JPH04281692A - Check device for disturbance of picture - Google Patents

Abstract

PURPOSE:To check the disturbance of a pattern automatically by comparing a picture element level difference between an arrived video signal and frame information stored in a frame memory with a threshold level and counting number of times in excess of the threshold level. CONSTITUTION:A video signal of a VTR being a retrieved object is digitally converted by an A/D converter 2 and a synchronizing signal is separated by a synchronizing separator timing signal generating circuit 3. An output of the A/D converter 2 is stored in a frame memory 4 in the unit of one pattern, in which the signal is delayed by one or several pattern periods and a subtractor circuit 5 compares the result with a current output of the A/D converter 2. The result is compared with a threshold level by a comparator circuit 7 and a signal generated in excess of the threshold level is counted by a counter circuit 8. The result is stored in a register 9 and fed to a control computer or the like via an interface 11 and displayed on a display device 10. Thus, the disturbance of the pattern is automatically checked and the result is displayed and sent to the control system.

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for inspecting and evaluating disturbances in reproduced images in VTRs and other video equipment.

0001

2. Description of the Related Art After the assembly and adjustment of conventional VTRs and other video equipment is completed, the quality of the equipment is inspected and evaluated based on dropouts, jitter, noise, etc. on the playback screen. Also, in Japanese Patent Application Laid-open No. 109392/1983,
Monochromatic screens of different colors are sequentially projected, each image data is stored in a frame memory, and white unevenness in the image is inspected based on the difference between the image data. Further, in Japanese Patent Laid-Open No. 64-4193, the luminance signal level of an image is automatically measured from the result obtained by adding AD-converted composite video signals a predetermined number of times.

0002

[Problems to be Solved by the Invention] In the above conventional technology, for example, when measuring dropout, it is necessary to extract a signal from inside the finished product, and when observing jitter, only the synchronization signal is observed. Therefore, there were problems in that the deterioration of the screen could not be observed, and when observing "white spots", the pattern shape could not be observed. In addition, even if it is possible to calculate brightness, hue, etc. individually, it is not possible to comprehensively measure "disturbance of the screen", so in the end it is necessary to rely on human visual inspection, making automatic inspection difficult. there were.

[0003]Furthermore, since each of the above-mentioned tests is performed based on the synchronization signal, in trick plays such as "fast-forward playback" where the synchronization signal is missing, problems such as "distorted screen" or "range where the screen is disturbed" may occur. could not be measured. Furthermore, in order to compare and inspect a plurality of images with each other, a frame memory proportional to the number of images is required, so there is a problem that the inspection equipment becomes large-scale. The purpose of the present invention is to improve the above-mentioned problems, so that even when the synchronization signal is partially lost, "distortion of the screen" or "
An object of the present invention is to provide an image disturbance inspection device that can continuously inspect the range of disturbance on the screen.

0004

[Means for Solving the Problems] In order to solve the above-mentioned problems, the pixel level difference of the same part in different screens is calculated, and the number of pixels for which this difference exceeds a predetermined threshold level is counted. For this purpose, the input video signal is digitally converted and one frame's worth is stored in a frame memory, and the information in the frame memory and the digitally converted video signal are transferred to pixels at the same location within the frame. and each difference signal is compared with a predetermined threshold signal to count the comparison results. Further, the synchronization signal is separated from the video signal to generate each timing signal necessary for synchronized operation of the system.

[0005] Furthermore, the input video signal is displayed on a video monitor, and the display screen is imaged by a TV camera to obtain the video signal, so that the input video signal and the video signal output from the TV camera, whichever has less synchronization signal loss, are selected. The timing signal is generated from this selection. Furthermore, the output of the AD converter is alternately stored in two frame memories for each frame, and information for one frame is alternately read out from these memories to eliminate image disturbance. Enables continuous inspection of each frame.

Furthermore, the output of the comparison circuit is counted for each of a plurality of consecutive horizontal scanning periods within one screen, thereby making it possible to distinguish the disturbed portion of the image within the screen. Furthermore, the input video signal is separated into a luminance signal and a hue signal, or a luminance signal and three primary color signals, and the above-mentioned image disturbance inspection is performed for each signal.

[0007]

[Operation] The image disturbance detection device of the present invention detects and displays the number of pixels with an excessive level difference within different screens such as within a frame or within a field. For this reason, the level difference between the past image information stored in the frame memory or field memory and the current image information is compared at the pixel level.
The number of pixels with excessive level difference is counted and displayed.

