JPH1042302A - Field sequential color image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a field sequential color image pickup device which substantially improve the speed of fetching from an image pickup device, reduces color breakup and on the other hand, prevents resolution from deteriorating at the time of a still picture. SOLUTION: An image of light component which passes through a color transmission filter of R, G and B is incident on an image pickup device 3 that is arranged on an optical path by the rotation of a rotational filter. Entire pixels 11 of the device 3 are divided into pixel blocks whose horizontality ×verticality is one pixel × four pixels, and each changeover switch 12, 13, etc., can select an optional block. At the time of animation, pixels in a block which is selected by the changeover switches 12, 13, etc., are fixed, 1/4 of entire pixels is read by one rotation of the rotational filter, and the rest is interpolated and shown as one frame of pixels. At the time of a still picture, pixels which are selected are switched every rotation of the rotational filter and entire pixels are read with four rotations.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a means for reading out image signals of respective reference colors in time series, an image pickup device capable of switching pixels to be read out, and a method for simultaneously outputting image signals of reference colors read out in time series. The present invention relates to a field sequential color image pickup apparatus having a memory for implementing the image processing.

[0002]

2. Description of the Related Art Conventionally, as a frame sequential color image pickup apparatus,
For example, a configuration represented by the following two conventional examples is known. For simplicity, the three reference colors are R,
Description will be given as G and B.

FIG. 10 shows a simple block configuration of a conventional general frame sequential color image pickup device 31. An image pickup device 33 having a function of performing photoelectric conversion is arranged at an image forming position on an optical axis of an image pickup lens or an image forming lens 32 for forming an optical image of a subject (not shown). A rotary filter 34 having a color transmission filter for transmitting light of each wavelength of R, G, and B is disposed between the rotary filter 33 and the rotary filter 34. The rotary filter 34 is rotated by a driving unit such as a motor (not shown).

[0004] By rotating the rotation filter 34, R, G, and B color transmission filters are sequentially set on the optical path, so that an image of light of each of the R, G, and B wavelength components is formed on the image sensor 33. Tied. The image pickup device 33 uses the scanning signal synchronized with the irradiation period of the light of each wavelength component of R, G, and B from the scanning control unit 35 to generate a signal (R, G, and G) corresponding to the image of each wavelength component that has been photoelectrically converted. B signal) is the image sensor 3
3 are read out in chronological order.

The time-series R, G, and B signals are supplied to an A / D converter 3
6 are converted into digital R, G, and B signals, which are sequentially written into the respective color memories 38R, 38G, and 38B under the control of the memory control unit 37, and are read out and synchronized at the same timing. It becomes color image signal data. Then, the synchronized color image signal data is input to the signal processing unit 39, where it is subjected to signal processing to become R, G, and B color signals, and is input to a color monitor (not shown) to display the subject image in color. The image is input to the image recording device and recorded.

Next, the operation when the XY address type solid-state image sensor is adopted as the image sensor 33 and the XY address type solid-state image sensor is scanned in a non-interlace manner will be described.
This will be described with reference to the timing chart of FIG.

In FIG. 11, the rotation filter 34 has a cycle of 9T.
In this case, the R, G, and B color transmission filters are present in the optical path at intervals of approximately 3T, and the switching period is approximately 1T. In FIG. 11, the incident light that enters the image sensor 33 via the R color transmission filter in the first rotation cycle is indicated by R-1. Therefore, I (I = R,
G, B), the incident light passing through the color transmission filter is I
−n. Also, an effective output signal that is imaged under the incident light In and output from the image sensor 33 to the memories 38R, 38G, 38B is indicated by In, and the memories 38R, 38
The output signals output from G and 38B are also shown in the same manner.

The incident light transmitted through the rotary filter 34 is R-
1, G-1, B-1, R-2, G-2, B-2, R-
, But time t = 0 to T, 3T to 4T, 6
Each period of T to 7T,... 3nT to (3n + 1) T,.
Since the switching section of the R, G, and B color transmission filters crosses on the optical path or on the image sensor 33, the incident light is mixed.
Here, T is one frame period, and n = 0, 1,
2, ...

