JPH0715692A - Picture correction device for projection type display - Google Patents

Abstract

PURPOSE:To provide a picture correction device of a projection type display capable of automatically performing the various kinds of the correction of convergence, geometrical distortion, luminace and focus, etc., and considerably shortening adjustment time regarding a device for correcting the projection type display. CONSTITUTION:An optical transmission/reflection body 3 is installed between a projection magnified display device 1 and a screen 2 and a calculation circuit 5 for image picking up pictures from a optical transmission/reflection body 3 and calculating error values at every color and a correction waveform generation circuit 6 for generating correction waveforms for correcting the convergence, geometrical distortion, luminace and focus of the entire screen by calculation signals are provided. The projection magnified display device 1 is driven by the correction waveforms and the correction is automatically performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for performing various corrections on a projection display, and more particularly to an image correction apparatus for a projection display that automatically performs various corrections such as convergence, geometric distortion, brightness and focus. Is.

[0002]

2. Description of the Related Art Generally, in a projection type display (video projector) for enlarging and projecting in a screen by using three projection tubes that emit three primary colors, an incident angle (hereinafter referred to as a concentration angle) with respect to a screen of the projection tube is Calling is different for each projection tube, so color shift, focus shift on the screen,
Deflection distortion and luminance change occur. These various corrections adopt a method in which an analog correction waveform is created in synchronism with the horizontal and vertical scanning periods, and the size and shape of this waveform are changed for adjustment, but there is a problem in terms of correction accuracy. is there. Further, since various corrections are manually observed by visually observing deviations on the screen, there is a problem that adjustment time is required.

Therefore, as a method with high convergence accuracy, a digital convergence device described in Japanese Patent Publication No. 59-8114 and a method for automatically correcting deflection distortion are disclosed in Japanese Patent Publication No. 3-38797. Tokkyo 1-4
The automatic convergence correction device disclosed in Japanese Patent No. 8553 discloses a method for detecting a convergence error and a correction method therefor.
Japanese Patent Laid-Open No. 63-48987 discloses a convergence error correction method disclosed in Japanese Patent No. 549993 and a method for automatically detecting and correcting a convergence error of a projection display.
The method disclosed in the convergence error correction apparatus for a projection display of Japanese Patent Publication is disclosed.

FIG. 37 shows a block diagram of a conventional automatic convergence correction device capable of automatic correction. As shown in FIG. 37, in order to adjust the convergence of the color image display device, a region obtained by dividing the entire display screen of the image display device 101 into positive integers N and M in the horizontal and vertical directions is formed, and each region is formed in a matrix. A low-frequency signal in which the display signal waveform of each color in the area is line-symmetrical in the horizontal and vertical directions is supplied from the signal generator 102 to the image display device 101 through the signal switch 103.

Further, a signal from the image pickup device 104 for picking up the display screen of the image display device 101 is sent to the image processing device 10.
In order to calculate the horizontal and vertical barycentric position of the signal for each region, the signal converted into the digital signal introduced into the image processing apparatus 105 is subjected to interpolation processing to obtain the threshold value. And the low-frequency signal waveform is approximated by a quadratic equation to obtain the barycentric position for each region. Next, calculate the centroid error value between each color,
The convergence of the image display device 101 is automatically adjusted based on this center-of-gravity error value.

FIG. 38 shows a block diagram of a conventional image correction apparatus capable of various automatic adjustments. The projection device 111 is a projector for each color, that is, an R projector 112, a G projector 113, and a B projector.
The projection K device 114 is included, the light of each color is projected on the projection screen 115, and the images of the projectors 112 to 114 are formed on the projection screen 115. At this time, the auxiliary screen 116 is installed on the non-imaging surface, the non-imaging image on the auxiliary screen 116 is detected by the photosensor 114, and the convergence error information existing in this image is detected as described in FIG. Is calculated by calculating the matrix center-of-gravity error value, and the convergence error on the projection screen 115 is calculated from the convergence error information existing in this non-imaged image, whereby the convergence of the projection display is automatically adjusted.

[0007]

However, in the correction device having the conventional structure as described above, the image pickup means for detection can be incorporated in the display device to perform an integrated automatic correction. Since only the static convergence correction can be adjusted, there is a problem that complicated adjustment and time are required to adjust the entire screen.

Further, since the barycentric position of the low-frequency signal waveform in the area obtained by dividing the entire display screen in the horizontal direction N and the vertical direction M is calculated by the quadratic approximation, complicated processing is required in the image processing section. Therefore, there is a problem that the circuit scale becomes very large and the adjustment time becomes very long.

Further, since the image processing is performed by the low frequency signal which is line-symmetrical to the angled waveform, there is a problem that the position detection sensitivity and the accuracy of each level change due to the image receiving gamma characteristic of the image display apparatus and the correction accuracy is lowered. Had.

In view of the above point, the present invention has an optical transmission / reflector installed between the projection optical system and the screen, picks up an image from the optical reflector to calculate an error value for each color, and outputs the calculated signal. To provide an image correction device for a projection display that can significantly reduce the adjustment time by creating and automatically correcting a correction waveform for correcting the convergence, geometric distortion, brightness and focus of the entire screen by With the goal.

[0011]

According to a first aspect of the present invention, there is provided an optical transmission / reflector disposed between a projection optical system and a screen, and an image pickup means for picking up an image from the optical transmission / reflector. The configuration includes a calculating unit that calculates an error value for each color from the output signal of the image pickup unit, and a creating unit that creates various correction waveforms based on the output signal of the calculating unit.

A second invention is an optical transmission / reflector provided between a projection optical system and a screen, and the optical transmission / reflector.
An image pickup means for picking up an image from the reflector; a calculation means for calculating an error value for each color from an output signal of the image pickup means;
A configuration is provided that includes means for creating various correction waveforms based on the output signal of the calculation means, and means for controlling the transmittance of the optical transmission / reflector by the correction waveforms.

[0013]

According to the first aspect of the present invention, an image from an optical transmission / reflector is picked up to calculate an error value for each color, and the calculated signal is used to correct the convergence, geometric distortion, brightness and focus of the entire screen. Since the correction waveform for performing the correction is automatically created and corrected, various complicated adjustments are not required, and the adjustment time can be significantly shortened.

According to the second aspect of the invention, an image from an optical transmission / reflector provided between the projection optical system and the screen is picked up to calculate an error value for each color, and the calculated signal is used. Stable by automatically creating and correcting the correction waveform to correct the convergence of the whole screen, geometric distortion, brightness and focus, and controlling the transmittance of the optical transmission / reflector with this brightness correction waveform. It is possible to perform highly accurate correction with a simple configuration together with a uniform image and high resolution display.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a block diagram of an image display device of a projection type display according to the first embodiment of the present invention, FIG.
Shows the configuration in the first embodiment of the present invention.

