JPS59196665A - Electronic still camera and its recording and reproducing device - Google Patents

Abstract

PURPOSE:To attain the correction of deformation of a lens at reproduction of a picture by storing the information of deformation of the optical lens to a storage means at every storage of a picture signal for one screen's share in an electronic still camera. CONSTITUTION:The deformation information of the lens is stored in a memory 5 at image pickup. When the memory 5 is set to a reproducing device at reproduction, the deformation information is read by a command from a microcomputer 12 and written in an RAM 19 and the picture information in the memory 5 is transferred to a reproducing memory 14. The deformation processing data corresponding to the deformation information written in the RAM 19 is read among deformation processing data 18a, 18b, 18c- in response to the kinds of the lens of the camera and the picture information transferred to the reproducing memory 14 is processed. The processed picture information is converted into an analog signal by a D/A converter 16 and displayed on a monitor 17.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic still camera in which lens bias is corrected during signal processing during image reproduction.

In a patent application entitled "Electronic Still Camera" filed on the same date as the present application, the inventors convert two-dimensional image information from a subject into an image signal using an image sensor, and convert this image signal into an image signal.
We have proposed an electronic still camera that performs -D conversion and stores the converted digital image information in a removable storage means. Since this electronic still camera digitally processes image signals, high-quality still images can be obtained without signal deterioration during signal processing.Also, since digital image data is stored in memory, there is no need for a rotating machine, and consumption is reduced. It is superior to conventional electronic still cameras in many ways, including reduced power consumption, smaller camera body size, and improved reliability.

Figure 1 shows the basic circuit configuration of this electronic still camera. 1 is an optical lens that forms an optical image of the subject, and 2 is an optical image (
Generally known imaging devices that convert a two-dimensional image (↑H signal) into an analog image signal and output it as an analog image signal include Sachicon, Vidicon, Flambicon, Cosbicon, and New Cosbifun, CCD, and MOS.

There are solid-state imaging devices such as CPD. A color filter 2a is provided on the light-receiving surface of the image sensor 2 to obtain a color image.
It is pasted. The image sensor 2 outputs all analog image signals in response to the drive signal from the driver 3, and this image signal is converted into a digital signal at high speed by the A/D converter 4. In this case, the quantization level is determined by the required image quality, but a typical television image requires about 8 bits. The sampling rate is generally 2 to 4 times higher than the color subcarrier (3.58 MHz), but in electronic still cameras, if the imaging unit has a temporary storage function, this is not necessarily the case. Not.

The image signal digitally converted by the A/D converter 4 is stored in the memory 5. The memory 5 can be anything that can store digital signals stably.
N-MO8RAM, C-MOS RAM, COD
In addition to semiconductor memory such as memory, magnetic bubble elements,
A magnetic disk, magnetic tape, etc. are used. Writing and reading of image signals to and from the memory 5 is controlled by a driver 6. The memory 5 is, for example, in the form of a cassette and is replaceable from the outside at a predetermined position VC@C of the camera body. Depending on the type of memory, batteries may also need to be included in the cassette.

On the other hand, the digital image signal output from the A/D converter 4 is directly or once stored in the memory 5 and then converted into an analog image signal by the D/A converter 7V. The image is sent to the finder 9, where it is displayed as an image on a monitor cathode ray tube.

In this case, the selector switch 8 is set by the driver 6 by external operation.
Contacts a and b are switched by a switching signal from. In addition, the output of the image sensor 2 is directly connected to the changeover switch 8 (contact a).
It is also possible to visualize the image using the electronic 7-inder 9 via the electronic 7-inder 9. In this case, the output of the image sensor 2 is modulated by the color filter 2a, so when the image is displayed directly with the electronic viewfinder 9'', it differs from a normal black and white image, but it is difficult to know what is being shown. I can do it.

Note that llj is a battery that serves as a power source for each of the circuits mentioned above.

FIG. 2 is a block diagram of one embodiment of the player, in which the memory 5 is removed from the camera and set at a predetermined position in the player (indicated by a broken line). In the reproducing machine, the microcomputer 12 reads the video data recorded in the memory 5 according to the software in the ROMI 31 in the storage means 13, and processes the data using the RAM 132 as a production area. The processed data is sent to the microcomputer 12
This field memo IJ141dl (except when accessed by the computer 12) is always driven by the TV rate drive circuit 15, and its output is sent to the field memory 14 via the D/A converter 16. An image is displayed on the monitor 7. As a result, the recorded video gradually appears on the monitor 17.

In the above ゛α electronic still camera, the optical lens f/C
! An optical image of the subject is formed on the light-receiving surface of an image sensor, photoelectrically converted, and output as an analog image signal. For example, the image sensor is a CCD.

