JPH07143501A - Convergence error detector - Google Patents

Abstract

PURPOSE:To provide a convergence error detector for detecting convergence errors with high precision. CONSTITUTION:This device is provided with a vertical interpolation means 50 for interpolating the vertical data of test signal data at plural convergence error detecting points stored in a memory 11, a D/A converter 4 for converting digital signals from the vertical interpolation part 50 into analog signals, a horizontally interpolated signal preparation section 19 for horizontally interpolated signals, a multiplier 3 for interpolating horizontal data by multiplying the signals from the D/A converter 4 with the horizontally interpolated signals, an image pickup 2 for the image projected on a screen 16 by supplying horizontally interpolated test signals to a display device 17, a position calculator 5 for the head position from the image pickup signal from the image pickup part 2, and an error detector 6 for detecting the convergence error for each color from the signal of the position calculator 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for automatically adjusting a color television receiver, and more particularly to a convergence error detecting apparatus for detecting a convergence error.

[0002]

2. Description of the Related Art Generally, in a projection type display (video projector) for enlarging and projecting an image on a screen by using three projection tubes which emit three primary colors, an incident angle of the projection tube with respect to the screen (hereinafter referred to as a concentration angle). Is different for each projection tube, color shift, brightness change, and focus shift occur on the screen. Since these various corrections are manually corrected visually, there is a problem that adjustment time is required.

Therefore, as a method with high convergence accuracy, a digital converter disclosed in Japanese Patent Publication No. 59-8114.
As a method of automatically correcting the deflection distortion by the presence device, Japanese Patent Publication No. 3-38797 and Japanese Patent Publication No. 1-4855.
No. 3 and U.S. Pat. No. 4,999,703, the automatic convergence correction device detects a convergence error and a method for correcting the convergence error is the convergence error correction method disclosed in Japanese Patent Laid-Open No. 64-54993, and also detects the convergence error of a projection display. As a method for automatically performing correction, there is known a convergence error correction device for a projection display disclosed in Japanese Patent Laid-Open No. 63-48987.

FIG. 33 shows a block diagram of a conventional automatic convergence correction device capable of automatic correction. In FIG. 33, 101 is a display device for which the convergence is to be adjusted, 1
Reference numeral 02 is a signal generator that generates a signal for convergence adjustment, 103 is a signal switcher that switches the signal, 104 is an image pickup device that picks up the display screen of the display device 101, and 105
Is an image processing device for calculating the center of gravity and detecting a misconvergence error, and 106 is a controller for controlling the signal generating device 102, the signal switching device 103 and the image processing device 105.

The operation of the automatic convergence correction device configured as described above will be described below. First, the signal generator 102 generates a low frequency repeating pattern shown in FIG. Here, in FIG. 34, x is the horizontal direction of the screen and y is the vertical direction of the screen. This repetitive pattern is displayed on the display device 101 by the signal switch 103.
The displayed repeated pattern is imaged by the imaging device 104, and the top position of the peak of each waveform (hereinafter abbreviated as the center of gravity position)
Is calculated by the image processing device 105. This is R
The misconvergence error is detected by performing waveforms for each color of (red), G (green), and B (blue), and detecting the difference between their barycentric positions.

The calculation of the position of the center of gravity will be described in detail.
First, the signal of the repetitive pattern picked up by the image pickup unit 104 is A / D converted, and the digital data is linearly interpolated. This figure is shown in FIG. Hi in this figure
(x) is the data of the repeated pattern. Here, only one data of the repetitive pattern has been described, but the same applies to other repetitive patterns.

The position of the center of gravity is obtained by the following quadratic curve approximation. D = {hi (x) - (A · x 2 + B · x + C)} 2dx integral range of the equation is determined by threshold hTH. Here, A · x ² + B · x + C is an approximate quadratic curve, and the coefficient is determined so as to minimize the above equation. That is, D / A = 0, D / B = 0, D / C = 0, and the position x0 of the center of gravity is x0 =-(B / 2A).

As described above, the barycentric position is calculated for each color of R, G, and B by performing the quadratic curve approximation for each repeated pattern, and the difference between the barycentric positions is detected. By using this as the amount of misconvergence error and performing the convergence correction of the display device, the automatic convergence correction can be performed.

[0009]

However, in the conventional image correction apparatus as described above, the calculation of the center of gravity position of the repeated pattern for convergence adjustment is performed by the quadratic curve approximation. Since complicated processing is required, there is a problem in terms of processing speed. Further, since the convergence adjustment signal imaged by the image pickup unit is made into a mountain-shaped waveform line-symmetrical signal and the center of gravity is detected by quadratic curve approximation based on this, multi-scan corresponding to various scanning frequencies, for example. When the convergence adjustment signal picked up by the video projector, color shading, or the gamma characteristic of the display device is not a mountain-waveform line-symmetrical signal, the center-of-gravity detection accuracy deteriorates. .

In view of the above points, the present invention generates a test signal for obtaining a picked-up image signal having a constant inclination and a constant amplitude even for display devices having different scanning frequencies and optical characteristics, and from the picked-up image signal, the start position and each color are generated. An object of the present invention is to provide a convergence error detection device for various displays, which is capable of accommodating various scanning frequencies with high accuracy by detecting the convergence error for each.

[0011]

To achieve the above object, a first invention is to provide a detection point generating means for generating a plurality of convergence error detection points horizontally and vertically on a screen of a display device, and the detection point generating means. Storage means for digitally storing the test signal data for the point; vertical interpolation means for interpolating vertical data from the data from the storage means;
Conversion means for converting the digital signal from the vertical interpolation means into an analog signal, interpolation signal generation means for generating a horizontal interpolation signal for horizontal direction data interpolation from the address signal of the storage means, and a signal from the conversion means Is supplied to the display device by a horizontal interpolating means for interpolating horizontal direction data by multiplying by the interpolating signal from the interpolating signal creating means, and an image displayed on the display screen is supplied to the display device. An image pickup unit for picking up an image, a position calculation unit for calculating a head position from an image pickup signal whose inclination from the image pickup unit is a straight line, and an error detection unit for detecting a convergence error for each color from the signal of the position calculation unit are provided. ing.

According to a second aspect of the present invention, a signal generating means for generating a plurality of mountain-shaped detecting test signals on the screen of the display device, and a test signal from the signal generating means are supplied to the display device. Image pickup means for picking up a test signal image displayed on a display screen; position calculating means for calculating a head position from an image pickup signal corresponding to a detection point from the image pickup means where the inclination is a straight line and the amplitude is constant; An error detection unit that detects a convergence error for each color from the signal of the position calculation unit is provided.