In FIG. 1, reference numeral 1 is a projection magnifying display device for magnifying and projecting with a projection tube and lenses of three primary colors of light, and 3 is optical transmission / reflective for transmitting and reflecting the image light from the projection magnifying display device 1. A reflector, 2 is a screen for displaying an image from the optical transmission / reflector 3, 4 is an image sensor for capturing the reflected light from the optical transmission / reflector 3, and 5 is an output signal from the image sensor 4. A calculation circuit for calculating an error value for each color based on the following, 6 is a correction waveform generation circuit for generating a correction waveform of convergence, geometric distortion, brightness, and focus from the output signal from the calculation circuit 5, The correction waveform from the correction waveform generating circuit 6 drives the projection magnifying display device 1 to perform various corrections.

The configuration of the image correction apparatus for a projection type display of the present embodiment having the above configuration will be described below with reference to FIG. FIG. 2 shows a transmissive screen 11
2A and 2B show a configuration diagram of a rear projection type video projector using a camera, FIG. 2A shows a set configuration, and FIG.
Indicates an optical configuration.

In FIG. 2, the image light from the CRT 8 is enlarged and projected by the lens 9 and then enlarged and projected on the transmissive screen 11. The mirror 7 provided between the screen 11 and the lens 9 is an optical reflection means for shortening the depth of the set having an integral structure. The optical transmissive / reflector 3 provided between the lens 9 and the mirror 7 is a detection surface for automatic adjustment. Most of the image light from the lens 9 is transmitted and projected on the screen 11 to partially reflect light. Is imaged by the image sensor 4.

As shown in FIG. 2B, the image light from the CRT 8 and the lens 9 is projected at a right angle on the display surface of the screen 11, but with respect to the reflected light from the surface of the optical transmission / reflector 3. The image is picked up by the image pickup device 4 provided obliquely and the image light is detected. The optical transmissive / reflector 3 is made of an acrylic plate similar to the material of the transmissive screen 11,
Further, a reflective material is applied for reflection, and the transmitted light is used for image display and the reflected light is used for image adjustment.

Next, in order to describe in detail the method of detecting the reflected light from the optical transmission / reflector 3 and creating various correction waveforms, the block diagram of FIG. 3, the display screen diagram of FIG. 4, and the display screen diagram of FIG. The operation waveform diagram is used. First, in FIG. 3, a synchronization signal is input to the input terminal 15, a deflection circuit 18 creates a correction current for raster scanning the screen, and this correction current is supplied to the deflection yoke 26 to control scanning. There is. The video signal from the input terminal 14 is input to the video circuit 17, and C
Various signal processings and amplifications for driving the cathode electrode of the RT8 are performed. The synchronizing signal from the input terminal 15 is supplied to the test signal generating circuit 25, and the synchronizing signal 25 shown in FIG.
A number of conical test signals are projected on the screen 11.

Generally, the relationship between the input signal voltage (E) and the light emission output (L) of a CRT such as a projection tube can be approximated by the equation L = kE ^r , and both the input signal voltage (E) and the light emission output (L) can be obtained. In a logarithmic scale, gamma (γ) has its slope, which is the gamma (γ) characteristic of CRT.
In general, the gamma characteristic of a CRT is γ = 2.2. From the above, in the test signal generating circuit 25, the gamma characteristic 2.
The converted data of 2 is written, and the conical test signal shown in FIG. 5A is generated. The test signal is supplied to the switching circuit 16 in the display device, switched to the video signal from the input terminal 14, and supplied to the video circuit 17 so that the test signal is displayed on the screen 11.

First, the case of adjusting the convergence and the geometric distortion of the first adjustment item will be described. Since it is at the imaging position on the screen 11 surface, a cone signal with an acute vertex is projected as shown in FIG. 5A, but the optical transmission / reflector 3 located in the non-imaging position is shown in FIG. Since the defocus occurs as shown in (3), image light of a cone signal having an obtuse vertex is obtained.

As a reason why highly accurate position detection can be realized in the non-imaging image from the optical transmission / reflector 3 located on the non-imaging surface, the inclination can be obtained even in the non-imaging state as shown in FIG. 5B. This is because a photoelectric conversion signal that changes substantially linearly is obtained. Since the frequency band of the conical test signal shown in FIG. 5A is a low frequency signal component of 1 MHz or less,
As shown in FIG. 5, a photoelectric conversion signal having a correlation and a substantially linear change in inclination can be obtained regardless of whether the image is formed or not.

In the present embodiment, for the sake of easy understanding,
The case where the CCD camera 13 is used as the image pickup element will be described. However, even an image pickup device having a slow pulse response speed such as a photodiode can realize highly accurate detection and correction because it is a test signal of a low frequency component as described above. Needless to say.

The reflected light from the optical transmission / reflector 3 is CCD
The image is taken by the camera 13. The photoelectric conversion signal from the CCD camera 13 is supplied to an analog / digital converter (hereinafter referred to as A / D) 21 for performing image processing, and the photoelectric conversion signal shown in FIG.
The information on the test signal display screen shown in (b) is converted into a digital signal. The digital signal from the A / D 21 is supplied to the frame memory 22 to store display information. Data corresponding to each adjustment area is extracted and read out from the frame memory 22, and is supplied to the CPU 23 to detect the position of the center of gravity and calculate an error value.

High-precision position detection is required for the CPU 23 even in the current system of a black and white CCD camera of about 380,000 pixels and a system with a low detection accuracy in which the sample frequency of the A / D 21 is processed at about 14.32 MHz. Will be. In FIG. 6A, the sampling frequency f with the A / D 21
The photoelectric conversion signal converted at sap = 14.32 MHz (sampling period 70 ns) is shown. The center of gravity position, which is the apex of the photoelectric conversion signal at this time, exists at the sample point S7.

FIG. 6B shows a case where the position of the center of gravity, which is the apex of the photoelectric conversion signal, exists between the sample points S6 and S7. In this case, since the sample points are coarse, highly accurate position detection cannot be performed. Therefore, highly accurate position detection is performed by calculating the barycentric position by linear approximation from the voltage of the sample point near the barycentric position.

As shown in FIG. 6 (c), the linear approximation data of the data D4 to D6 of the rising sampling points S4 to S6 of the photoelectric conversion signal and the data D9 to the sampling points S9 to S7 of the falling edge of the photoelectric conversion signal. By calculating the intersection of the D7 linear approximation data, it is possible to calculate the barycentric position with high accuracy even in a system with coarse detection accuracy.

