JPH0675815A - Crt interface signal inspection device - Google Patents

Abstract

PURPOSE:To execute an inspection by an inspection reference being similar to a visual inspection by comparing a pattern of an energy spectrum with a pattern of a CRT interface signal of non-defective prepared in advance, and deciding its quality. CONSTITUTION:An image pattern to be inspected is fetched and conditions (horizontal synchronizing frequency, vertical synchronizing frequency, etc.) are set by using an initial condition setting means 1. In such a state, image data of a one-line portion being in each period corresponding to the horizontal synchronizing signal frequency is subjected to high speed Fourier-transformation by using a high speed Fourier-transformation means 2, with regard to image data of a one-frame portion, and an energy spectrum of a frequency component of the data is calculated. Subsequently, an energy spectrum pattern of a frequency component of a non-defective and an energy spectrum pattern of the calculated frequency component are compared by a frequency component comparing means 3, and in the case of the same spectrum distribution, it is decided to be a non-defective, and in the case a different spectrum distribution is detected, it is decided to be a defective, and a result of quality is outputted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of a CRT interface signal inspection device. In particular, it is an object of the present invention to provide a CRT interface signal inspection device capable of automatically inspecting the quality of a CRT interface based on an inspection standard close to an inspection standard in a visual inspection by an inspector of an image pattern displayed on a CRT. Regarding improvements to be made.

[0002]

2. Description of the Related Art The quality of a CRT interface used in a personal computer or the like is initially checked by inputting an output signal of the CRT interface to the CRT, visually inspecting an image displayed on the CRT screen, and checking the quality of the CRT interface. Came to judge. After that, the automation of the inspection came to be carried out for the purpose of improving the efficiency of the inspection. The CRT interface signal inspection apparatus according to the prior art used for this automated inspection has an R for every dot for one frame of the CRT interface signal.
The voltage values for the gradations of (red), G (green), and B (blue) are loaded into the memory, and compared with the expected value data prepared in advance to C.
An inspection device for inspecting the quality of the RT interface, an inspection device for inspecting the quality of the CRT interface by integrating the voltage value of each dot for each line, and comparing the integrated voltage value with expected value data prepared in advance. There is.

The former CRT for comparing voltage values of all dots
In the interface signal inspection device, the image configuration is 1
In the case of 120 × 750 dots, the amount of information per screen is about 2.5 Mbytes, which requires a huge memory capacity when inspecting a plurality of image patterns. In addition, the data transfer time becomes long and the inspection time per screen becomes longer than that of the visual inspection.

In the latter CRT interface signal inspection device that integrates the voltage value for each dot for each line and compares it with the expected value data, since the amount of data to be compared is small, it is more advantageous than the former in memory capacity and inspection time. is there.

However, all the inspection devices are common in that the voltage value of the CRT interface signal is compared with the expected value data.

[0006]

As described above, in the CRT interface signal inspection apparatus according to the prior art, the voltage value of each dot on the screen is compared with the expected value data, or the voltage of the dot for each line is compared. Since the integrated value of is compared with the expected value data, there is a drawback in that the criterion of the quality judgment is too strict and excessive detection of defects is performed. The reason is that even if the voltage value of the dot or the integrated value of the voltage deviates from the expected value data and is judged to be defective, if the deviation is uniformly deviated over the entire screen, it is visually inspected by an inspector. This is because it is difficult to recognize this shift in the inspection and it is determined to be normal.

An object of the present invention is to eliminate the above-mentioned drawbacks, and the quality of the CRT interface is automatically determined based on the inspection standard close to the inspection standard in the visual inspection by the inspector of the image pattern displayed on the CRT. An object is to provide a CRT interface signal inspection device capable of performing inspection.