Therefore, effective signals without color mixture for incident light of R, G, B are t = TＴ3T, 4T〜6T, 7T.
９9T,..., (3n−2) T３3 nT,..., Signals R1, G1, B1, R2,.
Becomes

The effective read signals R1, G1, B
, R2,... Are A / D-converted by an A / D converter 36, and then R memory 38R and G memory 38 for synchronization are used, respectively.
The data is written to the G and B memories 38B, respectively.

Next, each of the memories 38R, 38G, 38B
, Digital R, G, B signals are read out at the same timing and are synchronized. Here, each memory 38R, 38
From G and 38B, the same signal is repeatedly read a plurality of times until it is rewritten to the next new valid read signal. The synchronized signal is then subjected to necessary signal processing in a signal processing unit 39 to become an output signal.

A second conventional example is disclosed in Japanese Patent Application Laid-Open No. 7-79.
No. 448. In this publication, one of the rotary filters
At each rotation, an image for one field of each color is read from the image sensor, and a moving image / still image is detected. When a still image is formed, one frame is formed by two rotations. A field-sequential color camera is disclosed, in which one frame is completed by interpolating the other field with a fraction. As a result, at the time of a moving image, a frame can be displayed for each rotation of the rotation filter, and the image capturing speed by the frame sequential method is increased to reduce color breakup.

[0013]

In a conventional frame sequential color image pickup apparatus, if an object moves within a time period in which R, G, and B primary color signals are stored in a memory in order to perform synchronization, R, G , B output images no longer match each other, causing color breakup and disturbing the image.

According to Japanese Patent Application Laid-Open No. 7-79448, which is an apparatus for solving such a problem, it is possible to display a frame by using an image for one field in the time of one rotation of the rotation filter at the time of moving image. First, it was not possible to improve the capture speed over the image reading time of one field. Also, there is no disclosure about non-interlaced scanning.

SUMMARY OF THE INVENTION In view of the above problems, the present invention further improves the capture speed of a frame sequential color image pickup apparatus and reduces color breakup, while preventing the resolution from deteriorating during a still image. It is intended to provide a device.

[0016]

In the field sequential color image pickup apparatus of the present invention, distributed light rays of three reference colors are sequentially and temporally separated and incident on a single image pickup element, and an image pickup signal of each reference color is obtained. In a field sequential color imaging apparatus that reads out the image in chronological order, switching means for handling a moving image or a still image, dividing all pixels into predetermined blocks, and selecting a readout signal to an arbitrary pixel in the block. A possible image sensor and a memory for simultaneously outputting time-series image signals of respective reference colors are provided, and the image sensor selects an arbitrary pixel of the block by the switching unit. .

According to the above configuration, the pixels selected from the blocks are changed in synchronization with the cycle of reading out the imaging signals of each reference color in time series corresponding to a moving image or a still image. A small number of color images can be obtained, and in the case of a still image, a high-resolution color image can be obtained.

[0018]

Embodiments of the present invention will be specifically described below with reference to the drawings. 1 to 5 relate to a first embodiment of the present invention, FIG. 1 shows a schematic configuration of a frame sequential color image pickup apparatus according to the first embodiment of the present invention, and FIG. 3 to 5 show timing diagrams for explaining the operation.

The field sequential color image pickup apparatus 1 of the present embodiment has a function of performing photoelectric conversion at an image forming position on the optical axis of an image forming lens or an image forming lens 2 for forming an optical image of a subject (not shown). An image pickup device 3 is disposed, and a rotary filter 4 provided with a color transmission filter that transmits light of each wavelength of R, G, and B in the circumferential direction is disposed between the image pickup lens 2 and the image pickup device 3. The rotary filter 4 is rotated at a constant speed by a driving means such as a motor (not shown).

When the rotary filter 4 is rotated,
R, G, B color transmission filters are sequentially set on the optical path,
Therefore, an image is formed on the image pickup device 3 by distributed light beams of R, G, and B wavelengths as three reference colors. The image pickup device 3 uses the scanning signal synchronized with the irradiation period of the light of each wavelength component of R, G, and B from the scanning control unit 5 to generate a signal (R, G, and G) corresponding to the image of each wavelength component that has been photoelectrically converted. B signal) is read out from the image sensor 3 in time series.