Next, the block diagram of FIG. 7 and the operation waveform diagram of FIG. 8 will be used to describe the operation of detecting the position of the center of gravity in detail. The CPU 23 includes a center-of-gravity position detector 72, an error value detector 73, a difference filter 70, and a linear area detector 71, and detects the center-of-gravity position and calculates an error value. Figure 8
The solid line in (a) shows the actual test signal, and the broken line shows the sampling signal from the CCD camera.

As can be seen from FIG. 8A, when the sampling frequency is low, the apex part of the test signal is rounded, and when the barycentric position is obtained from the CCD output signal, the actual barycentric position is Although it is the point A, the point A'is mistakenly determined to be the center of gravity of the test signal. In order to eliminate such a detection error, the position of the center of gravity is calculated. The calculation of the position of the center of gravity is performed by extending the linear portion excluding the rounded portion and setting the intersection of the extended portions as the position of the center of gravity. That is, on the data, the test signal data as shown by the solid line in FIG.

To detect the position of the center of gravity, the data is divided into areas corresponding to the respective test signals shown in FIG. 4, and the arithmetic processing for detecting the position of the center of gravity is performed on each area. By performing the arithmetic processing by dividing into such regions, parallel arithmetic processing such as pipeline processing can be performed.
Although the following description of the arithmetic processing is performed only for one area, the same arithmetic processing is performed for other areas.

As the first step of the arithmetic processing, an operation for detecting only the linear portion of the test signal data is performed excluding the rounding area by sampling. This converts the image data of the test signal into digital data by A / D21,
This data is passed through the difference filter 70 to detect the difference signal. When the image data of the test signal shown in FIG. 8A is input to the differential filter 70, the output data is as shown in FIG. 8B. Further, from the output data, the linear area detection unit 71 detects the data difference signal, that is, the periods A and B in which the slope of the test signal is constant. 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 barycentric position is calculated by extending the linear periods A and B on the data and setting the test signal at this intersection as the barycenter. As shown in FIG. 8B, in the calculation of the position of the center of gravity, the data D _A (corresponding address n _A ) from the highest vertex of the linear part A, the slope of the linear part A, and the linear part B If the data D _B (corresponding address n _B ) from the most apex and the inclination of the linear portion A are β, the center of gravity position x can be determined by the following equation.

X = n _A + (D _B −D _A −β · (n _B −n _A )) / (α−
β) Thus, by determining the position of the center of gravity by linear extrapolation,
For example, even if the CCD camera is coarsely sampled, the position of the center of gravity can be detected with high accuracy.

FIG. 9A shows an address map of the position of the center of gravity when a 380,000-pixel monochrome CCD camera is used. In this way, the address is composed of 768 points (x1 to x768) in the horizontal direction and 493 points (y1 to y493) in the vertical direction. FIG. 9B shows a partially enlarged view of the address map when the barycentric position (black circle ●) of the test signal is calculated. As shown in FIG. 9B, the barycentric position is represented by (x = 12.7, y = 11.3). The data corresponding to the addresses of x and y becomes the data of the center of gravity.

Next, a method of calculating the error value will be described. When calculating the convergence error, FIG. 10A is used.
Treat the G signal as a reference signal as shown in the waveform diagram
An error value of t1 is calculated for the R signal to the left, and an error value of t2 is calculated for the B signal to the right.

Further, when the geometric distortion error is calculated, as shown in the waveform chart of FIG.
20 is used as a reference signal, and the R signal is t3, G to the left.
An error value of t4 is calculated for the signal to the left, and an error value of t5 is calculated for the B signal to the left. The calculation of the barycentric position and the error value is managed by the information corresponding to the address of the sample point.

As described above, the data in which the position of the center of gravity and the error value are calculated by the CPU 23 are supplied to the correction signal generating circuit 24, and the correction signal for correcting the convergence and the geometrical distortion is generated, and the data is displayed in the display device. It is supplied to the convergence correction circuit 19, the deflection circuit 18, the video circuit 17, and the focus circuit 20.

Next, in order to describe in detail the operation of the method of creating the convergence correction waveform in the correction signal creating circuit 24 shown in FIG. 3, the block diagram of FIG. 11 and FIGS.
The corrected waveform diagram of FIG. 14 and the operation waveform diagram of FIG. The correction signal generating circuit 24 shown in FIG. 3 includes a correction waveform generating circuit 28 for generating a basic correction waveform, a correction control circuit 29 for controlling the correction waveform, and various correction waveforms from the correction control circuit 29. It is composed of a correction signal generation circuit 30 for generating the correction signal of.

The horizontal synchronizing signal and the vertical synchronizing signal from the input terminals 33 and 34 are supplied to the correction waveform generating circuit 28, and the correction waveform generating circuit 28 has at least 12 types of basics required for the convergence correction shown in FIGS. 12 and 13. Correction waveform (WF1 ~
WF12) is generated. The correction waveform generation circuit 28 is
For example, a correction waveform composed of a plurality of Miller integrating circuits and synchronized with the input synchronizing signal is created. The correction waveform from the correction waveform generating circuit 28 shown in FIGS. 12 and 13 is a multiplication type D /
It is supplied to the reference potential terminals of the A converters 35 to 46. The correction data is stored in the memory 31 and is supplied to the serial data creation circuit 32 through the CPU 23.

In the serial data creating circuit 32, the CPU 2
A serial signal as shown in FIG. 14 is created on the basis of the control signal from 3. The serial signals shown in FIG. 14A are address signals (A3 to A0) and data signals (D7 to D).
0) is multiplexed, and the multiplication type D /
The A converters 35 to 46 are selected, and then the amplitude control is performed by the data signal. Further, clock signals and load signals for reading in synchronization with the serial data of FIG. 14A are shown in FIGS. 14B and 14C. In the multiplication type D / A converters 35 to 46, the load signal of FIG.
Moreover, the clock signal of FIG. 14B is set so that data is input at the positive edge.

The three serial signals shown in FIG. 14 are supplied to the input terminals of the multiplication type D / A converters 35 to 46, and 12 kinds of basic correction waveforms (WF) from the correction waveform generating circuit 28 are supplied.
The polarities and amplitudes of 1 to WF12) are controlled. Multiplying type D /
Amplitude-controlled signals from the A converters 35 to 46 are supplied through resistors to an inverting amplifier circuit 47 composed of operational amplifiers, which adds and amplifies twelve kinds of correction waveforms and outputs to the output terminal 48, for example, red ( An R) horizontal direction (H) convergence correction signal can be created and supplied to the convergence correction circuit 19 shown in FIG. 3 for correction.

