Evaluation standard and method of the hottest smal

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Evaluation standards and methods of small spacing LED display screen

a small spacing LED display screen that is qualified and can stand the test must have been strictly tested before leaving the factory. Only in this way can the normal operation and good display effect be guaranteed for a long time and the failure rate be reduced after the formal delivery to the customer

I. test methods and conditions of small spacing LED display screen

(1) equipment: 1080p (1920 × 1 Blu ray HD player with 1080 full frame) resolution; One high-performance computer with 1080p HDMI output; 1 video signal distributor with 4-component color difference output

(2) standard video source, pictures, etc. for test: blue light source disk; Professional test video hi definition reference (select multiple scenes); Displayx, sj/t standard test software of light emitting diode (LED) display screen test method; Computer generated 1080p standard color scale, full color gradient, gray scale and pictures from the Internet, the pictures intercepted or generated by the above two items, and the night view of the highway bridge

(3) test method: before the formal evaluation, each manufacturer is allowed to conduct multiple on-site debugging on its own led large screen (due to the limited site size, it is recommended to test the resolution of the splicing screen 720p or 1080p line), so as to achieve the best effect of their products. At the specified time, a review group composed of experts with rich experience in image transmission, video display and LED large screen hardware will evaluate the actual application effect

II. Evaluation requirements of small spacing LED display screen

(1) gray scale image test

① the test of gray scale and color scale has always been an important index reference for dlp/plasma/LCD/led and other large screens or splicing large screens, which is used to evaluate the gray scale transition ability of large screen splicing and controller (if any), as well as the black-and-white conversion ability. The more obvious the contrast, the stronger the ability of the display system to process color images due to the serious deviation between the price and value of rare earth in China

bidirectional gray-scale signal is used to test the 16 gray-scale levels that the system should display at least. If each level can be distinguished, 3 points will be obtained; Less discrimination will reduce 1 point, and this item has a minimum of 0 point

25 +2 gray scale image should be able to distinguish the darkest three gray scales a, B, C and the brightest three gray scales u, V, w on the screen at the same time. A. B and C must be layered and not look black; Similarly, u, V and W should also have layers, and they should not look white. If the large screen image has any color/color deviation during playback, points shall be deducted. If there is no color difference (black and white are impure and have other colors), 2 points shall be added. If there is color deviation, 1-2 points shall be deducted as appropriate

② comprehensive test of sharpness and gray scale. This scenario is used to comprehensively test the performance of the whole system, such as line number, gray scale, geometric distortion and so on. At 1080p (1920 × 1080), each gray level and the number of lines should be clearly identifiable, and the black-and-white purity of gray level can also be tested. If there is a problem, reduce 1 point; Minimum 1 point

③ gray scale realistic picture. The more black-and-white levels are displayed, the better the gray-scale processing ability of the system can be reflected. Minimum 2 points, maximum 5 points

(2) color picture test

① dark part comprehensive test of color pictures. This scene is a night scene, which focuses on the intensity changes of color brightness and halo. It is used to test the color, gray scale, detail display and other performances of the system. If the left boat under the bridge and the top halo and bridge deck cable above the main tower can be clearly identified, 4 points will be given. Deduct 1-2 points depending on the severity of the problem. If there is no problem in distinguishing the light and dark changes of other details, 1 point will be added

② detail test of bright part: detail restoration ability test with bright white as the keynote. This scene is a dining table and dressing table with high brightness. It mainly tests the restoration ability of the white part of the system under high light and the gray scale dynamic range. The grain details of window curtains, cloth, brushes and other objects should be completely preserved. If all items are met, 5 points. If there is any nonconformity, 0.5% will be deducted for each item 5 points, up to 2 points can be deducted in total

③ face detail definition test. This scene is a close-up static picture of a girl and flowers, which reflects the fidelity of the large screen splicing system to various details such as face skin color and spots, as well as the authenticity of skin color. The total score is 5 points. If the facial details are not clear, 0 5 points. Deduct 1 point if the face color is impure