The time-series R, G, and B signals are converted by an A / D converter 6
Are converted into digital R, G, and B signals by the control of the memory control unit 7,
R, 8G, and 8B are sequentially written, and are read out at the same timing to become synchronized color image signal data. Then, the synchronized color image signal data is input to the signal processing unit 9 and is subjected to signal processing to become R, G, and B color signals, and is input to a color monitor or the like (not shown) to display a subject image in color. It can also be input to an image recording device and recorded.

In this embodiment, a configuration is provided in which a motion detection unit 10 is provided, and the operations of the scanning control unit 5 and the memory control unit 7 are switched by the output of the motion detection unit 10 so that different controls are performed for a still image and a moving image. It has become. That is, the motion detection unit 1
Numeral 0 forms switching means for switching between a display mode corresponding to a moving image and a display mode corresponding to a still image. In the case of a moving image, the operation mode of image display can be changed according to the amount of movement by selecting a selection switch or a changeover switch (not shown).

More specifically, in this embodiment, an XY address type solid-state image pickup device is employed as the image pickup device 3, and the XY address type solid-state image pickup device is scanned in a non-interlace manner. And a control pattern of the scanning control unit 5 and the memory control unit 7 which can switch the pixel read out from each time of the rotation of the rotation filter 4 according to the motion detection of the motion detection unit 10. It has a block configuration that can be used.

For example, as shown in FIG. 2, horizontal × vertical; X × Y
All the pixels 11 of the image sensor 3 composed of a plurality of pixels are divided into blocks of horizontal × vertical; 4 × 1 = 4 pixels which can be switched by the changeover switches 12, 13, 14, 15,. . That is, as shown in FIG. 2, in the horizontal pixel column of X = 1, four of 1-1, 1-2, 1-3 and 1-4 are used.
First pixel block composed of pixels, 2-1, 2-2, 2
-3, 2-4, a second pixel block composed of four pixels, 3
A third pixel block including four pixels -1, 3-2, 3-3, and 3-4. A fourth pixel block including four pixels 4-1, 4-2, 4-3, and 4-4. Are sequentially arranged in the horizontal direction.

The four pixels in each block can be arbitrarily selected by the changeover switches 12, 13, 14, 15,.... That is, the changeover switch 12 is configured to control the four pixels of the first pixel block, 1-1, 1-2,
Select one from 1-3 and 1-4, and select switch 1
3 is the four pixels of the second pixel block, 2-1, 2-2, 2
-3, 2-4, and selects one of the switches.
Are the four pixels of the third pixel block, 3-1, 3-2, 3-
3, and 3-4, and the changeover switch 15 is connected to the four pixels 4-1, 4-2, and 4-
One is selected from 3, 4-4.

In FIG. 2, for simplicity, reference numerals for horizontal pixels at X = 2 and the like are not shown, but, for example, four pixels 1-1, 1-2, 1- 1 of the first pixel block. 3, 1-4
The lower four pixels can be selected and read out by the changeover switch 12. The same applies to other pixel blocks.

In this embodiment, the rotation speed of the rotary filter 4 is increased without having to increase the reading speed of the image sensor 3. In this case, by increasing the rotation speed, it is necessary to increase the reading speed in order to read all the pixels of the image sensor 3 without dropping. However, in the present embodiment, the number of pixels to be read is set according to the frame display period. By changing (adjusting), more specifically, by thinning out the pixels to be read out, it is possible to cope without improving the reading speed.

For example, when the rotation speed of the rotation filter 4 is set to, for example, four times (p times when generalized) so as to correspond to the display of a moving image, and one frame display period is shortened, for example, In the case of the same period as one rotation of the above, the number of pixels to be read is reduced to 1/4 (1 / p in a general case), so that the reading speed of the image sensor 3 does not need to be changed. Is unnecessary.
In the still image mode, one frame display period is extended to read all the pixels, thereby preventing a reduction in resolution.

Then, in one rotation of the rotation filter 4, only one pixel in each pixel block is read and sequentially switched by the switches 17a, 17b, 17c, 17d,. , 1
5,... Are sequentially output and output from the output terminal via an amplifier or the like inside the image sensor 3.
Output to the / D conversion unit 6 side.

