JPH08331611A - Automatic low light controller - Google Patents

Abstract

PURPOSE: To provide high-accuracy automatic low light control with an inexpensive and satisfactorily portable system. CONSTITUTION: A TEST pattern for low light control is supplied from a TEST pattern generator 1 for automatic control to a CRT type display device 2 and projected on a screen 3. At such a time, the state of reducing a deflection size and increasing current density is provided at the CRT type display device 2 based on the instruction of a control data arithmetic unit 5, this image is picked up by a camera 4 for control error detection, and the optimum control data of low light are arithmetically found from that result by the control data arithmetic unit 5 and fed back to the CRT type display device 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low light automatic adjusting device for a CRT type display device.

[0002]

2. Description of the Related Art Conventionally, in the case of a CRT type display device, particularly a two-body type projection type display device, the display device body and the screen are separate, so that when trying to reproduce a good image, the display device and the screen are separated. After the installation, it was necessary to readjust the white balance on-site again according to the installation conditions of the display device and the types and installation conditions of the screen.

However, until now, the white balance adjustment has often been performed manually by a service person or the like, and automation of the adjustment has been strongly desired from the viewpoint of shortening the adjustment time and stability of the adjustment accuracy.

Therefore, an automatic white balance adjusting device as disclosed in Japanese Patent Laid-Open No. 6-98346 has been proposed. Here, a brief description will be given of the configuration of Japanese Patent Laid-Open No. 6-98346 with reference to FIG.

The drive voltage of each cathode ray tube 1R, 1G, 1B is varied to several tens of levels from low light to high light, and R, G, B projected on the screen 3 is changed.
The brightness of the window pattern is measured by the optical measuring device 10. Then, the data of the drive voltage-luminance characteristic is stored in the RAM1.
Store in 8. The light emission characteristic calculation circuit 20 uses a correlation function that corrects each of the R, G, and B luminance characteristics using this data,
Calculate the drive ratio. Using the data of this correlation function, the video signal processing circuit 17 creates a correction drive signal, and automatically controls so as to obtain a uniform white color from low light to high light.

[0006]

However, when the low light is automatically adjusted by using the image data of the CCD camera or the like to detect the adjustment error, the brightness level of the test pattern itself used for the low light adjustment is low. Therefore, the detection level of the image pickup system that can obtain sufficient adjustment accuracy cannot be ensured, or the detection itself may not be possible depending on the installation conditions of the display device and the type and installation conditions of the screen.

Further, when only a low light adjustment is considered and a special camera capable of detecting in a low level illuminance condition is used,
It is difficult for the camera to coexist when detecting under high-level illumination conditions for other highlight adjustments and convergence adjustments, and because it is a special camera, it becomes expensive and large, so the total cost of the system is also high. However, it is also disadvantageous in portability when considering local adjustment.

Further, even if an attempt is made to infer the adjustment state of low light from the result of detection using a test pattern having a high brightness level, there is a large variation in the gamma characteristics of each CRT of red, green and blue. It is difficult to adjust with high accuracy.

The present invention secures the detection level of the image pickup system to the level required for low light adjustment by reducing the deflection size and increasing the current density during low light adjustment, and the system is inexpensive and highly portable. The purpose is to realize accurate automatic adjustment of low light.

[0010]

In order to solve the above problems, according to the present invention, an automatic adjustment test pattern generator for generating an automatic adjustment test pattern and an automatic adjustment test pattern generated by the automatic adjustment test pattern generator are provided. CRT type display device having a function of communicating with the adjustment data calculation device and a function of reducing the deflection size, the screen, and the adjustment error calculation of the automatic adjustment test pattern projected on the screen. Error detection camera for taking in as brightness information for the adjustment error, and the adjustment error calculation based on the brightness information taken in by the adjustment error detecting camera, and the optimum adjustment data obtained from the result is calculated by the CRT formula. It is composed of an adjustment data calculation device capable of communication for sending to a display device.

[0011]

According to the present invention, the detection level of the image pickup system is adjusted with high accuracy by reducing the deflection size of the CRT type display device and increasing the current density at the detection point of the image pickup system at the time of adjusting the lowlight. It secures up to the required level and enables highly accurate automatic adjustment of low light.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An automatic low light adjusting apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an automatic low light adjusting device according to an embodiment of the present invention. In FIG. 1, reference numeral 1
Is a test pattern generator for automatic adjustment for generating a test pattern for automatic adjustment, 2 is a CRT type display device, 3 is a screen, 4 is a camera for detecting an adjustment error, 5 is
Is an adjustment data calculation device.

