JPH07154808A - Image pickup device and image adjusting device - Google Patents

Abstract

PURPOSE:To provide an exact image pickup device corresponding to a multi- scanning and an image adjusting device which is capable of performing an image adjustment with high precision. CONSTITUTION:These device are provided with a flicker detection signal generation part 1 generating a flicker detection signal, an image pickup part 6 imaging the flicker detection signal projected on the screen 5 of a projector 4, a frame memory 8 storing the image pickup signal of an image pickup part 6, a flicker area detection part 12 detecting the flicker area of the image pickup signal and a memory control signal generation part 13 generating the control signal controlling the frame memory 8. By generating a memory control signal performing the siting of the data of an area where a flicker does not exist in the flicker area that the memory control signal generation part 13 detects by the flicker area detection part 12, the flicker generated when a multi-scanned image is imaged is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device for picking up a display screen of a color television receiver and an image adjustment device for adjusting an image.

[0002]

2. Description of the Related Art Generally, in a video projector for magnifying and projecting on a screen by using three projection tubes that emit three primary colors, the incident angle (hereinafter referred to as the "concentration angle") of the projection tube with respect to the screen is different. Since the projection tubes are different, color shift, deflection distortion, and brightness change occur on the screen. In a multi-scan compatible video projector corresponding to various scanning frequencies, the above-mentioned various distortions are generally caused by a frequency characteristic of a correction system that corrects convergence and a change in scanning line density due to a change in the number of scanning lines. Because it has characteristics,
An image adjustment device compatible with multi-scan is required. As an image adjusting apparatus compatible with multi-scan, there is, for example, Japanese Patent Laid-Open No. 1-99394. Further, as an image capturing apparatus compatible with multi-scan, Japanese Patent Laid-Open No. 5-305
There is a publication No. 44.

FIG. 23 is a block diagram showing the basic structure of a conventional image adjusting apparatus described in Japanese Patent Laid-Open No. 1-99394. In FIG. 23, 101 is a color cathode ray tube to be measured,
102 is a CCD camera for picking up an image displayed on the color cathode ray tube, 103 is an image memory circuit, and 104 is a calculation of a convergence correction amount based on the image data stored in the image memory circuit 103. An arithmetic control circuit to be executed, 105 is a memory for storing the arithmetic control program of the arithmetic control circuit 104 and the arithmetic result of the arithmetic control circuit, 10
6 is a data output circuit for outputting the calculation result of the calculation control circuit 104, 107 is a waveform shaping circuit for shaping the waveform of the light receiving element output provided in the CCD camera, and 108 is a CCD image.
A di-sensor drive circuit, 109 is a color cathode ray tube drive circuit, and 110 is a pattern generator for convergence measurement.

FIG. 24 shows a detailed structure of the CCD camera 102. In FIG. 24, 111 is a taking lens, and 112
Is a CCD image sensor, 113 is a signal amplifier which amplifies the signal output from the CCD image sensor, and 114 is a light receiving element which is arranged so as to look at the area imaged by the CCD image sensor 112.

The operation of the convergence correction device constructed as above will be described below. Here, FIGS. 24 to 30 are used in the description. 25 is a block diagram of the CCD image sensor 112, FIG. 26 is a detailed block diagram of the CCD image sensor drive circuit 108, FIG. 27 is an operation waveform diagram for explaining the operation of the CCD image sensor, and FIG. 28 is an operation of the arithmetic control circuit 104. 29 is a flow chart for explaining the operation of the arithmetic control circuit 104, and FIG.
Is a pattern for measuring convergence.

First, the operation of the CCD image sensor will be briefly described. The CCD image sensor shown in FIG. 25 is a frame transfer type CCD image sensor, and in FIG. 25, reference numeral 115 denotes an image sensor.
The image sensor area, 116 is an image storage area,
117 is a horizontal shift register. As the operation of the CCD image sensor, first, the charge representing the image information stored in the image sensor area 115 is transferred to the storage area 116 by the refresh clock RF.

Next, the horizontal clock signal HCK causes an image
Drives the vertical shift register in the storage area,
The image information for one line is transferred to the horizontal shift register for each one pulse. Further, the image information stored in the horizontal shift register is read out by the CCD and the image signals are sequentially read out by the clock CCK. Each of these clocks CCK, H
CK and RF are supplied by the drive circuit of the CCD image sensor shown in FIG.

In FIG. 26, reference numeral 118 is a synchronizing signal generating circuit which generates a basic clock signal CK, a horizontal synchronizing signal HD and a vertical synchronizing signal VD. Reference numeral 119 denotes the CCD based on the basic clock CK, the horizontal synchronizing signal HD, and the vertical synchronizing signal VD.
Image sensor drive clocks CCK, HCK, RF
CCD drive signal generation circuit that creates a switch, 120 is a switch,
Reference numeral 121 is a pulse generation circuit that generates a pulse under the control of the arithmetic control circuit, and reference numeral 122 is a time counting counter.

FIGS. 27A and 27B show the timing relationship of each drive clock of the CCD image sensor generated by the drive circuit of the CCD image sensor shown in FIG.

Next, the operation of this convergence correction device will be described. First, a method of measuring the light emission period of the cathode ray tube to be measured will be described. In FIG. 23, a light receiving element 114 provided in the CCD camera 102 monitors the light emitting state of the image pickup area of the CCD image sensor 112 on the cathode ray tube. Therefore, for example, the NTSC system color
When the measurement pattern is displayed by the television circuit, the light receiving element 114 outputs a pulse having a cycle of 60 Hz. This operation waveform diagram is shown in FIG. FIG. 27 shows a waveform-shaped output (114) of the light receiving element.
It is (117) of (C).

In FIG. 26, the counter 122 measures the basic clock signal CK after being reset by the falling pulse of the vertical synchronizing signal VD. The coefficient output of the counter 122 is shown at (122) in FIG. As shown in this figure, the counter 122 has a cycle T of the vertical synchronizing signal VD.
Counting is repeated at D. The arithmetic control circuit 104 is shown in FIG.
As shown in (C), for example, the count value T1 of the counter 122 at that time is read by the rising pulse of the output signal of the waveform shaping circuit 107 and stored in the memory. Next, at the next rising pulse of the output signal of the waveform shaping circuit 107, the count value T2 of the counter 122 at that time is read and stored in the memory. Further, the arithmetic control circuit 104 uses the coefficient value T
The emission period TCRT of the cathode ray tube is calculated by obtaining the difference between 2 and T1.

Next, the determination of the timing of reading the image signal detected by the CCD image sensor to the image memory circuit will be described. Now, consider a case where the drive circuit of the cathode ray tube to be measured and the drive circuit of the CCD are not synchronized, for example, the emission period of the phosphor on the cathode ray tube to be measured is shorter than the drive period of the CCD drive circuit. The operation in this case will be described with reference to FIG. In FIG. 29, the period of the vertical synchronizing signal VD is TD, the pulse width of the vertical synchronizing signal VD is TVD, and the emission time width of the cathode ray tube is TW, and TS = TD-TCRT-TW, TR = TD-TCRT, TQ = TD- Set it as TCRT + TVD.

In the CCD image sensor drive circuit 108, the switch circuit 120 is connected to the terminal Sa side at the time of image pickup, and the vertical synchronizing signal VD output from the synchronizing signal generating circuit 118 is horizontal to the CCD driving signal generating circuit 119. While being input to the clock HCK generation circuit 119b,
It is input to the refresh clock RF generation circuit 119c. When reading an image signal from the CCD image sensor 112 to the image memory 103, first, the switch 120 of the CCD image sensor drive circuit is switched to the terminal Sb side,
The generation of the refresh clock signal RF in the CCD drive signal generation circuit 119 is moved under the control of the arithmetic control circuit 104.

The processing in the arithmetic control circuit 104 will be described below with reference to the flowchart of FIG. C mentioned above
Switch 1 in CD image sensor drive circuit 108
After switching 20 (step P1), the counter 122
Wait for the count value of Ts to reach Ts (step P2). When the cathode ray tube starts to emit light while the count value of the counter is from Ts to TR. This is the count value TR of the counter to TQ
Since the light will be emitted during the period up to, the image is not read during this period. Therefore, the output of the waveform shaping circuit 107 which receives the output of the light receiving element 114 is monitored during the count value TS to TR of the counter (step P3), and when the cathode ray tube starts emitting light, the process returns to step P2. If the CRT does not emit light between the counter count values Ts and TR, a pulse is generated in the pulse generation circuit 119c at the count value TR, and the CCD
A refresh pulse is generated (step P4, step P5).