According to a third aspect of the present invention, a signal generating means for generating a plurality of mountain-shaped detection test signals on the screen of the display device, and a test signal from the signal generating means are supplied to the display device. Image pickup means for picking up the test signal image displayed on the display screen, position calculation means for calculating the head position from the image pickup signal from the image pickup means, and convergence error value and vector for each color from the signal of the position calculation means. An error detecting means for detecting the direction and a correction waveform creating means for creating a convergence correction waveform of a correction area corresponding to the display area of the test signal from the signal of the error detecting means are provided.

[0014]

According to the first aspect of the present invention, a test signal for obtaining an image pickup signal whose inclination is always linear is generated even for different scanning frequencies, and the leading position and the convergence error for each color are detected from the image pickup signal. By this, a highly accurate convergence error in the multi-scan display is detected.

According to the second aspect of the present invention, even for display devices having different optical characteristics, the convergence error between the head position and each color is always detected from the image pickup signal of which the inclination is linear and the amplitude is constant. Detect the high-precision convergence error of.

According to the third aspect of the invention, by detecting the convergence error from the error value from the scanning direction of the display device, the image pickup signal, and the vector direction, the time required for the adjustment is greatly shortened and the error is highly accurate. Detection can be realized. Also,
By performing automatic adjustment using these error signals, complicated adjustment becomes unnecessary and the adjustment time is greatly shortened.

[0017]

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 convergence error detection device in the first embodiment of the present invention.

In FIG. 1, 1 is a detection test signal corresponding to an image adjustment point of the projector 17 in the convergence error detection, 2 is an image pickup unit for picking up the screen 16, and 5 is an image pickup signal from the image pickup unit 2. A position calculation unit that calculates position information from data, 6 is an error detection unit that detects a convergence error from the output of the position calculation unit 5, and 7 is a correction signal for convergence correction from the output of the error detection unit 6. A control signal generator 8 for controlling the deflection unit 9 (DY) of the CRT and an auxiliary deflection unit 10 (convergence yoke = CY) by a correction signal generated by the correction signal generator 7. A switch for switching between a video signal and a test signal, 13 is a drive circuit for driving the CRT 14 of the projector 17, and 15 is an image displayed on the CRT 14 on the screen 16. Projection lens for morphism, 20 converter -
A test signal generator that generates a test signal for adjusting the presence.

The test signal generator 20 also detects a detection point generator 18 for generating an address signal of a detection point, a memory 11 for storing test signal data, and data interpolation in the vertical direction from the data from the memory 11. Vertical interpolation unit 5
0, a D / A converter 4 for converting a digital signal from the vertical interpolation unit 50 into an analog signal, and a horizontal interpolation signal creation unit 19 for creating a horizontal interpolation signal from the horizontal address signal from the detection point generation unit 18. And the horizontal interpolation signal creation unit 19
From the D / A converter 4 and the horizontal interpolation signal from the multiplication unit 3.

The operation of the convergence error detecting apparatus of the first embodiment of the present invention constructed as above will be described with reference to the operation diagram of FIG. First, the convergence error detection test signal 1 is displayed on the screen 16. Here, the convergence error detection is performed for each of the R, G, and B CRTs, but since the adjustment operation is the same, only G will be described here. The test signal of this embodiment is shown in FIG. As can be seen from FIGS. 2A and 2B, the test signal has a quadrangular pyramid shape when the screen 16 is the bottom surface and the signal level direction is the height direction. In order for the test signal displayed on the screen to be linear in the level direction as described above, gamma correction in the display device is required. The waveform diagram of FIG. 3 is used for the following description of the test signal generator 20 in consideration of gamma correction.

Generally, the relationship between the input signal voltage (E) of the CRT and the light emission output (L) can be approximated by the following equation 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 test signal voltage (E) is converted to E ^−r in the test signal generator 20, the light emission output (L) will be
L = k · E, which is linear to the input.

First, an outline of a method of creating a test signal will be described. In FIG. 1, the synchronization signal is supplied to the detection point generation unit 18 and, for example, in the horizontal direction 1 shown in FIG.
Three detection point address signals and nine detection point address signals in the vertical direction are created. Each address signal from the detection point generator 18 is stored in the memory 1
1 and the data of the test signal for detection is written in the address area corresponding to the detection point. Figure 3 (b) (c)
The data of two types of test signals are written (● mark)
A memory map is shown. For example, in FIG.
Data is written at the position of × 3 = 9 points, 5 × 5 = 25 points in FIG.

The nine detection points shown in FIG. 3 (b) are shown in FIG. 3 (c) when the error of geometrical distortion such as deflection distortion is detected.
Point detection points are used when detecting convergence errors. The data from the memory 11 is supplied to the vertical interpolation unit 50, and data interpolation is performed between the detection points in the vertical direction to perform data interpolation between adjacent detection points in the vertical direction as shown by the solid right line in FIG. Done. The digital signal in which the vertical data is interpolated from the vertical interpolator 50 is converted into an analog signal by the D / A converter 4. A signal shown in FIG. 3D is output as a horizontal conversion waveform from the D / A converter 4 when the data shown in FIG. 3C is written.
The horizontal address signal from the detection point generator 18 is supplied to the horizontal interpolation signal generator 19 to generate the horizontal interpolation signal shown in FIG.

The horizontal interpolation signal from the horizontal interpolation signal generating section 19 shown in FIG. 3 (e) and the analog signal from the D / A converter 4 shown in FIG. 3 (d) are supplied to the multiplying section 3 and both signals are supplied. Multiplication is performed, and as shown in FIG. 3 (f), a test signal in which horizontal data is interpolated is output. Therefore, as shown in FIGS. 4A and 4B, the test signal display screen when the data of the two types of test signals shown in FIGS. 3B and 3C is written is shown in FIG. 4 (a)) and 25 detection points (FIG. 4 (b)) are displayed on the screen as pyramidal test signals. In the description of the present embodiment, in order to make the basic operation easy to understand, the case where the gamma correction of the CRT is not taken into consideration has been described.

Next, FIG. 5, FIG. 6, FIG. 7 and FIG. 8 will be used to explain the case where the CRT gamma correction is taken into consideration. FIG. 5 shows a light emission characteristic diagram of drive voltage versus screen brightness of a general projector. As shown in FIG. 5, since the image receiving gamma coefficient γ of the CRT is 2.2, the inverse gamma correction is necessary to make the inclination of the test signal on the screen linear. This correction is determined by the vertical interpolation calculation method of the vertical interpolation unit 50 of FIG. 1 and the horizontal interpolation signal of the horizontal interpolation signal generation unit 19, and the interpolation method between the detection points is shown in FIG. It can be easily realized by performing. FIG. 7 shows the interpolation processing in the horizontal direction.