④ color reduction test. It mainly tests the uniformity of color and the purity of white. All kinds of ingredients and fruit colors in the kitchen, pure white crystals on the tray and the pen holder and wood grain part of color pencils. 1. At ordinary times, our standard fixture is 2 sets of restoration display of grassland, clouds, etc. If white is impure, 1-3 points will be deducted depending on the purity of color deviation. The full score is 5 points

⑤ color saturation and detail test. The edge fluff of the pile should be clearly visible, and the texture of the spool and pad should also be clearly identifiable. The full score is 5 points. 1 point will be deducted if the fuzz is not clear; Deduct 1 point if the spool texture is not clear; If the texture of the padding is not clear, 1 point will be deducted

(3) dynamic scene test

rock & wave (Blu ray video source: 00014. M2TS). This scene is a sea reef scene, which is used to test the image quality of the equipment containing a large number of small movements in a static background, especially the white balance and detail resolution. In addition, fog (water mist) generated by waves should be clearly distinguished at the 20-27s playback. 5 points is full score. If the layers of waves and reefs are not clear, 0 1-1 point. If the fog is not clearly displayed, 0 5-2 points

① light and shade detail test (Tokyo Night, Blu ray video source: 00019. M2TS). This scene is a moving image of the night scene in Tokyo, which is mainly divided into four scenes: the tower under the light; Christmas tree with embedded lights; The night view of the bridge and the two banks; Night view around the ferris wheel. It mainly tests the color restoration ability and the dynamic range of light and shade contrast of the system when playing dynamic video. The details of lines in highlighted neon lights, Christmas tree details, dark details on both sides of the bridge, Ferris wheel light and street dark details should be completely preserved. The minimum score is 2 points and the maximum score is 5 points (0.1-1 points will be deducted for each item with unclear details and levels, as appropriate)

② black and white contrast test (Black & white, Blu ray video source: 00020.m2ts). It mainly tests the edge discrimination ability of black-and-white scenes and black-and-white dressed people. The highest score is 5 points. If the black background and the edge of black clothes can be clearly distinguished, 3 points will be obtained. White error solution: if the background and the edge of white clothes can be clearly distinguished, 2 points will be given. If the same color edge is indistinguishable, 1-2 points will be deducted as appropriate

③ color expressiveness: accessories (blue light test source: 00021. M2TS). The main scenes are flowers and ornaments (necklaces, gloves, feather ornaments, etc.), which are mainly used to test the permeability of color and the texture of objects. In addition, the details of the tiny flutter of feathers are also very important. The highest score is 5 points. If the flower level is not enough, 1 point will be deducted; If the feather details are unclear, 1 point will be deducted; Deduct 1 point if the color is not transparent

④ dark detail test (black image blue light test makes the circuit simple source: 00027. M2TS). The more black-and-white levels are displayed, the better the system's ability to deal with dark details, and the higher the gray-scale level that can be displayed and restored. The black layer is clearly distinguished, and the full score is 10 points; If the black part is insufficient, 2-6 points will be deducted as appropriate

other tests will not be repeated

(4) professional software testing (displayxseries)

① solid color: black, RGB, P (purple), y, C (blue), white. If black and white and six colors are displayed in solid colors, the overall color is uneven, 0-1 points will be deducted in total, and the year-on-year comparison will be made. In case of bad points, 2-3 points will be deducted depending on the number of bad points, compared with the same period last year. Maximum 5 points

② color and gray scale: gradient test (no polarization). The r/g/b trichromatic signal with chromaticity gradient from left to right and the y/purple/cyan after two-color mixing are used to test the chromaticity and gray scale changes of the system. The gradient has no ladder sense, that is, the smoother the transition, the higher the gray level of the system. The colors are gradually transparent, and there are no faults and vertical steps, the full score of this item is 5 points. Depending on the severity of each color, 1-3 points will be deducted for year-on-year comparison

③ full color gradient. The full chromatogram is gradual and has no polar change. The more gorgeous and transparent the color is, the better. If there are more steps in each color, the less ideal it is. Points must be deducted accordingly during evaluation; The closer the color display is to the vertical, the better the synchronization of the gray changes of each color. Gradual and transparent, without faults and vertical steps, 4 points for this item. If there is no uneven change in color during gradual change, another 1 point will be given for this item. For the apparent severity of color faults, 1-3 points will be deducted for year-on-year comparison

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