JPH0779448A - Frame sequential color camera - Google Patents

Abstract

(57) [Summary] [Purpose] In a frame sequential color camera, while maintaining high resolution for still images, color breakup during moving images is reduced, image continuity is improved, and camera response is improved. . [Structure] In a frame-sequential color camera in which a subject image is captured by performing pixel scanning in an interlaced system, and the captured image signals for each color obtained are converted into simultaneous signals by capturing the captured signals in respective memories, the camera is a moving image. It is set whether to shoot in the mode or in the still image mode (18), and when it is set to the moving image mode, the data for each field of the captured color is stored in the corresponding field of each color. Memory (5,6,7)
And simultaneously write to the memories of other fields that compose the frame of each color. When the camera is set to the still image mode, the obtained data for each color field is sequentially written into the memory (5, 6, 7) of the corresponding field for each color.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frame-sequential color camera, and more particularly to a frame-sequential color camera capable of picking up a still image at a high resolution and further improving the responsiveness by substantially reducing color breakup during moving images. Regarding the camera.

[0002]

2. Description of the Related Art FIG. 6 shows a schematic structure of a conventional frame sequential color camera. The color camera shown in the figure includes an imaging lens 51, an imaging unit 52, a scanning control circuit 53, an image signal processing circuit 54, and a memory block 5 corresponding to the three primary colors R, G, and B.
5, 56, 57, output circuits 58, 59, 60, and a signal changeover switch 61.

The image pickup lens 51 projects an image of a subject (not shown) onto a light receiving area of an image pickup device (not shown) in the image pickup section 52. The image pickup unit 52 includes, for example, a rotary color filter for color separation, the image pickup device, and the like, and sequentially picks up a subject image for each color and converts it into a corresponding electric signal. The scanning control circuit 53 controls the scanning timing of the image pickup section 52 and, if necessary, the scanning position.

The image signal processing circuit 54 performs, for example, gamma correction and other image processing on the image signal output from the image pickup section 52 and also performs A / D conversion. The switch 61 switches and inputs the frame-sequential color signal output from the image signal processing circuit 54 to the memory blocks 55, 56, and 57 corresponding sequentially for each color. The output circuits 58, 59, 60 include signal processing circuits and output amplifiers corresponding to the colors R, G, B, respectively.

In the frame sequential color camera shown in FIG. 6, the scanning control circuit 53 interlaces the image pickup section 52 to obtain an image pickup signal for each color. The image pickup signal is appropriately subjected to image processing by the image signal processing circuit 54, converted into a digital signal, and then sequentially written into the corresponding memories 55, 56, 57 by the switch 61. Then, the image information corresponding to each color written in these memory blocks 55, 56, 57 is simultaneously read out and output as R, G, B simultaneous signals via the output circuits 58, 59, 60. It

In the above structure, the image pickup section 52 is interlaced by the scan control circuit 53 and sequentially outputs image pickup signals for each field of each color. Each of the memory blocks 55, 56, 57 has a storage area for one frame, which is composed of a plurality of fields for each color.
Therefore, the image pickup signal output from the image pickup unit 52 is sequentially written into the memory blocks of each color for each field, and the data for one block is written and then read.

[0007]

In such a conventional frame-sequential color camera, when the subject moves, if the frame-sequential cycle of the image-capturing section 52 for performing the frame-sequential color separation imaging is not fast, the color There are inconveniences that cracks occur, the continuity of images is significantly lost, there are many problems in the quality of captured images, and the operability of the camera deteriorates.

In order to improve the image quality during such a moving image, the frame-sequential cycle can be shortened by shortening the image pickup time for one frame of the image pickup system such as an image pickup device. It is necessary to perform a high-speed operation, and it is necessary to measure the speed of the image pickup device and other circuit elements, increase the sensitivity, and increase the band. Therefore, there are many technical problems and the cost is increased.

In view of the problems in the above-mentioned conventional apparatus, an object of the present invention is to use the same scanning speed of the image pickup system as the conventional one while increasing the frame-sequential color separation period at the time of moving image so that the apparent color is apparently increased. The object is to reduce cracking and improve the continuity of images to improve the operability of a frame-sequential color camera.