FIG. 7B shows a conversion signal obtained by D / A converting the data (marked with ●) written in the memory 11 shown in FIG. 7A by the D / A converter 4. As the horizontal interpolation signal from the horizontal interpolation signal creating circuit 19, a signal corresponding to the input / output characteristics of FIG. 6 is created as shown in FIG. 7C. The horizontal interpolation signal from the horizontal interpolation signal generation circuit 19 shown in FIG. 7C and the conversion signal from the D / A converter 4 shown in FIG. 7B are supplied to the multiplication unit 3 to generate the signal shown in FIG. The inverse gamma-corrected test signal shown in is obtained. This test signal is supplied to the projector 17,
By image-capturing the image light of the test signal displayed on the screen 16 by the image capturing unit 2 and photoelectrically converting the image light, a horizontal test signal having a linear inclination can be created as shown in FIG.

Similarly, FIG. 8 shows the interpolation processing in the vertical direction. Written in the memory 11 shown in FIG. 8A (marked with ●)
FIG. 8B shows a conversion signal obtained by linearly interpolating the data in the vertical interpolation unit 50 and D / A converting it in the D / A converter 4. The vertical interpolation unit 50 performs an approximate interpolation process of curve approximation corresponding to the input / output characteristic of FIG. 6 to obtain the inverse gamma-corrected test signal shown in FIG. 8C. This test signal is supplied to the projector 17, and the image light of the test signal displayed on the screen 16 is imaged by the image pickup unit 2 and photoelectrically converted, so that the inclination becomes a straight line as shown in FIG. 8D. A vertical test signal can be created. In this way, a quadrangular pyramid-shaped signal having a linear inclination, which is the test signal for detection shown in FIG. 2, can be created.

Next, a convergence error detecting method will be described. In the explanation, a block diagram showing a detailed configuration of the position calculation unit 5 in FIG. 9, FIG. 10, FIG. 11, FIG. 12, and FIG.
To use.

In FIG. 9, 21 is a CCD camera for picking up a test signal displayed on the screen, and 22 is a CC.
An A / D converter for A / D converting the image pickup signal from the D camera 21, 23 a frame memory for storing the image data from the A / D converter 22, 24 a differential filter for obtaining the difference between the imaged test signals , 25 is a linear region calculation unit that obtains a linear portion of the test signal from the output of the difference filter 24,
Reference numeral 26 is a center-of-gravity position calculation unit that calculates the center-of-gravity position of the test signal from the output of the linear region calculation unit 25, and 27 is an error detection circuit that detects an error for each color from the center-of-gravity position signal from the center-of-gravity position calculation unit 26. .

The method of calculating the barycentric position of the test signal will be described below. In the present embodiment, the CCD camera 21 is used as the image sensor of the image capturing unit 2 for the sake of explanation, but even an image capturing device having a slow pulse response speed such as a photodiode has a high accuracy because it is a test signal of a low frequency component as described above. Needless to say, the above can be detected and corrected, and can also be realized by detection on a non-imaging surface where the focus is deviated.

There are three reasons for the detection by the CCD camera 21. First, when the information of the entire screen is taken in and the geometric distortion is corrected, the geometric distortion of the detection system, which is the image sensor, cannot be ignored, so the element must have less than 1% distortion. Secondly, even on a display screen having a different scanning frequency of the display device, the scanning is converted to a specific scanning frequency of the image pickup system, so that subsequent image processing can be performed under constant conditions. 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 camera is used for the above reasons.

In the position calculation section 5, a high-accuracy position can be obtained even in a system with a low detection accuracy in which the current type black and white CCD of about 380,000 pixels and the sample frequency of the A / D converter 22 are processed at about 14.32 MHz. Detection is required.
In the A / D converter 22 of FIG.
= 14.32 MHz (sampling period 70 ns) is shown, and the center of gravity position which is the apex of the photoelectric conversion signal at this time exists at the sample point S7. In FIG. 10B, the barycentric position, 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, the position of the center of gravity is calculated by linear approximation from the voltage of the sample point near the position of the center of gravity, and the position can be detected with high accuracy.

As shown in FIG. 10C, 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 falling sampling point S9 of the photoelectric conversion signal.
By calculating the intersection of the linear approximation data of the data D9 to S7 of S7, the center of gravity position can be calculated with high accuracy even in a system with coarse detection accuracy.

The solid line in FIG. 11A represents the actual test signal,
The broken line shows the signal obtained by interpolating the sampling signal from the CCD camera by the low pass filter (LPF). As can be seen from FIG. 11 (a), rounding of the apex portion of the test signal occurs due to the low sampling frequency, and when the barycentric position is obtained from the output signal of such a CCD, the actual barycentric position is point A. However, 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.

The calculation of the position of the center of gravity is performed by dividing the data into a plurality of correction areas corresponding to the respective test signals as shown in FIG. 2 and calculating the position of the center of gravity of each area. 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, the operation of detecting only the linear portion of the test signal data is performed excluding the rounding area by sampling. This is performed by detecting the difference signal of the image data of the test signal by the difference filter 24. When the image data of the test signal shown in FIG. 11A is input to the differential filter 24, the output data is as shown in FIG. 11B. Further, from the output data, the linear area calculation unit 25 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 barycentric position 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 test signal at this intersection as the center of gravity. As shown in FIG. 11B, 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 part A, the linear part A.
Where α is the slope of the linear part B, data DB (corresponding address nB) is the most apex of the linear part B, and β is the slope of the linear part B,
The center-of-gravity position x can be determined by the formula shown below.

X = nA + (DB−DA−β · (nB−nA)) / (α−β) Thus, by determining the center of gravity position by linear extrapolation,
For example, even when the CCD camera is coarsely sampled, it is possible to detect the position of the center of gravity with a high precision of a sampling period or more.

The center of gravity obtained as described above is expressed as coordinates on the address map corresponding to each pixel of the CCD. For example, an address map when a black and white CCD camera having 380,000 pixels is used is shown in FIG. As shown in FIG. 12, this address map has 768 points (x1 ...
x768) and addresses of 493 points (y1 to y493) in the vertical direction. FIG. 12B shows a partially enlarged view of the address map when the center of gravity position (black circle ●) of the test signal is calculated. As shown in FIG. 12B, the position of the center of gravity is represented as a point on the address map, such as (x = 12.7, y = 11.3). Similarly, the position of the center of gravity of the test signal corresponding to each correction area on the display screen is mapped on this address map.

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 secondary test signal like a conventional SIN ² waveform, and FIG. 13B shows a quadrangular pyramid test signal of this embodiment. These test signals are applied to the horizontal scanning lines ln (n = 1 to 1).
The characteristic when cut in step 5) becomes a mountain-like characteristic in the same way, but in the case of the conventional test signal, since the waveform is secondary, the quantization error differs with the signal level, and the optimum quantum However, the detection accuracy is reduced. On the other hand, in the test signal of the quadrangular pyramid of the present embodiment, since the signal is linear, it is possible to perform highly accurate calculation by selecting the optimum number of quantization bits.