The refresh pulse RF is shorter than the vertical synchronizing signal VD. After the refresh pulse RF is generated, the output of the waveform shaping circuit 107 is monitored even in the period until the count value of the counter reaches TQ (step P
6) If the CRT emits light during this period, the process returns to step P2. If the CRT does not emit light, the switch circuit 120 is switched at the count value TQ of the counter, and the vertical synchronizing signal VD output from the synchronizing signal generating circuit 118 is supplied to the circuit 119c of the CCD drive generating circuit 119.
(Step P7, step P8).

When the next vertical synchronizing signal VD is generated, the CCD image is displayed during the period from the count value TQ to TD of the counter.
The image signal integrated on the di-sensor area 115 is the CCD
The image signal is transferred to the storage area 116 and the image signal is read out. The period from the count value TR to TD of the counter is the light emission period TCRT of the cathode ray tube, and the period from the count value TR to TQ is not emitting light from the cathode ray tube.
It always emits light once during the period TQ to TD. This period (T
Light emitted from the cathode ray tube to Q to TD) is incident on the CCD image sensor area 115 and integrated, and the arithmetic control circuit 104 controls the period from the rising edge to the falling edge of the pulse of the vertical synchronizing signal VD. Since the CCD output signal is stored in the image memory 103, accurate image output can be surely obtained.

Next, the measurement of the amount of convergence will be described. First, for example, a white dot pattern as shown in FIG. 30 is generated from the measurement pattern generator 110, and this pattern 130 is displayed on the color CRT to be measured. A predetermined area of this pattern, for example, 130a is imaged by the CCD camera 102. The image signal uses the predetermined algorithm under the control of the arithmetic control circuit 104, and the image memories 103a, 103b, 103
Store in c. Further, the arithmetic control circuit 104 detects the barycentric position of each of the green, red, and blue phosphor patterns of the measurement pattern from the data of these image memories, and the green pattern is detected.
Distances (Rx, Ry), (B) between the positions of the center of gravity R0 and B0 of the red and blue patterns with respect to the center of gravity G0 of the center
x, By) are respectively obtained and output to the data output circuit 106 as the amount of misconvergence, and the convergence is corrected by using this amount of misconvergence.

With the configuration as described above, the drive circuit of the display device to be measured and the CCD of the image pickup device
Even if the camera drive circuit is asynchronous, a stable image signal can be obtained, and an accurate converter that supports multi-scan
Jens correction can be performed.

FIG. 31 is a block diagram showing the basic structure of a conventional image photographing apparatus disclosed in Japanese Patent Laid-Open No. 30544/1993. In FIG. 31, 301 is a display for displaying an image to be captured, 302 is a video camera for capturing the display 301, 303 is a measuring device for processing an image captured by the video camera 302, 304 is the display 301 and the video camera 302. The display 301 outputs the video signal output from the video signal generation circuit 312 to the CRT 313 for display. The video signal generation circuit 312 is
A video signal can be generated in accordance with the sync signal input from the external sync signal input terminal 311. The video camera 302 captures the image displayed on the display 301 by the CCD imager 322 in synchronization with the synchronizing signal input from the external synchronizing signal input terminal 321, and outputs the output to the measuring device 303. ing.

The measuring device 303 is composed of a memory 331 for storing the image data input from the video camera 302 and an arithmetic unit 332 for arithmetically processing the data stored in the memory 331. The controller 304 includes a sync generation circuit 340 that generates a sync signal to be supplied to the video camera 302, an address counter 341 that counts a horizontal sync signal output from the sync generation circuit 340, and data corresponding to an address input from the address counter 341. A predetermined count value is set in the memory (RAM) 342 which outputs
CPU 343 for storing predetermined data in memory 342
And a sync generation circuit 3 for generating a composite sync signal (composite blanking signal) supplied to the display 301.
It is composed of 44. Next, the operation will be described with reference to the timing chart of FIG.

The horizontal and vertical blanking pulses output from the synchronizing signal generation circuit 344 are displayed on the display 301.
Is input to the video signal generating circuit 312. The video signal generation circuit 312 generates a predetermined video signal in synchronization with the horizontal and vertical blanking pulses and outputs it to the CRT 313. As a result, a predetermined image is displayed on the CRT 313. On the other hand, the horizontal and vertical sync signals output from the sync signal generation circuit 340 are supplied to the video camera 302, and the video camera 302 shoots the image displayed on the CRT 313 in synchronization with the sync signal. The image captured by the video camera 302 is supplied to the measuring device 301 and stored in the memory 331 thereof. The arithmetic unit 332 processes the data stored in the memory 331 and measures the characteristics of the CRT 313.

The CPU 43 stores in the memory 342 the data corresponding to the difference between the vertical scanning frequency supplied by the synchronization generating circuit 340 to the video camera 302 and the vertical scanning frequency supplied by the synchronization generating circuit 344 to the display 301. . That is, as shown in FIG. 32C, the memory 342 has a vertical scanning period (see FIG. 32) of the video camera 302.
(a)) and the vertical scanning cycle of the display 301 (see FIG. 32).
(b)) period corresponding to the difference, logical L, other period,
Data that is a logical H is stored. The address counter 341 counts the horizontal sync signal input from the sync generation circuit 340 and outputs an address corresponding to the count value to the memory 342. The count value of the address counter 341 is reset each time the vertical synchronizing signal is input from the synchronization generating circuit 340.

As a result, as shown in FIG. 32C, the memory 342 displays the display 301 and the video camera 302 immediately after the start of the vertical scanning cycle of the video camera 302.
During the period corresponding to the difference in the vertical scanning period of, a signal of logic L is output. The signal output from the memory 342 is supplied to the video camera 302. In the video camera 302, the charge of the CCD imager 322 is rapidly discharged while the signal supplied from the memory 342 is logic L. As a result, the data imaged by the CCD imager 322 is as shown in FIG.

That is, for example, in the first field of the video camera 302, when the charge discharge signal returns to logic H, the image of the A field on the display 301 is captured by the CCD imager 322. When the display of the image of the B field is started after the display of the image of the A field of the display 301 is finished, the image is captured by the CCD imager 322. As a result, in the first field section of the video camera 302. Data in a state where the image of the B field is displayed above the display 301 and the image of the A field is displayed below the display 301 is output from the video camera 302 as the data of the first field. Second of the video camera 302
When the field is started, the charge of the CCD imager 322 is discarded again while the signal supplied from the memory 342 is logic L.

Then, after the signal supplied from the memory 342 is returned to logic H, the image of the B field of the display 301 is captured, and when the display of the B field is completed, the image of the subsequent C field is captured. become. As a result, the image of the second field of the video camera 302 is the image of the C field displayed in the information of the display 301, and the image of the B field displayed below. Further, in the third field of the video camera 302, the image of the D field of the display 301 is captured. In this case, since the vertical synchronizing signals of the display 301 and the video camera 302 are generated at the same time, the image of the third field of the video camera 302 is only the image of the D field of the display 301. Thereafter, the image on the display 301 is captured by the video camera 302 in the same manner.

The data picked up by the CCD imager 322 is read at a normal speed and becomes as shown in FIG. That is, the luminance is constant in each of the first field to the fifth field. As a result, it is possible to prevent the measurement device 303 from erroneously measuring the luminance, for example.

As described above, the image data captured by the video camera is rapidly discarded during the period corresponding to the difference in vertical scanning frequency between the display and the video camera. Therefore, the output of the video camera is used to display the characteristics of the display. Can be measured correctly.

[0028]

[Patent Document 1] Japanese Unexamined Patent Application Publication No.
In the conventional configuration as disclosed in Japanese Patent Publication No. 99394, the light emitting element monitors the light emitting period of the phosphor at a certain point of the display device, and the image signal transfer period of the CCD image sensor is controlled by the period. , For example, when it is necessary to monitor the entire screen such as deflection distortion or geometric distortion of an image due to projection distortion in a video projector,
Since the timing of the light emission cycle is different over the entire screen, the light emission timing over the entire screen cannot be uniquely determined, so that there is a problem in that accurate convergence correction cannot be performed.