Furthermore, a timing signal necessary for controlling the storage operation, level comparison operation, counting operation, etc. is generated from a synchronization signal in the input video signal. Further, input video signals are alternately stored for each frame by two frame memories, and are read out alternately to continuously inspect image disturbances for each frame. Furthermore, the above-mentioned counting operation is counted for each of a plurality of horizontal scanning periods within one screen to classify the disturbed portion of the image within the screen. Further, the above counting operation is performed separately for each of the luminance signal and hue signal of the input video signal, or for each luminance signal and three primary color signals.

[0009]

[Examples] Next, the present invention will be explained in detail with reference to Examples. [Embodiment 1] FIG. 1 is a block diagram showing the most basic configuration of the present invention. The video signal of the VTR to be inspected is applied to terminal 1, converted into a digital signal by AD converter 2, and simultaneously separated into a horizontal synchronization signal and a vertical synchronization signal by synchronization separation/timing signal generation circuit 3. This generates timing signals necessary for inspecting "screen disturbances", "range of screen disturbances", etc. In order to avoid the influence of jitter, the sampling rate of the AD converter 2 is set to a period of 0.1 to 0.0.
It is preferable to set it to be larger than 2 μs, for example, about 5 MHz.

The output of the AD converter 2 is divided into frames in units of one screen.
The image is stored in the system memory 4, delayed by one or several screen periods, and compared with the output screen of the AD converter 2 at that point in time by the subtraction circuit 5. The subtraction circuit 5 calculates the difference between pixel signals at the same position on the screen one or several screens ago and the current screen. The output of the subtraction circuit 5 is sent to the threshold circuit 6 by the comparison circuit 7.
The comparator circuit 7 generates a true value signal when the output of the subtraction circuit 5 exceeds the threshold value. The counting circuit 8 calculates the start and end coefficients generated by the synchronization separation/timing signal generation circuit 3 from the vertical synchronization signal.
Since it operates based on the reset command signal and counts the number of true value signals on that screen, disturbances within one screen can be detected. Further, the register 9 temporarily stores the coefficient result and displays it on the display 10, and at the same time transmits the coefficient result to an external device such as a control computer via the interface 11.

[Embodiment 2] FIG. 2 is a diagram showing an embodiment of the present invention in which a video monitor 13 and a TV camera 14 are connected to the input section having the configuration shown in FIG. The input signal is displayed on a video monitor 13 and imaged by a TV camera 14. The output and input signals of the TV camera are selected by a changeover switch 15. The following operations are similar to those in FIG. Generally, the video monitor 13 has a built-in oscillation circuit with a large time constant, PLL, etc. to compensate for the loss of the synchronization signal, so even if the synchronization signal is lost due to screen disturbance, the video monitor 13 will still be able to detect the synchronization signal. can be output continuously. Therefore, if the synchronization separation/timing signal generation circuit 3 is vulnerable to loss of synchronization signals, the operation of the above [Embodiment 1] can be performed normally by switching the changeover switch 15 to the TV camera side. can.

[Embodiment 3] FIG. 3 shows a case where the number of frame memories 4 in FIG. 1 is increased to two. Frame memories 41 and 42 in FIG. 3 operate so that when one is performing a storage operation, the other is performing a reproduction operation. Then, the changeover switch 12 selects the frame memory side in which the reproduction operation is being performed. Therefore, the changeover switch 12 is switched in synchronization with the screen switching of the input signal. As a result, screen disturbances can be continuously inspected.

[Embodiment 4] FIG. 4 shows a case where the number of counting circuits and registers in FIG. 1 is increased to two systems. In FIG. 4, the counting circuit 81 is controlled by counting start, end, and reset signals obtained by appropriately dividing the horizontal synchronizing signal supplied by the synchronization separation/timing signal generation circuit 3, and outputs the counting result to the register 91. , it is possible to divide one screen into multiple parts and measure the screen disturbances in each.As a result, it is possible to rank and measure the areas where screen disturbances occur within the same screen, and also to detect screen disturbances. From the number of times, you can know the range where screen disturbances are occurring. The counting circuit 82 and register 92 are controlled by counting and storage control signals generated from the vertical synchronizing signal supplied by the synchronization separation/timing signal generation circuit 3, and detect disturbances within one screen as in the case of FIG. .

[Embodiment 5] FIG. 5 shows that after an input signal is separated into a luminance signal and a hue signal by a luminance/hue separation circuit 11, two circuits after the AD converter of FIG. 1 are provided for each. FIG. 6 is a diagram illustrating another embodiment of the present invention which is processed in the same manner. As a result, screen disturbance can be measured separately for each luminance signal and hue signal. It is also possible to further separate the hue signal into components such as red, green, and blue, and measure each component using a similar circuit after the AD converter.

