KR101186091B1 - System and method for testing motion picture quality - Google Patents

Abstract

The present invention provides a system that can measure the video quality of a liquid crystal display device and an image display device using the same by employing a low-cost photodetector device, wherein the video signals of the first and second images are alternately displayed. Signal generating means for supplying a device to alternately blink the first and second images and to change and supply the gray levels of the first and second images according to the blinking of the inspected image display device; Light detecting means for detecting and converting an optical signal representing a gray level of an image displayed on the image display apparatus under test into an electrical signal; And controlling the signal generation of the signal generating means, generating a waveform corresponding to the gray level of the image represented by the level of the electrical signal, and using the generated waveform to blur the image displayed on the inspected image display device. A video for calculating edge widths, calculating blurred edge times of an image displayed on the image-displayed apparatus using the blurred edge widths, and calculating a video response time of the image-displayed apparatus to be examined using the blurred edge times; Image quality measuring means.

LCD, Video, Image Quality, Response Time

Description

System and method for testing motion picture quality}

1 is an equivalent circuit diagram of a pixel formed in a general liquid crystal display device.

2 is a block diagram of a general liquid crystal display device.

3 is a block diagram of a conventional video quality measurement system.

FIG. 4 is an exemplary view of an image displayed on the image display apparatus under test in FIG. 3; FIG.

FIG. 5 is a graph showing a blurry edge width obtained by a computer in FIG. 3; FIG.

6 is a graph showing gray levels set in a conventional video quality measurement system.

FIG. 7 is a three-dimensional graph showing the cloudy edge time obtained by the computer in FIG.

8 is an exemplary view for explaining the characteristics of a conventional video quality measurement system.

9 is a block diagram of a video quality measurement system according to an embodiment of the present invention.

10 is a waveform generated by the oscilloscope in FIG.

FIG. 11 is a computer generated graph of FIG. 9;

12 is a block diagram of a computer in FIG.

13 is a block diagram of a video quality measurement system according to another embodiment of the present invention.

14 is a block diagram of a computer in FIG.

Description of the Related Art

100: liquid crystal display device 110: liquid crystal display panel

120: data driver 130: gate driver

140: gamma reference voltage generator 150: backlight assembly

160: inverter 170: common voltage generator

180: gate driving voltage generator 190: timing controller

300: video display device 400: video quality measurement system

410: photodiode 420: oscilloscope

430: signal generator 440: computer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video quality measurement system of an image display device such as a television receiver and a computer monitor. In particular, a system and method for measuring video quality of a liquid crystal display device and a video display device using the same using a low cost photodetector device. It is about.

The liquid crystal display device displays an image by adjusting the light transmittance of the liquid crystal cells according to the video signal, and the active matrix type liquid crystal display device in which the switching elements are formed for each liquid crystal cell enables active control of the switching elements. This is advantageous for video implementation. As a switching device used in the active matrix liquid crystal display device, a thin film transistor (hereinafter, referred to as TFT) is mainly used as shown in FIG. 1.

Referring to FIG. 1, an active matrix type liquid crystal display device converts digital input data into an analog data voltage based on a gamma reference voltage and supplies it to the data line DL and simultaneously supplies scan pulses to the gate line GL. The liquid crystal cell Clc is charged.

The gate electrode of the TFT is connected to the gate line GL, the source electrode is connected to the data line DL, and the drain electrode of the TFT is connected to the pixel electrode of the liquid crystal cell Clc and one electrode of the storage capacitor Cst. Connected.

A common voltage Vcom is supplied to the common electrode of the liquid crystal cell Clc.

The storage capacitor Cst serves to charge the data voltage applied from the data line DL when the TFT is turned on to maintain the voltage of the liquid crystal cell Clc constant.

When a scan pulse is applied to the gate line GL, the TFT is turned on to form a channel between the source electrode and the drain electrode to apply a voltage on the data line DL to the pixel electrode of the liquid crystal cell Clc Supply. At this time, the liquid crystal molecules of the liquid crystal cell Clc modulate the incident light by changing the arrangement by the electric field between the pixel electrode and the common electrode.

A configuration of a general liquid crystal display device having pixels having such a structure will be described with reference to FIG. 2.

2 is a configuration diagram of a general liquid crystal display device.

Referring to FIG. 2, the liquid crystal display device 100 includes a thin film transistor TFT for driving data lines DL1 to DLm and gate lines GL1 to GLn and driving the liquid crystal cell Clc at an intersection thereof. A liquid crystal display panel 110 having a thin film transistor, a data driver 120 for supplying data to the data lines DL1 to DLm of the liquid crystal display panel 110, and a gate of the liquid crystal display panel 110. A gate driver 130 for supplying scan pulses to the lines GL1 to GLn, a gamma reference voltage generator 140 for generating a gamma reference voltage and supplying it to the data driver 120, and a liquid crystal display panel 110. ) Generates a backlight assembly 150 for irradiating light, an inverter 160 for applying an alternating voltage and current to the backlight assembly 160, and a common voltage Vcom to generate liquid crystals of the liquid crystal display panel 110. A common voltage generator 170 for supplying the common electrode of the cell Clc, A timing for controlling the gate driving voltage generator 180 for generating the high voltage VGH and the gate low voltage VGL and supplying the gate voltage 130 to the gate driver 130, and for controlling the data driver 120 and the gate driver 130. The controller 190 is provided.