Further, in the structure as disclosed in Japanese Patent Laid-Open No. 30544/1993, the control data corresponding to the period corresponding to the difference in vertical scanning frequency between the display and the video camera is stored in the memory, and the video is output by the memory. Since we are trying to quickly discard the image data taken by the camera,
The image display area of the display and the image pickup area of the video camera must be equal, and the positional relationship between the image pickup device and the display device needs to be strictly adjusted during adjustment, resulting in an increase in adjustment time. Further, since it is necessary to hold control data corresponding to each frequency of the image signal, it is difficult to support any frequency.

In view of the above points, the present invention does not require strict position adjustment of the image pickup device with respect to the display device, and is compatible with a multi-scan image display device for displaying an image of an arbitrary frequency and enables accurate image pickup. An object is to provide an image pickup device. Another object of the present invention is to provide an image adjustment device capable of removing flicker that occurs when an image is displayed on a multi-scan image display device and performing highly accurate adjustment of geometric distortion, convergence, white balance, and the like. And

[0031]

According to a first aspect of the present invention, there is provided a flicker detection signal generating means for generating a flicker detection signal, and an image pickup means for picking up an image of the flicker detection signal displayed on a display screen of an image display device. Memory means for storing the image pickup signal picked up by the image pickup means, flicker area detection means for detecting a flicker area from the image pickup signal of the image pickup means, and control for controlling the memory means from the output of the flicker area detection means The memory control signal generating means for generating a signal is provided, and the memory control signal generating means generates a memory control signal for writing data in a flicker-free area to the flicker area detected by the flicker area detecting means.

A second aspect of the invention is an image adjusting signal generating means for generating an adjusting signal for adjusting geometric distortion, convergence, white balance, etc., and the above-mentioned image projected on the display screen of the image display device. Imaging means for imaging the adjustment signal,
Memory means for storing an image pickup signal picked up by the image pickup means, flicker area detection means for detecting a flicker area of the adjustment signal from the adjustment signal picked up by the image pickup means, and flicker area detection means A memory control signal generating means for generating a control signal for controlling the memory means from the output of, a position / level calculating means for calculating the position and level of the adjusting signal from the data stored in the memory means, and the position / level calculating means. Error calculation means for calculating geometric distortion, convergence error, and white balance error based on the output of the level calculation means, and correction signals for geometric distortion, convergence, and white balance from the output of the error calculation means. A correction signal generating unit that generates the correction signal and a control unit that controls the image display device based on the correction signal output from the correction signal generating unit. For example, a configuration for generating a memory control signal for data writing of the memory control signal generating means is not present in the flicker flicker area detected by the flicker region detection unit area.

A third invention is to generate an adjustment signal for adjusting geometric distortion, convergence, white balance and the like, and image adjustment signal generating means, and the adjustment displayed on the display screen of the image display device. Detecting means for detecting the image light of the adjustment signal, frequency detecting means for detecting the frequency of the adjusting signal, scan converting means for performing scan conversion of the detection signal of the detecting means from the output of the frequency detecting means, and Position / level calculating means for calculating the position / level of the adjustment signal from the detection signal scan-converted by the scan converting means, and geometric distortion and convergence error based on the output of the position / level calculating means. Error calculating means for calculating a white balance error, and correction signal generating means for generating correction signals for geometric distortion, convergence and white balance from the output of the error calculating means. Wherein a configuration in which a control means for controlling the image display device from the correction signal output by the correction signal generation means.

[0034]

According to the first aspect of the present invention, the flicker detection signal is imaged, and the flicker of the imaging signal is detected and removed based on the flicker detection signal, so that the strict position adjustment of the imaging device with respect to the display device can be performed. It is possible to perform accurate imaging without the need for a multi-scan image display device that displays an image of an arbitrary frequency.

According to the second aspect of the invention, flicker that occurs when a multi-scan image display device is imaged is eliminated,
Image adjustments such as highly accurate geometric distortion, convergence, and white balance can be performed.

According to the third aspect of the invention, by thinning out the scanning lines of the multi-scan image pick-up signal to a number corresponding to the number of lines of the frame memory, in the multi-scan compatible image adjusting apparatus, the frame memory for storing the image pick-up signal is stored. Since the memory capacity and timing signal can be fixed,
The circuit scale and cost are prevented from increasing, and the arithmetic processing in the subsequent stage of the frame memory is simplified.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the basic configuration of the first embodiment of the present invention.

In FIG. 1, 1 is a flicker detection signal generating section for generating a flicker detection signal, 2 is a switch for switching between the flicker signal and the video signal, 3 is a frequency detecting section for detecting the frequency of the video signal, and 6 is a An image pickup section for picking up an image displayed on the screen 5 by the projector 4, 7 is an A / D converter for converting the image pickup signal output from the image pickup section 6 into digital data, and 8 is an A / D converter 7. A frame memory that stores the image pickup signal converted into digital data, 9 is a calculation / measurement unit that measures the image displayed on the screen 5 from the image pickup data of the frame memory 8, and 10 is a flicker detection signal extracted from the image pickup signal. A flicker signal extraction unit, 11 a difference circuit for obtaining the difference between the flicker signals extracted by the flicker signal extraction unit 10,
Reference numeral 2 denotes a flicker area detection unit that detects the flicker area of the image pickup signal from the difference value of the flicker signal obtained by the difference circuit 11 and the output of the frequency detection unit 3. Reference numeral 13 denotes the output of the flicker area detection unit 12 to the frame memory 8. Memory control signal generator that generates various timing signals for control, 1
Reference numeral 4 is a synchronization processing / clock that creates each timing signal such as a horizontal synchronization signal (HD), a vertical synchronization signal (VD), and a clock (CLK) from the image pickup signal and supplies the timing signals to the A / D converter 7 and the memory control unit 13. It is a generating part.

The first embodiment of the present invention configured as above will be described below. First, the image pickup unit 6 will be described in detail. In this embodiment, a CCD will be used as the image pickup unit for explanation. Here, there are three reasons for performing detection by the CCD.

First, it is most suitable for practical use in terms of cost and ease of handling. Secondly, when the information of the entire screen is taken in and the geometrical distortion is corrected, the distortion of the detection system, which is the image sensor, cannot be ignored, so the element must have less than 1% of distortion. Thirdly, since the monitoring distance of the focal length can be dealt with by changing the optical lens, it is possible to deal with various display devices. The CCD is used for the above reasons.

Here, the structure of the image pickup section 6 will be described with reference to FIGS.
Will be described in detail. FIG. 2 is a block diagram showing a detailed configuration of the image pickup unit 6. In FIG. 2, 200 is CC
D image sensor, 210 is a sync signal generator for generating a horizontal sync signal (HD) and a vertical sync signal (VD), 220
Is a CCD drive unit that generates each pulse for driving the CCD image sensor from each synchronization signal generated by the synchronization signal generation unit, and 230 is a signal processing unit that adjusts the gain of the output signal of the CD image sensor and superimposes the synchronization signal.

In this embodiment, the CCD image sensor 200 of the image pickup unit 6 is the most common interline transfer C.
Although the following description will be made using a CD, this embodiment is also effective in other field transfer systems, for example. FIG. 3 shows a detailed configuration diagram of the interline transfer type CCD image sensor. In FIG. 3, 30 is an output terminal for an image signal picked up by a CCD, 31 is a photosensitive section for picking up an image signal projected on the screen 5 and performing photoelectric conversion, and 32 is an image signal charge accumulated in the photosensitive section. Are sequentially transferred in the vertical direction, 33 is a horizontal transfer unit for sequentially transferring the image signal charges transferred by the vertical transfer unit 32 to the output terminals, 3
Reference numeral 4 denotes an input terminal of the vertical transfer clocks φV1 to φV4 for transferring the image signal charge from the photosensitive section 31 to the vertical transfer section 32 and vertical transfer at the vertical transfer section 32. Reference numeral 35 denotes a horizontal transfer of the image signal charge at the horizontal transfer section 33. Input terminals for horizontal transfer clocks φH1 and φH2 for transfer. This CCD image
The operation of the disensor will be described below.