[0010]

In order to achieve the above object, according to the present invention, a color image of a subject is picked up and obtained by performing a frame sequential method and scanning pixels by an interlaced method. In a frame-sequential color camera that captures image signals for each color into each memory and converts them into simultaneous signals,

Mode setting means for setting whether the camera should shoot in the moving image mode or in the still image mode, and when the camera is set in the moving image mode by the mode setting means, the image pickup is performed. The data for each color field is written in the memory of the corresponding field of each color, and simultaneously written in the memory of the other fields that make up the frame of each color. When the mode is set, scanning control means is provided for sequentially writing the obtained data for each color field into the memory of the corresponding field for each color.

The scanning control means is arranged so that in the moving image mode or the still image mode, the vertical scanning timing of the camera is set in units of field units so that a predetermined field can be obtained in a predetermined sequence for interlacing. It is convenient to shift the vertical scanning position by a predetermined amount or the vertical scanning position by a predetermined amount.

Further, the mode setting means can be configured to include a mode determining means for automatically determining a moving image mode and a still image mode.

[0014]

In the frame-sequential color camera having the above construction, when the camera is set to the moving image mode by the mode setting means, the imaged data of each color field is written in the memory of the corresponding field of each color. At the same time, the same data is written in the memories of the other fields forming the same color field. by this,
Although the resolution in the vertical direction is lowered, the frame-sequential repetitive capturing period of a color image can be shortened, color breakup is reduced even in a moving image, and image continuity is improved. Further, when the camera is set to the still image mode by the mode setting means, the imaged data for each color field is sequentially written in the memory of the corresponding field of each color. Therefore, although the frame-sequential repetitive capturing period of the color image becomes long, a high quality image can be obtained without lowering the vertical resolution.

Further, the scanning control means shifts the vertical scanning timing of the camera in units of fields constituting one frame by a predetermined time, or by shifting the vertical scanning position by a predetermined amount. When writing the data for the fields of each color imaged in such a manner in the corresponding field of each color and other fields, the fields that form one frame can be appropriately interlaced Data can be output. As a result, even when the captured image is displayed on a display device or the like, appropriate interlace scanning, and thus appropriate image display is performed.

Further, by providing the mode setting means with a mode determination means for automatically determining the moving image mode and the still image mode, the state of the object, that is, a moving object or a stationary object. Depending on whether or not it is automatically set to the appropriate shooting mode,
It is possible to perform appropriate imaging according to the state of the subject.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic structure of a frame sequential color camera according to an embodiment of the present invention. The camera shown in FIG. 1 includes an image pickup lens 1, an image pickup section 2, a scanning control circuit 3, an image signal processing circuit 4, image data memories 5, 6 and 7, output circuits 8 and 9,
10, frame sequential signal changeover switch 11, output changeover switches 12, 13, 14, simultaneous writing switch 15,
16, 17, and a moving image / still image detection circuit 18 and the like.

The image pickup section 2 has a rotary color separation disc filter and an image pickup device (not shown), and a subject image is formed on the light receiving surface of the image pickup device by the image pickup lens 1.
The scanning control circuit 3 controls the scanning timing of the image pickup device of the image pickup unit 2 and, if necessary, the scanning position. The scanning control circuit 3 also controls the frame sequential signal changeover switch 11 so that the image signals of the respective colors are appropriately written in the image data memories 5, 6, 7 of the corresponding colors.

The image signal processing circuit 4 performs image processing such as gamma correction on the image pickup signal obtained from the image pickup section 2 and converts the processed image signal into a digital signal. The image data memories 5, 6 and 7 each have a storage area for one frame of each of the three primary colors R, G and B. In this embodiment, one frame is made up of an even field and an odd field. Therefore, the memory 5 has a storage area 5-E for the even field and a storage area 5 for the odd field.
-O. The memory 6 for storing green (G) data also includes a memory area 6-E for even fields and a memory area 6-O for odd fields. Further, the memory 7 for storing blue (B) image data also includes a storage area 7-E for even fields and a storage area 7-O for odd fields.