FIG. 15 shows a relational diagram of the movement on the screen of the correction change by the correction waveform of the analog system. As shown in FIG. 15, convergence correction can be automatically performed by calculating the barycentric positions of the screen center and the peripheral portion.

Generally, in the convergence correction of a video projector using three projection tubes which emit three primary colors,
Since it is necessary to correct the RGB of the three primary colors and the horizontal and vertical directions, it is necessary to control at least 12 × 6 = 72 systems.
A total of 100 lines of control are required for geometric distortion and other corrections.

Further, in order to explain the case of performing the digital convergence method for digitally creating a corrected waveform, the basic block diagram of FIG. 16 and the display screen diagram of FIG. 17 are used. As shown in FIG. 17, a plurality of adjustment points of 11 points in the horizontal direction and 7 points in the vertical direction are provided on the screen, and the correction data for each adjustment point is stored in the memory. This is a method for realizing highly accurate correction because an arbitrary correction waveform can be created by performing data interpolation.

As shown in the block diagram of FIG. 16, the configuration is such that an address generation circuit 49 for creating various address signals from a synchronization signal and an operation circuit 51 for calculating correction data based on a control signal. A memory 50 for storing data of each correction point, an interpolation circuit 52 for performing data interpolation between the correction points, a D / A converter 53 for converting the interpolated data into an analog amount, LPF (low pass filter) for smoothing analog quantity
This analog correction waveform drives the convergence yoke and is supplied to the convergence correction circuit 19 shown in FIG.

The same correction waveforms are created for the geometric distortion correction of the screen amplitude and deflection distortion in the deflection circuit 18, the luminance correction in the video circuit 17, and the focus correction in the focus circuit 20.

The CCD camera 13 and A / D 21 shown in FIG.
Since the operating dynamic range is limited,
As shown in (a), correction is performed so that the relationship between the drive voltage and the screen brightness changes proportionally, and the detection sensitivity and accuracy in all gradations are made constant to perform highly accurate position detection and level detection. Is. In this way, by creating a test signal corresponding to the image receiving gamma of the image display device, the detection sensitivity and accuracy in all gradations are made constant, and highly accurate position detection and level detection are realized, and the barycentric position is calculated. It is possible to simplify the approximate calculation processing for. Although the image receiving gamma of the image display device has been corrected on the test signal generation side, it is sufficient that the gamma correction exists in the loop of test signal generation-image display-imaging-centroid position detection.

Next, in order to explain the case of adjusting the brightness of the second adjustment item (white balance adjustment),
18 and 19 are used. Similarly to the above-mentioned convergence and geometric distortion adjustment, when performing the brightness adjustment, the test signal generation circuit 25 supplies the brightness adjustment test signal to the switching circuit 16 during the automatic adjustment, and the display screen shown in FIG. Is projected. At the image formation position on the screen 11 surface, an acute-angled window signal is displayed as shown in FIG. 19A, but the optical transmission / reflector 3 in the non-image formation position is shown in FIG. 19B. As described above, image light of an obtuse window signal such as defocus is obtained.

The reflected light from the optical transmission / reflector 3 is CCD
The image is taken by the camera 13. The photoelectric conversion signal from the CCD camera 13 is supplied to the A / D 21 for image processing, and the information on the test signal display screen shown in FIG. 19B is converted into a digital signal. The digital signal from the A / D 21 is supplied to the frame memory 22 to store display information. The data from the frame memory 22 is extracted and read out from the data corresponding to each adjustment area, is supplied to the CPU 23, and the level of each area and the error value of each color are calculated. The calculation signal from the CPU 23 is supplied to the correction signal creating circuit 24 to create various kinds of correction signals, and is supplied to the video circuit 17 of the display device for automatic white balance (highlight / gamma / lowlight) and uniformity. The brightness correction is performed.

Regarding the automatic brightness correction, the block diagram of FIG. 20 will be used to explain the operation thereof in detail below. Figure 2
Reference numeral 0 indicates a detailed block diagram of the video circuit 17 shown in FIG. Video signal from input terminal and test signal generation circuit 25
The test signal from is supplied to the switching circuit 55 for signal switching. The signal from the switching circuit 55 is a gain control circuit 56.
Is supplied to the clamp circuit 57 for gain control for contrast and highlight drive adjustment.

In the clamp circuit 57, the direct current is reproduced and supplied to the uniformity correction circuit 58. The uniformity correction circuit 58 performs uniformization correction on the brightness of the central portion and the peripheral portion of the screen, and supplies it to the gamma correction circuit 59. The gamma correction circuit 59 corrects the change in the RGB emission characteristics of the 7-inch projection tube shown in FIG. 21 and supplies the corrected output to the video output circuit 60. The video output circuit 60 amplifies the CRT to a state where it can be driven and applies it to the CRT afterward.

Before the description of the present embodiment, gamma correction when saturation of the phosphor occurs will be described with reference to the emission characteristic diagram of FIG. FIG. 21 shows red, green, and blue (hereinafter R,
It is a light emission characteristic diagram of R, G, and B of a video projector which displays a large screen using a 7-type CRT (abbreviated as G and B). As can be seen from FIG. 21, for the linear characteristic of G,
It can be seen that the emission characteristic of B has a non-linear region from a certain level of the beam current. The cause of the non-linear region is the saturation of the B phosphor in the large current region. As can be seen from this figure, this non-linear characteristic due to saturation is canceled to make it linear as shown by the dotted line in FIG. 21, and in order to keep the chromaticity constant in all areas from low luminance to high luminance, gamma It needs to be corrected.

Now, the operation of the embodiment of the brightness correction constructed as shown in FIG. 20 will be described below. To explain this operation, the adjustment order table (Table 1) and FIGS. 18 and 19 are used together.

[0055]

[Table 1]

[Table 1] is a table showing the adjustment order of the brightness adjustment. As the adjustment order, the first is to detect low brightness and adjust low light, and the second is to detect high brightness and highlight. Adjustment, the third is to detect the medium to high brightness due to phosphor saturation, and adjust the gamma, and the fourth is to detect the high brightness again to correct the change in the highlight at the time of gamma adjustment, and then highlight the highlight again. Adjustment, last whole screen (center and periphery of screen)
Uniformity adjustment for screen uniformity is performed by detecting medium to high brightness.