In this embodiment, the test pattern used for low light adjustment is the average peak level (hereinafter A
(Referred to as PL) uses an all white signal of about 10%. Here, the APL of the test pattern is changed according to the characteristics of the CRT type display device to be adjusted.

First, before explaining the actual adjustment procedure, the reason why the deflection size is reduced during low light adjustment will be described with reference to FIG.

FIG. 2 is a comparison of the output waveforms of the cameras when the all-white signal projected on the screen from the CRT type display device is imaged by the camera installed on the screen center axis.

In FIG. 2, condition A is an output waveform diagram when a camera captures a screen on which an all-white signal is projected with a deflection size in a normal use state from a CRT type display device, and condition B is from a CRT type display device. FIG. 9 is an output waveform diagram when a camera captures an image of a screen on which an all-white signal is projected in a state where the horizontal deflection size is reduced.
Both the condition A and the condition B have the same projection condition and imaging condition other than the horizontal deflection size of the CRT type display device, and in order to make it easier to think, shading caused by the characteristics of the display device in the CRT type (hereinafter referred to as projection shading). ) And the shading due to the directivity of the screen and the characteristics of the imaging system (referred to as imaging shading)
Is not affected.

In the case of a CRT type display device, the CRT gamma characteristic in the low luminance area can be ignored.

Under the above conditions, if the light energy output from the CRT type display device is the same,
Since the light energy detected by the imaging system, that is, the camera is also the same, the area a = area b is established. Here, if an attempt is made to detect a low light test pattern under condition A, the S / th of the image at the time of image capture is low because the illuminance on the screen is low.
The N ratio deteriorates, resulting in a detection waveform with poor accuracy. Furthermore, depending on the imaging conditions, it may be impossible to detect due to insufficient illuminance.

However, as in condition B, the deflection size is reduced and the current density is concentrated in a small area on the screen to increase the illuminance on the screen, and the light output of the CRT type display device is the same as condition A. However, the S / N ratio at the time of imaging can be improved.

Although the reason why the deflection size is reduced is not taken into account for easy understanding, when considering the projection shading, the directivity of the screen and the imaging shading, the area a <the area b. As a result, it is clear that the condition B is more advantageous.

The actual adjustment procedure will be described below. The low light adjustment test pattern generated in the automatic adjustment test pattern generator 1 is supplied to the CRT type display device 2. CRT type display device 2
Then, the low-light automatic adjustment test pattern sent from the automatic adjustment test pattern generator 1 is projected on the screen 3 with the deflection size reduced by an instruction from the adjustment data arithmetic unit 5.

In the adjustment error detecting camera 4, the screen 3
An image of the test pattern in which the deflection size projected on the screen is reduced and the current density is increased is captured, and the result is sent to the adjustment data calculation device 5.

The adjustment data calculation device 5 removes the influence of the image pickup system from the result sent from the adjustment error detection camera 4 and obtains the optimum low light adjustment data by calculation and feeds it back to the CRT type display device 2.
This is repeated to realize the optimum low light adjustment state.

[0025]

As is apparent from the above description, in the low light automatic adjustment device of the present invention, CR is adjusted at the time of low light adjustment.
By reducing the deflection size of the T-type display device and increasing the current density at the detection point of the image pickup system, the detection level of the image pickup system is secured to the level required for highly accurate low light adjustment, and it is inexpensive and highly portable. The system enables highly accurate automatic adjustment of low light.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a low light automatic adjustment device according to an embodiment of the present invention.

FIG. 2 is a comparison diagram of output signals at the time of capturing an all-white signal used in the description of FIG.

FIG. 3 is a block configuration diagram of a conventional white balance automatic adjustment device.

[Explanation of symbols]

 1 Automatic adjustment test pattern generator 2 CRT type display device 3 Screen 4 Adjustment error detection camera 5 Adjustment data calculation device

Claims (1)

[Claims] 1. A test pattern generator for automatic adjustment for generating a test pattern for automatic adjustment, and a test pattern for automatic adjustment generated by the test pattern generator for automatic adjustment is projected on a screen and the adjustment data is calculated. CRT with communication function with device and reduction function of deflection size
Type display device, a screen, an adjustment error detection camera for taking in an automatic adjustment test pattern projected on the screen as luminance information for adjustment error calculation, and a luminance taken in by the adjustment error detection camera Automatic adjustment of low light, which is provided with an adjustment data calculation device capable of calculating an adjustment error based on information and transmitting optimum adjustment data obtained from the result to a CRT type display device. apparatus.