Tham khảo tài liệu 'robotics handbook of computer vision algorithms in image algebra part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Notice that the modified Zhang-Suen transform right Figure does preserve homotopy. This is because the 2 X 2 in the lower right-hand corner of the original image was shrunk to a point rather than being erased. To preserve homotopy the conditions that make a point eligible for deletion must be made more stringent. The conditions that qualify a point for deletion in the original Zhang-Suen algorithm remain in place. However the 4-neighbors see Figure of the point p are examined more closely. If the target point p has none or one 4-neighbor that has pixel value 1 then no change is made to the existing set of criteria for deletion. If p has two or three 4-neighbors with pixel value 1 it can be deleted on the first pass provided p3 p5 0. It can be deleted on the second pass if p1 p7 0. These changes insure that 2 X 2 blocks do not get completely removed. Figure Original Zhang-Suen transform left and modified Zhang-Suen transform right . Image Algebra Formulation As probably anticipated the only effect on the image algebra formulation caused by modifying the Zhang-Suen transform to preserve homotopy shows up in the sets S1 and S2 of Section . The sets S21 and S 22 that replace them are S21 S1 28 30 60 62 and S22 S2 193 195 225 227 . Previous Table of Contents Next r------------------------------------------------------- HOME SUBSCRIBE SEARCH FAQ SITEMAP CONTACT US Products Contact Us About Us Privacy Ad Info Home Use of this site is subject to certain Terms Conditions Copyright 1996-2000 EarthWeb Inc. All rights reserved. Reproduction whole or in part in any form or medium without express written permission of EarthWeb is prohibited. Read EarthWeb s privacy statement. Notice that the modified Zhang-Suen transform right Figure does preserve homotopy. This is because the 2 X 2 in the lower right-hand corner of the original image was shrunk to a point rather than being erased. To preserve homotopy the conditions that make a point eligible for .
