EP0428795A1 — Binary image thinning and feature extracting meth…

Claim 1

Independent Claim 131 words

A binary image thinning and feature extracting device comprising: a central processing unit (1), an image data input device (2), memories (5,6,7) and a thinning and feature extracting device (3), wherein the thinning and feature extracting device includes: a logic control circuit for controlling the thinning and feature extracting operations; and a data processing circuit for performing a thinning and feature extracting process on the binary image data in specified memories; characterized in that when the data processing circuit performs thinning and feature extracting operations, data are put into a preset mask by means of parallel-sequential processing, then depending on the positional relation thereof in the mask, the data pixels are converted by using selected rules with the results from the conversion serving as the results of thinning and feature extraction.

Claim 2

Dependent Claim 131 words

A binary image thinning and feature extracting device comprising: a central processing unit (1), an image data input device (2), memories (5,6,7) and a thinning and feature extracting device (3), wherein the thinning and feature extracting device includes: a logic control circuit for controlling the thinning and feature extracting operations; and a data processing circuit for performing a thinning and feature extracting process on the binary image data in specified memories; characterized in that when the data processing circuit performs thinning and feature extracting operations, data are put into a preset mask by means of parallel-sequential processing, then depending on the positional relation thereof in the mask, the data pixels are converted by using selected rules with the results from the conversion serving as the results of thinning and feature extraction.

Claim 3

Dependent Claim 16 words

A device according to claim 1, wherein the mask is a 3 x 3 pixel array.

Claim 4

Dependent Claim 89 words

A device according to claim 2, wherein the thinning rules include the following Tables: 3 x 3 window 8-bit address (A0-A7) P0 - A0 P0 P3 P6 P1 - A1 P2 - A2 P1 P4 P7 P3 - A3 P4 - X P2 P5 P8 P5 - A4 P6 - A5 P7 - A6 P8 - A7 Note: If the data corresponding to the address is "00", then the pixel 4 can be changed or reset to "0", otherwise the pixel is not changed. Here "X" denotes don't care.

Claim 5

Independent Claim 29 words

A device according to any of the preceding claims, wherein the thinning device is performed in a back and forth manner until two successive data thus obtained are identical.

Claim 6

Dependent Claim 91 words

A device according to at least claim 2, wherein the thinning rules include the following table: 3 x 3 window 8-bit address (A0-A7) P0 - A0 P0 P3 P6 P1 - A1 P2 - A2 P1 P4 P7 P3 - A3 P4 - X P2 P5 P8 P5 - A4 P6 - A5 P7 - A6 P8 - A7 Note: If the data corresponding to the address is "00", then the "1" pixel 4 is not a feature point, otherwise the pixel is a feature point. Here "X" denotes don't care.

Claim 7

Independent Claim 29 words

A device according to any of the preceding claims, wherein the feature extracting operation is performed in a back and forth manner until successive data thus obtained are identical.

Claim 8

Independent Claim 57 words

A device according to any of the preceding claims, wherein the memories comprise at least a first temporary memory (5) and a second temporary memory (6) such that when the system processes the data in the first temporary memory (5), the data input from the input device (2) can be stored into the second temporary memory (6).

Claim 9

Independent Claim 60 words

A device according to any of the preceding claims, wherein when the input device (2) performs input operations, the input picture data are divided into a plurality of blocks to be processed, respectively, any two adjacent blocks being overlapped relative to each other, such that the thinning result can be corrected according to the data obtained from the overlapped portions.

Claim 10

Independent Claim 31 words

A device according to any of the preceding claims, wherein one of the memories (5) is connected to the thinning and feature extraction device (3) by a programmable first-in-first-out register (SR).

Claim 11

Dependent Claim 15 words

A device according to claim 9, wherein the first-in-first-out register (SR) includes an h-counter (14).

Claim 12

Independent Claim 133 words

A method for thinning and feature extracting binary image data in a system including: a central processing unit (1), an image data input device (2), memories comprising at least a first temporary memory (5), a second temporary memory (6) and a third temporary memory (7) and a thinning and feature extracting device (3) by means of the following steps: A. storing the image data binary in the first temporary memory (5) and/or the second temporary memory (6); B. putting the binary data into a preset mask by using a parallel-sequential processor, C. according to the positional relation of the image data in the mask, coverting the pixels by using specific rules, and D. through the parallel-sequential processor, storing the results of the pixel conversion into the third temporary memory (7) for image processing.

Claim 13

Independent Claim 133 words

A method for thinning and feature extracting binary image data in a system including: a central processing unit (1), an image data input device (2), memories comprising at least a first temporary memory (5), a second temporary memory (6) and a third temporary memory (7) and a thinning and feature extracting device (3) by means of the following steps: A. storing the image data binary in the first temporary memory (5) and/or the second temporary memory (6); B. putting the binary data into a preset mask by using a parallel-sequential processor, C. according to the positional relation of the image data in the mask, coverting the pixels by using specific rules, and D. through the parallel-sequential processor, storing the results of the pixel conversion into the third temporary memory (7) for image processing.

Claim 14

Dependent Claim 16 words

A method according to claim 11, wherein the mask is a 3 x 3 pixel array.

Claim 15

Dependent Claim 88 words

A method as Claim 12, wherein the thinning rules include the following Tables: 3 x 3 window 8-bit address (A0-A7) P0 - A0 P0 P3 P6 P1 - A1 P2 - A2 P1 P4 P7 P3 - A3 P4 - X P2 P5 P8 P5 - A4 P6 - A5 P7 - A6 P8 - A7 Note: If the data corresponding to the address is "00", then the pixel 4 can be changed or reset to "0", otherwise the pixel is not changed. Here "X" denotes don't care.

Claim 16

Independent Claim 30 words

A method according to any of claims 11 to 13, wherein the thinning operation is performed in a back and forth manner until two successive data thus obtained are identical.

Claim 17

Independent Claim 93 words

A method according to any of claims 11 to 14, wherein the thinning rules include the following table: 3 x 3 window 8-bit address (A0-A7) P0 - A0 P0 P3 P6 P1 - A1 P2 - A2 P1 P4 P7 P3 - A3 P4 - X P2 P5 P8 P5 - A4 P6 - A5 P7 - A6 P8 - A7 Note: If the data corresponding to the address is "00", then the "1" pixel 4 is not a feature point, otherwise the pixel is a feature point. Here "X" denotes don't care.

Claim 18

Dependent Claim 27 words

A method according to claim 15, wherein the feature extracting operation is performed in a back and forth manner until two successive data thus obtained are identical.

Claim 19

Independent Claim 100 words

A method according to any of claims 11 to 16, wherein the dual-value image data are first stored into the first temporary memory (5) such that when the system processes the first temporary memory, the next batch of data to processed can be stored into the second temporary memory (6) and that when the processing of the data in the second temporary memory is started after the processing of the data in the first temporary memory has been completed, the second next batch of data to be processed are strored into the first temporary memory, the process being thus repeated.

Claim 20

Independent Claim 55 words

A method according to any of claims 11 to 17, wherein the binary picture data are divided into a plurality of blocks to be processed in batches, characterized in that overlapped portions are provided between two adjacent blocks, such that the thinning result can be corrected according to the data obtained from the overlapped portions.

Binary image thinning and feature extracting method and processing device thereof

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