Next, a method of detecting an error value from the gravity center position calculation signal obtained as described above will be described. When calculating the convergence error, as shown in the waveform diagram of FIG. 14A, the G signal is treated as the reference signal, and the R signal calculates the error value of t1 in the left direction and the B signal calculates the error value of t2 in the right direction. .

Further, in the case of calculating the geometric distortion error, FIG.
As shown in the waveform diagram of FIG. 4 (b), a specific sampling point S20 is treated as a reference signal, and the R signal has an error value of t3 leftward, the G signal has a leftward t4, and the B signal has an error value of t5 leftward. It is calculated. The calculation of the barycentric position and the error value is managed by the information corresponding to the address of the sample point. Therefore, as the reference signal for calculating the geometric distortion error, for example, the horizontal direction 76
8 points (x1 to x768), vertical 493 points (y1 to y493)
Will be treated as a reference signal.

After calculating the position of the test signal as described above,
The error calculation circuit 27 calculates the error for each color.
A correction signal for geometric distortion / convergence is generated from the calculated error information by the correction signal generation unit 7, and the control unit 8 of the projector 17 is controlled so that the error becomes 0 by this correction signal. The correction signal generating section 7, the deflecting section 9 and the auxiliary deflecting section 10 perform the same operations as those of a general color television receiver, and therefore their explanations are omitted. Below, R, B
The geometric distortion / convergence error detection is completed by performing the same processing for the above.

Next, FIGS. 15 and 16 will be used to describe the test signal generation corresponding to the scanning frequency and the method of sharing the test signal generation section 20 and the correction waveform generation section 7.
It should be noted that the same reference numerals are given to those performing the same operation as in FIG.

First, the horizontal synchronizing signal from the input terminal 28 is supplied to a PLL (phase locked loop) circuit 30, and P
The LL circuit 30 creates the horizontal interpolation clock signal of FIG. The correction clock signal of FIG. 16C obtained by dividing the horizontal interpolation clock signal by 1/2 is supplied to the address generation circuit 14. Fig. 16 (e) shows the horizontal sync signal 1
Indicates the horizontal period. In addition, the detection point 1 in the screen of FIG.
3 points, 2 extrapolation points outside the screen and 1 data BLK in total 16
Figure 6 (f) shows the test signal and address signal when the points
It shows in (g).

FIG. 16A shows a test signal between the detection points 1 and 2, and between the detection points, as shown in FIG. 6B, there are four convergence correction data systems (RH, R-). V, B
-H, B-V) and test signal data 2 systems (test 1,
Addresses of correction data are time-division multiplexed in a total of 6 types of 2). Therefore, the correction clock signal is shown in FIG.
6 (c) shows the horizontal interpolation clock signal in FIG. 16 (d).
Is output as a clock signal. For example, the correction clock signal CLKC when the horizontal scanning frequency is 33.75 kHz
The horizontal interpolation clock signal CLKO is as follows. <Correction clock signal CLKC> CLKC = 33.75 kHz × 12 × 16 = 6.48 MHz <Horizontal interpolation clock signal CLKO> CLKO = 33.75 kHz × 12 × 16 × 2 = 12.96 MHz In the address generation circuit 31, the PLL circuit is used. Each address signal is created from the correction clock signal from 30 and the vertical synchronizing signal from the input terminal 29, and is supplied to the CPU 32 and the memory 11. The horizontal synchronizing signal and the vertical synchronizing signal from the input terminals 28 and 29 are supplied to the CPU 32, the number of horizontal synchronizing signals is counted in the vertical period, the number of scanning lines and scanning frequency of one field are obtained, and the scanning lines are also scanned. The number of scanning lines between detection points is calculated from the detection signal to generate a curve approximation coefficient corresponding to each scanning line. With this approximation coefficient, curve approximation interpolation between detections in the vertical direction as shown in FIG. 8 is performed. ing.

The CPU 32 calculates the number of scanning lines between the detection points from the scanning line detection signal to generate a corresponding approximate coefficient for each scanning line, and the approximate interpolation between the detection points is performed by this approximate coefficient. In FIG. 8E, the number of scanning lines between the detection points (P1, P2) is n, and the correction data of the adjustment points P1, P2 are D1, D2.
Then, the correction data Di of the i-th scanning line from the adjustment point P2 in FIG. 8 (f) is expressed by the following equation. Di = (D1−D2) × i / n + D2 where D1 is the correction data of the adjustment point P1, D2 is the correction data of the adjustment point P2, Di is the correction data of the i-th scanning line from D2, and n is between the adjustment points. The number of scanning lines, and i / n are interpolation coefficients.

The correction data D1 and D2 are stored in the memory 11, and the CPU 32 generates the number of scanning lines between detection points and the interpolation coefficient, and the signal is used to perform an approximate interpolation process in the vertical direction. .

Data corresponding to each scanning line which has been subjected to vertical interpolation processing by software processing from the CPU 32 is stored in the frame memory 33. A signal obtained by serial / parallel converting the time-division multiplexed data of the six types of correction data from the frame memory 33 is supplied to the D / A converter 34, and a convergence correction signal of an analog signal is output from the output terminal 38.

The horizontal interpolation clock signal and the horizontal address signal from the PLL circuit 30 are stored in the gamma correction ROM 35.
Is supplied to. The gamma correction data shown in FIG. 6 is written in the gamma correction ROM 35, the horizontal interpolation signal shown in FIG. 7 is read, and this signal is converted into an analog signal by the D / A converter 36. The horizontal interpolation signal from the D / A converter 36 is supplied to the reference potential terminal of the multiplication type D / A converter 34, the test signal data is multiplied by the horizontal interpolation signal, and the test signal shown in FIG. Is output from. The test signal data as shown in FIG. 3 is written in the data (tests 1 and 2) in the test signal area of the memory 11, and the test for geometric distortion and convergence shown in FIG. A signal is generated.

Further, as described above, in the horizontal data reading, since the clock signal corresponding to the horizontal scanning frequency is automatically generated in the PLL circuit 30 using the horizontal synchronizing signal as an input signal, the horizontal interpolation is performed. The processing is unnecessary.