In each of the embodiments of the present invention described above, one frame signal or one field signal can be used as one screen signal. However, when using a 1-frame signal, the difference between odd and even fields may cause a measurement error, so comparisons between fields should be made between odd and even fields. - Do this between the two fields. For example, in the case of FIG. 3, the frame memory becomes a field memory, and the number is changed to three. Furthermore, the embodiments of the present invention described above can be implemented in combination with each other. For example, the part after the AD converter 2 in FIG. 1 or 2 is replaced with the part after the AD converter 2 in FIGS. 3, 4, etc., or the part after the input part of the AD converter 2 in FIGS. can be replaced with the portion after the input section of the AD converter in FIG. 5 to obtain the respective effects.

[0016]

[Effects of the Invention] According to the present invention, "screen disturbances" such as jitter, brightness and hue are automatically inspected using the signal obtained from the video signal terminal of a completed VTR, and the results can be displayed or displayed externally. can be transmitted to the control computer. Furthermore, it is possible to automatically and continuously inspect ``screen disturbances'' and ``range of screen disturbances'' in trick plays such as ``fast-forward playback'' in which synchronization signals are missing.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an apparatus for inspecting image disturbance between frames according to the present invention.

FIG. 2 is a block diagram of an image disturbance inspection device according to the present invention in which a video monitor and a TV camera are connected to the configuration shown in FIG.

FIG. 3 is a block diagram of a device for continuously inspecting images for disturbances according to the invention;

FIG. 4 is a block diagram of an image disturbance inspection device according to the present invention, which has a function of dividing and measuring the disturbance portion of an image within one screen.

FIG. 5 is a block diagram of an image disturbance inspection device of the present invention that separates an image signal into a luminance signal and a hue signal and measures disturbances in each.

[Explanation of symbols]

1 Terminal 2 AD converter 3 Synchronization separation/timing signal generation circuit 4 Frame
Memory 5 Subtraction circuit 6 Threshold circuit 7 Comparison circuit 8 Counting circuit 9 Register 10 Display 11 Interface 12 Changeover switch 13 Video monitor 14 TV camera 16 Brightness/hue separation circuit

Claims

[Claims] 1. Subtraction means for comparing each pixel signal of a video signal between the same parts in different screens and calculating the difference, and a subtraction means for calculating the difference, and the number of pixels for which the output of the subtraction means exceeds a predetermined threshold signal. An image disturbance inspection device comprising: counting means. 2. An AD converter that digitally converts a video signal, a frame memory that stores one frame worth of pixel information output from the AD converter, and an output of the AD converter and the frame memory. a subtracting means for comparing the output of pixels between the same parts in a frame and calculating the difference; a comparison circuit for comparing the output level of the subtraction means with a predetermined threshold signal; and the comparison circuit. An image disturbance inspection device comprising: a counting circuit that counts the output of the image. 3. According to claims 1 and 2, the input section for the video signal includes a video monitor that displays the video signal, a TV camera that captures an image of the video monitor, and a video signal that is connected to the video signal and the TV camera. An image disturbance inspection device comprising a first switching circuit that selects one of the video signal outputs. 4. In claims 2 and 3, the above AD
Two frame memories that alternately store the output of the converter for each frame, and a second switch that alternately retrieves one frame's worth of information stored in each of the two frame memories. An image disturbance inspection device characterized by comprising a circuit. 5. The image disturbance test according to claim 2, further comprising a counting circuit that counts the output of the comparison circuit every predetermined continuous horizontal scanning period within one screen. Device. 6. According to claims 2 to 5, a luminance/hue separation circuit is provided at the input section of the video signal, and the luminance/hue separation circuit is provided at the input section of the video signal,
An image disturbance inspection device characterized in that each of the luminance signal output and the hue signal output of the hue separation circuit is processed by the means according to claim 2, 3, 4, or 5. 7. According to claim 6, a color separation circuit for separating the hue signal into three primary color signals is provided, and each of the three primary color signals is processed by the means according to claim 2, 3, 4, or 5. An image disturbance inspection device characterized by: 8. According to any one of claims 1 to 7, the apparatus is characterized in that it includes a synchronization separation/timing signal separation circuit that generates a timing signal from a synchronization signal in an input video signal, and performs synchronized operation using the timing signal. An image disturbance inspection device. Claim 9: In claims 3 to 7, the first
An image disturbance inspection device comprising: a synchronization separation/timing signal separation circuit that generates a timing signal from a synchronization signal in a video signal outputted from a switching circuit; and a synchronous operation is performed using the timing signal.