The output circuits 8, 9 and 10 for the respective colors each include a predetermined signal processing circuit and an output amplifier. The field-sequential signal changeover switch 11 sequentially sends image data of each color obtained in synchronization with the rotation of a rotating color separation disk filter (not shown) in the image pickup unit 2 via a control signal from the scanning control circuit 11 to a corresponding color. It is possible to switch to write to the memories 5, 6, and 7. Also, the output changeover switches 12, 1
Reference numerals 3 and 14 are for sequentially switching and outputting the even field and the odd field when outputting the data from the memories 5, 6, and 7, respectively. Further, the simultaneous write switches 15, 16 and 17 are for closing the image data of the same field to the even field memory area and the odd field memory area at the same time when closed in the moving image mode, as described later. Is.

Further, the moving image / still image detecting circuit 18 determines whether or not the subject is moving, inputs a control signal to the scanning control circuit 3, and sets the simultaneous writing switches 15, 16 and 17 in the moving image mode. Controls such as closing. The detection of a moving image / still image can be easily detected by, for example, determining whether or not the difference between the image signals at a time point when a predetermined time is away is a predetermined value or more. The scanning control circuit 3 also has a function of changing each scanning position of the even field and the odd field in the image sensor, or shifting the scanning timing for each field constituting one frame for a predetermined time. ing.

In the frame-sequential color camera having the above-mentioned structure, the image pickup device (not shown) of the image pickup unit 2 is scanned by the control of the scanning control circuit 3, and the image pickup lens 1 is connected to the light receiving surface of the image pickup device. Imaging signals corresponding to the formed image are sequentially output. The image pickup unit 2 is provided with a rotational color separation color filter having filter regions of respective colors R, G, B, and image pickup data for each color is output in a frame sequential method in synchronization with the rotation of the rotational color separation disk filter. To be done. The image signal processing circuit 4 receives such an image pickup signal, performs gamma correction and other processing, and then converts it into digital image data using an A / D converter. This image data is then input to the frame sequential signal switch 11 and sequentially written in the memories 5, 6, 7 of the corresponding color for each data corresponding to the field of each color. Therefore, the frame sequential signal switch 11 is sequentially switched in synchronization with the rotation of the rotary color separation disc filter of the image pickup unit 2.

When the image data is written in the memories 5, 6 and 7 as described above, the moving image / still image detecting circuit 18
When it is determined that the subject image has a motion and is in the moving image mode, the simultaneous writing switches 15, 16 and 17 are closed, and the image data of each color field is stored in the even field storage area and the odd field storage area. Written at the same time. Then, after such writing is performed, the image data is simultaneously read from the memories 5, 6, 7 and output as a simultaneous signal via the switches 12, 13, 14 and the output circuits 8, 9, 10. To be done. In this case, the change-over switches 12, 13 and 14 are switched so as to alternately output data from the memory area for even fields and the memory area for odd fields for interlacing. In this manner, in the moving image mode, the image data of the same field is simultaneously written in the odd field and the even field, so that the frame-sequential repetitive capturing period of the color image can be shortened.

When the moving image / still image detecting circuit 18 determines that the subject has no movement or almost no movement, the simultaneous writing switches 15, 16 and 17 are in the open state and the image is picked up. The image data is sequentially written into the corresponding memory area for each field. Therefore,
In this case, it takes longer time to write all the data in the data area of each field of each memory 5, 6, 7 than in the case of the moving image described above, but the resolution in the vertical direction does not decrease. High quality imaging becomes possible.

Next, with reference to FIGS. 2 to 4, the operation for specifically writing the image data in the image data memory of each color will be described. FIG. 2 shows the timing when a color image is taken in with 6 frames, that is, 12 fields as one cycle. In 1) of the figure, T indicates a period of one rotation of the rotary color separation disk filter, that is, one cycle, and is composed of 6 frames. And R1, G
Reference numerals 1 and B1 denote frames in which images of red, green, and blue colors are input to the image pickup device at the first rotation, and R2, G2, and B2 are red at the second rotation, respectively.
The frame periods in which the respective green and blue images are formed on the image pickup device are shown. And each frame period R1,
Each of G1, B1, ... Is composed of an even field E and an odd field O.