Changeover switches 12, 13, 14, 1
5, ON / OFF selection and horizontal scanning switch group 17
Of switches 17a, 17b, 17c, 17d,.
The selection of N or OFF is performed under the control of the scanning control unit 5 that operates according to the determination result of the motion detection unit 10. In response to this, the memory control unit 7 controls writing and reading to and from the memories 8R, 8G, and 8B, and a display suitable for each of a color still image and a moving image displayed on a color monitor via the signal processing unit 9. Display in form.

More specifically, the motion detecting section 10 determines a still image or a moving image by detecting a motion, and controls different image display as shown in FIG. 3 or FIG. 4 according to the determination result.

The motion detector 10 takes in, for example, the same time-series color signal components that have passed through the A / D converter 6 and detects the amount of correlation. If determined, it is determined as a still image, and if less than the set value, it is determined as a moving image. Further, in the case of a moving image, a multi-step movement such as a case where the movement is fast or a case where the movement is slow according to the value of the correlation amount can be determined.

When it is determined that the image is a still image, no color break occurs or almost no color break occurs.
By increasing the display period of the frame (9T in FIG. 3), the number of pixels used for displaying an image of one frame is increased, and when it is determined that the image is a moving image, the display period of one frame is reduced to reduce color breakup. The length is shortened ((9/4) T in FIG. 4), the number of pixels used for displaying an image of one frame is thinned out to reduce the number, and the shortage is interpolated by adjacent pixels.

Further, when it is determined that the moving image is a moving image, a mode for changing the control of image display according to the amount of movement is provided. In this case, the operation is performed as shown in FIG. 5, for example. Hereinafter, description will be made sequentially from the case of FIG. 3 corresponding to the operation of the still image.

In the case of an image determined to be a still image, every time the rotation filter 4 rotates, the pixels to be read in the block are sequentially switched by switches 12, 13, 14, 15,. When scanning is performed by the non-interlace method, synchronization timing is as shown in FIG.

In FIG. 3 (the same applies to FIGS. 4 and 5), (A), (B), (C), (D), (E), and (F)
Denotes time, incident light, a period of one rotation of the (rotation) filter, one frame display period, an effective output signal (memory input), and an output signal (memory output).

The incident light R-11, G-11, and G11 shown in FIG.
B-11, R-12,... Obtain an image of one frame in four rotations. For example, R-ij indicates R incident light at the j-th rotation in the i-th frame. The valid output signal (memory input) in FIG.
1, B11, R12,..., For example, Rij is the i-th
5 shows a signal imaged under the incident light of R at the j-th rotation in the frame of FIG. The output signal (memory output) in FIG. 3F also indicates the same signal as in FIG. Here, for example, R04 indicates a signal remaining in the R memory 38R before the time T is 0.

The reading order of the pixels is such that the switches 12, 13, 14, 15,... Shown in FIG. 2 are sequentially switched for each rotation of the rotation filter 4, and the first rotation of each pixel block in the first rotation. That is, 1-1,2-1,3-1,4-
.. Are sequentially read out, and in the second rotation, 1-2, respectively.
2-2, 3-2, 4-2,... Are read out, and a pseudo field is formed by pixels read out for each rotation.

At this time, the number of pixels to be read in the first rotation is only 1/4 of all pixels, and in a still image, four pseudo fields composed of 1/4 of the number of pixels are obtained in four rotations.
These are combined by the memories 8R, 8G, and 8B to form one frame. In terms of time, if T is one frame period (9 /
4) One pseudo field is obtained at T, and four pseudo fields are combined to form one frame at 9T. That is, a high-resolution color image is obtained by reading and using all the pixels in four rotations. The signal of the image sensor 3 is reset every time the rotation filter 4 makes one rotation.

FIG. 4 shows the display timing when the motion detector 10 detects a moving image. In this case, as can be seen from FIGS. 4C and 4D, one rotation of the rotation filter 4 is defined as one frame display period. Therefore, the incident light becomes R-11, G-11, and B-11 in the first rotation of the rotary filter 4 (similar to the case of FIG. 3), and (9
/ 4) In the second rotation from T, R- (from 9T in FIG. 3)
21, G-21 and B-21.

In FIG. 3, the pixels read from the pixel block of the image sensor 3 are switched every time the rotation filter 4 rotates.
In FIG. 4, without performing this switching, only specific pixels in each pixel block are read, and other pixels are thinned out and not read.