The following operation is for interlacing. The transfer operation of the CCD image sensor includes three basic operations of field shift, vertical transfer and horizontal transfer.
The field shift is an operation of transferring the image signal charges from the photosensitive section 31 to the vertical transfer section 32. When described with reference to FIG. 3, the odd-numbered pixels I11, I12, I in the vertical direction are described.
The signal charges photoelectrically converted by 31 and I32 are collectively transferred to V11V21, V12V22, V51V61 and V52V62 of the vertical transfer unit 32, respectively. In the vertical transfer, the vertical transfer units 32 are simultaneously operated by the vertical transfer clock to transfer the image signal charges of one line. That is, the signal charges accumulated in V11V21 and V12V22 are transferred to H1 and H3 of the horizontal transfer unit 33, respectively, and at the same time, the signal charges accumulated in V51V61 and V52V62 are passed through V41V31 and V42V32 respectively to V11V21 and V12.
Transfer to V22.

The horizontal transfer is an operation in which the horizontal transfer units 33 are simultaneously operated by a horizontal transfer clock to transfer the image signal charges sequentially to the output terminals, and the horizontal transfer unit 33 outputs the image signal charges accumulated in H1 to the output terminals. The image signal charges transferred to H30 are transferred to H1 via H2. At this point, the image signal charge accumulated in the cell I11 of the photosensitive portion 32 is obtained at the output terminal.

Subsequently, the horizontal transfer section 33 is operated to transfer the signal charge accumulated in H1 to the output terminal 30. At this time, the image signal charge accumulated in the cell I12 of the photosensitive section 32 is obtained at the output terminal 30. The above is the basic transfer operation of the image signal charges in the CCD. This scanning is sequentially repeated to read out the image signal charges accumulated in the photosensitive portion 31 to the output terminal 30, and the image signal picked up at the output terminal 30 is captured. Is obtained.

Here, various multi-scan images having different horizontal and vertical scanning frequencies displayed on the screen 5 of the projector 4 are picked up by a CCD camera such as the image pick-up unit 6 to obtain geometric distortion / convergence / white. Consider the case of adjusting balance. C on the screen where the frequency changes
When an image is picked up by a CD camera, flicker occurs in the picked-up image signal due to the difference between the scanning frequency of the display device and the scanning frequency of the CCD camera, which reduces the adjustment accuracy.

The flicker generating mechanism will be described below with reference to FIGS. 4 and 5. FIG. 4 is a characteristic diagram of the output signal of the CCD according to the relationship between the field period of the CCD and the field period of the image signal displayed on the screen 5 of the projector 4 when the image display area of the image display device and the image pickup area of the CCD are the same. FIG. 5 is a characteristic diagram of the output signal of the CCD according to the relationship between the field period of the CCD and the field period of the image signal displayed on the screen 5 when the image display area of the image display device and the image pickup area of the CCD are different.

The flicker of the CCD output signal caused by the difference between the image signal and the field period of the CCD has different characteristics depending on whether the field period of the image signal is longer or shorter than the field period of the CCD. This will be described first. Consider a case where the field period of the image signal is shorter than the field period of the CCD as shown in FIG. As shown in FIG. 4C, the field period of the image signal is 3 / for the CCD field period (FIG. 4B).
4, the projector 4 has finished scanning the first field of the image signal and the second field of 1
At the stage of scanning / 3 (area A in FIG. 4C), the signal charges of the first field of the CCD accumulated up to that point are transferred. That is, when the image display area of the projector 4 and the image pickup area of the CCD of the image pickup unit 6 are the same as shown in FIG. 4A, the first field of the image pickup signal of the CCD is
As shown in (d), the first field of the image signal is double-exposed to a 1/3 area of the second field (area A in FIG. 4C).

In the second field of the output signal of the CCD, the first ⅓ area of the third field of the image signal and the remaining ⅔ area of the second field are mixed, and the third field of the third field is further mixed. The subsequent 1/3 area (area B in FIG. 4C) is double exposed. Similarly, the double-exposed portion sequentially moves as indicated by C and D in FIG. 4D, which causes flicker. Next, as shown in FIG. 4 (e), CC
Consider a case where the field period of the image signal is longer than the D field period. As shown in FIG. 4D, since the field period of the image signal is 3/2 as long as the field period of the CCD (FIG. 4B), the image signal is 2/3 of the first field. Since the signal charge of the first field of the CCD is transferred at the stage when the scanning of the
The output signal of D is the remaining 1/3 of the first field of the image signal.
The signal in the area (area E in FIG. 4E) is missing (area E in FIG. 4F).

In the second field of the image pickup signal of the CCD, the first ⅓ area of the second field of the image signal first exists, and then the signal missing area (F area in FIG. 4E),
The remaining 1/3 area is the remaining 1 of the first field of the image signal.
The area becomes / 3. Similarly, the signal-missing portion sequentially moves as indicated by E and F in FIG. 4 (f), which causes flicker.

As described above, the frequency of the image signal and C
Due to the difference in the frequency of the CD camera, double exposure to the imaging signal,
Flicker occurs due to signal loss, and this flicker becomes an adjustment error in each adjustment such as geometric distortion / convergence and white balance.

Next, as shown in FIG.
Consider a case in which the image display area of 1 is different from the image pickup area of the CCD. In this case, the image signal displayed on the screen 5 and C
The flicker characteristics due to the difference in the field period of the CD are the same as those described with reference to FIG. 4, but the period in which the flicker component appears is 1/3 of the area corresponding to the image signal in the CCD field (see FIG. It becomes area A of d). As described above, the period of the flicker component appearing in the field of the CCD differs depending on the relationship between the image display area of the projector 4 and the imaging area of the CCD.

In general, a CCD camera has a CCD image sensor 200, a CCD drive unit 220 and the like as a unit, and the speed of a CCD drive clock is fixed. Therefore, it is difficult to make the CCD camera compatible with multi-scan according to the frequency of the image signal displayed on the display device in terms of circuit scale and performance. CCD
When the camera is compatible with multi-scan, an image pickup signal processing system that eliminates flicker is required. When this flicker component is removed, the flicker component appearing in the output signal of the CCD has various factors such as the difference between the image signal and the field period of the CCD and the relationship between the image display device and the image pickup area of the image pickup device, as described above. Because the characteristics vary depending on
The system configuration that detects and removes the flicker component from the actually picked-up signal is the most desirable.

The operation of removing the flicker will be described in detail below with reference to FIGS. 6, 7 and 8. FIG. 6 is a flowchart showing the procedure for removing the flicker component, and FIG. 7 is an operation waveform diagram for explaining the flicker component removing operation of the image pickup signal. FIG. 8 is a conceptual diagram illustrating the write operation of the frame memory. FIG. 7A shows the flicker detection signal and the adjustment signal displayed on the screen 5. This screen 5
The image above is picked up by the image pickup unit 6, and the flicker detection signal extraction unit 13 extracts the flicker detection signal from the image pickup signal (F101). Here, the data image of the image pickup signal on the frame memory is as shown in FIG.

In FIG. 7B, the line (ROW) address of the frame memory is the image on the screen 9 (FIG. 7A).
Corresponds to the vertical scanning line direction. When there is no flicker in the image pickup signal, the data extracted from the flicker detection signal by the flicker detection signal extraction unit 13 becomes constant in the vertical direction as shown in FIG. 7C. The data of the flicker detection signal imaged here is sampled by the CCD in the vertical scanning line direction of the image signal, and each point of the data corresponds to the scanning line of the image signal. Here, for simplification of the description, the discussion is made assuming that the luminance distribution in the vertical scanning line direction of the display device is uniform, but the following discussion will be influenced by the influence of the lenses of the display device and the imaging device, for example. It is effective even when it is a quadratic function.

When a flicker is present in the image pickup signal, the picked-up flicker detection signal is 2 as shown in FIG. 7D when the field period of the image signal is longer than the field period of the CCD as described above. When double exposure occurs and the field period of the image signal is shorter than the field period of the CCD, signal loss occurs as shown in FIG. 7 (f). Next, the difference value of the flicker detection signals extracted as shown in FIGS. 7D and 7F is obtained by the difference circuit 14 (F102). When the difference value of the flicker detection signal is calculated by the difference circuit 14, FIG.
It becomes like (e) and (g).

Next, the flicker area detection unit detects the area in which flicker occurs from this difference value (F10
3). The flicker area detection unit 15 compares the field period of the CCD with the field period of the image signal output from the frequency detection unit 5. For example, as shown in FIG. 7E, the field period of the image signal is the field period of the CCD. Longer than, the difference value of the flicker detection signal is the threshold value T ₊
From the sample point a next to the point that exceeds
_The point b beyond-is calculated as the flicker area, and the line (ROW) of the frame memory corresponding to the flicker area is calculated.
Holds the address.