As can be seen from Table 1, the low light, gamma, and highlight adjustments can be made only by detecting the brightness in the center of the screen, but the uniformity adjustment requires the brightness detection in the center and the peripheral part of the screen. Therefore, when the low light, uniformity, and highlight adjustments are performed, a window-shaped test signal for each gradation is generated at the screen central portion and the peripheral portion as shown in FIG. To be done.

FIG. 22 is an input / output characteristic diagram showing the test signal level for each adjustment item. In this way, the test signal of the level corresponding to each adjustment mode is generated. For example, a test signal having a level of 10 to 20 V for low light adjustment, 50 to 100 V for gamma adjustment, 100 V for highlight adjustment, and 50 to 60 V for uniformity adjustment is displayed on the display screen.

First, the case of adjusting the white balance will be described. The white balance adjustment is to adjust the color balance for each gradation due to the light emission characteristic of the projection tube. The test signal of each gradation shown in FIG. 22 is projected on the screen 11 to display the level amount of each gradation. It is detected by the CCD camera 13. The signal photoelectrically converted by the CCD camera 13 is supplied to the A / D 21, and the information on the test signal display screen is converted into a digital signal. The digital signal from the A / D 21 is supplied to the frame memory 22 to store display information.

Data corresponding to each adjustment area is extracted and read out from the frame memory 22, and the CPU 2
3, the level is detected and the error value is calculated. C
The error value signal from the PU 23 is supplied to the correction signal creating circuit 24. In the correction signal generating circuit 24, as shown in FIG. 22, a black level signal (10 to 20%) is a low light control signal, and an intermediate to white level signal (50 to 100%) is a gamma control signal. A white level signal (100%) creates a highlight control signal.

The low light control signal is supplied to the clamp circuit 57 and controls the cutoff of the RGB signals for driving the CRT. Further, the gamma control signal is supplied to a gamma correction circuit 59 configured by several line approximations to correct the saturation characteristic of the B phosphor. In addition, the highlight control signal is supplied to the gain control circuit 56 to control the amplitude of the RGB signals that drive the CRT, whereby the white balance can be automatically adjusted.

Second, the case of adjusting uniformity will be described. Uniformity adjustment is to correct the balance of brightness in each part of the screen due to the projection tube and the optical system (lens and screen), and the same operation as described above is performed, as shown in FIG. (5
The uniformity control signal is generated at 0 to 60%). The uniformity correction signal is supplied to a uniformity correction circuit 58 composed of an analog modulator that creates a modulated video signal by multiplying the video signal and the correction signal, and the CRT
By controlling the amplitude of each part of the RGB signal that drives the, it is possible to automatically adjust the uniformity for displaying a uniform screen.

Next, the operation control table (Table 2) is used to describe the level detection method.

[0064]

[Table 2]

The solid line in FIG. 22 shows the emission characteristics of the CRT.
Since the image receiving gamma coefficient is 2.2, comparing the luminance change amounts of the low drive voltage and the high drive voltage shows that the higher the drive voltage, the higher the sensitivity. This has a great influence on the CPU, the frame memory, and the number of quantization bits of D / A and A / D. That is, the amount of change in luminance per bit is small at a low drive voltage, but the amount of change in luminance per bit becomes very large at a high drive voltage, and the detection sensitivity in all gradations changes, so highly accurate detection and correction are possible. In addition to this, a quantization bit number of 10 bits or more is required. Therefore, as shown by a broken line in FIG. 22, correction is performed so that the relationship between the drive voltage and the screen brightness changes in proportion to make the detection sensitivity and accuracy in all gradations constant and perform highly accurate level detection. .

Generally, the number of quantization bits required for white balance adjustment and gamma correction is 10 bits (1024
Gradation) is required. Therefore, in this embodiment, by performing the gain and the image receiving gamma in the A / D front stage for each adjustment mode, the processing with the quantized bits of 8 bits is possible. As shown in the operation control table of (Table 2), during low light adjustment, as shown in FIG. 22, the gain of the A / D front stage is increased to detect the range of the low luminance region (10 to 30 V), The gamma correction coefficient (without gamma correction) indicated by the solid line in FIG. 22 is set, and during highlighting and gamma adjustment, the gain in the preceding stage of the A / D is reduced to detect the range of low to high luminance regions (10 to 100 V).
As a gamma correction coefficient (with gamma correction) indicated by a broken line in FIG. 22,
At the time of uniformity adjustment, the range of the middle luminance region (10 to 60 V) is detected with the gain of the A / D front stage as the middle level, and high-accuracy level detection is realized as the gamma correction coefficient (with gamma correction) of the broken line in FIG. There is.

As described above, from the data whose level has been detected, the brightness correction such as white balance and uniformity is automatically corrected.

Next, in order to explain the case of adjusting the focus of the third adjustment item, the relationship diagram between the display screen and the operation waveform of FIG. 23 is used. Also in the case of performing the electric focus adjustment, the focus adjustment test signal is supplied from the test signal generation circuit 25 to the switching circuit 16 during the automatic adjustment as in the convergence adjustment described above, and the screen 11 is displayed.
The test signal shown in FIG. 23A is projected on the CCD,
A conical photoelectric conversion signal captured by the camera 13 as shown in FIG. 23A is supplied to the A / D 21 and converted into a digital signal. The digital signal from the A / D 21 is supplied to the frame memory 22 to store display information.

The data from the frame memory 22 is read by extracting the data corresponding to each adjustment area.
The data for which the level of the high frequency component and the error value are calculated are supplied to the correction signal generating circuit 24, and the correction signal for correcting the focus is generated and supplied to the focus circuit 20 in the display device. It Since the CPU 23 detects the level of the high frequency component, a signal as shown in FIG. 23 (b) is obtained, and the correction waveform shown in FIG. 23 (c) at which the level of each correction region becomes the maximum value is calculated. ing.

By driving the focus circuit 20 based on this correction data, a photoelectric conversion signal whose focus is adjusted in the peripheral portion is obtained from the CCD camera 13 as shown in FIG. In this way, the high frequency component of the pattern signal at each adjustment point on the screen is detected, and the correction amount that maximizes the high frequency component is extracted.

Next, in order to explain the installation position of the optical transmission / reflector 3 in detail, the optical configuration diagrams of FIGS. 24, 25 and 26 are used. As shown in FIG. 24A, the lens 9
The optical transmission reflector 61 is provided at a non-imaging position between the screen and the screen 11.
The CCD camera 13 captures the image light formed by the detection plate 62 provided at a position where the reflected light from the optical transmission reflector 61 forms an image. With the optical configuration as shown in FIG. 24A, since detection is performed on the image plane, highly accurate detection and correction can be realized.