In the liquid crystal display panel 110, liquid crystal is injected between two glass substrates. On the lower glass substrate of the liquid crystal display panel 110, the data lines DL1 to DLm and the gate lines GL1 to GLn are orthogonal. TFTs are formed at intersections of the data lines DL1 to DLm and the gate lines GL1 to GLn. The TFT supplies the data on the data lines DL1 to DLm to the liquid crystal cell Clc in response to the scan pulse. The gate electrodes of the TFTs are connected to the gate lines GL1 to GLn, and the source electrodes of the TFTs are connected to the data lines DL1 to DLm. The drain electrode of the TFT is connected to the pixel electrode of the liquid crystal cell Clc and the storage capacitor Cst.

The TFT is turned on in response to the scan pulse supplied to the gate terminal via the gate lines GL1 to GLn. When the TFT is turned on, video data on the data lines DL1 to DLm is supplied to the pixel electrode of the liquid crystal cell Clc.

The data driver 120 supplies data to the data lines DL1 to DLm in response to the data driving control signal DDC supplied from the timing controller 190, and digital video data supplied from the timing controller 190. After sampling and latching the RGB, the liquid crystal cell Clc of the liquid crystal display panel 110 is converted into an analog data voltage capable of expressing gray scale based on the gamma reference voltage supplied from the gamma reference voltage generator 140. Supply to the data lines DL1 to DLm.

The gate driver 130 sequentially generates scan pulses, that is, gate pulses, in response to the gate driving control signal GDC and the gate shift clock GSC supplied from the timing controller 190, thereby providing the gate lines GL1 to GLn. To feed. The gate driver 130 determines the high level voltage and the low level voltage of the scan pulse in accordance with the gate high voltage VGH and the gate low voltage VGL supplied from the gate drive voltage generator 180, respectively.

The gamma reference voltage generator 140 receives a high potential power voltage VDD to generate a positive gamma reference voltage and a negative gamma reference voltage to output the data to the data driver 120.

The backlight assembly 150 is disposed on the rear surface of the liquid crystal display panel 110 and emits light by an AC voltage and a current supplied from the inverter 160 to irradiate light to each pixel of the liquid crystal display panel 110.

The inverter 160 converts the square wave signal generated therein into a triangular wave signal and compares the triangular wave signal with a DC power supply voltage (VCC) supplied from the system to generate a burst dimming signal proportional to the comparison result. . When a burst dimming signal determined according to an internal square wave signal is generated, a driving IC (not shown) for controlling the generation of AC voltage and current in the inverter 160 is supplied to the backlight assembly 150 according to the burst dimming signal. Control the generation of alternating voltage and current.

The common voltage generator 170 receives the high potential power voltage VDD to generate the common voltage Vcom and supplies the common voltage Vcom to the common electrodes of the liquid crystal cells Clc of each pixel of the liquid crystal display panel 110.

The gate driving voltage generator 180 receives the high potential power voltage VDD to generate the gate high voltage VGH and the gate low voltage VGL to supply the gate driver 130 to the gate driver 130. Here, the gate driving voltage generation unit 180 generates a gate high voltage VGH that is greater than or equal to the threshold voltage of the TFTs provided in each pixel of the liquid crystal display panel 110, and the gate low voltage that is less than or equal to the threshold voltage of the TFT. VGL). The gate high voltage VGH and the gate low voltage VGL generated in this way are used to determine the high level voltage and the low level voltage of the scan pulse generated by the gate driver 130, respectively.

The timing controller 190 supplies digital video data RGB, which is supplied from a digital video card (not shown), to the data driver 120, and also horizontal / vertical synchronization signals H and V according to the clock signal CLK. The data driving control signal DDC and the gate driving control signal GDC may be generated and supplied to the data driver 120 and the gate driver 130, respectively. The data driving control signal DDC includes a source shift clock SSC, a source start pulse SSP, a polarity control signal POL, a source output enable signal SOE, and a gate driving control signal GDC. ) Includes a gate start pulse (GSP) and a gate output enable (GOE).

A liquid crystal display device having such a configuration and function is provided in an image display device such as a television receiver and a computer monitor to display various images and characters including a moving image. The video displayed on the LCD displays a phenomenon in which the screen quality is deteriorated according to the response time of the liquid crystal or the response speed of the video display device itself. Is measured through.

3 is a block diagram of a conventional video quality measurement system.

Referring to FIG. 3, the video quality measurement system 200 includes an optical sensor 210 for detecting light generated from the image display apparatus 300 to be inspected and light incident from the image display apparatus 300 to be inspected. Rotating mirror 220 for reflecting the light, the mirror control unit 230 for controlling the rotation of the rotating mirror 220, and the light reflected by the rotating mirror 220 is integrated to output the integral value A CCD camera 240, a signal generator 250 for generating a video signal and supplying the video signal to the inspected video display device 300, and a computer for controlling video quality measurement of the inspected video display device 300 ( 260.