Here, the threshold is set to distinguish the difference value due to noise from the difference value due to data transition, and to prevent malfunction due to noise, and the other one is to rapidly shift the image pickup signal due to the flicker component. This is for distinguishing from a gradual signal displacement when a quadratic luminance distribution characteristic occurs in the image pickup signal due to the influence of the projection lens of the projector 4 or the lens of the image pickup apparatus as described above. . Contrary to the case of FIG. 7B, when the field period of the image signal is shorter than the field period of the CCD, the point d that exceeds the threshold T ₊ from the sample point c next to the point where the difference value exceeds the threshold T _−. The areas up to are calculated as flicker areas, and the line (ROW) address of the frame memory corresponding to the flicker areas is held.

Next, the memory control signal generator 16
As shown in FIG. 8A, the flicker area of the memory image in which flicker exists is set as the overwritable area (F105), and only this area is overwritten with the data of the next frame (F106). Further, the above steps F101 to F103 are repeated, and in F104, if the flicker area held in the previous frame and the flicker area of the current frame do not overlap with each other as shown in FIGS. Finish writing. At this point, in the frame memory, the flicker area of the previous frame is overwritten with the valid data of the current frame as shown in FIG.

If the flicker area of the previous frame and the flicker area of the current frame overlap here, the above-described steps F105, F106, F101 to F103 are repeated to remove the flicker-free data image. Can be obtained. Thereafter, the arithmetic / measurement unit 9 measures the image displayed on the screen 5 from the data image from which the flicker has been removed.

As described above, according to the first embodiment of the present invention, the flicker detection signal is picked up, and the flicker of the picked-up image signal is detected and removed based on the flicker detection signal. It is possible to perform accurate image pickup in correspondence with a multi-scan image display device in which an image of an arbitrary frequency is displayed without requiring strict position adjustment of the image pickup device.

FIG. 9 is a block diagram showing the basic configuration of the second embodiment of the present invention. In FIG. 9, 401 is a flicker detection signal generator 402 and image adjustment signal generator 40.
3, and an adjustment signal generation unit 405 including a superposition unit 404 that superimposes the flicker detection signal on the image adjustment signal, and 405 performs switching between the image adjustment signal on which the flicker detection signal is superimposed and the video signal. A switch, 406 is a frequency detection unit that detects the frequency of the video signal, 407 is a drive circuit that drives the CRT (cathode ray tube) 408 of the projector 425, 409 is a projection lens that projects the image displayed on the CRT 408 onto the screen 410, Reference numeral 411 denotes an imaging unit that captures an image displayed on the screen 410, 41
Reference numeral 2 is an A / D converter for converting the image pickup signal output from the image pickup unit 411 into digital data, and 413 is an A / D converter 41.
2 is a frame memory that stores the image pickup signal converted into digital data by 2; a flicker signal extraction unit that extracts a flicker detection signal from the image pickup signal; a difference that obtains a difference between the flicker signals extracted by the flicker signal extraction unit 414; A circuit 416 detects a flicker region of the image pickup signal from the difference value of the flicker signal obtained by the difference circuit 415 and the output of the frequency detection unit 406. A flicker region detection unit 417 outputs the output of the flicker region detection unit to the frame memory 413. A memory control signal generation unit 418 that generates various timing signals for controlling the A, creates each timing signal such as a horizontal synchronization signal (HD), a vertical synchronization signal (VD), and a clock (CLK) from the image pickup signal. Synchronous processing supplied to the D converter 412 and the memory control unit 417 /
A clock generation unit 419 is a position / level calculation unit that calculates the position and level of the adjustment signal from the image signal from which flicker has been removed, and 420 is geometric distortion and convergence from the output of the position / level calculation unit 419. An error calculation unit that calculates an error, a white balance error, and the like; 421 is a correction signal generation unit that generates each correction signal such as geometric distortion, convergence, and white balance from the output of the error calculation unit 420;
Reference numeral 422 denotes the output of the correction signal generator 421 from the drive circuit 40.
7 and CRT 408 deflection section 423 and auxiliary deflection section 424
This is a control unit that controls the (convergence yoke).

A second embodiment of the present invention constructed as shown in FIG. 9 will be described. In the second embodiment of the present invention, the image pickup unit 411, the A / D converter 412, the frame memory 41.
3, a flicker detection signal extraction unit 414, a difference circuit 415,
Flicker area detector 416, memory control signal generator 41
7. The operation of flicker removal of the image pickup signal by the synchronization processing / clock generation unit 418 is the same as the operation of flicker removal described in the first embodiment of the present invention, and therefore its description is omitted.
In order to make the description easier to understand, the present embodiment describes a case where the flicker detection signal and the image adjustment signal are separated.

The method of adjusting geometric distortion, convergence, white balance, etc., using the adjustment signal generated by the adjustment signal generator 401 will be described below. Geometric distortion,
The information necessary for the convergence adjustment is position information of the adjustment signal, and the level information of the adjustment signal is necessary for the white balance adjustment.

First, the geometric distortion and convergence adjustment will be described. FIG. 10 shows image adjustment signals for geometric distortion and convergence adjustment. As shown in FIGS. 10 (a) and 10 (b), the geometrical distortion and convergence adjustment signals have a quadrangular pyramid shape when the display screen is the bottom surface and the signal level direction is the height direction. In order for the image adjustment signal displayed on the screen to be linear in the level direction in this way, gamma correction in the display device is required. The image adjustment signal considering the gamma correction will be described below.

Generally, the relationship between the input signal voltage (E) of the CRT and the light emission output (L) can be approximated by the following formula L = k · E ^r . The index γ of the input voltage (E) in this equation represents the gamma characteristic of the CRT, and this value is generally γ = 2.2.
Becomes Since this gamma characteristic is an amount that is uniquely determined for the CRT, if the image adjustment signal generator 403 converts the adjustment signal voltage (E) to E ^−r using, for example, a ROM, the light emission output ( L) becomes L = k · E and becomes linear with respect to the input. In the following description of geometric distortion / convergence correction using a quadrangular pyramid-shaped image adjustment signal,
The description will proceed assuming that the gamma characteristic has been corrected.

The outline of geometric distortion and convergence adjustment using the image adjustment signal shown in FIG. 10 will be described. First,
Image adjustment signals for R (red), G (green), and B (blue) are generated, and the position / level calculator 419 generates image adjustment signals for each color from the data on the frame memory from which flicker has been removed. The position of the center of gravity is calculated as position information. Next, the deflection unit 423 and the auxiliary deflection unit 42 of the projector 425 are adjusted so that these positions become equal to the reference position at the time of adjustment.
4 is controlled. The reference position at the time of adjustment is, for example, a square lattice point corresponding to the adjustment signals shown in a to i of FIG. 10B when the geometric distortion is adjusted, or, for example, G when the convergence is adjusted. It is the position of the adjustment signal. The position calculation as described above is performed for each area divided into a plurality of correction areas corresponding to each of the adjustment signals as shown in FIG. Although the following description of the arithmetic processing is performed only for one area, the same arithmetic processing is performed for other areas.

Next, the position calculation operation of the position / level calculator 419 will be described in detail. For the explanation, see FIG.
The operation waveform diagrams of FIGS. 12 and 13 are used. The solid line in FIG. 11A is the adjustment signal output by the adjustment signal generator. The broken line is, for example, a general black and white CC of about 380,000 pixels.
Sampling frequency 1 which is D and NTSC rate
The imaging signal when processed by the system of about 4.32 MHz is shown. As can be seen from the characteristic of the broken line in FIG. 11A, the detection accuracy of the imaging system is low, so that the apex portion of the adjustment signal is rounded, and such a CC
When the peak position as position information of the adjustment signal is to be obtained from the output signal of D, the actual peak position is point A, but point A ′ is erroneously the peak position of the adjustment signal. I will judge. In order to eliminate the influence of an error caused by the low detection accuracy of such an imaging system, in the present invention, the position information is the barycentric position of the adjustment signal, and the barycentric position is the linear part excluding the rounded part. Calculated as the intersection of the extended parts.