Further, as shown in FIG. 24 (b), the lens 9
An optical transmissive reflector 63 is provided at an image forming position between the screen 11 and the screen 11, and reflected light of the image formed by the optical transmissive reflector 63 is captured by the CCD camera 13. In the optical configuration as shown in FIG. 24 (b), since the detection surface is unnecessary and the detection is performed on the image plane, highly accurate detection and correction can be realized with a simple configuration. As shown in FIG. 24B, the screen 11
As a method of providing the optical transmissive reflector 63 and the optical transmissive reflector 63 at the same position, a method using a liquid crystal panel as shown in FIG. 25 can be applied.

As shown in FIG. 25, a liquid crystal plate 74 is provided as an optical transmission / reflection means at the image forming position on the screen 11 surface.
The reflected light of the image formed by the liquid crystal plate 74 is captured by the CCD camera 13. The operation of the liquid crystal plate 74 can be realized by using it as a transmissive body during normal image projection and as a reflective body during adjustment.

FIG. 26 shows a case where the screen 11 shown in FIG. 25 and the optical transmission reflector 63 have the same structure. As shown in FIG. 26, the transmissive screen 68 is composed of a Fresnel lens 67 and a lenticular 66 and a black stripe 79 for improving the contrast ratio in order to widen the viewer's favorite area.
Black stripe 7 which has a low transmittance in
By providing the reflecting surface 80, which is coated with a reflecting material, on the incident surface of the image light 9 of FIG.

As the material of the optical transmission / reflector 3,
It can be realized by using a reflecting material or a diffusing material used in a general transmissive or reflective screen. The optical reflection means can be realized by applying an oxide paint such as zinc, aluminum or magnesium as a white screen as an oil-based paint, or by mixing a pearl-like powder with a paint and applying it as in a pearl white screen. Also, it can be realized by applying aluminum powder like a silver screen or spraying milky white glass particles like a bead screen.

Next, as an effective method of this method, a case of a "cube" type in which a plurality of rear projection type video projectors form a multi-screen will be described.
7 is used. FIG. 27A shows a “cube” type projection display device 69. in this way,
When a total of 12 rear projection type video projectors are arranged in a row of 4 rows in the horizontal direction and 3 rows in the vertical direction to display a large screen, a joint between the units, which is a plurality of the rear projection type video projectors, is important. Therefore, the uniformity of the screen size, phase, and brightness are important factors. Considering that the adjustment time is very long due to a plurality of display devices, this is a very effective method because it is possible to automatically adjust the integrated structure as shown in FIG. 27 (b). As described above, according to the present embodiment, the optical transmission / reflector is installed between the projection optical system and the screen, the image from the optical transmission / reflector is captured, and the error value for each color is calculated. By creating a correction waveform to correct the convergence, geometric distortion, brightness and focus of the entire screen by the calculated signal and automatically correcting it, various complicated adjustments are unnecessary and the adjustment time can be greatly shortened. realizable.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 28 is a block diagram of an image correction device for a projection type display according to the second embodiment of the present invention.

In FIG. 28, reference numeral 76 is an optical transmission / reflector for transmitting and reflecting the image light from the projection enlargement display device 1, and 4 is an image pickup element for picking up the reflected light from the optical transmission / reflector 76. Reference numeral 5 is a calculation circuit for calculating an error value for each color from the output signal from the image pickup device 4, and 6 is for creating a correction waveform of convergence, geometric distortion, brightness, or focus from the output signal from the calculation circuit 5. The correction waveform generating circuit 75 is a transmittance control circuit for controlling the transmittance of the optical element based on the correction waveform. The correction waveform from the correction waveform generating circuit 6 drives the projection enlargement display device 1 to perform various corrections. Is done. It should be noted that the same operations as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

Before describing the operation of this embodiment, the brightness characteristics of a projection display such as a video projector will be described. 29 and 30 show the directional characteristics and structure of the transmissive screen 68 of the rear projection type video projector.
Shown in.

As shown in FIG. 30, a Fresnel lens 67 and a trapezoidal lenticular 6 are provided in order to widen the viewer's favorite area.
5 and a cylindrical lenticular 66, the image light 64 is transmitted from the Fresnel lens 67 surface to the lenticular 65 and 66 surfaces. FIG. 29 shows the directional characteristics of the screen having such a shape. As shown in FIG. 29, the screen gain is lowered and the luminance is lowered due to the deviation from the main axis of the optical system, and the luminance is lowered toward the periphery of the screen.

Next, FIGS. 31 and 32 show the light amount of each part of the screen when the center of the screen is 100% in the case of the rear projection type video projector. Left and right of the display screen shown in FIG.
FIG. 32 shows the amount of light obtained by normalizing the luminance distribution in the two directions (broken line), the vertical 11 direction (solid line), and the diagonal l3 (dotted line).
As shown in FIG. 32, the peripheral light amount is 33% on the left and right sides, 45% on the upper and lower sides, and 15% on the periphery of the diagonal.

Therefore, the optical transmission reflector of this embodiment is shown in FIG.
Uniform brightness can be realized by using it as a means for correcting the peripheral light amount in the direction of 2. For example, it can be realized by selecting a material in which the transmittance of the optical transmissive reflector made of an acrylic plate is low in the central portion of the screen and high in the peripheral portion. This means that, as described in the emission characteristics of FIG. 21, since the phosphor is used in a saturated state, it is not possible to realize highly accurate image homogenization even if electrical correction is performed. By performing the optical brightness correction in this manner, correction with a higher resolution can be realized as compared with electrical correction.

In order to describe the method of controlling the optical transmittance of this embodiment in detail, the block diagram of FIG. 33, the operation waveform diagram of FIG. 34, and the characteristic diagram of FIG. 35 are used. A configuration using the light transmittance of the liquid crystal device will be described with reference to the block diagram shown in FIG. FIG. 33 is a block diagram of a basic drive circuit of the liquid crystal device 78 having a pair of electrodes S and C.
And the drive waveforms thereof are shown in FIG.

The drive circuit shown in FIG. 33 has an exclusive OR (E
XC. OR) gate 77 having a duty ratio of 5
The rectangular wave of 0% is EXC. To one input of the OR gate 77 and one electrode C of the liquid crystal device 78, the EXC. By applying the output of the OR gate 77 to each of the other electrodes S, the AC voltage applied to the liquid crystal is turned on / off as shown in FIG.
According to the off signal v _sig , they become ± (V _DD −V _SS ), 0 as shown in FIG. 34 (d). Also,
This operation is shown in FIG.

