High precision target sphere center extraction method in unstructured environment

An unstructured and extraction method technology, applied in the field of binocular vision, can solve the problems of uneven illumination of high-precision target balls, uneven surface gray scale, difficulty in extracting the center point of the sphere, etc., and achieve the improvement of visual measurement accuracy and extraction accuracy High, the effect of improving precision

Inactive Publication Date: 2017-11-21
DALIAN UNIV OF TECH
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Problems solved by technology

[0003] The technical problem to be solved by the present invention is that in a non-structural environment, the surface gray level of the high-precision target ball is uneven due to uneven illumination, and the problem that the center point of the sphere is difficult to extract

Method used

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  • High precision target sphere center extraction method in unstructured environment
  • High precision target sphere center extraction method in unstructured environment
  • High precision target sphere center extraction method in unstructured environment

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Embodiment 1

[0034]Embodiment 1, the measured object of the present invention is a group of high-precision standard target balls with a center distance of 59.9506 mm. Two View Works cameras are used to obtain the original target ball image, which is processed as the original noisy image src. This example operates in the environment of Visual Studio2013 platform, C / C++ language and OpenCV visual library.

[0035] then follow the attached figure 1 The flow chart shown proceeds as follows.

[0036] The first step is to denoise the image src in order to improve the stability and robustness of subsequent contour extraction and feature point set acquisition. Through the function cvSmooth, where the input method parameter is set to CV_MEDIAN, the median filter is performed on the image src, and the resulting image medDst is obtained as attached figure 2 shown. Then set the binarization threshold thr=55, and perform image binarization processing to obtain a binarized image thrDst. And becaus...

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Abstract

A high precision target sphere center extraction method in an unstructured environment provided by the invention belongs to the field of binocular vision technology. According to the invention, denoising is performed based on median filtering and deletion of small area noisy points on an image obtained through photographing and pretreatment such as binarization processing is carried, so that an outline point set of a high precision target sphere center in the image is acquired. By adopting a quick sort algorithm, sorting of the outline point set specific to y coordinates is performed, so that a valid fit pint set used for oval fitting on the outline of the high precision target sphere with non-uniform surface gray level is acquired. By adopting an oval fitting algorithm, the coordinate value of the outline center of the high precision target sphere with non-uniform surface gray level is calculated. The method is high in extraction precision and is used for subsequent operation such as camera calibration, image processing and the like. Especially, the precision of a calibration method utilizing the high precision target sphere is improved and improvement on visual measurement precision is realized in a specific degree.

Description

technical field [0001] The invention belongs to the technical field of binocular vision and relates to a method for extracting the center of a high-precision target ball in an unstructured environment. Background technique [0002] Since the sphere has the advantage that its geometric characteristics will not change when viewed from any angle, the sphere as a common target has been widely used in many fields such as machine vision calibration and feature recognition. In order to obtain better calibration accuracy, a closed environment and a stable light source system are often built to form a structured environment with uniform illumination, which is convenient for the extraction of the center point of the high-precision target ball outline. However, for industrial measurement fields such as aerospace, the working conditions are complex, the field of view background is difficult to control, and the structured environment is difficult to construct. Therefore, the high-precis...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06T5/00G06T7/187G06T7/60
CPCG06T5/002G06T7/187G06T7/60G06T2207/20032
Inventor 刘巍张致远叶帆张洋兰志广赵海洋马建伟贾振元
Owner DALIAN UNIV OF TECH
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