Next, FIGS. 17 and 18 will be used to describe in detail the method of interpolating the test signal corresponding to the scanning frequency. 17A and 17B show operation waveforms of horizontal interpolation. FIG. 17A shows a horizontal inter-detection point signal, and FIG. 17B shows a horizontal interpolation clock signal. The horizontal interpolation data (hexadecimal) shown in FIG. 17C is written in the gamma correction ROM 35 shown in FIG.
The A converter 36 converts the analog signal into an analog signal to generate a horizontal interpolation signal shown in FIG. For example, horizontal interpolation clock signals CLKO at horizontal scanning frequencies of 33.75 kHz and 67.5 kHz are shown in FIGS. 17 (b) and 17 (f), and the detection points of FIGS. 17 (a) and 17 (e) are shown. The frequency is 24 times the frequency of the inter-signal, and the clock frequency is as follows. <At fH = 33.75 kHz> CLKO = 33.75 kHz × 12 × 16 × 2 = 12.96 MHz <at fH = 67.5 kHz> CLKO = 67.5 kHz × 12 × 16 × 2 = 25.92 MHz Since the clock signal corresponding to the horizontal scanning frequency can be automatically created, the horizontal interpolation signal corresponding to the scanning frequency is created as shown in FIGS. 17D and 17G. By performing the horizontal interpolation processing using this horizontal interpolation signal, the horizontal interpolation processing corresponding to the scanning frequency is performed.

FIG. 18 shows operation waveforms for vertical interpolation. FIG. 18A shows a signal between detection points in the vertical direction, and FIG.
The horizontal sync signal is shown in FIG. In the signal source shown in FIG. 18B, the detection points are composed of nine scanning lines.
In the signal source shown in (d), 19 scanning lines are provided between the detection points. With the number of scanning lines shown in FIG. 18 (d), the interpolation coefficient indicated by ● in the solid line in FIG. 18 (c) is generated, and in the scanning line shown in FIG. 18 (d), the correction coefficient indicated by ● in the solid line in FIG. Generated, Figure 8
Interpolation processing in the vertical direction is performed based on the approximation formula described in (1).

Thus, even when the number of scanning lines is different, the correction coefficient corresponding to the number of scanning lines is created as shown in FIGS. 18B and 18D. By performing vertical interpolation processing using this interpolation coefficient, vertical interpolation processing corresponding to the number of scanning lines is performed.

As described above, according to the present embodiment, a test signal is generated that can obtain an image pickup signal whose slope is always linear even for different scanning frequencies, and the leading position and the convergence error for each color are detected from the image pickup signal. By detecting it, highly accurate convergence error detection in a multi-scan display can be realized.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 19 is a block diagram of the convergence error detecting device in the second embodiment of the present invention.

In FIG. 19, reference numeral 39 denotes a position calculation unit for calculating the center-of-gravity position information from the data of the image pickup signal output from the image pickup unit 2 and having a linear inclination and a constant amplitude. 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.

In order to improve the detection accuracy of the barycentric position detection in the position calculation unit 39, there are many linear regions in the signal component as described in the first embodiment, and the optimum quantized bit High precision calculation can be performed by selecting the number.

First, before describing the operation of the present embodiment, the brightness characteristics of a projection display such as the projector 17 will be described. 20 and 21 show the directional characteristics and structure of the transmissive screen 68 of the rear projection type projector.

As shown in FIG. 21, 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. 20 shows the directional characteristics of the screen having such a shape. As shown in FIG. 20, 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. 22 and 23 show the light quantity of each part of the screen when the center of the screen is 100% in the case of the rear projection type projector. FIG. 23 shows the amount of light obtained by normalizing the luminance distribution in the left-right 12 direction (broken line), the vertical 11 direction (solid line), and the diagonal l3 (dotted line) of the display screen shown in FIG. Figure 2
As shown in FIG. 3, 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. This is due to the projection optical system such as a lens and a screen.

Therefore, in the position calculating section of this embodiment, FIG.
By correcting the decrease in the amount of peripheral light shown in and detecting the center of gravity position from the image pickup signal having a constant amplitude, highly accurate detection of the center of gravity position can be realized.

The block diagram of FIG. 24 and FIGS. 25 and 26 will be used in order to explain in detail the method of controlling the constant amplitude in this embodiment.

In FIG. 24, 21 is a CCD camera for picking up the test signal 1 displayed on the screen, and 40 is the peripheral luminance lowered by the luminance characteristics of the display device from the CCD camera 21 and shown in FIG. 25 (a). A sensitivity setting circuit for setting the sensitivity of the image pickup signal, 22 is an A / D for A / D converting the image pickup signal output from the sensitivity setting circuit 40 and having a constant amplitude.
A converter, 41 is an amplitude detection circuit for detecting the amplitude of a predetermined level from the A / D converter 22, 23 is a frame memory for storing the image data from the A / D converter 22, and 24 is a captured test signal. A difference filter for obtaining the difference, 25 is a linear region calculation unit for obtaining a linear portion of the test signal from the output of the difference filter 24, and 26 is a center of gravity position calculation unit for calculating the center of gravity position of the test signal from the output of the linear region calculation unit 25. Therefore, the detection signal from the amplitude detection circuit 41 is supplied to the sensitivity setting circuit 40 to make the amplitude of the image pickup signal constant.

FIG. 25 (b) shows an image pickup signal input to the quantized 8-bit A / D converter 22, which is a digital signal corresponding to 256 steps of quantized 8-bit. As shown in the waveform of the case where the number of bits is effectively used in the solid line in FIG. 25B and the case where the number of bits is not effectively used in the broken line, the accuracy of the linear region calculation and the center of gravity position calculation in the subsequent stage is as shown in FIG. b) The broken line has half the detection accuracy of the solid line. Therefore, the amplitude detection circuit 41 detects whether the image pickup signal of the detection region for which the center of gravity position is to be calculated is at the amplitude detection level (200 steps) shown in FIG. 25B, and controls the sensitivity setting circuit 40. ,
Feedback control is performed so that the image pickup signal in the detection area always has 200 steps. Therefore, the amplitude indicated by the broken line in FIG. 25B is set to the amplitude detection level indicated by the solid line. The subsequent position calculation operation is the same as that of the first embodiment, and therefore its explanation is omitted.

The means for making the inclination of the image pickup signal linear are the test signal generator 20 as described in the first embodiment.
The image receiving gamma correction is performed in. The sensitivity can be set on the side of the test signal generator, but it is necessary to control the gamma slope in accordance with the inverse correction of the constant amplitude. From the above points, as a method of inputting a signal having a linear inclination of the image pickup signal to the position calculating section 39, linearization of the inclination is performed by the test signal generating section (electrical signal), and constant amplitude is detected by the position detecting section. (Photoelectric conversion signal) is used to perform stable position calculation.