Since the liquid crystal is bidirectional and responds to the effective value, the pulse duty ratio for driving the liquid crystal is 100% during the ON period of the liquid crystal applied voltage v _C -v _S shown in FIG. 34 (d). This is static drive. FIG. 35 shows a characteristic diagram of the light transmittance with respect to the applied voltage of the liquid crystal. As shown in FIG. 35, in the case of static drive, the operating voltage (V _DD -V _S
S ) can be set to a high value above the saturation voltage V _sat , and TN (T
Wisted Nematic) and GH (Guest)
In the −Host) method, the voltage is, for example, 2 to 5V. It can be seen that the light transmittance can be controlled by controlling the applied voltage in this way.

The same operations as those in the first embodiment are performed for image pickup, calculation, and correction waveform generation, and a correction signal for luminance correction is supplied from the correction waveform generation circuit 6 to the transmittance control circuit 75. The transmittance control circuit 75 creates a control signal for controlling the transmittance of the optical transmissive / reflector 76 formed of a liquid crystal device as shown in FIG.

FIG. 36A shows the amount of light obtained by normalizing the luminance distribution in the left and right 12 directions (broken line) and the up and down 11 direction (solid line) of the display screen. In this way, control is performed so as to reduce the transmittance at the center of the screen. The liquid crystal control signal from the transmittance control circuit 75 is supplied to the optical transmissive / reflector 76 to control the transmittance, and as shown in FIG. 36 (b), a uniform image with constant brightness is obtained at both the center and the periphery of the screen. be able to.

As the liquid crystal control signal from the transmittance control circuit 75, the applied voltage at the center of the screen is set between the applied voltages V _{C and} V _{sat of the} characteristics shown in FIG. 35 (transmittance 45% to 33%). The peripheral portion is set to V _DD -V _SS (transmittance (100%)).

As an effective method of this method, as described in the first embodiment, a very effective method in the case of the "cube" type in which a plurality of rear projection type video projectors shown in FIG. 27 form a multi-screen. Needless to say.

Further, as described in the first embodiment, the method of calculating the position of the center of gravity is also set so that the inclination of the photoelectric conversion signal from the CCD camera changes into a conical shape which changes substantially linearly.
Highly accurate correction can be realized with a simple detection system by calculating the center of gravity position and level that are symmetrical in the horizontal and vertical directions and calculating various correction waveforms.

As described above, according to this embodiment, the optical transmission / reflector is installed between the projection optical system and the screen, the image from the optical transmission / reflector is picked up, and the error value for each color is calculated. However, this calculation signal is used to automatically create and correct a correction waveform for correcting the convergence, geometric distortion, brightness and focus of the entire screen, and controlling the transmittance of the optical element by this brightness correction waveform. Thus, it is possible to realize stable uniform image and high-resolution display, and highly accurate correction with a simple configuration.

In this embodiment, the image display device using the CRT has been described for easy understanding, but it goes without saying that other display devices are also effective.

Further, in the present embodiment, the case where an integrated type or a two-body type video projector is used as the projection enlargement display device has been described, but a direct-view type display device other than that may be used.

Further, although the case where the CCD camera is used as the image pickup device for detecting the image light has been described in the present embodiment, other two-dimensional or one-dimensional detection device may be used.

In this embodiment, the case where the communication signal between the correction circuit and the projection magnifying display device is the correction waveform signal for correcting the drive circuit in the display device has been described. It may be a control signal for controlling.

In this embodiment, the image receiving gamma of the image display device has been described as being corrected on the test signal generation side. However, gamma correction is performed in the loop of test signal generation-image display-imaging-centroid position detection. Needless to say, the existence of.

Further, although the case where the position of the test signal displayed on the image display device is detected as a conical shape has been described in the present embodiment, another shape such as a quadrangular pyramid may be used.

Further, although the case where the screen is divided and the convergence correction is performed in an analog manner has been described in this embodiment, another method may be used as long as the convergence adjustment is effectively performed.

Further, in the present embodiment, the case where the horizontal and vertical barycentric position of each region is calculated by linear approximation from the conical photoelectric conversion signal whose rising and falling are changed substantially linearly from the image pickup means As described above, the calculation may be performed by non-linear approximation if the approximation can be simplified.

Further, although the case where the liquid crystal device is used as the device for controlling the light transmittance has been described in the present embodiment, other light control elements may be used.

Further, in the present embodiment, the case where the brightness correction of the peripheral portion is performed by controlling the transmittance of the optical system has been described, but the correction is further improved by using the optical system and the electric system together. It goes without saying that precision can be achieved.

[0102]

As described above, according to the first aspect of the present invention, an optical transmission / reflector is installed between the projection optical system and the screen, and an image from the optical reflector is picked up to obtain an error value for each color. By using this calculation signal to create a correction waveform to correct the convergence, geometric distortion, brightness, and focus of the entire screen and automatically correct it, various complicated adjustments are unnecessary and significant adjustments can be made. Time can be shortened.

Further, an optical transmission / reflector is installed at a non-imaging position between the projection optical system and the screen, and a non-imaging image from this optical reflector or an image at the imaging position is picked up. A correction device having an integrated structure can be realized.

Further, when the optical transmission / reflector is adjusted, a reflection image is taken as a reflector and used as a transmission element at the time of displaying an image so that the optical element can be commonly used and a simple structure can be realized.

In addition, it is easy to calculate the various correction waveforms by calculating the center of gravity position and level that are symmetrical in the horizontal and vertical directions with a conical photoelectric conversion signal whose slope changes substantially linearly, and thereby obtaining various correction waveforms. The detection system can realize highly accurate correction.

Further, since the frequency band of the test signal is a low-frequency signal component, a photoelectric conversion signal with a stable slope can always be obtained regardless of whether the projected image light is imaged or non-imaged. Even when changes occur, stable and highly accurate correction can be realized.

According to the second aspect of the invention, an optical transmission / reflector is installed between the projection optical system and the screen, and an image from the optical transmission / reflector is picked up to calculate an error value for each color. , This calculation signal automatically creates and corrects the correction waveform for correcting the convergence, geometric distortion, brightness and focus of the whole screen, and controls the transmittance of the optical transmission / reflector by this brightness correction waveform. By doing
Highly accurate correction can be realized with a simple configuration together with a stable uniform image and high resolution display.

Further, a cone-shaped photoelectric conversion signal whose inclination changes substantially linearly is used to calculate the center of gravity position and level which are symmetrical in the horizontal and vertical directions, and various correction waveforms are calculated to obtain a simple correction waveform. The detection system can realize highly accurate correction.

