the pixel 45 of the next scanning line 43 represented by the black circle.

Reference numeral 46 indicates the size of the line memory 9. The size 46 of the line memory 9 is a capacity capable of storing the data of the pixels 31 of the CCD 10 so that all the values of the pixels 44 of the most curved scanning line 42 can be calculated. That is, the size 46 of the line memory 9 is the number of rows including the number of rows of the pixels 31 of the CCD 10 which the most curved scanning line 42 straddles, and the peripheral rows required for interpolation processing if necessary. Of course, it may be more than this.

The calculation of the value of the pixel 44 on the most curved scanning line 42 is performed by the line memory 9 using the size 4 of the line memory 9.
If the capacity is only 6, it can be calculated completely from the pixel 41 of the line memory 9.

Next, when the value of the pixel 45 on the next scanning line 43 is calculated, the pixel data of the bottom row in the line memory 9 is discarded and the next row which is not yet stored in the line memory 9, For example, in FIG. 4, the pixel data of the top row is read. Since the size 46 of the line memory 9 is guaranteed to be able to store the pixel data 41 of the line memory 9 sufficient for calculating the values of all the pixels on the scanning line for any scanning line, the next scanning is performed. All values are calculated for the pixel 45 on the line 43. The pixel value is calculated in the same manner for the other scanning lines.

Depending on the shape of the scanning line, there is a case where it is not necessary to read new pixel data when calculating the pixel value, and there are cases where it is necessary to read pixel data of two or more rows. These are adjusted by a timing control circuit (not shown) in response to a signal from the address storage circuit 11. If the final output signal of the solid-state imaging camera is a video signal, pixel data for each row must be output at regular time intervals. Therefore, in some cases, the line memory 9 may further have a buffer memory for timing adjustment. It is possible.

Next, the interpolation processing performed in the interpolation circuit 12 will be described with reference to FIG.

In FIG. 8, 51 is a scanning line, 52 ₁ , 5
2 ₂ are the pixels of each scan line. In addition, 53 ₁ , 5
3 ₂ , ..., 53 ₅ are pixels of the line memory 9.

When calculating the pixel value for the scanning line 51, the positions of the pixels 52 ₁ and 52 ₂ of the scanning line are determined by the line memory 9
Since different pixel 53 _{1-53 5} position, it is necessary to calculate the value as an interpolation value. In the simplest case, the value of the nearest pixel among the pixels 53 _{1 to} 53 ₅ of the line memory 9 is given as the value of the pixels 52 ₁ and 52 ₂ of the scanning line. That is,
The values of pixels 52 ₁ and 52 ₂ of the scanning line are the values of pixels 53 ₄ and 53 ₇ of the line memory 9, respectively. In the case of this processing, if the address storage circuit 11 appropriately determines the address, the interpolation processing is performed at the time of reading from the line memory 9, and the special interpolation circuit 12 can be eliminated.

Another approximation method is a method of calculating an interpolated value from four pixels of the adjacent line memory 9 by linear approximation. That is, the calculation of the values of the pixels 52 ₁ and 52 ₂ of the scanning line is performed by the pixels 53 ₁ , 53 ₂ and 5 of the line memory 9, respectively.
3 ₄ , 53 ₅ and 53 ₂ , 53 ₃ , 53 ₅ , 53 ₄ 4
The pixels are sent to the interpolation circuit 12 and linear approximation is performed from them.

There is a "cubic convolution method" as a method of approximating the values. This is to interpolate from the values of the neighboring pixels using a cubic spline curve, and in this case, the values of the neighboring 16 pixels are required for the calculation of one pixel.

In FIG. 2, the output of the interpolation circuit 12 is sent to the video signal processing circuit 13 and converted into an NTSC signal and a high-definition signal in a predetermined format. The sync signal is supplied from the sync signal adding circuit 14 to the video signal processing circuit 13 to form a final video signal. Output video signal 15 from video signal processing circuit 13
Is displayed on the monitor according to the configuration of the entire system and sent to the processing circuit of the next stage.

Next, the distortion correction process will be described with reference to FIG.

Reference numeral 61 is an example of an object. 62 is the image obtained by the image pickup zoom lens,
The charge pattern on the CCD 10 has the same shape. 63 is an image of the output video signal.