That is, the changeover switches 12, 1 shown in FIG.
Are fixed, for example, 1-1, 2-
.. Are always read out and this 1
The pseudo fields decimated to / 4 are converted into four frames by the memories 8R, 8G, and 8B as one frame for each rotation of the filter.
Interpolate twice and update. In terms of time, (9/4) T
Is interpolated by the same data of four pixels in the horizontal direction for each pixel, and the pseudo field data obtained in
4) T constitutes one frame.

By doing so, the read time for the number of pixels smaller than the number of pixels in one field can be reduced by one.
A frame image can be displayed, and it is possible to cope with a case where color breakup occurs even when reading the number of pixels in one field (the second conventional example requires time to read the number of pixels in one field). On the other hand, in this embodiment, it is possible to form an image of one frame in half the time.) Further, by increasing the number of pixels in each pixel block, it is possible to form an image of one frame in a shorter time.

When the motion detecting section 10 detects the moving image as a moving image, the moving speed of the moving image is recognized, the number of pixels to be read is changed in accordance with the stage, and the image display speed is switched in multiple stages. Do as follows.

For example, the motion detecting section 10 performs three-stage speed recognition, and switches the reading of the image sensor 3 and the interpolation pattern of the memory according to each stage. When it is determined that the movement is the fastest, the operation is performed in the mode of the timing (pattern) shown in FIG. 4, and when it is determined that the movement is medium, the operation is performed in the mode of the timing shown in FIG. In FIG. 5, one frame display period is set to a period (9/2) T of two rotations of the rotation filter 4, as shown in FIG. This period is twice as long as that of FIG.

Therefore, when displaying at the timing shown in FIG. 5, the four-pixel switch shown in FIG. 2 is switched between any two pixels for each pseudo field, and only two specific pixels in each pixel block are read out. Two pixels are not used for display. In terms of time, one pseudo field is obtained at (9/4) T, and two pseudo fields are synthesized to form one frame at (9/2) T.

When it is determined that the movement is the slowest, although not shown, for example, one frame display period is set to a cycle (27/4) T of three rotations of the rotary filter 4, and the rotary filter 4 makes one rotation. One pixel is sequentially selected from each pixel block every time, and at the fourth rotation, the first one pixel is selected again without selecting the remaining one pixel. That is, three of the four pixels are used for display, and the remaining one pixel is not selected.
The shortage in the number of pixels in one frame is interpolated by adjacent pixels. Then, the cycle of three rotations of the rotary filter 4 (2
7/4) One frame of image is displayed at T. In addition to the multi-step setting method, besides the motion detection, a method of forcibly switching from the outside by a changeover switch or the like according to the user's purpose is also conceivable.

According to the frame sequential color image pickup apparatus 1 of the present embodiment, the image pickup device 3 is divided into a plurality of blocks each having a predetermined number of pixels, and an arbitrary pixel in each block can be selected. When it is determined that the image is a still image according to the motion detection determination by the unit 10, one frame display period is lengthened, and the number of pixels read and used in each frame display period is increased. More specifically, since all the pixels are read, it is possible to prevent a decrease in resolution and display a clear image.

When it is determined that the moving image is a moving image, one frame display period can be shortened by thinning out and reading, and an image having no or little color breakup can be displayed.
Further, since the number of pixels to be read out is changed in accordance with the frame display period, the number of pixels to be read out can be changed without changing the readout speed of the image sensor 3, and the configuration of the apparatus can be simplified and the cost can be reduced.

In the above description, a case has been described where all the pixels of the image pickup device 3 are divided horizontally and vertically into 1 × 4 pixel blocks. Alternatively, 1 × n pixel blocks may be used. Here, n is a natural number of 2 or more, that is, n = 2, 3, 4,.
And the number of In this case, when only one specific pixel in the pixel block is read every time the rotation filter 4 rotates,
The take-up speed can be increased n times.

Further, when all pixels of the image sensor 3 are divided horizontally and vertically into n × m pixel blocks, and only one specific pixel in the pixel blocks is read out every time the rotation filter 4 rotates, The take-up speed can be increased by n × m times. However, at least one of n and m is a natural number of 2 or more.

When the pixel block is divided into n × m pixel blocks in the horizontal and vertical directions, one of the rotation filters 4 is used.
When the pixel to be read is changed by one pixel for each rotation and for each rotation in the pixel block, and only b specific pixels are constantly read, the value of b is switched according to the speed of movement of the subject during moving image. By changing the interpolation of the memory accordingly, it is possible to set the capture speed and the resolution in multiple steps.