FIG. 26 is a projector 17 for displaying a large screen using red, green and blue (hereinafter abbreviated as R, G and B) CRTs.
FIG. 3 is a light emission characteristic diagram of R, G, and B of FIG. 27 (a) shows a waveform of a quadrangular pyramidal test signal similar to that of FIG. 2, and FIG. 27 (b) shows a photoelectric conversion of the quadrangular pyramidal test signal of FIG. 27 (a) affected by the saturation of the phosphor. The waveform of the scanning line cross section of the signal is further shown in FIG.
7 (c) shows the waveform of the video signal applied to the CRT cathode electrode. As can be seen from FIG. 26, in contrast to the linear characteristic of G, the emission characteristic of B has a non-linear region above 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, the characteristics of the photoelectric conversion output obtained by imaging the quadrangular pyramidal test signal displayed on the display device by the imaging unit by the saturation characteristics of the phosphor are, for example, when viewed in the scanning line cross section of the test signal, As shown by the solid line in FIG. 27 (b), it has a saturation characteristic in the high luminance region. In order to correct this saturation characteristic, the drive circuit 1
The gamma correction circuit in FIG. 3 performs gamma correction of the video signal as shown by the solid line in FIG. 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. 27 (b), and detection with higher accuracy becomes possible.

As described above, according to the present embodiment, even for display devices having different optical characteristics, by detecting the leading position and the convergence error for each color from the image pickup signal having a constant inclination and a constant amplitude, It is possible to realize highly accurate convergence error detection in the display device.

Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 28 is a block diagram of the convergence error detecting device in the third embodiment of the present invention.

In FIG. 28, reference numeral 43 is a position calculation unit for calculating position information from the data of the image pickup signal output from the image pickup unit 2, and 42 is an error for each color based on the gravity center position calculation signal from the position detection unit 5. In the error / vector detection unit that detects the value and vector direction, the position calculation unit 43 and the error / vector detection unit 42 calculate the relative relationship between the display system and the imaging system, and the error value and the vector are detected from this information, The time required for adjustment can be greatly shortened and highly accurate error detection can be realized.
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.

First, before explaining the operation of the present embodiment, it is necessary to know the relative positional relationship between the display system and the image pickup system. The position calculating section 43 for calculating this relative positional relationship will be described with reference to FIG. The operation will be described. FIG. 29 shows the photoelectric conversion signal from the image pickup unit 2 for the G test signal 12 which is the reference color signal displayed on the screen 16 and the signal waveform for each scanning line. The scanning direction of the projector 17 and the imaging unit 2
29 (a) to 29 (d) show operation waveforms when the imaging directions of are the same.
29 (e) to (j) show operation waveforms when the scanning direction of the projector 17 and the imaging direction of the imaging unit 2 are different from each other.

First, the case where the scanning direction of the display system and the imaging direction of the imaging system are the same will be described. 29 (a) shows the photoelectrically converted signals composed of the scanning lines (l11 to l15) in the image pickup unit 2, and FIG. 29 (b) shows the signals of the scanning lines (l11, l15) in FIG. ), The signals of the scanning lines (l12, l14),
FIG. 29D shows the signal of the scanning line (l13). The position calculating unit 43 calculates the position of the center of gravity and the rising and falling slopes of the quadrangular pyramidal photoelectric conversion signal. In this case, as shown in FIGS. 29 (c) and 29 (d), the rising and falling slopes have a relationship of inclination angles θ1 = θ2 and θ3 = θ4.
Therefore, the relative relationship between the display device and the image pickup device can be known from the rising and falling inclination angles of the photoelectric conversion signal.

Next, the case where the scanning direction of the display system and the imaging direction of the imaging system are different will be described. FIG. 29 shows signals photoelectrically converted by the scanning lines (l21 to l25) in the imaging unit 2.
29E shows the signal of the scanning line (l21), FIG. 29 (g) shows the signal of the scanning line (122), and FIG.
The signal of the scanning line (l23) is shown in (h), the signal of the scanning line (l24) is shown in FIG. 29 (i), and the scanning line (l25) is shown in FIG. 29 (j).
Signal of. Similar to the above, the rising and falling slopes of these signals are calculated. In this case, FIG.
The inclination angles shown in (g), (h), and (i) have a relationship of θ5 ≠ θ6 and θ9 ≠ θ10.

As described above, the rising and falling slopes of each scanning line unit of the quadrangular pyramid signal are calculated, and by comparing them, the positional relationship between the scanning direction of the display device and the scanning direction of the image pickup device is calculated. By calculating the information based on the positional relationship, it is possible to perform highly accurate geometric distortion and convergence correction irrespective of the relative positional relationship between the display system and the imaging system.

The relative positional relationship between the display system and the image pickup system and the calculation used will be described below. FIG. 30A shows an address map of the frame memory in the position calculation unit 43 when the display scanning direction and the imaging direction are the same direction, and FIG.
8 shows an address map of the frame memory of the position detection unit 43 when the display scanning direction and the imaging direction are different (when the imaging unit is tilted in the right rotation direction). If the address map shown in FIG. 30B is treated as a reference signal of geometric distortion, the imaging condition of the imaging system is also corrected, so that the geometric distortion correction in the opposite direction is performed. Therefore, as described above, the inclination angle of the rising and falling of the linear portion of the test signal is detected to detect the relative relationship between the display system and the image pickup system, and the inclination angle is detected before the correction shown in FIG. 30 (b). By converting the address map of FIG. 30 into the address map shown in FIG. 30C, highly accurate geometric distortion correction and convergence error detection are performed without being affected by the relative relationship between the display system and the imaging system.

Next, the block diagram of FIG. 31 will be used to describe the operations of the position detecting section and the error / vector detecting section in detail. Descriptions of operations that are similar to those of FIG. 9 are omitted. As described with reference to FIG. 30, the calculation signal from the linear region calculation unit 25 is supplied to the inclination detection circuit 44, and the inclination of the rising and falling of each scanning line unit of the quadrangular pyramid signal determines the scanning direction of the display device and the imaging direction. The relative relationship between the positional relationship display system and the imaging system in the scanning direction of the device is detected. Tilt detection circuit 44
The detection signal from is supplied to the center-of-gravity position calculation unit 26, and the center-of-gravity position and tilt detection signals are created. Center of gravity position calculator 26
The center of gravity position signal from is supplied to the error detection circuit 27 and the vector detection circuit 45.

The error detection circuit 27 detects the error for each color, and the vector detection circuit 45 detects the relative relationship between the display system and the image pickup system, the data, and the vector before / after correction. Both detection signals from the error detection circuit 27 and the vector detection circuit 45 are supplied to the control signal generation circuit 46, and a control signal for controlling the correction signal generation unit 7 is created.

Next, FIG. 32 will be used to explain the operation of the error / vector detection unit 42. In FIG. 32, the solid line shows the test signal coordinates before the correction, the broken line shows the test signal coordinates after the first correction, and the + mark shows the final convergent coordinates. Since the quadrangular pyramidal test signal from the test signal generator 20 always has the maximum value in the same scanning direction of the display system, the vector of the maximum value is detected to detect the horizontal direction (horizontal direction) of the display system. / Vertical direction) will be known.