Here, the image display device 300 to be inspected may be a television receiver having a liquid crystal display device 100, a computer monitor, or the like. The image display device 300 may be a liquid crystal display device. That is, the conventional video quality measurement system 200 measures video quality affected by the response speed of the image display apparatus 300 under test.

The optical sensor 210 detects light generated from the image display device 300 to be detected and outputs a light detection value to the computer 260, which indicates that the gray level of the image displayed on the image display device 300 to be inspected is increased. It is for the computer 260 to recognize the change.

The rotating mirror 220 reflects the light incident from the image display apparatus 300 under test to the CCD camera 210. The rotating mirror 220 is rotated by a motor (not shown), the rotation of which is controlled by the mirror controller 230. The rotating mirror 220 rotated as described above is rotated whenever the boundary surfaces of the first and second images representing the gray level of the image displayed on the inspected image display apparatus 300 are scrolled in one direction as shown in FIG. 4. In addition, the CCD camera 240 can capture the boundary surface movement, ie, the gray level change, of the first and second images displayed on the inspected image display device 300 at a fixed position.

The mirror controller 230 controls the rotation of the rotating mirror 220 under the control of the computer 260. Substantially, as illustrated in FIG. 4, the mirror controller 230 may display the first and second displays displayed on the image display apparatus 300 under test. Each time the boundary of the image is scrolled in one direction, the rotating mirror 220 is rotated under the control of the computer 260.

The CCD camera 240 integrates the light reflected by the rotation mirror 220 and outputs the integrated value to the computer 260.

The signal generator 250 generates a predetermined video signal under the control of the computer 260, and generates a video signal composed of first and second images as shown in FIG. ). Here, the first and second images may be implemented as a black image and a white image.

And, as shown in A1 to An of FIG. 4, the signal generator 250 controls the boundary surfaces of the first and second images displayed on the image display device 300 under the control of the computer 260 in one direction, for example. The gray level is changed by moving in the right direction. The graybell of the image displayed on the inspection target image display device 300 is composed of the '256' level from the '0' level to the '255' level, but the conventional video quality measurement system 200 In consideration of the brightness, the video quality is measured by dividing the gray levels of the first and second images displayed on the inspected image display apparatus 300 into seven levels.

The computer 260 measures video quality according to the response speed of the image display apparatus 300 under test, which will be described in detail below. However, the computer 260 considers the gray levels of the first and second images displayed on the image display apparatus 300 under consideration in consideration of the brightness of the image having the '256' level from the '0' level to the '255' level. Video quality is measured by dividing into 7 levels.

The computer 260 controls the signal generation of the signal generator 250 to display the video signal composed of the first and second images on the inspection target image display device 300 as shown in FIG. 4 according to a user's instruction. do. When the first and second images generated by the signal generator 250 are displayed on the inspected image display apparatus 300, the computer 260 may display the first and second images displayed as shown in FIG. 4. It is determined whether the first movement of the interface is detected by the photosensor 210.

In this case, when the first movement of the boundary between the first and second images is detected, the computer 260 may rotate the rotation mirror 220 and the first and second signals generated from the signal generator 250 in synchronization with the first movement of the gray level. The gray level change of the second image is controlled.

When the video signal composed of the first and second images is displayed on the image display device 300 through the above-described process and the gray level of the image is changed, the CCD camera 240 rotates the light representing the image. When incident through the mirror 220, the incident light is integrated to output the integrated value to the computer 260.

When the integral value is input in this way, the computer 260 calculates and calculates a blurred edge width (BEW) using the integral value of the CCD camera 240, and then displays a graph indicating the blurred edge width (BEW). Produced as in FIG. 5 is a graph showing a plurality of blur edge widths BEW calculated according to gray level changes of the first and second images displayed on the image display apparatus 300 under test. In the graphs shown in FIG. 5, the 'S' graph shown to be increased from the lower left to the upper right is a case where the gray level is increased, and the 'inverted S' graph is reduced from the upper left to the lower right. Is the case where the gray level is reduced. In FIG. 5, the x axis is Time_Shutter_Scale and the y axis is Luminance.

Then, the computer 260 calculates Blurred Edge Times (BET: Blurred Edge Times) as shown in Table 1 by using a plurality of blurred edge widths (BEW) calculated in gray level units.

                                   BET [msec] STL: 0 STL: 1 STL: 2 STL: 3 STL: 4 STL: 5 STL: 6 DTL: 0   - 14.39 15.02 15.28 15.63 15.95 16.48 DTL: 1 17.42   - 14.94 16.35 16.82 16.77 16.91 DTL: 2 15.06 15.63   - 15.77 16.05 16.31 16.54 DTL: 3 14.85 15.19 15.15   - 16.64 16.28 16.52 DTL: 4 14.85 14.78 15.20 14.64   - 15.97 16.40 DTL: 5 15.00 15.95 16.41 15.89 15.48   - 16.59 DTL: 6 18.21 17.97 17.76 17.55 17.37 17.51   - MPRT 16.08 Max BET 18.21 Min BET 14.39 Standard Deviation 0.99

In [Table 1], the STL is the gray level of the first image, the DTL is the gray level of the second image, and the motion picture response time (MPRT) is calculated using blurry edge times (BETs). Value, the maximum BET is the maximum among the blurry edge hours (BET), the minimum BET is the minimum among the cloudy edge times (BET), and the standard deviation is the standard deviation of the cloudy edge times (BET).