1) to 5) show operation timings in the moving image mode. In 2), R1O represents the image data of the odd field (odd) of the first rotation of the disk filter, and this image data is simultaneously written as R1 in each field of the memory as shown in 3). In 2), G1O represents the data of the first-round green odd field of the disc filter. As shown in 4), G1O represents the first-round green image data G1 in the odd and even fields. It is written at the same time. Similarly, the data of the blue odd field of the first rotation of the disk filter is indicated by B1O, and as shown in 5), the blue data B1 of the first rotation is simultaneously written in the memory of the odd and even fields. Similarly, in the second rotation of the disc filter, simultaneous writing is sequentially performed in the memory of the odd and even fields. In addition, reading from each memory is performed by the changeover switches 12, 1
This is performed while switching between 3 and 14, and an interlaced signal is output.

6) to 10) show timings in the case of a still image. In this case, one rotation of the rotary disk filter, that is, one cycle, every half cycle of the vertical scanning signal of the camera on the camera side. By shifting by the amount, the fields are combined and sequentially written into the memory. That is, odd-numbered scanning positions are imaged in the first cycle of the rotating disk filter, and even-numbered in the second cycle.
n) The scanning position is imaged, and the color high-resolution screen for one screen is loaded into the memory in two cycles of the rotary disk filter. As a result, the even and odd fields of the image data memories 5, 6 and 7 for the respective colors are sequentially loaded with the imaging data of the even and odd fields, respectively. Therefore, a high-resolution image can be obtained by reading such memories 5, 6 and 7 alternately at even and odd fields at the original timing. In addition, since a color image can be captured in half the time of a still image during a moving image, color breakup can be reduced and continuity can be improved.

FIG. 3 shows an example of capturing a color image with 4.5 frames, that is, 9 fields as one cycle. Therefore, in this case, the rotating disk filter makes one rotation in 4.5 frames. Also in this case, 1 in 2 fields
It is in the interlaced imaging mode that constitutes a frame. 11) to 15) of FIG. 3 show the case of the still image mode, in which the high resolution color screen for one screen is sequentially written in the memory of each color with two rotations of the rotating disk as one cycle.

On the other hand, at the time of a moving image, as shown in 16) to 20), the scanning system on the camera side is arranged so that the writing field to the memory is the same in each color channel, that is, does not change to an odd number or an even number. Then, the vertical scanning signal is appropriately shifted by 1/2 horizontal period to change all the color signals at the timing of loading into the memory to odd numbers (odd), and simultaneously write the data of these odd number fields to the odd number and even number memory areas. . Therefore, in this example,
The color image can be captured in the time required for one rotation of the rotating disk filter, that is, in 4.5 frames, which is faster than in the case of FIG.

FIG. 4 shows an example of capturing a color image with three frames, that is, six fields as one cycle in the interlaced image pickup mode in which two fields form one frame. At the time of moving image, as shown in the charts 21) to 25), data is written in the data memory of each color in the odd field of each color channel to be imaged, and the same odd number is written in the odd and even data areas of each memory. Field data is being written at the same time.

In addition, at the time of a still image, the rotary disc filter 1
Every time the camera rotates, the vertical scanning signal of the camera is halved.
The horizontal scanning shifts the even scanning positions, and the vertical scanning signals of the camera are fetched in the odd scanning positions in a period in which the horizontal scanning signals are not shifted by ½ horizontal period. As a result, a high-resolution color image for one screen is loaded into the memory by two rotations of the rotary disc filter. This situation is shown in charts 26) to 30).
Shown in.