In FIG. 9, the scale relationship between the three figures is exaggerated to be different from the actual one.

The image 62 is distorted with respect to the object 61 due to the distortion of the imaging zoom lens 23. However, since the aberration correction is electrically performed as described above, it is shown that a pixel similar to the original object 61 of the image 63 by the output video signal 15 can be obtained.

(Second Embodiment) FIG. 10 is a diagram showing an example of the optical performance of the image pickup zoom lens used in the second embodiment of the present invention.

Here, the distortion aberration of the image pickup zoom lens used in the second embodiment is very large at the wide-angle end, and has substantially the same amount of aberration at the telephoto end and the middle, and the focal length from the middle to the telephoto end. However, the distortion aberration changes monotonically. Therefore, in this embodiment, distortion aberration correction is performed only near the wide-angle end.

FIG. 11 is a diagram showing an example of changes in distortion aberration depending on the shooting distance in the vicinity of the wide-angle end. When shooting from the left to infinity, the distortion at the object distance of 3 m and the shortest shooting distance (1.2 m) is shown. is there.

It can be seen that even if the focal length is the same, the variation of the distortion aberration depending on the photographing distance is large. Therefore, in the second embodiment, not only the focal length information but also the shooting distance information is used as the discrimination information for distortion aberration correction as follows.

FIG. 12 is a block diagram of the focal length and photographing distance detection unit of the solid-state image pickup camera in the second embodiment of the present invention. Other configurations are the same as those in FIG. 2, and are omitted here.

In FIG. 12, 101 is a first lens group (focus lens) having a focal position adjusting action, 102 is a second lens group (variator lens) having a zooming action,
Reference numeral 103 denotes a third group lens (compensator lens) having a focal position correcting action, and 104 denotes a fourth group lens having an image forming action.
An imaging zoom lens is formed at 4.

Reference numeral 105 denotes a detector for detecting the position of the variator lens 102, 106 denotes a focal length detecting circuit for calculating the focal length from the position of the variator lens 102 and sending focal length information to the CPU 16, 107 denotes the position of the focus lens 101. A detector for detecting 108 is a photographing distance detecting circuit for calculating the photographing distance from the position of the focus lens 10 and sending the photographing distance information to the 16 CPU.

FIG. 13 is a flow chart showing the operation of the above-mentioned solid-state image pickup camera, which will be described below. [Step 111] The shooting operation is started. [Step 112] The focal length is detected through the focal position detection circuit 106 to obtain the current focal length information. [Step 113] It is determined whether the focal length information is within a predetermined distortion correction range near the wide-angle end. If it is within the distortion aberration correction range, step 114
Otherwise go to step 115. [Step 114] Since the focal length information of the current imaging zoom lens (specifically, the variator lens 102) is within the distortion correction range, the variable SW2 is turned on. As a result, the switch SW1 is turned on and the signal from the CCD 10 is connected to the amplifier 6 side. And step 11
Go to 6. [Step 115] Since the current focal length information of the imaging zoom lens is out of the distortion correction range, the variable SW2 is turned off. As a result, the switch SW1 is turned off and the signal from the CCD 10 is directly supplied to the video signal processing circuit 13
Connected to the side. Then, the process proceeds to step 117. [Step 116] The current shooting distance information is detected via the shooting distance detection circuit 108, it is then determined where this shooting distance corresponds to a predetermined shooting distance zone, and this is stored as a variable SW3. To do. Then, the process proceeds to step 117.

Specifically, when the distance is short, the variable SW3 = 1, when the distance is intermediate, the variable SW3 = 2, and when the distance is long, the variable SW3 = 1.
It is stored as SW3 = 3. [Step 117] Whether the variable SW2 is ON or OFF is determined. If the variable SW2 is ON, the process proceeds to step 118, and if OFF, the process proceeds to step 119. [Step 118] Here, from the amplifier 6 to the interpolation circuit 1
Operate the distortion correction circuit formed by up to 2,
Signals from the CCD 10 and shooting distance data (variable SW
The distortion aberration correction is performed based on the address information selected by the signal type 3), and the process proceeds to step 119. [Step 119] Here, the video signal processing circuit 13
To operate the distortion aberration correction circuit or the CCD 10
A video signal is generated based on the signal from and the video signal is output. Then, the process proceeds to step 120. [Step 120] It is determined whether or not the zoom mechanism is operated. If the zoom mechanism is operated, the zooming mechanism may operate and the focal length may change after the video signal is output. Returning to step 112, the focal length information is newly detected, and the operations after step 113 are performed. If the zoom mechanism is not operating, the process proceeds to step 121. [Step 120] It is determined whether the variable SW2 is ON (= focal length is within the distortion correction range) and the focus adjustment mechanism is operating. If so, step 11
6, and the above-mentioned operations after step 116 are advanced. On the other hand, if the condition is other than the above, the process proceeds to step 117, and the operations after step 117 are advanced.

