tailieunhanh - Machine Vision - David Vernon Part 4

Tham khảo tài liệu 'machine vision - david vernon part 4', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Fundamentals of digital image processing 1 2 3 6 11 18 28 43 65 95 135 1 186 3 249 11 324 28 411 65 506 135 606 3 249 706 28 411 800 135 606 882 411 800 945 800 945 986 1000 1000 1000 800 945 986 411 800 945 135 606 882 28 411 800 3 249 706 135 606 65 506 28 411 11 324 3 249 1 186 135 95 65 43 28 18 11 6 3 2 1 20 Figure The Gaussian function for three values of Ơ and together with their corresponding discrete one-dimensional masks note that the result of convolution with these masks should be normalized by dividing by the sum of the mask weights. 60 Neighbourhood operations the function has a limited support in space. The Gaussian function optimizes the trade-off between these two conflicting requirements. Thinning erosion and dilation Thinning is an iterative neighbourhood operation which generates a skeletal representation of an object. It assumes of course that you know exactly what constitutes the object in the image and what constitutes the background . everything which is not part of the object . Such an image is said to have been segmented into its component parts the topic of segmentation is extremely important and will be discussed in detail in the next chapter. The skeleton of an object may be thought of as a generalized axis of symmetry of the object and hence it is a suitable representation for objects which display obvious axial symmetry. The medial axis transform MAT proposed by Blum is one of the earliest and most widely studied techniques for generating the skeleton. More recently Brady has introduced the related but extended concept of smoothed local symmetries SLS which we will discuss in the last section of Chapter 7. The skeleton is frequently used as a shape descriptor which exhibits three topological properties connectedness one object generates one skeleton invariance to scaling and rotation and information preservation in the sense that the object can be reconstructed from the medial axis. The concept of thinning a