Research On Vision Reognition And Location Of The Up-down Material Robot Serving For NC Machine Group

The robot with object recognition is an important symbol of intelligence. Intelligent robot can realize the capture or tracking task through the position and shape of object perception. The shape information is a kind of high-level visual features, analysis on the characteristics of shape information can make robot realize the understanding of the object shape. How to make robots represent and abstract shape information of the aim object from natural images is a core of computer vision. A lot of achievements have been made in analysis and research on pure shape, but a few are rarely used in practice, influenced by the noise and shape model.In this paper, mainly research on positioning and objects recognition such as robot grapping workpiece, chuck, is about the robot special used in the service of NC Machine Group. Enlightened by Gestalt psychology cognitive theory, the paper puts forward the hybrid strategy, which combines the feature extraction of bottom-up and top-down the shape of the guidance, and solve the key problems in the workpiece and chuck identification and location.(1) According to the target object and the background are blended in the natural images, this paper proposes a high-level vision based on the theory of the Gestalt perception under the guide of discrete contour recognition method. The algorithm presents local shape fragment descriptors, and establishes the shape similarity evaluation function to determine the segment between the model and subordinate probability, enhances the role of local shape fragments on the model, improves the convergence speed of the fitting process. For the discontinuous contour chain,"Gestalt" operation on the discontinuous contour in figure on the basis of the model, finds a minimum cost simple ring. The high order problem can be converted to optimization problems, and the computational complexity is reduced to polynomial level. Through the neighborhood voting mechanism, the background noise is eliminated and inhibited. After excluding abnormal value profile reduced the data computation, the positioning precision is improved. The accurate space location information about feeding NC machine is got by the curve fitting of the contour of the object.(2) In order to select the blank workpiece accurately, and ensure the minimum machining allowance, this paper puts forward the sub-pixel edge detection methods based on modified Bezier point spread function. According to the gray level distribution of the initial edge localization, the subpixel is located by the quafric curve. The quafric curve uses the modified Bezier point spread function. Revised Bezier point spread function takes the advantages of Gauss point spread function. The introduction of variable parameters on the Bezier point spread function for a correction and the second amendment, improves the flexibility and accuracy of Bezier point spread function, the experimental results show that the revised Bezier fitting has a higher accuracy than Gauss fitting, and a correction is faster, to meet the real-time requirements for edge detection.(3) Research on the methods of camera calibration, and analyze the main cause of the camera calibration error and complete the error correction. Based on the analysis of experimental data, summarizes nonlinear relation between calibration accuracy and the baseline distance, focal length, distance; then draw the curve of calibration error change. Through the internal and external parameters of camera calibration and optimization choice of baseline distance, binocular calibration precision and stability is improved.(4) In the denoising image, this paper proposes a smooth filtering method of retention characteristics of image edge details. This method constructs window mask based on nine neighborhoods with pentagons and hexagons. Because pentagons and hexagons in the mask neighborhood all have acute Angle, this design has the advantage that the pixels are in acute angle of a complex shape field, the mask can also find a homogeneous neighborhood consistent with edge shape basically. The edge details are retained while removing the noise.The research works above laid a theoretical foundation for the engineering practice of the up-down material robot serving for numerical control machine tool group, and those are of great significance not only to improve the level of automation of manufacturing industry,but also to enhance the applicability of computer vision technology in the industrial field.