FIG. 32 (a) shows a case where the convergence point 1 exists in the same horizontal direction of the display system and the image pickup system. The position calculation unit 43 calculates the barycentric position of the solid line coordinates, and the error / vector detection unit 42 creates approximate data based on the coordinates of the barycentric position. This approximate data is supplied to the correction waveform generation unit 7 to create a correction waveform, and then the control unit 8 is driven (operation B) to reach the coordinate position of the broken line. The position of the center of gravity is calculated again by the position calculation unit 43 from the coordinates of the broken line, and the error and vector of the solid line (before correction) and the broken line (after correction) are calculated by the error detection circuit 27 and the vector detection circuit 45 based on the coordinates of the position of the center of gravity. The direction is being detected. This movement amount and vector direction (movement direction)
More predicted data at the convergence point 1 is created by the control signal generation circuit 46. After the predicted data is supplied to the correction waveform generation unit 7 to create a correction waveform, the control unit 8 is driven again (operation B) to reach the coordinate position of the final convergence point 1 (+ mark).

FIG. 32B shows the case where there is a convergence point 2 in which the display system and the image pickup system are different in the horizontal direction, and the case where the camera of the image pickup system is tilted. The position calculation unit 43 for solid line coordinates calculates the center of gravity position, and the error / vector detection unit 42 creates approximate data based on the coordinates of the position of the center of gravity. This approximate data is supplied to the correction waveform generation unit 7 to create a correction waveform, and then the control unit 8 is driven (operation B) to reach the coordinate position of the broken line. The position calculation unit 43 calculates the barycentric position again from the coordinates of the broken line, and the error / vector detection unit 42 detects the error between the solid line (before correction) and the broken line (after correction) and the vector direction based on the coordinates of the center of gravity position. To do. Prediction data of the convergence point 2 is created from this movement amount and the vector direction (movement direction).
This predicted data is supplied to the correction waveform generation unit 7 to create a correction waveform, and then the control unit 8 is driven (operation B) to reach the coordinate position of the final convergence point 2 (+ mark).

FIG. 32C shows the case where there is a convergence point 3 which is different from the scanning direction of the display system. As a cause for this, particularly in a projector using an electromagnetic focusing CRT or the like, even if the horizontal direction is corrected due to the interference of the magnetic field between the electromagnetic focus coil and the convergence coil, it does not move in the horizontal direction and is corrected in the left-handed direction. That is the case. The position calculation unit 43 for solid line coordinates calculates the center of gravity position, and the error / vector detection unit 42 creates approximate data based on the coordinates of the position of the center of gravity.

After this approximate data is supplied to the correction waveform generator 7 to create a correction waveform, the controller 8 is driven (operation a) to reach the coordinate position indicated by the broken line. The position calculation unit 43 calculates the barycentric position again from the coordinates of the broken line, and the error / vector detection unit 42 detects the error between the solid line (before correction) and the broken line (after correction) and the vector direction based on the coordinates of the center of gravity position. To do. Prediction data of the convergence point 3 is created from this movement amount and the vector direction (movement direction). In this case, as the prediction data, prediction data for correcting the horizontal direction and the vertical direction is created. This predicted data is supplied to the correction waveform generation unit 7 to create a correction waveform, and then the control unit 8 is driven (operation B) to reach the coordinate position of the final convergence point 3 (+ mark). In this way, by detecting the coordinate error value and the vector direction based on the approximate data, it is possible to perform convergence error detection that can converge at least twice.

As described above, according to this embodiment, by detecting the convergence error from the scanning direction of the display device, the error value from the image pickup signal, and the vector direction, the time required for the adjustment is greatly shortened and the convergence time is increased. Accuracy error detection can be realized. In addition, since automatic adjustment is performed using these error signals, complicated adjustment becomes unnecessary, and a significant reduction in adjustment time can be realized.

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, 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 of detecting the convergence error as the position detection of the display device has been described, but other position detection errors may be performed.

In the first embodiment, the horizontal and vertical barycentric positions of each area are linearly approximated from the quadrangular pyramidal photoelectric conversion signals whose rising and falling are substantially linearly changed from the image pickup means. Although the case of calculating is described, the calculation may be performed by non-linear approximation as long as simple approximation is possible.

Further, in the first embodiment, the case where the test signal is a quadrangular pyramid-shaped mountain-shaped signal has been described, but other signals may be used as long as the signal has a linearly changing slope. Good.

In the first embodiment, the image reception gamma of the display device has been described as being corrected on the test signal generation side. However, the gamma is set in the loop of test signal generation-image display-imaging-centroid position detection. It goes without saying that there should be a correction.

In the second embodiment, the case where the image receiving gamma of the display device is corrected on the test signal generation side and the amplitude control is performed on the image pickup side has been described. However, test signal generation-image display-imaging- It goes without saying that gamma correction and amplitude control may be present in the loop for detecting the center of gravity.

Further, in the third embodiment, in order to make the explanation easy to understand, the case where the relative relationship is calculated from the rising and falling inclination angles of the quadrangular pyramid signal has been described. Calculation may be performed.

In the third embodiment, the case where the relative relationship between the display system and the image pickup system is calculated by the position calculation section and the corrected vector is detected by the error detection section has been described. You can go.

[0094]

As described above, according to the first aspect of the present invention, a test signal for obtaining an image pickup signal whose slope is always linear is generated even for different scanning frequencies, and the start position and each color are generated from the image pickup signal. By detecting the convergence error for each, highly accurate convergence error detection in the multi-scan display can be realized.

Since each independent interpolation processing is possible,
It is also possible to deal with discrimination of the scanning direction and arbitrary gamma characteristics. Also, when the display screen is viewed from the bottom and the signal level direction is viewed as the height direction, it is possible to set a wide linear region for the calculation processing of the center of gravity position by creating a test signal that makes a square pyramid shape. It becomes possible to detect. Further, the calculation processing speed can be increased by linearly approximating the position of the center of gravity of the leading value from the linear portion of the image pickup signal.

Further, according to the second aspect of the invention, even for display devices having different optical characteristics, by detecting the head position and the convergence error for each color from the image pickup signal having a constant inclination and a constant amplitude, various displays can be obtained. Highly accurate convergence error detection in the device can be realized.

Further, according to the third invention, by detecting the convergence error from the error value from the scanning direction of the display device, the error value from the image pickup signal and the vector direction, the time required for the adjustment can be greatly shortened and the accuracy can be improved. Error detection can be realized. In addition, by performing automatic adjustment using these error signals, complicated adjustment becomes unnecessary, and the adjustment time can be greatly shortened, and its practical effect is great.

[Brief description of drawings]

FIG. 1 is a block diagram showing a system configuration of a convergence error detection device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a test signal for detection of the embodiment.

FIG. 3 is a diagram for explaining the creation of a test signal of the same embodiment.

FIG. 4 is a diagram for explaining the creation of a test signal of the same embodiment.

