Method and device for detecting lens stain

A technology for detecting lenses and stains, applied in image data processing, television, instruments, etc., can solve the problems of low accuracy and efficiency

Active Publication Date: 2017-02-15
GOERTEK OPTICAL TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] In view of the above problems, the present invention provides a method and device for detecting lens stains, to solve the problem of low accuracy and efficiency of existing methods for detecting lens stains

Method used

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  • Method and device for detecting lens stain
  • Method and device for detecting lens stain

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] Embodiments of the present invention provide a method for detecting lens stains, such as figure 1 As shown, the method includes:

[0036] Step S110: Take a picture with the camera or select a picture from the video shot by the camera;

[0037] Step S120: Select the region of interest of the picture, select test pixels row by row in the region of interest with the first step length, and select a number of reference pixel points around the test pixel point with the second step length, each test pixel point and The surrounding reference pixels form a test unit, such as figure 2 The test units labeled a, b, and c, respectively. For example, in the test unit labeled c, 1 is the test pixel, and 2-5 are reference pixels. The number of reference pixels can be flexibly selected according to needs. The more reference pixels, the more accurate the test result.

[0038] Among them, the second step is longer than half of the first step, so that two adjacent test units in the sam...

Embodiment 2

[0061] In the embodiment of the present invention, such as Figure 6 As shown, the image gradually darkens radially from the center to the edge. Since the brightness of the central area has a small change, while the brightness of the edge area has a large change, if the variance threshold is set to be uniform, it is easy to miss the slight stain with a small variance of the brightness value of the central area, and it is also easy to set the brightness of the edge area The place where the value variance itself is relatively large is misjudged as a stain. Therefore, when setting the variance threshold, the experience value corresponding to the area with a larger average brightness value is set smaller, and the experience value corresponding to the area with a smaller average brightness value is set larger, that is, the variance threshold of the central area is smaller than that of the edge The variance threshold for the region. For example, the variance corresponding to a cer...

Embodiment 3

[0065] Such as Figure 7 As shown, the embodiment of the present invention provides a device for detecting lens stains, the device comprising:

[0066] The variance threshold acquisition module 100 is used for:

[0067] Under the same shooting conditions as the test environment, take a picture with a non-stained lens or select a picture from a video shot with a non-stained lens;

[0068] Obtain the brightness values ​​of the central pixel in the different brightness areas of the picture and several pixels in a predetermined step around it;

[0069] Calculate the average luminance value and the variance of the luminance value of several pixels within the central pixel point and its surrounding predetermined step;

[0070] The variance thresholds corresponding to different average brightness values ​​are obtained by adding an empirical value to the variance of the average brightness value, and the empirical value varies with the average brightness value.

[0071] For a pictur...

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Abstract

The invention discloses a method and device for detecting a lens stain. The method comprises a step of selecting an interest area of an image, and selecting a test unit in the interest area, a step of obtaining the test pixel in each test unit and the brightness value of each reference pixel, and calculating the average brightness value of the test pixel in each test unit and the reference pixel and the variance of the brightness value, a step of comparing the variance and the variance threshold corresponding to the average brightness value obtained in advance, if the variance is larger than the variance threshold, judging the test pixel in the test unit as a stain, and outputting the pixel position of the stain. For an image which is gradually darkened in a radiating form from a center to an edge, the variance threshold corresponding to the center area with high brightness is smaller than the variance threshold corresponding to an edge area with low brightness, the slight stain of the center area can be easily detected, the edge area with a large variance is not wrongly judged as a stain, and the accuracy and efficiency of a test are improved.

Description

technical field [0001] The invention relates to the technical field of lens detection, in particular to a method and device for detecting lens stains. Background technique [0002] In recent years, smart products have penetrated into all aspects of life, and now smart product cameras should be used as a standard, so for lens manufacturers and lens intermediate manufacturers, how to detect whether the lens is a good product has become a problem. challenge. [0003] Lens detection is a complex process, including testing the resolution of the lens to color, the distortion rate of the lens, whether there is dirt on the lens, etc., here we only focus on detecting whether the lens is dirty, that is, testing the lens Stain, proposes a new detection method that can improve or solve some of the previous shortcomings. [0004] It is very simple for our human eyes to distinguish stains, but it is not an easy task for computers, because there are only numbers in the world of computers...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04N17/00G06T7/40G06T7/00
CPCG06T7/0002G06T2207/10004H04N17/002
Inventor 高新亮
Owner GOERTEK OPTICAL TECH CO LTD
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