As shown in FIG. 6, a gray level set to calculate a blurred edge time (BET) and a video response time (MPRT: Motion Picture Respose Time) calculated using the same as shown in [Table 1] are shown in FIG. 6.

That is, FIG. 6 is a graph illustrating gray levels set in a conventional video quality measurement system. In the drawing, the x axis is a set relative gray level and the y axis is a relative luminance. Here, the relative luminance is a luminance value that is determined relatively according to an ON / OFF duty of a backlight (not shown) provided in the image display apparatus 300 under test, and is turned on from the duty of the backlight. If the period is 60% and the off period is 40%, the relative luminance is 0.6.

When the blurred edge times BETs obtained by the computer 260 are divided into gray level units and displayed in a 3D graph, a 3D graph as shown in FIG. 7 is generated.

As described above, the conventional video quality measurement system 200 measures a phenomenon in which the width of the boundary between the first and second images displayed on the image display device 300 to be examined is widened as shown in FIG. 4. 2 This function is to generate a graph by quantifying the blurring degree of the boundary of the image. In this case, the width of the boundary between the first and second images is widened because the response speed of the image display device 300 to be inspected becomes slow.

For example, when the inspection target video display device 300 has a response speed close to real time, as shown in B1 of FIG. 8, the width of the boundary between the first and second images is hardly present. When the response speed is slow, the width of the boundary of the first and second images becomes wider as shown in B2 of FIG. 8. That is, the conventional video quality measurement system 200 generates a graph by quantifying the degree of blurring of the boundary surface due to the widening of the boundary surface of the first and second images as shown in B2 of FIG. 8.

However, the conventional video image quality measurement system as described above, the high production cost of the rotating mirror 220 and CCD camera 240 by using a high manufacturing cost and selling price of the product, and also to the optical sensor 210 The error occurred frequently by synchronizing the video quality measurement process to the gray level change detected by the gray level, and the video quality could not be accurately measured when the amount of light was low by changing the gray level in a scrolling manner.

The present invention has been made to solve the above problems, an object of the present invention is a video quality measurement system and method that can measure the video quality of the liquid crystal display device and the image display device using the same using a low-cost photodetector device To provide.

An object of the present invention is to provide a moving picture quality measurement system and method that can change the gray level through the flicker of the screen in measuring the moving picture quality of the liquid crystal display device and the image display device using the same.

SUMMARY OF THE INVENTION An object of the present invention is to provide a moving picture quality measurement system and method that can significantly reduce the manufacturing cost and price of a product by measuring the moving picture quality of a liquid crystal display device and an image display device using the same by employing a low cost photodetecting device. have.

An object of the present invention is to measure a video quality of a liquid crystal display device and an image display device using the same, and to change the gray level through flickering of a screen, thereby reducing the number of parts mounted on a product and a video quality measuring system and method. To provide.

In order to achieve the above object, the present invention alternately supplies the video signals of the first and second images to the image display apparatus under test so that the first and second images alternately flicker, and the blood Signal generating means for changing and supplying gray levels of the first and second images as the inspection image display device blinks; Light detecting means for detecting and converting an optical signal representing a gray level of an image displayed on the image display apparatus under test into an electrical signal; Waveform generation means for generating a waveform corresponding to the gray level of the image represented by the level of the electrical signal; And controlling the signal generation of the signal generating means, calculating blurring edge widths of an image displayed on the inspected image display apparatus by using the generated waveform, and displaying the inspected image using the calculated blurring edge widths. And a moving picture quality measuring means for calculating the blurred edge times of the image displayed on the device and calculating the moving picture response time of the image display apparatus under test using the calculated blurred edge times.

According to the present invention, the video signals of the first and second images are alternately supplied to the image display apparatus under test so that the first and second images alternately flicker and the flashing of the image display apparatus under test is performed. Signal generation means for supplying the gray levels of the first and second images by varying and supplying the gray levels; Light detecting means for detecting and converting an optical signal representing a gray level of an image displayed on the image display apparatus under test into an electrical signal; And controlling the signal generation of the signal generating means, generating a waveform corresponding to the gray level of the image represented by the level of the electrical signal, and using the generated waveform to determine the image displayed on the inspection target image display device. Calculate the blurry edge widths, calculate the blurry edge times of the image displayed on the inspected image display device using the calculated blurry edge widths, and use the calculated blurry edge times to respond to the video response of the inspected image display device. And a moving picture quality measuring means for calculating the time.

According to the present invention, the video signals of the first and second images are alternately supplied to the image display apparatus under test so that the first and second images alternately flicker and the flashing of the image display apparatus under test is performed. Changing the gray levels of the first and second images accordingly; Detecting an optical signal representing a gray level of an image displayed on the image display apparatus under test and converting the optical signal into an electrical signal; Generating a waveform corresponding to a gray level of an image represented by the level of the electrical signal; And calculating the blurry edge widths of the image displayed on the inspected image display apparatus using the generated waveform, and calculating the blurry edge times of the image displayed on the inspected image display apparatus using the calculated blurry edge widths. And calculating a video response time of the image display apparatus under test using the calculated blurred edge times.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

9 is a block diagram of a video quality measurement system according to an embodiment of the present invention.