FIG. 5 is a light emission characteristic diagram of a projector which is a display device of the same embodiment.

FIG. 6 is a characteristic diagram for explaining generation of a test signal of the same example.

FIG. 7 is a diagram for explaining the operation of horizontal interpolation processing of the same embodiment.

FIG. 8 is a diagram for explaining the operation of vertical interpolation processing of the same embodiment.

FIG. 9 is a detailed block diagram of a position calculation unit of the embodiment.

FIG. 10 is a view for explaining the operation of calculating the position of the center of gravity of the embodiment.

FIG. 11 is a diagram for explaining the operation of calculating the position of the center of gravity of the embodiment.

FIG. 12 is a diagram showing the operation of calculating the center of gravity of the embodiment.

FIG. 13 is a waveform diagram of a test signal for explaining the operation of calculating the position of the center of gravity of the embodiment.

FIG. 14 is a waveform diagram for explaining the error detection operation of the same embodiment.

FIG. 15 is a detailed block diagram of a test signal generator of the same embodiment.

FIG. 16 is a diagram showing an operation of generating a test signal in the embodiment.

FIG. 17 is a waveform diagram showing a horizontal interpolation operation for test signal generation according to the embodiment.

FIG. 18 is a waveform diagram showing a vertical interpolation operation for generating a test signal in the example.

FIG. 19 is a block diagram of a convergence error detection device according to a second embodiment of the present invention.

FIG. 20 is a directional characteristic diagram of a projector screen which is the display device of the embodiment.

FIG. 21 is a structural diagram of a projector screen of the same embodiment.

FIG. 22 is a display screen diagram of the projector according to the embodiment.

FIG. 23 is a light emission characteristic diagram of the projector of the example.

FIG. 24 is a detailed block diagram of a position calculation unit of the embodiment.

FIG. 25 is a diagram showing an operation of amplitude control of the embodiment.

FIG. 26 is a light emission characteristic diagram of an RGB CRT of the projector of the example.

FIG. 27 is a diagram showing a detection operation of the embodiment.

FIG. 28 is a block diagram of a convergence error detection device according to a third embodiment of the present invention.

FIG. 29 is a diagram showing an operation of the example.

FIG. 30 is a display screen diagram showing the operation of the embodiment.

FIG. 31 is a block diagram showing the error / vector detection operation of the same embodiment.

FIG. 32 is a diagram showing an operation of error / vector detection of the example.

FIG. 33 is a block diagram showing a configuration of a conventional convergence error detection device.

FIG. 34 is a waveform diagram showing an adjustment test signal of a conventional convergence error detection device.

FIG. 35 is a waveform diagram showing the operation of calculating the center of gravity of the conventional convergence error detection device.

[Explanation of symbols]

 1 Detection Test Signal 2 Imaging Section 3 Multiplying Section 4 D / A Converter 5, 39, 43 Position Calculation Section 6 Error Detection Section 7 Correction Signal Generation Section 11 Memory 18 Detection Point Generation Section 19 Horizontal Interpolation Signal Generation Section 25 Linear Area Calculation unit 26 Centroid position calculation unit 27 Error detection circuit 40 Sensitivity setting circuit 41 Amplitude detection circuit 42 Error / vector detection unit 44 Slope detection circuit 45 Vector detection circuit 50 Vertical interpolation unit

Claims (11)

[Claims] 1. A detection point generating means for generating a plurality of convergence error detection points in the horizontal and vertical directions on a screen of a display device, and a storage means for digitally storing test signal data for the convergence error detection points. Vertical interpolation means for interpolating vertical data from the data from the storage means, conversion means for converting a digital signal from the vertical interpolation means into an analog signal, and horizontal data interpolation from the address signal of the storage means Of the horizontal interpolation signal, horizontal interpolation means for interpolating horizontal direction data by multiplying the signal from the conversion means by the interpolation signal from the interpolation signal generation means, and the horizontal interpolation means An image pickup unit that supplies a test signal to the display device to pick up an image displayed on a display screen, and a tilt from the image pickup unit. Convergence error detecting apparatus characterized by comprising: a position calculating means for calculating a start position from the image signal composed of a straight line, and error detection means for detecting the convergence error of each color from the signal of the position calculating means. 2. The convergence error detecting device according to claim 1, wherein the interpolation means performs curve approximation interpolation corresponding to the image receiving gamma correction of the display device. 3. The convergence error according to claim 1, wherein the test signal is a signal having a quadrangular pyramid shape when the display screen is the bottom surface and the signal level direction is the height direction. Detection device. 4. The convergence error detecting apparatus according to claim 1, wherein the position calculating means obtains the position of the leading value from the linear portion of the image pickup signal by approximate calculation. 5. The convergence error detecting device according to claim 1, wherein the interpolating means detects the scanning frequency from the input synchronizing signal and performs the interpolation processing by the detected signal. 6. The convergence error detection device according to claim 1, wherein the detection point generation means is set so that the convergence error detection point and the convergence correction point of the display device are the same. 7. A signal generating means for generating a plurality of mountain-shaped detection test signals on the screen of the display device, and a test signal from the signal generating means are supplied to the display device and displayed on the display screen. Image pickup means for picking up the test signal image thus obtained,
A position calculation unit that calculates a head position from an image pickup signal that is output from the image pickup unit and that corresponds to a detection point where the inclination is straight and the amplitude is constant, and a convergence error for each color is detected from the signal of the position calculation unit. A convergence error detection device comprising: an error detection means. 8. The head position calculating means calculates a head position by generating a signal having a straight slope by the signal generating means and generating a signal having a constant amplitude by the image pickup means. 7. The convergence error detection device according to 7. 9. A signal generating means for generating a plurality of mountain-shaped detecting test signals on the screen of the display device, and a test signal from the signal generating means are supplied to the display device and displayed on the display screen. Image pickup means for picking up the test signal image thus obtained,
A position calculating means for calculating a head position from an image pickup signal from the image pickup means, an error detecting means for detecting a convergence error value and a vector direction for each color from the signal of the position calculating means, and a signal from the error detecting means for detecting Convergence error detection, characterized in that a correction waveform generating means for generating a convergence correction waveform of a correction area corresponding to a display area of a test signal and a correction signal from the correction waveform generating means are used to correct the display device. apparatus. 10. The signal generating means and the error detecting means, when viewing the display screen as the bottom and the signal level direction as the height direction,
It is characterized in that a pattern having a quadrangular pyramid shape having a maximum value in the same direction as the scanning direction of the display device is generated, and the convergence direction is predicted from the scanning direction of the display device, the error value, and the vector direction. The convergence error detection device according to claim 1. 11. The convergence error detecting apparatus according to claim 1, wherein the head position calculating means obtains the position of the head value from the linear portion of the image pickup signal by approximate calculation.