In a multi-screen display by arranging a plurality of projection optical systems and projecting and enlarging the projection optical systems, the adjustment of each projection optical system is automatically performed by an integrated structure, so that the plurality of projection optical systems can be easily performed. Can be adjusted, and is a very effective means especially for a cube such as a multi-screen, and its practical effect is great.

[Brief description of drawings]

FIG. 1 is a block diagram of an image correction apparatus for a projection type display according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram for explaining the operation of the embodiment.

FIG. 3 is a block diagram for explaining the operation of the embodiment in detail.

FIG. 4 is a display screen diagram for explaining the operation of the embodiment.

FIG. 5 is an operation waveform diagram for explaining the operation of the embodiment.

FIG. 6 is an operation waveform chart for explaining the operation of detecting the position of the center of gravity of the embodiment.

FIG. 7 is a detailed block diagram for explaining the operation of the position of the center of gravity of the embodiment.

FIG. 8 is an operation waveform diagram for explaining the operation of detecting the position of the center of gravity of the embodiment.

FIG. 9 is a display screen diagram for explaining the operation of detecting the position of the center of gravity of the embodiment.

FIG. 10 is an operation waveform diagram for explaining an error value calculation operation of the embodiment.

FIG. 11 is a detailed block diagram of correction waveform creation according to the embodiment.

FIG. 12 is an operation waveform diagram for explaining an operation of creating a correction waveform in the embodiment.

FIG. 13 is an operation waveform chart for explaining an operation of creating a correction waveform according to the same embodiment.

FIG. 14 is an operation waveform diagram for explaining a positive operation of the correction waveform creation in the embodiment.

FIG. 15 is a diagram showing a relationship between a correction wave and a correction change for explaining the operation of the embodiment.

FIG. 16 is a block diagram for explaining a correction waveform creation positive operation of the embodiment.

FIG. 17 is a display screen diagram for explaining a correction waveform creation positive operation of the embodiment.

FIG. 18 is a display screen diagram of the display device for explaining the brightness correction operation of the same embodiment.

FIG. 19 is an operation waveform diagram for explaining the brightness correction operation of the same embodiment.

FIG. 20 is a block diagram for explaining the operation of the video circuit of the embodiment.

FIG. 21 is a characteristic diagram for explaining the gamma correction operation of the same embodiment.

FIG. 22 is a characteristic diagram for explaining the brightness correction operation of the same embodiment.

FIG. 23 is a correspondence diagram of a display screen and an operation waveform showing the focus correction operation of the same embodiment.

FIG. 24 is an optical configuration diagram for explaining the operation of the embodiment.

FIG. 25 is an optical configuration diagram for explaining the operation of the same example.

FIG. 26 is an optical configuration diagram for explaining the operation of the same example.

FIG. 27 is an optical configuration diagram for explaining the operation of the example.

FIG. 28 is a block diagram of an image correction device for a projection type display according to a second embodiment of the present invention.

FIG. 29 is a characteristic diagram of the screen of the projection device for explaining the operation of the embodiment.

FIG. 30 is a structural diagram of a screen of a projection device for explaining the operation of the embodiment.

FIG. 31 is a display screen diagram for explaining the operation of the embodiment.

FIG. 32 is a characteristic diagram for explaining the operation of the embodiment.

FIG. 33 is a block diagram for explaining the light transmittance control operation of the same example.

FIG. 34 is an operation waveform diagram for explaining the light transmittance control operation of the same Example.

FIG. 35 is a characteristic diagram for explaining the light transmittance control operation of the same example.

FIG. 36 is a characteristic diagram for explaining the light transmittance control operation of the same example.

FIG. 37 is a block diagram of an image correction apparatus for a conventional first projection type display.

FIG. 38 is a block diagram of an image correction device for a conventional second projection display.

[Explanation of symbols]

 1 Projection Enlargement Display Device 2 Screen 3 Optical Transmission / Reflector 4 Image Sensor 5 Calculation Circuit 6 Correction Waveform Creation Circuit 13 CCD Camera 21 A / D 22 Frame Memory 23 CPU 24 Correction Signal Creation Circuit 25 Test Signal Generation Circuit 70 Differential Filter 71 Linear area detector 72 Center of gravity position detector 73 Error value calculator 75 Transmittance control circuit 76 Optical transmission / reflector

Claims (7)

[Claims] 1. A means for projecting and enlarging and displaying an image on a screen using a projection optical system, an optical transmission / reflector disposed between the projection optical system and the screen, and the optical transmission / reflection. Image pickup means for picking up an image from the body, calculation means for calculating an error value for each color from the output signal of the image pickup means, and for correcting convergence, geometric distortion, brightness, and focus by the output signal of the calculation means And an image correcting apparatus for a projection display, which includes a creating unit that creates a corrected waveform of the image. 2. The optical transmission / reflector is installed at a non-imaging position between the projection optical system and the screen, and the image pickup means picks up a non-imaging image from the optical transmission / reflector. The image correction device for a projection display according to claim 1, wherein the image correction device is installed in the image display device. 3. The optical transmission / reflector is installed at a non-imaging position between the projection optical system and the screen, and the imaging means forms a non-imaging image from the optical transmission / reflector. The image correction apparatus for a projection display according to claim 1, wherein the image correction apparatus is installed so as to capture an image of a position. 4. The optical transmission / reflector is installed at an image-forming position between the projection optical system and the screen, takes a reflection image as a reflector at the time of adjustment, and as a transmissive body at the time of image projection on the screen. The image correction apparatus for a projection display according to claim 1, wherein an image is displayed. 5. The generating means is a conical photoelectric conversion signal whose inclination changes substantially linearly, and calculates the center of gravity position and level which are symmetrical in the horizontal and vertical directions to calculate convergence, geometric distortion, brightness and focus. 2. The image correction apparatus for a projection display according to claim 1, wherein the correction amount is calculated. 6. A means for projecting and enlarging and displaying an image on a screen using a projection optical system, an optical transmission / reflector disposed between the projection optical system and the screen, and the optical transmission / reflection. Image pickup means for picking up an image from the body, calculation means for calculating an error value for each color from the output signal of the image pickup means, and convergence by the output signal of the calculation means,
Image of projection type display having means for creating a correction waveform for correcting any or all of geometric distortion, luminance and focus, and means for controlling the transmittance of the optical transmission / reflector by the correction waveform Correction device. 7. The calculating means calculates the position of the center of gravity and the level that are symmetrical in the horizontal and vertical directions by using a conical photoelectric conversion signal whose slope changes substantially linearly, and then converges the convergence, the geometric distortion and the brightness or the focus. 7. The image correction apparatus for a projection display according to claim 6, wherein the correction amount is calculated.