Referring to FIG. 9, the video image quality measurement system 400 of the present invention includes a photodiode 410 for detecting and converting an optical signal representing a gray level of an image displayed on the image display apparatus 300 to be converted into an electrical signal. ), An oscilloscope 420 for generating a waveform corresponding to the electric signal level output from the photodiode 410, and a video signal of the first image and the second image are alternately generated, An image displayed on the inspection target image display device 300 by controlling the signal generation unit 430 and the signal generation of the signal generation unit 430, and using the waveform generated by the oscilloscope 420. Calculate the blurry edge widths (BEW) of the image, calculate the blurry edge time (BET) of the image displayed on the image display device 300 using the calculated blurry edge widths (BEW), Blood test using BET A computer 440 for calculating a video response time of the image display device 300 is provided.

Here, the image display device 300 to be inspected may be a television receiver having a liquid crystal display device 100, a computer monitor, or the like. The image display device 300 may be a liquid crystal display device. That is, the video quality measurement system 400 of the present invention measures the video quality affected by the response speed of the video display device 300 to be inspected.

The photodiode 410 is a light detecting element that detects an optical signal generated when the image of the inspection target image display device 300 blinks and converts the light signal into an electrical signal. The photodiode 410 adjusts the gray level of the image displayed on the inspection target image display apparatus 300. The optical signal is detected and converted into an electrical signal and output to the oscilloscope 420. Here, the electrical signal level output by the photodiode 410 is changed corresponding to the gray level of the image displayed on the image display apparatus 300 to be inspected. When the gray level of the image increases, the electrical signal level also increases. The lower the gray level, the lower the electrical signal level.

The oscilloscope 420 generates a waveform corresponding to the electrical signal level output from the photodiode 410 and outputs the waveform to the computer 440. That is, the oscilloscope 420 receives an electrical signal from the photodiode 410 in units of predetermined time to generate a waveform as shown in FIG. 10, and the generated waveform is an electrical signal level output from the photodiode 410. Since the difference is shown, the gray level of the image is substantially changed by the blinking of the image display apparatus 300 under test. In FIG. 10, an off period is a period in which the backlight provided in the image display apparatus 300 under test is turned off, and an on period is a period in which the backlight is turned on. In FIG. 10, the x axis is a frame of an image displayed on the inspected image display apparatus 300, and the y axis is a relative amplitude of a waveform.

The signal generator 430 alternately supplies the video signals of the first image and the second image to the inspected image display device 300 so that the first and second images alternately flash and the inspected image. As the display device 300 blinks, the gray levels of the first and second images are changed and supplied. The signal generation process is controlled by the computer 440. Here, the first and second images may be implemented as a black image and a white image. The graybell of the image displayed on the inspection target image display device 300 is composed of '256' levels from '0' level to '255' level, but the video quality measurement system 400 of the present invention displays the displayed image. The video quality is measured by dividing the gray levels of the first and second images displayed on the inspected image display apparatus 300 into seven levels in consideration of the brightness of the screen.

The computer 440 measures video quality according to the response speed of the image display apparatus 300 under test, which will be described in detail below. However, the computer 440 may determine the gray levels of the first and second images displayed on the image display apparatus 300 under consideration in consideration of the brightness of the image having the '256' level from the '0' level to the '255' level. Video quality is measured by dividing into 7 levels.

The computer 440 controls the signal generation of the signal generator 430 to alternately supply video signals formed of the first and second images to the image display apparatus 300 under test according to a user's instruction. Accordingly, the signal generator 430 alternately supplies the first and second images and supplies the gray levels by changing the gray levels, thereby changing the gray level of the first and second images. Allow 300 to flash.

The photodiode 410 is generated when the image to be inspected blinks in the state in which the first and second images are alternately blinking in the image to be inspected display 300 according to the gray level change. When the detected optical signal is converted into an electrical signal and output to the oscilloscope 420, the oscilloscope 420 generates a waveform corresponding to the electrical signal level output from the photodiode 410 and outputs the waveform to the computer 440.

The computer 440 integrates the waveform generated by the oscilloscope 420 for a predetermined time, and divides the waveform by dividing it in units of frames.

For example, computer 440 integrates the waveform for 16.7 msec if one frame is 60 Hz, integrates the waveform for 11.1 msec if one frame is 90 Hz, and integrates for 8.35 msec if one frame is 120 Hz.

When the integration of the waveform is completed for a predetermined time, the computer 440 calculates the moving average value by substituting the integral value of the waveform into the following Equation 1.

Moving Average = Integral / Frame Time

Here, the frame time may be changed according to the frame of the image displayed on the image display apparatus 300 under test. For example, if one frame is 60 Hz, the frame time is 16.7 msec, and if one frame is 90 Hz, the frame time is 11.1 msec. If one frame is 120 Hz, the frame time is 8.35 msec.

