Line structured light center line extraction method and storage medium

Abstract

The invention discloses a line structured light center line extraction method, which belongs to the technical field of machine vision, and comprises the following steps of: carrying out a series of processing such as clipping, image graying, image enhancement, image denoising, image binarization, morphological opening and closing operation, image light bar region segmentation and the like on an image acquired by a CCD (Charge Coupled Device) industrial camera; performing refinement processing by adopting a refinement algorithm to obtain an image containing a single-pixel light bar center line;and improving a Steger algorithm. ;firstly, determining a region of interest and performing median filtering on the region; secondly, moving on an image row according to the determined constraint threshold and a 1 * 5 movable template, and finding out a rough center point; solving a Hessian matrix through the separability and the symmetry of a Gaussian function; and finally, carrying out Taylor secondary expansion to obtain sub-pixel-level center coordinates. The algorithm is good in connectivity, free of burrs, easy to operate, high in operation efficiency, high in extraction speed and highin precision. According to the invention, the real-time requirement of a visual detection system can be met.

Description

technical field [0001] The invention belongs to the technical field of machine vision, and in particular relates to a method for extracting a center line of line structured light. Background technique [0002] Three-dimensional measurement technology is the basis of three-dimensional reconstruction technology, which can be divided into contact measurement and non-contact measurement according to different measurement methods. With the rapid development of non-contact measurement technology, especially the non-contact measurement method based on structured light has been widely used in actual production and life. [0003] In 3D reconstruction, the extraction of the centerline of the structured light stripe is extremely important. Since the projection angle of the stripe needs to be calculated based on the centerline of the stripe, the result of the centerline extraction of the structured light stripe will directly affect the result of the 3D reconstruction. precision. [00...

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Problems solved by technology

[0004] Among them, the geometric center method is to use the midpoint of the two endpoints of the light bar in each section as the center point of the light bar of the section. This method has a simple algorithm and fast extraction speed, but has low precision and poor versatility; Synthesize the gray distribution curve of the light band and find the position of the maximum value of the curve. This method can overcome the error caused by the asymmetry of the gray distribution of the light strip, but the stability is poor and the precision is low; the skeleton extraction method is on the image boundary In the neighborhood of a certain point, it is judged by certain conditions that the point is retained or deleted, and the iterative operation is performed until the position of the center line of a single pixel is obtained. This algorithm is simple to operate, but the accuracy is low; Carry out weighted average to obtain the extreme value point as the center position of the light strip. This method has better robustness, but the amount of calculation is large; the extreme value method uses the maximum value point of the light bar gray level as the point on the center line. This method extracts The speed is fast, but the noise resistance is poor; the Steger algorithm uses the Hessian matrix to obtain the extreme points in the normal direction of each point of the light band in the image, so as to obtain the sub-pixel position of the center line of the light band

This method has high precision and good robustness, but it has a large amount of computation and is difficult to meet the real-time requirements

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