(Second Embodiment) Next, a second embodiment of the present invention will be described.
An embodiment will be described. FIG. 6 is a diagram showing a schematic configuration of a frame sequential color imaging device 20 according to the second embodiment of the present invention, and FIG. 7 is a diagram showing a main part of an image sensor according to the second embodiment of the present invention. FIG. 3 is a diagram illustrating a configuration. In contrast to the single-line readout in the first embodiment, the present embodiment is configured to perform the same operation as the first embodiment by the double-line readout.

Accordingly, as shown in FIG. 6, the frame sequential color image pickup device 20 according to the present embodiment uses a two-line readout image pickup device shown in FIG. 7 instead of the image pickup device 3 shown in FIG. 3 'and A in FIG.
An A / D converter 6 'corresponding to two inputs is applied instead of the / D converter 6. The rotation filter 4 is rotated at twice the speed of the first embodiment.

As shown in FIG. 7, two lines are read in the horizontal direction from all the pixels 21 of the image pickup device 3 'composed of X.times.Y pixels. This image sensor 3 'has two horizontal scan switch groups 27 and 28 instead of one horizontal scan switch group 17 in the image sensor 3 shown in FIG. The horizontal scanning switch group 27 includes switches 27
, and the horizontal scanning switch group 28 includes switches 28a, 28b,.

Further, all the pixels 21 of the image pickup device 3 'are divided into blocks each of 8 pixels (horizontal × vertical) = 8 × 1 = 8 pixels, and a pair of changeover switches 22a, 23a; 22b, 23
b; so that a block of four pixels belonging to the A line and the B line can be equivalently switched by one switch. For example, in a first horizontal pixel column of X = 1, eight pixels A1-1, B1-1, A1-
2, B1-2, A1-3, B1-3, A1-4, B1-
Reference numeral 4 denotes four pixels A1-1, A1-2, and A1 on the A line.
-3, A1-4 are switches 22a, and four pixels B1-1, B1-2, B1-3, B1-4 of the B line are connected to be selectable by switches 23a, respectively.
a is connected to the switch 27a of the horizontal scanning switch group 27, and the switch 23a is connected to the switch 28a of the horizontal scanning switch group 28.

The eight pixels A2-1, B2-1, A2-2, B2-2, A2-
3, B2-3, A2-4, and B2-4 are four pixels A2-1, A2-2, A2-3, and A2-4 on the A line with the switch 22b, and four pixels B2 on the B line. -1, B2-
2, B2-3 and B2-4 are connected to be selectable by a switch 23b, the switch 22b is connected to a switch 27b of a horizontal scanning switch group 27, and the switch 23b is connected to a switch 28b of a horizontal scanning switch group 28. I have. Other pixel blocks have the same configuration.

The pixel on the A line is the switch 22
a, 22b,... are sequentially output through switches 27a, 27b,.
Are output to the A / D conversion unit 6 ', and the pixels of the B line are sequentially selected by the switches 23a, 23b,.
Are output as output B to the A / D converter 6 'through the terminals 28b,.

Also in the present embodiment, the motion detecting section 10
Thus, whether the image is a still image or a moving image is determined, and the operation pattern of the display is changed according to the determination result, similarly to the first embodiment.

In this case, each time the rotary filter 4 rotates, FIG.
, Switches the signals of the selected pixels through the switches 22a, 23a, 22b, 23b,. Specifically, when it is determined that the image is a still image, the pixels of A1-1, A2-1,... Are read from the A line through the switches 22a, 22b,. , The pixels of B1-1, B2-1,...
23b,... Respectively. In the second rotation, pixels A1-2, A2-2,... Are read out from line A via switches 22a, 22b,..., And pixels B1-2, B2-2,. , 23
are read out via b,.

In the third rotation, A1-A1-
, Pixels A2-3,... Are switches 22a, 22b,.
From the B line, and B1-3, B2-
,... Are read out via the switches 23a, 23b,. In the fourth rotation, A1-
, 4, 2-4,... Are read out via the switches 22a, 22b,.
.. Are read out via switches 23a, 23b,.