When the moving average value is calculated for a predetermined time through the calculation process of Equation 1, the computer 440 arranges the moving average value calculated for a predetermined time according to the calculated time sequence to display a graph as shown in FIG. Create In FIG. 11, the x-axis is the blurry edge width BEW, the y-axis is the relative amplitude, and this relative amplitude is substantially the relative luminance. Here, the relative luminance is a luminance value that is determined relatively according to the ON / OFF duty of the backlight provided in the image display apparatus 300 under test, and the on-period at the duty of the backlight is 60 degrees. % And the off period is 40%, the relative luminance is 0.6.

Such a graph is continuously generated by the computer 440 during the video quality measurement period of the image display apparatus 300 under test, wherein all the graphs generated by the computer 440 are plotted on the coordinate plane of the x and y axes. Arranged in the graphs produces the same graphs as the graphs shown in FIG. This is because the conventional video quality measurement system 200 and the video quality measurement system 300 of the present invention not only generate the same graph but also calculate the same blurry edge width BEW.

In addition, the computer 440 calculates the blurring edge width (BEW) in the generated graph every time the graph as shown in FIG. 11 is generated, and corresponds to the lower amplitude of 10% to the upper amplitude of 90% among the amplitudes of the generated graph. Calculate the blurry edge width (BEW). Since the ripple is substantially generated in the graph, the amplitude portion of the graph excluded from the calculation of the blurry edge width (BEW) is regarded as ripple. Here, the amplitude of the graph is the y-axis value, and the blur edge width (BEW) is the x-axis value.

Referring to FIG. 11, a method of calculating a blurry edge width (BEW) is performed. The y-axis value corresponding to 10% of the lower amplitude of the graph is 0.06, and the x-axis value 0.53 corresponding to the lower amplitude of 0.06 is blurred. Calculated as BEW. The y-axis value corresponding to 90% of the upper amplitude of the generated graph is 0.54, and 1.02, which is the x-axis value corresponding to the upper amplitude of 0.54, is calculated as the blurring edge width (BEW).

When the blurry edge width BEW is calculated through the above process, the computer 440 calculates the blurry edge time BET by multiplying the blurry edge width BEW by the frame time as shown in Equation 2 below.

BET = BEW * frame time

In Equation 2, the frame time may be changed according to a frame of an image displayed on the image display apparatus 300 under test. For example, if one frame is 60 Hz, the frame time is 16.7 msec. If the frame is 90 Hz, the frame time is 11.1 msec. If one frame is 120 Hz, the frame time is 8.35 msec.

The computer 440 calculates the blurry edge times BET as shown in Table 1 by using the blurry edge widths BEW calculated in the gray level. That is, the conventional video image quality measurement system 200 and the video image quality measurement system 300 of the present invention not only calculate the same graphs and the same blurry edge widths BEW, but also the blurry edge time BET of [Table 1]. ) Are calculated equally.

After the blurry edge times BET of Table 1 are calculated through the calculation process according to Equation 2, the computer 440 integrates the calculated blurry edge times BET to obtain the blurry edge time BET. ) To calculate the video response time (MPRT) of the inspection target video display device 300 by dividing the integration value of the blurry edge times (BET) by a predetermined number of image measurements as shown in Equation 3 below. do.

MPRT = integral value of BET / number of image measurements

As described above, the video image quality measurement system 400 of the present invention generates a graph by quantifying the degree of blur of the gray change part when the gray level of the image displayed on the image to be inspected 300 is changed.

FIG. 12 is a diagram illustrating the configuration of the computer in FIG. 9, and illustrates only the components provided for implementing the present invention in addition to the components for performing the unique functions of the computer.

Referring to FIG. 12, the computer 440 calculates a moving average value by using an integrating unit 441 for integrating a waveform generated by the oscilloscope 420 and a moving average value using the integrated value of the waveform. A graph generator 442 for generating graphs arranged in the order of the calculated time, a BEW calculator 443 for calculating a blurry edge width (BEW) in gray level units in the generated graph, and a gray level BET calculation unit 444 for calculating the blurry edge hours BETs in gray level units using the blurry edge widths BEW calculated in units, and an image to be inspected by using the calculated blurry edge times BET. A MPRT calculator 445 for calculating a video response time (MPRT) of the device 300, a controller 446 for controlling video quality measurement of the video display device 300 under test, and storing various kinds of information. Output by the storage unit 447 and the control unit 446 Monitor for displaying various images and characters 448 and receives the user command and a keyboard (449) to pass to the control unit 446.

The integrator 441 integrates the waveform generated by the oscilloscope 420 for a predetermined time, divides the waveform by frame unit, and integrates the waveform to output the integrated value to the graph generator 442.

For example, the integrating unit 441 integrates the waveform for 16.7 msec when one frame is 60 Hz, integrates the waveform for 11.1 msec when one frame is 90 Hz, and integrates for 8.35 msec when one frame is 120 Hz.

The graph generating unit 442 calculates the moving average value by substituting the integral value of the waveform into the above Equation 1 and arranges the moving average value calculated for a predetermined time according to the calculated time sequence, as shown in FIG. 11. A graph is generated and output to the BEW calculator 443.

The BEW calculation unit 443 calculates the blurring edge width (BEW) in the generated graph whenever the graph as shown in FIG. 11 is generated, and corresponds to the lower amplitude of 10% to the upper amplitude of 90% among the amplitudes of the generated graph. The blurred edge width BEW is calculated and output to the BET calculator 444.