The above operation is repeated to perform photographing.

According to the above-mentioned first and second embodiments, the optical condition is designed in advance so that the photographing condition to be corrected at the time of photographing is limited to a very small part of the entire photographing pattern, and the present condition at the time of photographing. Since the imaging position of the zoom lens during shooting is detected and the aberration generated by the imaging zoom lens is corrected only when correction is necessary, that is, when the distortion correction is being performed, the signal processing circuit during shooting It is possible to reduce the scale of, and it is possible to afford the signal processing capacity during shooting. Further, the number of lenses of the image pickup zoom lens is small, a lightweight and compact design is possible, and a cheaper and smaller solid-state image pickup camera can be obtained.

(Third Embodiment) FIG. 5 is a schematic view showing an image pickup zoom lens in the third embodiment of the present invention.

In FIG. 5, 21 is the object plane, and 22
Is an example of an object. Reference numeral 23 denotes an image pickup zoom lens including the lens groups shown in FIG. 24 is the image plane, 2
5 is an image.

The object 22 on the object plane 21 is imaged on the image plane 24 by the image pickup zoom lens 23 and becomes an image 25.
The CCD 216, which is a solid-state image sensor to be described later, displays the image 2
5 will be arranged on the image plane 24 for photoelectric conversion. The image pickup zoom lens 23 has distortion (hereinafter, referred to as distortion) set to be larger than a normal allowable value, and therefore the image 25 is distorted as compared with the object 22 as illustrated.

However, in the lens design, as is well known, if a certain aberration value is allowed to be larger, it becomes easy to correct other aberrations, and the image pickup zoom lens 23 is downsized, the number of lenses is reduced, and the glass is inexpensive. The use of materials can be promoted.

FIG. 14 is a block diagram showing the schematic arrangement of a solid-state image pickup camera equipped with the above-mentioned image pickup zoom lens.

Reference numeral 201 denotes a solid-state image sensor (image sensor).
The photoelectric conversion part 202 of the CCD 216, which is the above, is an example of an image pattern, and is formed on the photoelectric conversion part 201. Reference numeral 203 is a storage unit of the CCD 216, and 204 is a charge pattern. Reference numeral 205 denotes a shift register, and the photoelectric conversion unit 201, the storage unit 203, and the shift register 205 form a CCD 216.

Reference numeral 206 designates an amplifier, and 207 designates S / H (S /
H) circuit, 208 is an analog / digital (A / D) converter. 209 is a line memory, and the CCD 21
It has the capacity to store the output from 6 for several digits. Reference numeral 210 denotes a lens state signal, which indicates the current state of the image pickup zoom lens 23 and includes information regarding the zoom state, the focus state, the zoom speed, and the like. Reference numeral 211 denotes an address storage circuit, which outputs address information for reading from the line memory 209. Reference numeral 212 is an interpolation circuit. 213 is a video signal processing circuit, 214 is a synchronizing signal adding circuit, and 215 is an output video signal.

Although the operation of the element circuit described above is controlled by the timing control circuit, the control circuit, control signals and the like are omitted for simplification.

Next, the operation will be described.

In FIG. 14, the signal of the pixel of the CCD 216 read from the shift register 205 is the amplifier 2
After being amplified by 06, it is sent to the S / H circuit 207 and held there. Further, the output signal of the S / H circuit 207 is digitized by the A / D converter 208, sent to the line memory 209, and stored therein. The line memory 209 has a CCD 216 before starting reading.
The signals for several rows of are stored. This is because the pixel signal is read out according to the curved scanning line, and this scanning line extends over several rows of pixels. Lens status signal 21
When 0 is input to the address storage circuit 211, the address storage circuit 211 can know the current lens state.

