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Sub-pixel contour extraction based on Gaussian influences and optimization under scene of sheet metal detection by using Softmax regression

A sub-pixel-level, sheet-metal technology, applied in measuring devices, image analysis, image data processing, etc., can solve problems such as inability to perform one-time measurement, low measurement efficiency, and affecting measurement accuracy

Inactive Publication Date: 2017-11-07
SICHUAN UNIV
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, large sheet metal parts usually cannot be measured at one time. Even if a vernier caliper with a range of 3m or more is used on the market, the measurement efficiency is very low, and the measurement accuracy will be greatly affected

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  • Sub-pixel contour extraction based on Gaussian influences and optimization under scene of sheet metal detection by using Softmax regression
  • Sub-pixel contour extraction based on Gaussian influences and optimization under scene of sheet metal detection by using Softmax regression
  • Sub-pixel contour extraction based on Gaussian influences and optimization under scene of sheet metal detection by using Softmax regression

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Embodiment Construction

[0014] 1) Space coordinate system correction

[0015] Such as figure 1 As shown, if the contour point p(u,v) is known, its position in the three-dimensional coordinate system needs to be obtained first. To map the two-dimensional point in three-dimensional space, it is necessary to use the plane F and the point O of the camera coordinate system The focus of the line connecting p through the plane F is the position of p in the three-dimensional coordinate system. Let F be the plane of the sheet metal platform based on the camera coordinate system, and its expression is now required. Here, a grid calibration plate is introduced as an auxiliary tool for detection, which is used to obtain the physical scale on the F plane and the angle information with the imaging plane, that is, the translation vector T and the rotation matrix R. The world coordinate system is established here, with the lower left corner of the calibration board as the origin, the rightward direction of the cor...

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Abstract

The invention relates to a monocular vision based sheet metal measurement system. In the first stage, distortion correction is performed on an image, a smoothing operation is carried out on the image, upper and lower edges of the side surface of sheet metal are filtered, and pixel-level edge detection is performed on the sheet metal by adopting a Canny operator; then a Gaussian influence based sub-pixel offset (GIM) algorithm is proposed according to acquired image grayscale gradient distribution so as to perform sub-pixel positioning on the image; and then true-scale restoration is performed on planar information of sub-pixel image edges by using calculated internal and external parameters of camera calibration; and in the second stage, a Gaussian influence-based contour extraction process is applied to an application scene of sheet metal contour detection, and distortion correction and spatial coordinate system correction are performed on the image so as to restore true information of the image contour. Factors such as sub-pixel positioning offset caused by a model error and a calculation error are considered, the extracted sub-pixel contour is corrected again by using Softmax regression, and thus the accuracy of contour extraction is improved.

Description

technical field [0001] The invention belongs to the field of improving measurement accuracy in a monocular vision sheet metal measurement system, and in particular relates to a method for improving contour accuracy. Background technique [0002] Sheet metal is a kind of metal that is processed into flat sheets in the industry. It has the characteristics of high strength, strong shielding, low cost, and easy mass production. It has a wide range of applications and is one of the essential raw materials for air conditioners, refrigerators, mobile phones, and televisions. Sheet metal is often processed into a wide variety of shapes to meet product appearance and functional requirements. Usually, the thickness of the same sheet metal part is uniform, the thickness range is between 1mm and 5mm and is an integer, and the outer contour of most sheet metal parts is rectangular. An important criterion for judging whether the processing of sheet metal parts is qualified is the degree...

Claims

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Application Information

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IPC IPC(8): G01B11/24G06T7/80
CPCG01B11/24G06T7/80
Inventor 彭舰薛鹏飞陈瑜
Owner SICHUAN UNIV