The BET calculation unit 444 calculates the blurry edge time (BET) by multiplying the blurry edge width (BEW) and the frame time as shown in [Equation 2], but using the blurry edge widths (BEW) calculated in gray level units. As shown in Table 1, cloudy edge times BET are calculated in gray level and output to the MPRT calculator 445.

The MPRT calculating unit 445 integrates the calculated cloudy edge times BET to obtain an integral value of the cloudy edge times BET, and then calculates integral values of the cloudy edge times BET as shown in Equation 3 above. The video response time (MPRT) is calculated by dividing by the number of video measurements.

The controller 446 controls video quality measurement of the image display apparatus 300 under test according to a user's instruction input through the keyboard 449. For example, the controller 446 controls the signal generation of the signal generator 430, stores the graph generated by the graph generator 442 in the storage 447, and / or outputs the graph to the monitor 448. The stored edge width BEW calculated by the BEW calculation unit 443 is stored in the storage unit 447 and / or output to the monitor 448, and the blurred edge time calculated by the BET calculation unit 443 ( BET) is stored in the storage unit 447 and / or output to the monitor 448, and the video response time (MPRT) calculated by the MPRT calculation unit 445 is stored in the storage unit 447 and / or the monitor ( 448).

Therefore, as described above, the present invention does not employ expensive equipment such as a CCD camera and a rotating mirror, thereby significantly reducing manufacturing cost and selling price, compared to a conventional video quality measurement system, and also using a liquid crystal display and an image using the same. By measuring the video quality of the display device using a low-cost photodetector, the manufacturing cost and price of the product can be greatly reduced.

13 is a block diagram of a video quality measurement system according to another embodiment of the present invention.

Referring to FIG. 13, the video quality measurement system 500 according to another exemplary embodiment of the present invention includes a photodiode 410 and a signal generator 430, as in FIG. 9, and also has a waveform generation function. An additional computer 510 is provided.

The computer 510 performs a function as described above with reference to FIG. 9 while also having a waveform generation function.

The computer 510 generates a waveform corresponding to the electric signal level output from the photodiode 410. Here, the computer 510 receives an electric signal from the photodiode 410 in units of a predetermined time and generates a waveform as shown in FIG. 10.

That is, the video quality measurement system 500 according to another exemplary embodiment of the present invention does not include the oscilloscope 420 separately from the computer 510, and allows the computer 510 to perform the waveform generation function of the oscilloscope.

FIG. 14 is a diagram illustrating the configuration of a computer in FIG. 13. In addition to the components for performing the unique functions of the computer, only the components provided for implementing the present invention are shown.

Referring to FIG. 14, as in FIG. 12, the computer 510 includes an integrating unit 441, a graph generating unit 442, a BEW calculating unit 443, a BET calculating unit 444, and an MPRT calculating unit 445. ), A control unit 446, a storage unit 447, a monitor 448, and a keyboard 449.

The computer 510 includes a waveform generator 511 for generating a waveform.

The waveform generator 511 generates a waveform corresponding to the electrical signal level output from the photodiode 410 and outputs the waveform to the integrating unit 441. The waveform generator 511 receives an electrical signal from the photodiode 410 on a predetermined time basis. Generate a waveform as shown at 10. That is, the waveform generator 511 performs the same function as the oscilloscope 420.

Here, the integrator 441 integrates the waveform generated by the waveform generator 511 for a predetermined time and outputs an integrated value to the graph generator 442.

As described above, the present invention can significantly reduce the manufacturing cost and price of the product by measuring the video quality of the liquid crystal display device and the image display device using the same by employing a low cost photodetector device. In addition, the present invention can significantly reduce the number of components mounted in the product by changing the gray level through the flicker of the screen in measuring the video quality of the liquid crystal display device and the image display device using the same. In particular, in the present invention, by not employing a high-cost equipment such as a CCD camera and a rotating mirror, the moving image quality measuring system of the present invention can significantly reduce the manufacturing cost and selling price compared to the conventional moving image quality measuring system.

Although the technical spirit of the present invention has been described in detail according to the above preferred embodiment, it should be noted that the above embodiment is for the purpose of illustration and not for the purpose of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

Claims (22)