A ROM is provided in the address storage circuit 211.
(Read-only memory) is built in, and the shape data of the scanning line corresponding to the lens state is stored. The shape data of the scanning line may be in the form of a direct sampling of the scanning line, or may be in the form of a coefficient obtained by performing an appropriate function approximation. The scanning line shape data corresponding to these lens states are obtained at the time of designing the imaging zoom lens 23 or at the time of optical measurement after trial manufacture.

When zooming is stopped, the address storage circuit 211 reads out according to the data in the ROM and the lens state, thereby generating an address for reading the pixel signal in the line memory 209. Then, this signal is sent to the video signal processing circuit 213 via the path A to the CCD 216.
Signal is corrected and output. Since the pixel positions obtained by the CCD 216 generally do not match, the pixel positions on the curved scanning line require interpolation processing. Therefore,
Data for several pixels is read from the line memory 209 and sent to the interpolation circuit 212, where the value of one pixel on the scanning line is calculated.

Here, FIG. 15 is an explanatory diagram showing the distortion correction processing.

In FIG. 15, 231 is an example of an object.
The image 232 is obtained by the image pickup zoom lens 23. The charge pattern on the CCD 216 also has the same shape. 233 is an output video signal 1
5 is an image.

In FIG. 15, the scale relationships of the three figures are exaggerated so that they are different from the actual ones.

The image 232 is distorted with respect to the object 231 due to the distortion of the imaging zoom lens 23. However, as described above, since the aberration correction is electrically performed, it is shown that an image similar to the original object 231 of the image 233 by the output video signal can be obtained.

During the zoom operation, the image distortion correction data in the ROM data is not used as described above, and therefore the interpolation is not performed, and the distorted image itself in the CCD 216 is output along the path B.

The above distortion correction operation will be described with reference to the flowchart of FIG. [Step 241] The photographing operation is started. [Step 242] It is determined whether the zoom is on or off. When it is ON, since distortion correction is not performed WA, this step remains. On the other hand, if it is OFF, the process proceeds to step 243 to correct the distortion. [Step 243] The zoom position and the focus position are detected, and the process proceeds to step 244. [Step 244] The shape data of the scanning line corresponding to the lens state is taken out, and the process proceeds to step 245. [Step 245] Interpolation processing is performed on the basis of the above-described scanning line shape data to perform distortion correction.

Although distortion has been taken as an example of the geometric distortion here, other geometric distortion may be used.

When the zoom is turned on, the image on the CCD 216 may be directly output to the video signal processing circuit 213 by an analog circuit.

According to the third embodiment described above, since distortion correction is not performed during zooming, it is possible to simplify the arithmetic processing and perform quick zooming.

(Fourth Embodiment) FIG. 17 is a flow chart showing the distortion correction operation of the solid-state image pickup camera according to the fourth embodiment of the present invention, and FIG. 18 is an explanation of the correction amount calculation in step 253 of FIG. It is a figure.

When the zoom is OFF and at the focal length f = Z, the distortion correction is performed through the interpolation circuit based on the scanning line shape data based on the lens state at that time.

However, when the zoom is ON, the correction amount f (Z ′) at the focal length Z ′, which may have changed when Δt from the current focal length Z due to zooming, is
When the zoom speed is v and the distortion correction calculation processing time is Δt, it is obtained in advance by Z ′ = Z + v · Δt, and the correction is simultaneously performed when the focal length Z ′ is reached by zooming.

The above-described operation when the zoom is turned on is from step 251 to step 254 in FIG.

By performing such control, it is possible to solve the unnaturalness of the image due to the distortion correction being unable to catch up with the zoom speed at the time of zooming without delaying the zoom speed.

According to the fourth embodiment described above, since the distortion correction is performed based on the zoom speed during zooming, it is possible to obtain a natural image in real time.

[0100]

As described above, according to the present invention, the imaging zoom lens formed by concentrating the distortion aberration only on a part of the imaging position, and the detection for detecting the imaging position of the imaging zoom lens. Means and the image pickup position of the image pickup zoom lens at the time of shooting is detected by the detection means to be in a position with large distortion, the geometric distortion of the image generated by the image pickup zoom lens. Is provided with a correction means for correcting by reading the image data of the solid-state image pickup device based on geometrical deformation, and when forming an image pickup zoom lens, the distortion aberration is concentrated only in a part of the image pickup position during optical design, When the imaging position of the imaging zoom lens at the time of shooting is within the distortion, the geometric distortion of the image generated by the imaging zoom lens And it is to perform the distortion correction image data is read out of the solid-state image pickup device along the geometric deformation.