FIG. 5 shows a detailed operation in the case of changing the field by shifting the vertical scanning signal in the scanning system on the camera side in the image capturing operation as described above. Note that FIG. 5 shows the charts 11) to 20) of FIG.
Corresponding to the case of 4.5 frames, or 9
The case where a color image for one cycle is captured in the field is shown. In such a case, as described above, the field is set for simultaneous writing during a moving image.

As shown in FIG. 5, a black-white-black portion of a subject is imaged, and at the time of a still image, a scanning position (even) of an even field shown by a solid line and an odd field shown by a dotted line. Scan positions (odd) are alternately present at intervals of 1 / 2H. Further, at the time of a moving image, the start position of vertical scanning is shifted by 1 / 2H only in the odd field to change all the fetch timings into the memory to the odd field. However, in order not to shift the center of gravity of the display position of the subject on the display when moving from a still image to a moving image, the entire field is shifted by 1 / 4H in advance on the camera side and then the odd field is shifted by 1 / 2H to perform field inversion. I am doing it. Therefore, in the display on the display, the white portion is displayed wide. However, since the upper edge and the lower edge of the white portion of the screen are displayed in different directions in the opposite directions, the center of gravity of the displayed image is not displaced as compared with the case of a still image. Such processing can be similarly applied to the case where the rotation speed of the rotary disk filter is different, that is, the case of FIG. 2 and FIG.

[0034]

As described above, according to the present invention, at the time of a moving image, the data for one field in the interlaced mode is simultaneously written to the other fields forming the frame of the corresponding color, On the other hand, in the case of a still image, the obtained data for each field is sequentially written in the corresponding field. For this reason, the resolution in the vertical direction is reduced during moving images, but the image capturing period is shortened, and even in a frame sequential color imaging system, color breakup can be substantially reduced and image continuity is improved. You can Further, in the case of a still image, it is possible to capture a high-resolution image, although the capture cycle is long. Therefore, optimum image pickup is performed according to the condition of the subject, that is, whether the subject is stationary or moving, and the operability of the camera is improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a frame sequential color camera according to an embodiment of the present invention.

FIG. 2 is a time chart for explaining an image data capturing operation in the frame sequential color camera of FIG.

FIG. 3 is a time chart for explaining an image data capturing operation in the frame sequential color camera of FIG.

FIG. 4 is a time chart for explaining an image data capturing operation in the frame sequential color camera of FIG.

5 is an explanatory diagram showing a shift operation of a vertical scanning position in the frame sequential color camera of FIG.

FIG. 6 is a block diagram showing a schematic configuration of a conventional frame sequential color camera.

[Explanation of symbols]

 1 Imaging Lens 2 Imaging Section 3 Scanning Control Circuit 4 Image Signal Processing Circuit 5, 6, 7 Image Data Memory 8, 9, 10 Output Circuit 11 Frame Sequential Signal Changeover Switch 12, 13, 14 Field Changeover Switch 15, 16, 17 Simultaneous Writing switch 18 Video / still image detection circuit

Claims (3)

[Claims] 1. A color image of a subject is picked up by a frame sequential method and pixels are scanned by an interlaced method, and the obtained picked-up image signals for each color are stored in respective memories to be converted into simultaneous signals. And a mode setting means for setting whether the camera should shoot in the moving image mode or the still image mode, and the camera sets to the moving image mode by the mode setting means. At this time, the imaged data for each color field is written to the memory of the corresponding field of each color and simultaneously written to the memory of the other fields forming the frame of each color. When the camera is set to still image mode by, the obtained data for each color field is Corresponding fields of the field sequential color camera, characterized by comprising, scanning control means for sequentially writing into a memory of. 2. The scanning control means configures one frame of vertical scanning timing of the camera so that a predetermined field is obtained in a predetermined sequence for interlacing in the moving image mode or the still image mode. 2. The frame sequential color camera according to claim 1, wherein the field-sequential color camera is shifted for each field for a predetermined time or for shifting a vertical scanning position by a predetermined amount. 3. The frame sequential color camera according to claim 1, wherein the mode setting unit includes a mode determination unit that automatically determines a moving image mode and a still image mode.