Browsing by Author "Han, WY"

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Edge detection and edge-preserved compression for error-diffused images
(1997-11-01)
Han, WY
;
Lin, JC
;
資訊工程學系
;
Department of Computer Science
In this paper, a new approach to edge detection and image compression of bilevel error-diffused images is proposed. The proposed approach is directly applied to the error-diffused images without any inverse halftoning technique. The main idea behind the proposed edge detection method is to compute the consistency value of each pixel of the error-diffused image, and the computed values are then clustered into two classes to obtain the desired edges. Here, the consistency value is a function of the mass center and geometric center of the window; more precisely, it represents the possibility that the area covered by the window can be uniform. As for compression, each error-diffused input image is compressed by dividing the image into non-overlapping blocks with size 8x8, then each highly-consistent block is encoded by its average illumination, and each lowly-consistent block is transmitted directly using the original bitmap. The threshold to distinguish these two kinds of blocks is automatically calculated based on the compression rate required by the users. The complexity of our compression technique is low, and this fast method can be used in real-time application. (C) 1997 Elsevier Science Ltd. All rights reserved.
Edge detection and edge-preserved compression for error-diffused images
(1997-11-01)
Han, WY
;
Lin, JC
;
資訊工程學系
;
Department of Computer Science
In this paper, a new approach to edge detection and image compression of bilevel error-diffused images is proposed. The proposed approach is directly applied to the error-diffused images without any inverse halftoning technique. The main idea behind the proposed edge detection method is to compute the consistency value of each pixel of the error-diffused image, and the computed values are then clustered into two classes to obtain the desired edges. Here, the consistency value is a function of the mass center and geometric center of the window; more precisely, it represents the possibility that the area covered by the window can be uniform. As for compression, each error-diffused input image is compressed by dividing the image into non-overlapping blocks with size 8x8, then each highly-consistent block is encoded by its average illumination, and each lowly-consistent block is transmitted directly using the original bitmap. The threshold to distinguish these two kinds of blocks is automatically calculated based on the compression rate required by the users. The complexity of our compression technique is low, and this fast method can be used in real-time application. (C) 1997 Elsevier Science Ltd. All rights reserved.
Error diffusion without contouring effect
(1997-01-01)
Han, WY
;
Lin, JC
;
資訊工程學系
;
Department of Computer Science
A modified error-diffusion algorithm that eliminates the false-texture contour phenomenon that usually appears in the halftone images is presented. The main idea behind our modification is to introduce a local filter that can smooth the false-texture contours of the low variation regions in the images generated by the standard error-diffusion algorithm. Experimental results are included. (C) 1997 SPIE and IS&T.
Minimum-maximum exclusive mean (MMEM) filter to remove impulse noise from highly corrupted images
(1997-01-16)
Han, WY
;
Lin, JC
;
交大名義發表
;
資訊工程學系
;
National Chiao Tung University
The minimum-maximum mean (MMEM) filter is presented to remove impulse noise from highly corrupted images. Simulation results show that even if the occurrence rate of the impulse noise is very high (70%), the restoration performance is still acceptable.