When a solid-state imaging device such as a CPD or MOS is used, there is a phenomenon in which the imaging point at the periphery of the VC lens is distorted from the outside to the inside due to the upward tilt of the lens. Figure 3 shows this situation. If the circles in the figure are the light receiving positions of each pixel of the same body image sensor, ideally the power straight line that forms the image as shown by the thick line is due to lens distortion. It is distorted as shown by the broken line and the image is formed at tL. For this purpose, for example, an image that would normally be imaged at the light receiving position C5; α is fixed at the light receiving position 85, and then the image signal obtained in this way is used as it is (as it occurs). , the original linear grid pattern is displayed as a distorted grid pattern shown by broken lines.The degree of this distortion varies depending on the lens.

In order to eliminate such lens distortion, conventional efforts have been made at the lens manufacturing stage to adjust the diameter and thickness of the lens or the curvature of the lens surface, or to increase the number of combined lenses. Because of this, the lenses of recent video cameras and electronic still cameras are much more expensive than ordinary ones because of the fact that the lens diameter is large or heavy, and the cost is also high.
The reality is that it is getting bigger.

The invention is that the distortion of the lens in an electronic still camera is corrected by electrical processing of the image signal without using any ingenuity in the manufacturing of the lens, and the distortion information of the optical lens of the electronic still camera is displayed on a single screen. The image signal is stored every time an image signal is stored, and the readout address of the image signal is corrected based on the distortion information at the time of image reproduction.

The present invention will be explained in detail below based on the drawings.

The fourth fundamental concept of the uninvented lens distortion correction method
This will be explained using figures.

Now, as a diagram corresponding to FIG. 3, FIG. 4 VC shows the light-receiving position of each iii+1 element of the solid-state image sensor (r[!Ii prime number 9×9) with a circle, and the subject iI! This shows a state in which an f-line grating (actual m) is imaged as a pincushion-shaped grating (dashed line) due to lens distortion. At this time, image signals are stored in the arrangement shown in Table 1 below corresponding to each ii+I+ element in the memory of image 4@.

Table 1 When reproducing such a memory, in order to correct lens distortion, in the case of pincushion distortion (Figure 4), each pixel must be rearranged as shown in Table 2 below. Read out the image signal.

In the case of barrel distortion (FIG. 3), the data are read out after being rearranged into the arrangement shown in Table 3.

Table 3 If the image signal is read out as shown in Table 21 and Table 3 when the image signal is low (4+), lens distortion can be corrected, and the reproduced image will be almost straight! Displayed as a 4-shaped grid pattern. In addition, if the lens distortion is not pincushion type, as shown in Figure 3, the image information on the left and right edges of the 7th floor of the art dealer will be lost;
Because not all of the generated 111JJ image signals are displayed within the TV frame, image imitations are lost.
If the signal is within this range, there is no problem in practical use.

Taking this point into consideration, the distortion tolerance is a few percent, so the lens can be made considerably smaller and lighter.

By the way, as for a specific method for reading out image signals to correct lens distortion, I can think of the following method.

(]) Now, the coordinates in the pixel of the solid-state imager are (xn, y,
l), and the light 4·a signal that should originally be incident on that pixel is reflected at point Q(Xn' ly, , + >v due to lens distortion)
Suppose c people are incident. In this case, 1(xn', Yn'
) −(xm, y,, l) Point R such that l is minimum
(Xi + Ym) is selected, and the signal of the pixel at this point R is used as the signal of the pixel P (Xn+Yn).

(2) Similar to the above (su), the image of the solid-state image sensor P (x
Suppose that optical information that should have originally entered n+Yn)I' is incident on point q(xn'+yI')V due to lens distortion. In this case, l (xn', yn') (X
lTl, lY+n) 4 points where l is the smallest (Xm
l + Y++++ ), (Xm21yIT+2), (
xm3 + '1rn3), (XmA + Ym4)
The signal calculated by selecting f and applying appropriate h jR to the signal of the light receiving section at each point is set as the pixel signal of point P (Xn + Yn). The weighting is determined according to the sensitivity shape (C) of the pixel, and if the sensitivity of each pixel decreases in proportion to the distance from the center position regardless of the direction, then the weighting is determined by the distance between the point Q and the above four points. If the change in sensitivity of each pixel has a special directionality, then the weighting is performed in consideration of that directionality.Weighting 11gj Regardless of the sensitivity of the element, It may be determined based on where the point Q exists in the defined area.

Therefore, in the invention, lens distortion information, which is information that determines how to read out image signals, is stored for each image direction at the time of imaging, but the following method has been considered as a storage method. Ru.

(1) Utilization of free space in memory: For example, when using a water SF image sensor with 385 pixels, the normal scanning line is often configured with 512 bytes for ease of signal processing. The wasted memory area can be used to store lens distortion information.

(2) Use of one scanning line: One screen of image sensor information is scanned with 525 scanning lines.
However, the first few scanning lines and the last few scanning lines are not displayed on the monitor screen of the player. Therefore, lens distortion information can be stored in an area corresponding to this scanning line portion.