The pixel on the A-line is a switch 22a,
.. Of the horizontal scanning switch group 27 are sequentially turned on to be output as an output A to the A / D converter 6 'side, and the pixels on the B line are connected to the switch 23a. , 23b,...
The switches 28a, 28b,... Of the horizontal scanning switch group 28
Are sequentially turned on and output as an output B to the A / D converter 6 '.

Then, a display period of one frame is obtained by four rotations. In this case, since two-line reading is performed in which reading is performed one pixel at a time from the A line and the B line, (the total number of pixels of the image sensor is assumed to be the same as in the first embodiment,
Further, assuming that the readout speed of one pixel is the same, the substantial readout speed is twice that of the first embodiment, and the rotation speed of the rotary filter 4 can be doubled. That is, the first
The same operation as that of FIG. 3 in the embodiment can be realized at twice the reading speed.

When it is determined that the moving image is a moving image, one pixel is read out in each block for both the A line and the B line. In this way, the same operation as that of FIG. 4 in the first embodiment can be realized at twice the reading speed.

In other cases, for example, the operation of FIG. 5 can also be realized at twice the reading speed. According to the frame sequential color imaging device 20 of the present embodiment, the same effect as that of the first embodiment can be realized at a higher reading speed.

Although the reading speed can be doubled in the second embodiment, the number of pixels may be increased instead of increasing the reading speed. For example, even if the number of pixels is doubled, an image with higher resolution may be displayed in the same frame display period as in the first embodiment.

In the second embodiment, an example of two-line read has been described. However, multi-line read such as three-line read may be performed. In addition, the first embodiment or the second embodiment
The operation pattern is not limited to the pixel block value in the above embodiment, and the operation pattern may be changed according to a still image or a moving image by dividing the pixel block into another value. As described above, also in the first and second embodiments, various applications are possible by changing the switching pattern of the switch and the number of pixels to be switched.

In the above-described embodiment, the case where plane-sequential color imaging is performed using a color transmission filter that transmits light of each wavelength of R, G, and B as three reference lights has been described. As the three reference lights, a rotary filter that transmits light in other wavelength ranges may be used.

Next, a third embodiment of the present invention will be described. FIG. 8 is a diagram illustrating a schematic configuration of a frame sequential color imaging device 40 according to the third embodiment of the present invention. The surface sequential color imaging device 40 includes an LED 4 that sequentially emits R, G, and B wavelength light of a reference color as a light source for illuminating the subject 41.
2 so that the rotary filter 4 is not required. The other configuration is the same as the configuration of the device of the first embodiment.

In the frame sequential color image pickup device 40, the light of the reference color sequentially emitted from the LED 42 is reflected by the subject 41. The R, G, and B image signals due to the reflected light are read out from the image sensor 3 in time series. The subsequent processing of the image signal is the same as the processing in the first embodiment.

According to the field sequential color image pickup device 40 of the third embodiment, in addition to the effect of the device of the first embodiment, the structure is simple because there is no need to use a rotating filter. The size of the device can be reduced.

Next, a fourth embodiment of the present invention will be described. FIG. 9 is a diagram illustrating a schematic configuration of a frame sequential color imaging device 50 according to a fourth embodiment of the present invention. The plane sequential color imaging apparatus 50 uses a white light source 52 as a light source for illuminating a subject 51, and arranges a rotary filter 4 having R, G, and B reference color transmission filters in front of the white light source 52. I do. The other configuration is the same as the configuration of the device of the first embodiment.

In the frame sequential color image pickup device 50, the light emitted from the white light source 52 is
And is radiated to the subject 51 as light of each reference color. The R, G, B image signals due to the reflected light are transmitted to the image sensor 3
Are read out in chronological order. Subsequent processing of the image signal is the same as the processing according to the first embodiment.

According to the frame sequential color image pickup apparatus 50 of the fourth embodiment, in addition to the effects of the apparatus of the first embodiment, good even when the luminance of the subject 51 is low. You can take a picture. Note that embodiments formed by partially combining the above-described embodiments and the like also belong to the present invention.