Therefore, the image quality can be good and the cost can be reduced not only in the image pickup zoom lens but also in the circuit scale.

Further, according to the present invention, the control means for switching the correction of the geometrical distortion during the zooming operation and the time when the zooming operation is not performed is provided, and the geometrical distortion correction operation is performed during the zooming operation. Alternatively, the geometrical distortion is corrected by using the zooming speed information.

Therefore, the zoom speed is increased, and
It is possible to make the output image natural.

[Brief description of drawings]

FIG. 1 is a diagram showing optical performances of an image pickup zoom lens and a general image pickup zoom lens according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of a solid-state imaging camera according to the first embodiment of the present invention.

3 is a mechanism diagram showing an imaging zoom lens and a focal length detection unit of the solid-state imaging camera of FIG.

FIG. 4 is a flowchart showing an operation of the solid-state imaging camera of FIG.

5 is a schematic diagram for explaining the operation of the imaging zoom lens of FIG.

FIG. 6 is a schematic diagram showing a relationship between pixels and an image of the CCD shown in FIG.

FIG. 7 is a diagram showing a relationship between pixels and scanning lines in the line memory shown in FIG.

FIG. 8 is a diagram for explaining an interpolation process in the interpolation circuit of FIG.

FIG. 9 is a diagram for explaining a distortion correction process in the first embodiment of the present invention.

FIG. 10 is a diagram showing an example of optical performance of an image pickup zoom lens used in a second embodiment of the present invention.

FIG. 11 is a diagram showing an example of a change in distortion aberration depending on a shooting distance in the vicinity of a wide angle end of an image pickup zoom lens used in Example 2 of the present invention.

FIG. 12 is a mechanism diagram showing respective detection units of a focal length and a photographing distance of a solid-state imaging camera according to a second embodiment of the present invention.

FIG. 13 is a flowchart showing an operation of the solid-state imaging camera of FIG.

FIG. 14 is a block diagram showing a schematic configuration of a solid-state imaging camera according to a third embodiment of the present invention.

FIG. 15 is a diagram for explaining distortion correction processing in the third embodiment of the present invention.

FIG. 16 is a flowchart showing a distortion correction operation of the solid-state imaging camera according to the third embodiment of the present invention.

FIG. 17 is a flowchart showing a distortion correction operation of the solid-state imaging camera according to the fourth example of the present invention.

18 is an explanatory diagram of a correction amount calculation in step 253 of FIG.

[Explanation of symbols]

 9,209 Line memory 10,216 CCD 11,211 Address storage circuit 12,212 Interpolation circuit 13,213 Video signal processing circuit 16 CPU 23 Imaging zoom lens 76 Focus position detection circuit 108 Shooting distance detection circuit

Claims (4)

[Claims] 1. An image pickup zoom lens formed by concentrating distortion aberration only in a part of an image pickup position, a solid-state image pickup element photoelectrically converting an image formed by the image pickup zoom lens, and the image pickup zoom lens. If the detecting means detects the image pickup position and the image pickup position of the image pickup zoom lens at the time of shooting is within a position with large distortion, the image pickup zoom lens causes the image pickup position. The geometric distortion of the image,
A solid-state imaging camera, comprising: a correction unit that corrects the image data of the solid-state imaging device by reading the image data based on geometrical deformation. 2. An imaging zoom lens, and a solid-state imaging device for photoelectrically converting an image formed by the imaging zoom lens, wherein geometric distortion of an image generated by the imaging zoom lens is corrected by the solid-state imaging device. In the solid-state imaging camera for correcting by reading out the image data of 1. based on the geometrical deformation, the solid-state imaging is provided with a control means for switching the above correction during the zooming operation and when the zooming operation is not performed. camera. 3. The solid-state image pickup camera according to claim 2, wherein the control means is means for not performing the geometric distortion correction operation during the zooming operation. 4. The solid-state image pickup camera according to claim 2, wherein the control means is means for performing a geometric distortion correction operation using the zooming speed information during the zooming operation.