(3) Use of horizontal or vertical retrace period: When using a memory with a mechanical drive mechanism such as a magnetic disk or magnetic tape as the memory of an electronic still camera, these memory media must be Since the period is during the i+ line period, lens distortion information can be stored in the memory medium portion corresponding to the retrace line period V.

FIG. 5 is a block diagram when a memory is set in a player (encircled by a broken line) and images are played back. The regenerator is basically the same as the one shown in the second part (d'),
Several different lens distortion processing data 18 a +
It is characterized by having a ROMI 8 such as a programmable ROM that stores 18 b 118 c =.

It! was shot with an electronic still camera! ! When the memory 5 that recorded the i image is set in the playback machine L', the memory 5 contains the image 1'0 information and the distortion information of the lens used by the camera V.
The distortion information is read out according to a command from the microcomputer 12 and stored in the RAM 1 of 3.
1) and transfers the image information in the memory 5 to the reproduction memory 14. At this time, some distortion processing data 18 a + 18 is stored in the ROM 18 and is stored in the non-reproducible device according to the type of electronic still camera to which the memory 5 can be attached or removed, that is, according to the type of camera lens. b, 18 c・-,
The distortion processing data corresponding to the VC is read out from the memory 5 currently set in the playback machine and stored in the RAM 13, and the image information to be captured is continuously sent to the rlj raw memory. Process η1f.

The image information stored in the reproduction memory 14 is read out at a television rate, for example, and converted into an analog image signal by a D/A converter 6 and displayed on a monitor 17. In the above description, the ROM may be either a normal ROM or a programmable ROM, and the ROM 18 and the like may be configured to include a ROM that can be removed for each processing data.

As explained above, the present invention directly converts an image signal obtained by inputting light from a subject into an image sensor through an optical lens, and removably stores digital information extracted by this conversion. In electronic still cameras, distortion information of the optical lens is stored in the storage means each time an image signal for one screen is stored, and this distortion information is used during image playback. lens distortion can be corrected. Specifically, the image signal readout address stored in the storage means is corrected based on lens distortion information.

In this way, there is no need to correct lens distortion at the lens manufacturing stage, so the lens diameter does not become larger or heavier, and if the lens is made smaller, costs can be reduced. can be achieved.

[Brief explanation of the drawing]

Figure 1 is a schematic configuration diagram of an electronic still camera that is subject to non-invention, Figure 2 is a schematic configuration diagram of a Vi writing machine, Figures 3 and 4 are explanatory diagrams illustrating the state of lens distortion, and Figure 5 FIG. 2 is a block diagram of a playback machine shown in the /ξ state with the memory set to . 1... Optical lens, 2... Image sensor, 4. A/
1. ) converter, 5... memory, 6... driver
[Ba, 7.16...D/A converter, 8...Switch, 9...Electronic finder, 1o...Battery,
12. Microcomputer, ], 31, ] 8
...ROM, 132°】9...RAM, 14...
Field memory, 15...TV rate drive circuit, 17...Monitor Patent applicant: Konishi Roku Photo Industry Co., Ltd. Agent, Patent attorney: Hiroshi Suzuki Figure 3 Figure 4 Procedural amendment document June 4, 1980 Patent Agency Commissioner Kazuo Wakasugi1, Indication of the case: Patent Application No. 57963 of 1982, Name of the invention: Electronic still camera and its recording/reproducing device3, Relationship with the person making the amendment: Address of the patent applicant: Tokyo 1-26-2 Nishi-Shinjuku, Shinjuku-ku Name
(127) Konishiroku Photo Industry Co., Ltd. 4, Agent address: 3-4-11-5 Shiba, Minato-ku, Tokyo, Date of amendment order (voluntary) 6. Subject of amendment: Claims column 7 of the description , Contents of Correction 2, Claims (1) Direct A-D conversion of an image signal obtained by making light from a subject enter an image sensor through an optical lens, and the converted digital information is removable. 1. An electronic still camera capable of storing distortion information of the optical lens in a storage means provided in the electronic still camera, wherein distortion information of the optical lens is stored in the storage means each time an image signal for one screen is stored. (2) In a recording and reproducing apparatus that reads, records and reproduces an image signal obtained by making light from a subject enter an image sensor through an optical lens and stored in a storage means after A-D conversion, the storage means is Image recording and reproduction characterized in that the stored image signals are read out after being rearranged in the storage means or in a memory mortar based on lens distortion information stored in a part of the storage means. Device.

Claims (2)

[Claims] (1) Direct A-D conversion of the image signal obtained by making light from the subject enter the image sensor through an optical lens, and store the converted digital information in a removably provided storage means. 1. An electronic still camera capable of storing distortion information N of the optical lens in a storage means each time an image signal for one screen is stored. (2) In the recording and reproducing apparatus for reading, recording and reproducing an image signal obtained by making light from a subject enter an image sensor through an optical lens and stored in a storage means VC after A-D conversion, An image recording and reproducing apparatus characterized in that image signals stored in a storage means are read out after being rearranged in the storage means based on lens distortion information stored in a part of the storage means. .