The video signals of the first and second images are alternately supplied to the image display device under test so that the first and second images alternately flash and the first image is displayed according to the blinking of the image display device under test. And signal generation means for changing and supplying the gray level of the second image. Light detecting means for detecting and converting an optical signal representing a gray level of an image displayed on the inspected image display apparatus into an electrical signal; Waveform generation means for generating a waveform corresponding to the gray level of the image represented by the level of the electrical signal; And Controlling the signal generation of the signal generating means, calculating blurring edge widths of the image displayed on the inspected image display apparatus using the generated waveform, and using the calculated blurring edge widths, Video quality measurement means for calculating the blurred edge times of the image displayed on the image, and calculating the video response time of the image display apparatus under test using the calculated blurred edge times. Video quality measurement system comprising a. The method of claim 1, And the light detecting means is a photodiode for detecting light and converting the light into an electrical signal. The method of claim 1, The waveform generating means is a video quality measurement system, characterized in that the oscilloscope for generating a waveform by receiving an electrical signal. 4. The method according to any one of claims 1 to 3, The video quality measuring means is a video quality measuring system, characterized in that a computer. The method of claim 4, wherein The computer, An integrating unit for integrating the waveform generated by the waveform generating means; A graph generator for generating a graph by calculating a moving average value using the integrated value of the waveforms and arranging the calculated moving average values according to the calculated time sequence; A BEW calculator configured to calculate a blurry edge width in units of gray levels in the generated graph; A BET calculator configured to calculate blurry edge times in gray level using the blurry edge widths calculated in gray level; An MPRT calculator configured to calculate a video response time of the image display apparatus under test using the calculated edge time; And Control unit for controlling the video quality measurement of the video display device to be tested, and for controlling the signal generation of the signal generating means Video quality measurement system comprising a. 6. The method of claim 5, The graph generating unit calculates a moving average value by dividing the integral value of the waveform by the frame time. The method of claim 6, The BEW calculation unit is a video quality measurement system, characterized in that for calculating the blurring edge width corresponding to the upper amplitude 90% from the lower amplitude 10% of the generated amplitude of the graph. The method of claim 7, wherein And the BET calculator calculates the blurry edge time by multiplying the blurry edge width by the frame time. 9. The method of claim 8, The MPRT calculator calculates the video response time by integrating the calculated cloudy edge times to obtain an integral value of the cloudy edge times, and then dividing the integral of the cloudy edge times by a predetermined image measurement number. Video quality measurement system. The video signals of the first and second images are alternately supplied to the image display device under test so that the first and second images alternately flash and the first image is displayed according to the blinking of the image display device under test. And signal generation means for changing and supplying the gray level of the second image. Light detecting means for detecting and converting an optical signal representing a gray level of an image displayed on the inspected image display apparatus into an electrical signal; And Controlling the signal generation of the signal generating means, generating a waveform corresponding to the gray level of the image represented by the level of the electrical signal, and using the generated waveform to blur the image displayed on the inspection target image display device. Calculating the widths of the images, calculating the blurred edge times of the image displayed on the image display apparatus using the calculated blurred edge widths, and using the calculated blurred edge times, determining the video response time of the image to be examined. Video quality measurement means to calculate Video quality measurement system comprising a. 11. The method of claim 10, And the light detecting means is a photodiode for detecting light and converting the light into an electrical signal. The method of claim 10 or 11, The video quality measuring means is a video quality measuring system, characterized in that a computer. 13. The method of claim 12, The computer, A waveform generator for generating a waveform corresponding to the gray level of the image represented by the level of the electrical signal; An integrator for integrating the generated waveform; A graph generator for generating a graph by calculating a moving average value using the integrated value of the waveforms and arranging the calculated moving average values according to the calculated time sequence; A BEW calculator configured to calculate a blurry edge width in units of gray levels in the generated graph; A BET calculator configured to calculate blurry edge times in gray level using the blurry edge widths calculated in gray level; An MPRT calculator configured to calculate a video response time of the image display apparatus under test using the calculated edge time; And Control unit for controlling the video quality measurement of the video display device to be tested, and for controlling the signal generation of the signal generating means Video quality measurement system comprising a. The method of claim 13, The graph generating unit calculates a moving average value by dividing the integral value of the waveform by the frame time. 15. The method of claim 14, The BEW calculation unit is a video quality measurement system, characterized in that for calculating the blurring edge width corresponding to the upper amplitude 90% from the lower amplitude 10% of the generated amplitude of the graph. 16. The method of claim 15, And the BET calculator calculates the blurry edge time by multiplying the blurry edge width by the frame time. 17. The method of claim 16, The MPRT calculating unit calculates the video response time by integrating the calculated cloudy edge times to obtain an integral value of the cloudy edge times, and then dividing the integral value of the cloudy edge times by a predetermined image measurement number. Image quality measurement system. The video signals of the first and second images are alternately supplied to the image display device under test so that the first and second images alternately flash and the first image is displayed according to the blinking of the image display device under test. Changing the gray level of the second image; Detecting and converting an optical signal representing a gray level of an image displayed on the inspected image display device into an electrical signal; Generating a waveform corresponding to a gray level of an image represented by the level of the electrical signal; And Calculates blurring edge widths of an image displayed on the inspected image display apparatus by using the generated waveform; calculates blurry edge times of an image displayed on the inspected image display apparatus by using the calculated blurry edge widths; Calculating a video response time of the image display apparatus under test using the calculated blurred edge times; Video quality measurement method comprising a. The method of claim 18, In the calculating step, a moving average value is calculated by dividing the integral value of the waveform by the frame time. 20. The method of claim 19, In the calculating step, the moving average value is arranged according to the calculated time sequence video quality measurement method, characterized in that for calculating the blurring edge width corresponding to the lower amplitude 10% to the upper amplitude 90%. 21. The method of claim 20, In the calculating step, the blurring edge time is calculated by multiplying the blurry edge width by the frame time. 22. The method of claim 21, In the calculating step, after calculating the integrated value of the cloudy edge hours by integrating the calculated cloudy edge times, the video response time is calculated by dividing the integral value of the cloudy edge times by a predetermined image measurement number. How to measure video quality.

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