As the first step of the arithmetic processing, an operation for detecting only the linear portion of the adjustment signal data is performed except for the rounding area by sampling. This is performed by detecting the differential signal of the image data of the adjustment signal. Figure 11
The difference signal of the adjustment signal indicated by the broken line in (a) is as shown in FIG. 11 (b). The periods A and B in which the inclination of the adjustment signal is constant are detected from this difference signal. Here, the period when the slope is 0 is ignored. Hereinafter, only the image data within the periods A and B are valid and the position of the center of gravity is calculated. Here, the position of the center of gravity is calculated by extending the linear periods A and B on the data and using the adjustment signal at this intersection as the center of gravity. Figure 11
As shown in (b), the calculation of the position of the center of gravity is performed by the data DA (corresponding address nA) from the highest vertex of the linear portion A, the inclination of the linear portion A is α, and the data D from the highest vertex of the linear portion B.
If B (corresponding address nB) and the slope of the linear portion B are β, the center of gravity position x can be determined by the following equation.

X = nA + (DB−DA−β · (nB−nA)) / (α−β) In this way, by determining the barycentric position by linear approximation, for example, even when the CCD camera has a rough sampling, The center of gravity position can be detected with high accuracy. As described above, the barycentric position is calculated in the horizontal scanning line direction as shown in FIG. 12, and the barycentric position is calculated in the vertical direction from the obtained barycentric point. Determine the center of gravity of the signal.

In order to improve the detection accuracy of the barycentric position detection, it is necessary that many linear regions exist in the signal component. This will be described with reference to FIG. FIG.
FIG. 13A shows a quadratic function adjustment signal like a conventional SIN ² waveform, and FIG. 13B shows a scanning line sectional view of the quadrangular pyramid adjustment signal of the present invention. As can be seen from this figure, since the conventional adjustment signal has a secondary waveform,
Since the quantization error differs depending on the signal level, the optimum quantization cannot be performed and the detection accuracy will be reduced. On the other hand, in the quadrangular pyramid adjustment signal of the present invention, since the signal characteristic is linear, it is possible to perform highly accurate calculation by selecting the optimum number of quantization bits.

After calculating the position of the adjustment signal as described above,
The error detector 420 calculates an error with respect to the adjustment reference coordinates. As described above, the adjustment reference coordinate is the position of the G adjustment signal in the case of the convergence adjustment, and the geometrical distortion adjustment is performed by, for example, a to a in FIG. 10B.
It is a square lattice point indicated by i. Further, based on the obtained error information, a correction signal for geometric distortion and convergence is generated by a correction signal generation unit 421, and the control unit 422 makes the error with respect to the adjustment reference coordinates zero based on this correction signal. The deflection unit 423 and the auxiliary deflection unit 424 of the image display device are controlled. The correction signal generator 421 and the controller 42
2, the deflection unit 423 and the auxiliary deflection unit 424 are general color
Since the same operation as that of the television receiver is performed, the description thereof will be omitted.

Next, the white balance adjustment will be described. A block diagram showing a detailed configuration of the drive circuit 407 in FIG. 14, a display screen diagram showing a signal for white balance adjustment in FIG. 15, and a drive voltage vs. screen luminance characteristic diagram of the CRT in FIG. 16 are used for the description. Generally, white balance adjustment includes highlight adjustment (white balance adjustment in high brightness area), low light adjustment (white balance adjustment in low brightness area), uniformity adjustment (screen uniformization), and gamma correction (CRT). Structure, and gamma characteristic correction due to saturation of the phosphor).

In FIG. 14, reference numeral 140 is a gain control circuit for controlling the gain of the video signal, 141 is a clamp circuit for clamping the video signal, 142 is a uniformity circuit for performing uniformity adjustment, and 143 is a gamma correction circuit for performing gamma correction. Is a video output circuit that amplifies the video signal to a level capable of driving the CRT 7.

When performing white balance adjustment, the white balance adjusting signal is supplied from the image adjusting signal generating section 403 to the drive circuit 407, as in the case of the above-mentioned convergence and geometric distortion adjustment.
As shown in (a), an adjustment signal corresponding to the adjustment area on the screen is displayed. FIGS. 15B to 15D are enlarged views of the image adjustment signal shown in FIG. Fig. 15 (b) shows the highlight adjustment / low light adjustment and uniformity adjustment.
15C to 15E are test signals used in gamma correction. The level of the image adjustment signal shown in FIG. 15B is 10 to 20% of the dynamic range of the drive voltage in the low light adjustment as shown in FIG. 16, and 100 in the highlight adjustment. %, The signal level becomes 50 to 60% in uniformity correction. As the test signal at the time of gamma correction in FIGS. 15C to 15E, the quadrangular pyramidal signal explained in the calculation of the center of gravity shown in FIG. 15E and the test signals shown in FIGS. 15C to 15D are shown. As described above, in order to minimize the influence of the transfer characteristics of the display and the image pickup system, the ramp signal that linearly changes in the vertical direction is used.

First, the highlight / low light adjustment will be described. As shown in FIG. 16, the screen 410
The image pickup unit 411 picks up an image of an adjustment signal having a level corresponding to the adjustment mode displayed above, and makes an adjustment based on the image signal data of the frame memory 413 from which flicker has been removed. In the low light / highlight adjustment, since adjustment can be performed only by the adjustment signal pattern in the central portion of the display screen, the data of the adjustment signal corresponding to the central portion of the screen from the frame memory 413 is stored in the position / level calculation unit 419. Supplied. The position / level calculator 419 calculates the signal level of the adjustment signal, and the error calculator 420 calculates the white balance error based on the signal level data.

The white balance error is calculated by obtaining the chromaticity coordinates from each of the RGB signal levels obtained by the position / level calculating unit 419, and calculating the chromaticity coordinates and, for example, the reference white D65 (x = 0.313, y = 0.329) and calculate the difference as a white balance error. Further, the correction signal generation unit 421 generates a correction signal such that the white balance error becomes zero. The control unit 422 controls the clamp circuit 141 by a correction signal generated by the correction signal generation unit 421 for controlling the cutoff of the RGB signal for driving the CRT during the low light adjustment, and for the RGB signal during the highlight correction. The white balance is adjusted by controlling the gain control circuit 140 with a correction signal that controls the amplitude of the signal.

Next, the case of performing gamma correction will be described. There are two types of gamma correction: CRT gamma and gamma correction due to saturation of the phosphor. For CRT gamma,
As described above, the gamma correction associated with the saturation of the phosphor will be described here. The light emission characteristic diagram of FIG. 17 and the operation waveform diagram of FIG. 18 are used for the description. FIG. 17 shows RGB C
It is a typical figure of the luminescent property of the fluorescent substance of the video projector which displays a big screen using RT.

As can be seen from FIG. 17, the emission characteristic of B has a non-linear region above a certain level of the beam current in contrast to the linear characteristic of G. The cause of this non-linear region is
This is due to the saturation of the B phosphor in the large current region. As can be seen from this figure, the characteristics of the photoelectric conversion output obtained by imaging the quadrangular pyramid-shaped adjustment signal displayed on the display device by the image pickup unit due to the saturation characteristics of the phosphor are, for example, seen in the scanning line cross section of the adjustment signal Then, as shown by the solid line in FIG. In order to correct this saturation characteristic, the position / level calculator 419 and the error calculator 420 are shown in FIG.
An error with respect to the linear characteristic shown by the broken line in (b) is calculated, and the gamma correction circuit 143 is arranged to eliminate this error.
Control and perform gamma correction.

The calculation of the error in this gamma correction will be described in detail with reference to FIGS. FIG.
18C is the first-order difference of the data obtained by A / D of the photoelectric conversion output signal having the linear characteristic shown by the broken line in FIG. 18B, and FIG. 18D is the phosphor shown by the solid line in FIG. 18B. It is a first-order difference of the photoelectric conversion output signal having a saturation characteristic due to FIG. 18 (e) is the second-order difference of the linear characteristic signal, and FIG. 18 (f) is the second-order difference of the saturation characteristic signal. 18 (c) to 18 (f), for simplification of description, the difference data is taken only on one side of the apex of the signal in FIG. 18 (b), but the difference data for all regions of the signal may be used. , And the following discussions are the same as those using FIGS. 18 (c) to 18 (f).