[0008]

Means for Solving the Problems The above-mentioned object is to set an initial condition setting means (1) for setting an initial condition such as a horizontal synchronizing frequency and a vertical synchronizing frequency and a synchronization set by the initial condition setting means (1). Fast Fourier transform means (2) for fast Fourier transforming the input image pattern in each cycle corresponding to the frequency to calculate the distribution of frequency components;
Frequency component comparing means (3) for comparing the frequency component distribution calculated by the fast Fourier transforming means (2) with a frequency component distribution of a non-defective image pattern prepared in advance.
And a CRT interface signal tester having

[0009]

When the inspector visually inspects the image pattern displayed on the CRT, the sensitivity with respect to the position such as the displacement of the regular image pattern is sharp, but the sensitivity with respect to the displacement of the color gradation (contrast) is low. It has the characteristic of being dull. Therefore, in the present invention, instead of the conventional technique in which the voltage value of each dot that determines the gradation of color is an inspection target,
Focusing on the frequency component of the image signal that determines the position of the image pattern, fast Fourier transform of the image signal waveform is performed to calculate the distribution of the frequency component, and the pattern of the obtained energy spectrum is prepared in advance. The quality of the CRT interface is judged by comparing with the pattern of. As a result, it is possible to perform the inspection according to the inspection standard close to the inspection standard of the visual inspection by the inspector.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A CRT interface signal inspection apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a claim correspondence diagram showing a configuration of a CRT interface signal inspection apparatus according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 is an initial condition setting means for setting conditions (horizontal synchronizing frequency, vertical synchronizing frequency, etc.) for taking in an image pattern to be inspected, and 2 is this initial condition setting means 1.
Is a fast Fourier transform means for calculating the distribution of frequency components by fast Fourier transforming the input image pattern in each cycle corresponding to the horizontal synchronizing signal frequency set by. Reference numeral 3 denotes frequency component comparison means for comparing the above-mentioned frequency component distribution calculated by the fast Fourier transforming means 2 with a frequency component distribution of a non-defective image pattern prepared in advance, and outputting the comparison result.

Next, the operation of this embodiment will be described with reference to the flow chart. FIG. 2 is a flowchart thereof.

Referring to FIG. 2, first, conditions for capturing an image pattern to be inspected (horizontal synchronizing frequency, vertical synchronizing frequency, etc.) are set using the initial condition setting means 1 (a).

The image data for one line in each period corresponding to the frequency of the horizontal synchronizing signal is subjected to fast Fourier transform using the fast Fourier transform means for the image data for one frame to obtain the frequency component of the data. Calculate the energy spectrum (b).

Next, the energy spectrum pattern of the frequency component of the non-defective product is compared with the energy spectrum pattern of the frequency component calculated above, and if the same spectrum distribution is obtained, it is determined as a non-defective product, and if a different spectrum distribution is detected. Outputs a pass / fail result as (c).

[0017]

As described above, the CR according to the present invention
The T-interface signal inspection apparatus is a high-speed fast Fourier transform for initial condition setting means for setting an initial condition such as a synchronizing signal frequency and an input image pattern in each cycle corresponding to the synchronizing frequency set by the initial condition setting means. It has Fourier transform means and frequency component comparison means for comparing the frequency component distribution of the image pattern converted by this fast Fourier transform means with the frequency component distribution of a non-defective image pattern prepared in advance. As a result of the comparison, it is determined that the products have a good spectrum distribution when they have the same spectrum distribution, and that they have a defective product when they have different spectrum distributions. Since the main purpose is to detect .

Therefore, the present invention is a CRT interface signal inspection apparatus capable of automatically inspecting the quality of a CRT interface based on an inspection standard close to an inspection standard in a visual inspection by an inspector of an image pattern displayed on a CRT. Can be provided.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram showing a configuration of a CRT interface signal inspection device according to an embodiment of the present invention.

FIG. 2 is a flowchart of a CRT interface signal inspection device according to an embodiment of the present invention.

[Explanation of symbols]

 1 initial condition setting means 2 fast Fourier transform means 3 frequency component comparison means

Claims (1)

[Claims] 1. Initial condition setting means (1) for setting initial conditions such as horizontal synchronizing frequency and vertical synchronizing frequency, and input in each cycle corresponding to the synchronizing frequency set by the initial condition setting means (1). Fast Fourier transforming means (2) for fast Fourier transforming the image pattern to calculate the distribution of frequency components, and the frequency of the non-defective image pattern prepared in advance with the frequency component distribution calculated by the fast Fourier transforming means (2). A CRT interface signal inspection device, comprising a frequency component comparison means (3) for comparing with a component distribution.