tailieunhanh - Lecture Digital image processing - Lecture 30: Morphology

This chapter presents the following content: Morphological closing, morphological opening, hit and miss transform, boundary extraction, region filling, extraction of connected component, thinning, thickening, skeletonization. | Digital Image Processing CSC331 Morphological image processing 1 Summery of previous lecture Morphological image processing Set points Structuring Elements Morphological operations Dilation and Erosion 2 Todays lecture Morphological closing Morphological opening Hit and Miss transform Boundary extraction Region filling Extraction of connected component Thinning Thickening Skeletonization 3 4 Closing Closing is similar in some ways to dilation in that it tends to enlarge the boundaries of foreground (bright) regions in an image (and shrink background color holes in such regions), but it is less destructive of the original boundary shape. As with other morphological operators, the exact operation is determined by a structuring element. The effect of the operator is to preserve background regions that have a similar shape to this structuring element, or that can completely contain the structuring element, while eliminating all other regions of background pixels. a Closing - Guidelines for Use One of the uses of dilation is to fill in small background color holes in images, . `pepper noise'. One of the problems with doing this, however, is that the dilation will also distort all regions of pixels indiscriminately. By performing an erosion on the image after the dilation, . a closing, we reduce some of this effect. The effect of closing can be quite easily visualized. Imagine taking the structuring element and sliding it around outside each foreground region, without changing its orientation. For any background boundary point, if the structuring element can be made to touch that point, without any part of the element being inside a foreground region, then that point remains background. If this is not possible, then the pixel is set to foreground. After the closing has been carried out the background region will be such that the structuring element can be made to cover any point in the background without any part of it also covering a foreground point, and so . | Digital Image Processing CSC331 Morphological image processing 1 Summery of previous lecture Morphological image processing Set points Structuring Elements Morphological operations Dilation and Erosion 2 Todays lecture Morphological closing Morphological opening Hit and Miss transform Boundary extraction Region filling Extraction of connected component Thinning Thickening Skeletonization 3 4 Closing Closing is similar in some ways to dilation in that it tends to enlarge the boundaries of foreground (bright) regions in an image (and shrink background color holes in such regions), but it is less destructive of the original boundary shape. As with other morphological operators, the exact operation is determined by a structuring element. The effect of the operator is to preserve background regions that have a similar shape to this structuring element, or that can completely contain the structuring element, while eliminating all other regions of background pixels. a Closing - Guidelines .