[0075]

As described above, according to the frame sequential color image pickup apparatus of the present invention, an image pickup signal of each reference color is selected from a block in synchronization with a cycle of reading out an image signal of each reference color in a time series corresponding to a moving image or a still image. By changing the pixels, it is possible to obtain a color image with few color breaks in the case of a moving image, and to obtain a high-resolution color image in the case of a still image. In addition, in the case of a moving image, it is possible to perform thinning-out reading. For each primary color signal, the number of pixels smaller than the number of pixels to be read in one field by normal interlaced scanning is reduced by one cycle for reading out the imaging signal of each reference color in time series. , A pseudo field is read out, and the thinned pixels are interpolated by a memory to create an image for one frame every one cycle. Accordingly, the speed of capturing the image signals of the three reference colors increases without increasing the reading speed of the image sensor, so that color breakup can be reduced. Further, in the case of performing double-line readout, the speed at which an image pickup signal of three reference colors can be acquired can be increased without increasing the readout speed of the image pickup device, so that color breakup can be reduced. In addition, since a moving image or a still image is automatically determined, it is possible to display a moving image or a still image in a display form suitable for each. In other words, it is possible to display an image with less color breakup at the time of a moving image, and to display a high-resolution image at the time of a still image.
In addition, full-screen display can be performed by interpolating the thinned pixels. Further, it is possible to display a more suitable color image according to the speed of the motion during the moving image.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a frame sequential color imaging apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a main part of an image sensor.

FIG. 3 is a timing chart for explaining an operation when a still image is determined.

FIG. 4 is a timing chart for explaining an operation when it is determined that the moving image is a moving image;

FIG. 5 is a timing chart for explaining an operation in the case of a moving image and a case of a further intermediate movement speed.

FIG. 6 is a schematic configuration diagram of a frame sequential color imaging apparatus according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a main part of an image sensor for performing two-line reading according to the second embodiment of FIG. 6;

FIG. 8 is a schematic configuration diagram of a frame sequential color imaging apparatus according to a third embodiment of the present invention.

FIG. 9 is a schematic configuration diagram of a frame sequential color imaging apparatus according to a fourth embodiment of the present invention.

FIG. 10 is a schematic configuration diagram of a conventional frame sequential color imaging apparatus.

FIG. 11 is a timing chart for explaining the operation of FIG. 11;

[Explanation of symbols]

 1, 20, 40, 50 plane sequential color imaging device 2 imaging lens (imaging lens) 3, 3 'imaging device 4 rotation filter 5 scanning control unit 6, 6' A / D conversion unit 7 memory control unit 8R, 8G, 8B memory 9 signal processing unit 10 motion detection unit 12, 13, 14, 15 changeover switch 17 horizontal scanning switch group

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshiyuki Noguchi 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd.

Claims (8)

[Claims] 1. A plane-sequential color imaging device for sequentially distributing light beams of three reference colors into a single image pickup device in a time-separated manner and sequentially reading image signals of each reference color in a time-series manner. Switching means for responding to a still image, an image sensor capable of dividing all pixels into predetermined blocks, and selecting a readout signal for an arbitrary pixel in the block,
A memory for synchronizing and outputting image signals of respective reference colors in a time series, wherein the image sensor selects an arbitrary pixel of the block by the switching means. 2. The plane sequential color imaging apparatus according to claim 1, wherein the imaging element performs reading by thinning out only specific pixels in the block. 3. The plane sequential color imaging apparatus according to claim 1, wherein the imaging element has a plurality of output lines for simultaneously reading a plurality of pixels, and performs a multi-line reading. 4. The frame sequential color image pickup apparatus according to claim 1, wherein the switching unit automatically determines a moving image or a still image and switches a pixel to be read out. 5. The method according to claim 1, wherein the horizontal × vertical pixels of the block are nx
The frame sequential color imaging device according to claim 1, wherein the number of pixels is m (where at least one of n and m is a natural number of 2 or more). 6. The frame sequential color imaging device according to claim 1, wherein the memory interpolates the thinned pixels according to a thinned ratio at the time of reading. 7. The field sequential color image pickup apparatus according to claim 1, wherein the image pickup element reads out a specific pixel among all the pixels in one cycle of reading out the image pickup signal of each reference color in time series. 8. The frame sequential color image processing method according to claim 1, wherein said switching means performs switching in multiple stages in accordance with a moving speed at the time of moving image, thereby selecting a pixel to be read out and interpolating in said memory. Imaging device.