Comparing FIG. 18 (e) and FIG. 18 (f), the sum of the absolute values of the data of the second-order differences of the signals having the saturation characteristics shown by the solid line in FIG. 18 (b) is It can be seen that the value becomes larger than the sum of the absolute values of the data of the second-order difference of the signal having the linear characteristic shown by the broken line in FIG. The position / level calculator 419 and the error calculator 420 calculate the sum of absolute values of the secondary difference data due to the saturation characteristic of the phosphor as an error of the gamma characteristic. A correction signal corresponding to this gamma error is generated by the correction signal generation unit 421, and the control unit 4
22 controls the gamma correction circuit 143 based on this correction signal to perform gamma correction. As a result, the signal displayed on the display screen has a linear characteristic at each signal level as shown by the broken line in FIG. 18 (b), and the chromaticity in all areas from low luminance to high luminance is kept constant. You can

Next, the case of adjusting uniformity will be described. Uniformity adjustment is to correct the brightness balance in each part of the screen due to the projection tube and the optical system (lens and screen), and performs the same operation as described above, and as shown in FIG. (50-6
0%) creates a uniformity control signal. The uniformity correction signal is supplied to the uniformity correction circuit 142 composed of an analog modulator that multiplies the video signal and the correction signal to create a modulated video signal, and controls the amplitude of each part of the RGB signal that drives the CRT. , It is possible to automatically adjust the uniformity for displaying a uniform screen.

In this embodiment, the case of using a flicker detection signal which is a constant signal in the vertical scanning line direction to perform highly accurate flicker removal has been described. However, the image adjustment signal is used as the flicker detection signal. Needless to say, it can be easily realized even if it is done as.

In this embodiment, the case has been described in which the flicker detection signal is displayed on the entire screen for detection. However, the flicker is detected in consideration of the scanning frequency of the input signal, the image display area of the projector and the image pickup area of the CCD. It is needless to say that since the period and direction of the component are predicted, the flicker detection signal can be displayed only at the first and last points of the display area.

As described above, according to the second embodiment of the present invention, the flicker detection signal is imaged, and the flicker area of the imaging signal is detected and removed based on the flicker detection signal for image adjustment. By detecting the position and level of the signal, it is possible to perform highly accurate image adjustment compatible with multi-scan.

FIG. 19 shows the basic configuration of the third embodiment of the present invention. FIG. 19 (a) is a block diagram showing the configuration of the third exemplary embodiment of the present invention, and FIG. 19 (b) is a configuration diagram showing the system configuration of the third exemplary embodiment of the present invention.

In FIG. 19 (a), 180 is a geometric distortion,
An adjustment signal generation unit that generates adjustment signals for various adjustments such as convergence and white balance, 181 is a switch that switches between the adjustment signal and the video signal, 182 is a frequency detection unit that detects the frequency of the video signal, Reference numeral 183 is a drive circuit for driving a CRT (cathode ray tube) 184 of the projector 198, 185 is a projection lens for projecting an image displayed on the CRT 184, 186 is a mirror for projecting the projection light from the projection lens 185 onto the screen 187, 188. Is a detection unit that detects the image light projected on the screen 187,
Reference numeral 189 is an A / D converter that converts the image pickup signal output from the detection unit 188 into digital data, and 190 is a scan conversion unit that performs scan conversion of the image pickup signal converted into digital data by the A / D converter 189, 191 Generates a timing signal such as a horizontal synchronizing signal (HD), a vertical synchronizing signal (VD), and a clock (CLK) from the image pickup signal, and supplies it to the A / D converter 189 and the scan conversion unit 190 for synchronization processing / clock generation. 192 is a position / level calculation unit that calculates the position and level of the adjustment signal from the image signal scan-converted by the scan conversion unit 190, and 193 is geometric distortion and conversion from the output of the position / level calculation unit 192. An error calculation unit that calculates an error such as a presence error and a white balance error; and 194, geometric distortion from the output of the error calculation unit 193.
A correction signal generation unit 195 that generates correction signals for convergence, white balance, etc., and a correction signal generation unit 194.
From the output of the driving circuit 183 and the deflection unit 19 of the CRT 184.
6 and the auxiliary deflection unit 197 (convergence yoke).

The operation of the third embodiment of the present invention constructed as above will be described below. Figure 2 for explanation
0, FIG. 21 is used. 20 is a block diagram showing a detailed configuration of the detection unit 188, and FIG. 21 is a block diagram showing a detailed configuration of the scan conversion unit 190.

First, the detector 188 will be described. Here, the most general photodiode as a detection element will be described. FIG. 20 shows the basic structure of the photodiode. As shown in FIG. 20, the photodiode has a structure in which a p-type silicon substrate 51 is stacked on an n-type silicon substrate 50, and a junction surface 5 of n-type and p-type silicon is formed.
When 2 becomes a light-receiving surface and light is incident on this junction, a voltage corresponding to the energy of light appears at the output terminal 53 due to the photoelectric effect. The photodiode is the CCD described above.
Unlike the above, since the external clock for driving the element is not required, the frequency of the detection output corresponds to the scanning frequency for imaging.

When a linear sensor such as a photodiode is used as a detection element of a multi-scan compatible image correction device, the frequency of its output is the frequency of the image signal displayed on the screen 187. If this multi-scan signal is processed as it is, the position / level calculation unit 19
It is necessary to change the control timing of the memory for calculation 2 according to the frequency of the image signal. In addition, the memory capacity is not practical because it requires an increase in circuit scale and cost because it is necessary to prepare a capacity corresponding to a signal having the largest data amount in the multi-scan compatible range of the image display device.

Therefore, the signal of the detection element is converted into the scan conversion section 19
Convert to a fixed frequency by 0. The operation of the scan conversion unit 190 will be described in detail below. FIG. 21 shows a detailed configuration diagram of the scan conversion unit 190. In FIG. 21, 41
Is a frame memory for storing the detection signal from the detection unit 188 converted into digital data by the A / D converter 189, 42 is a scanning line calculation unit for calculating the scanning line of the image signal from the output of the frequency detection unit 182, 43 Is the scanning line calculation unit 4
2 is a memory control signal generation unit that generates each control signal of the frame memory 41 from the output of 2.

The operation of the scan conversion unit 190 will be described below. FIG. 21 is used for the description. First, the frequency detector 1
From the horizontal scanning frequency fH and the vertical scanning frequency fV of the image signal detected by 82, the number of scanning lines calculation unit 42 calculates the number of scanning lines of the image signal and determines whether it is interlaced or non-interlaced. The scanning line of the image signal and the judgment of interlaced / non-interlaced can be obtained by calculating fV / fH. For example, the frequency of the image signal is fH = 33.75kHz, fV = 60Hz, and the ratio of the horizontal scanning frequency to the vertical scanning frequency of the image signal is fH / fV = 562.5 lines. From this value, the image signal is interlaced and the scanning line of one frame is used. It turns out that the number is 1125.

Next, the thinning rate of the scanning lines of the image signal is determined from the obtained number of scanning lines of one frame and the number of lines of the frame memory 41. This is done by calculating from the integer part of the ratio of the calculated number of scanning lines to the number of lines of the frame memory 41 (for example, 512 lines). If the number of scanning lines of the image signal is 1125 per frame, the ratio of the number of scanning lines to the number of lines of the frame memory 41 is 1125/512, which is about 2.2, and the thinning rate is 2 from the integer part. One out of every two scan lines of a signal is thinned out.

Since an interlaced image is assumed here, only one field of an image signal of one frame consisting of an image of two fields is used. If the image signal is a non-interlaced signal, one of two continuous scanning lines is thinned out. Further, the fractional part of the ratio of the number of scanning lines of the image signal and the number of lines of the frame memory 41 is thinned out from the blanking portion of the image signal. That is, of 1125/2 = 562.5
562.5-512 = 50.5 lines are thinned out from the blanking portion of the image signal.

Here, since the horizontal direction data is generated by the synchronization processing / clock generator 191 by dividing the horizontal synchronization signal of the detection signal by a certain value to generate a clock, the number of data in the horizontal scanning direction is the scanning frequency. Since it is fixed even when changes occur, it is not necessary to thin out the data in the horizontal direction of the image signal. The control signal generator 42 generates a control signal for the frame memory 41 from the thinning rate calculated by the scanning line calculator. This control signal is performed by, for example, writing prohibiting the write enable signal of the frame memory 41 in the thinning scan line.

Hereinafter, the position / level calculation is performed using the detection data of the image signal stored in the frame memory 41, and the geometric distortion, the convergence, and the white balance are adjusted from this value. Since it is similar to the first embodiment of the present invention, it is omitted here.

