Image::Leptonica::Func::binreduce
version 0.04
binreduce.c
binreduce.c Subsampled 2x reduction PIX *pixReduceBinary2() Rank filtered 2x reductions PIX *pixReduceRankBinaryCascade() PIX *pixReduceRankBinary2() Permutation table for 2x rank binary reduction l_uint8 *makeSubsampleTab2x(void)
l_uint8 * makeSubsampleTab2x ( void )
makeSubsampleTab2x() This table permutes the bits in a byte, from 0 4 1 5 2 6 3 7 to 0 1 2 3 4 5 6 7
PIX * pixReduceBinary2 ( PIX *pixs, l_uint8 *intab )
pixReduceBinary2() Input: pixs tab (<optional>; if null, a table is made here and destroyed before exit) Return: pixd (2x subsampled), or null on error Notes: (1) After folding, the data is in bytes 0 and 2 of the word, and the bits in each byte are in the following order (with 0 being the leftmost originating pair and 7 being the rightmost originating pair): 0 4 1 5 2 6 3 7 These need to be permuted to 0 1 2 3 4 5 6 7 which is done with an 8-bit table generated by makeSubsampleTab2x().
PIX * pixReduceRankBinary2 ( PIX *pixs, l_int32 level, l_uint8 *intab )
pixReduceRankBinary2() Input: pixs (1 bpp) level (rank threshold: 1, 2, 3, 4) intab (<optional>; if null, a table is made here and destroyed before exit) Return: pixd (1 bpp, 2x rank threshold reduced), or null on error Notes: (1) pixd is downscaled by 2x from pixs. (2) The rank threshold specifies the minimum number of ON pixels in each 2x2 region of pixs that are required to set the corresponding pixel ON in pixd. (3) Rank filtering is done to the UL corner of each 2x2 pixel block, using only logical operations. Then these pixels are chosen in the 2x subsampling process, subsampled, as described above in pixReduceBinary2().
PIX * pixReduceRankBinaryCascade ( PIX *pixs, l_int32 level1, l_int32 level2, l_int32 level3, l_int32 level4 )
pixReduceRankBinaryCascade() Input: pixs (1 bpp) level1, ... level 4 (thresholds, in the set {0, 1, 2, 3, 4}) Return: pixd, or null on error Notes: (1) This performs up to four cascaded 2x rank reductions. (2) Use level = 0 to truncate the cascade.
Zakariyya Mughal <zmughal@cpan.org>
This software is copyright (c) 2014 by Zakariyya Mughal.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.
To install Image::Leptonica, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Image::Leptonica
CPAN shell
perl -MCPAN -e shell install Image::Leptonica
For more information on module installation, please visit the detailed CPAN module installation guide.