As described above, according to the third embodiment of the present invention, by thinning out the scanning lines of the multi-scan signal from the detecting unit 188 to the number corresponding to the number of lines of the frame memory 41, the multi-scan is performed. In the corresponding image adjustment apparatus, the memory capacity of the frame memory 41 and the timing signal can be fixed, an increase in the circuit scale and the cost can be prevented, and the subsequent arithmetic processing can be simplified.

In the first and second embodiments of the present invention, the flicker detection signal is a band-shaped pattern that is constant in the vertical scanning line direction. For example, a signal displayed on the entire screen such as an all-white signal, an image adjustment signal used in the second embodiment of the present invention, or a part of the screen displayed as shown in FIG. It may be a signal.

In the present invention, the image display device is a CR.
Although the description has been given using the projection type display for projecting the image projected on T to the screen, the present invention is not limited to the CR.
It is also effective in a system such as a T-view type monitor and a liquid crystal projector.

Further, in the present invention, geometric distortion and conversion are performed.
Although the adjustment signal for the presence adjustment has a quadrangular pyramidal pattern, this may be a waveform having a peak value such as a SIN ² waveform or a circular or conical waveform.

[0101]

As described above, according to the first invention, the flicker detection signal is imaged, and the flicker of the imaging signal is detected and removed based on the flicker detection signal.
Strict position adjustment of the image pickup device with respect to the display device is not required, and accurate image pickup can be performed corresponding to a multi-scan image display device that displays an image of an arbitrary frequency.

According to the second aspect of the invention, flicker that occurs when a multi-scan image display device is imaged is removed,
By detecting the position and level of the image adjustment signal,
Image adjustments such as highly accurate geometric distortion, convergence, and white balance can be performed.

According to the third aspect of the invention, by thinning out the scanning lines of the multi-scan image pick-up signal to a number corresponding to the number of lines of the frame memory, the image adjusting apparatus for multi-scan can store the image pick-up signal in the frame memory. Since the memory capacity and timing signal can be fixed,
The circuit scale and cost are prevented from increasing, and the arithmetic processing in the subsequent stage of the frame memory is simplified.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a first embodiment of the present invention.

FIG. 2 is a block diagram showing a detailed configuration of the image pickup apparatus according to the embodiment.

FIG. 3 is a block diagram showing a detailed configuration of a CCD image sensor in the image pickup apparatus of the embodiment.

FIG. 4 is a diagram showing an operation of the embodiment.

FIG. 5 is a diagram showing an operation of the embodiment.

FIG. 6 is a flowchart for explaining the operation of the embodiment.

FIG. 7 is a diagram showing the operation of the embodiment.

FIG. 8 is a diagram showing an operation of the embodiment.

FIG. 9 is a block diagram showing a basic configuration of a second embodiment of the present invention.

FIG. 10 is a waveform diagram illustrating an image adjustment signal according to the same embodiment.

FIG. 11 is an operation waveform chart for explaining the operation of the embodiment.

FIG. 12 is an operation waveform chart for explaining the operation of the embodiment.

FIG. 13 is an operation waveform chart for explaining the operation of the embodiment.

FIG. 14 is a block diagram showing a detailed configuration of a drive circuit of the embodiment.

FIG. 15 is a diagram showing an adjustment signal of the embodiment.

FIG. 16 is a characteristic diagram showing the operation of the same embodiment.

FIG. 17 is a characteristic diagram showing the operation of the same embodiment.

FIG. 18 is an operation waveform chart for explaining the operation of the embodiment.

FIG. 19 is a diagram showing a basic configuration of a third embodiment of the present invention.

FIG. 20 is a configuration diagram showing a detailed configuration of a detection unit of the embodiment.

FIG. 21 is a block diagram showing a detailed configuration of a scan conversion unit according to the embodiment.

FIG. 22 is a diagram showing a flicker detection signal of the present invention.

FIG. 23 is a block diagram showing the basic configuration of a conventional image adjustment device.

FIG. 24 is a detailed configuration diagram of the CCD camera.

FIG. 25 is a detailed configuration diagram of the CCD image sensor.

FIG. 26 is a detailed configuration diagram of a drive circuit of the CCD image sensor.

FIG. 27 is an operation waveform diagram of the drive circuit of the CCD image sensor.

FIG. 28 is a flowchart illustrating the operation of the arithmetic control circuit.

FIG. 29 is an operation waveform diagram for explaining the operation of the arithmetic control circuit.

FIG. 30 is a view showing a pattern for adjusting the convergence.

FIG. 31 is a block diagram showing the basic configuration of a conventional image capturing device.

FIG. 32 is an operation waveform diagram illustrating the operation of the conventional image capturing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flicker detection signal generator 3 Frequency detector 6 Imager 8 Frame memory 10 Flicker detection signal extractor 11 Difference circuit 12 Flicker area detector 13 Memory control signal generator

Claims (11)

[Claims] 1. A flicker detection signal generating means for generating a flicker detection signal, an imaging means for imaging the flicker detection signal displayed on a display screen of an image display device, and an imaging signal imaged by the imaging means. A flicker area detecting means for detecting a flicker area from an image pickup signal of the image pickup means, and a memory control signal generating means for generating a control signal for controlling the memory means from an output of the flicker area detecting means. An image pickup device, comprising: a memory control signal generating means for generating a memory control signal for writing data in a flicker-free area to the flicker area detected by the flicker area detecting means. 2. The image pickup device according to claim 1, wherein the flicker detection signal generating means generates a constant signal in the vertical scanning line direction of the image display device. 3. The image pickup apparatus according to claim 1, wherein the flicker area detecting means detects the flicker area of the image pickup signal from the difference signal of the picked-up flicker detection signals. 4. An image adjustment signal generating means for generating an adjustment signal for adjusting geometric distortion, convergence, white balance, etc., and the adjustment signal displayed on the display screen of the image display device. An image pickup means for picking up an image; a memory means for storing an image pickup signal picked up by the image pickup means; and a flicker area detection means for detecting a flicker area of the adjustment signal from the adjustment signal picked up by the image pickup means. A memory control signal generation means for generating a control signal for controlling the memory means from the output of the flicker area detection means, and a position / level calculation for calculating the position and level of the adjustment signal from the data stored in the memory means. Means and error calculating means for calculating geometric distortion, convergence error, and white balance error based on the output of the position / level calculating means. A correction signal generating means for generating correction signals for geometric distortion, convergence and white balance from the output of the error calculating means, and a control means for controlling the image display device from the correction signal output by the correction signal generating means. An image adjusting apparatus, comprising: the memory control signal generating means for generating a memory control signal for writing data in a flicker-free area to the flicker area of the memory means detected by the flicker area detecting means. 5. The image adjusting apparatus according to claim 4, wherein the adjusting signal generating means generates a constant signal in the vertical scanning line direction of the image display apparatus. 6. The image adjusting apparatus according to claim 4, wherein the flicker area detecting means detects the flicker area of the image pickup signal from the difference signal of the imaged flicker detection signals. 7. The adjusting signal generating means has a display screen on the bottom surface,
The image adjusting apparatus according to claim 4, wherein at least one pattern having a quadrangular pyramid shape is output when the signal level direction is viewed as a height direction. 8. The image adjustment according to claim 4, wherein the position / level calculation means obtains the position of the peak value of the adjustment signal by approximate calculation from the linear portion of the imaged adjustment signal. apparatus. 9. An image adjustment signal generating means for generating an adjustment signal for adjusting geometric distortion, convergence, white balance, etc., and an image of the adjustment signal displayed on a display screen of an image display device. The detection means for detecting light, the frequency detection means for detecting the frequency of the adjustment signal, the scan conversion means for performing scan conversion of the detection signal of the detection means from the output of the frequency detection means, and the scan conversion means. Position / level calculation means for calculating the position / level of the adjustment signal from the scan-converted detection signal; and geometric distortion, convergence error, based on the output of the position / level calculation means.
Error calculation means for calculating a white balance error, correction signal generation means for generating correction signals for geometric distortion, convergence and white balance from the output of the error calculation means, and a correction signal output by the correction signal generation means And an image adjusting device for controlling the image display device. 10. The adjusting signal generating means is configured to output at least one pattern having a quadrangular pyramid shape when the display screen is the bottom surface and the signal level direction is the height direction. The image adjusting device according to claim 9. 11. The position / level calculation means obtains the position of the peak value of the adjustment signal by approximate calculation from the linear portion of the imaged adjustment signal.
The image adjustment device described.