Image::Leptonica::Func::morph
version 0.04
morph.c
morph.c Generic binary morphological ops implemented with rasterop PIX *pixDilate() PIX *pixErode() PIX *pixHMT() PIX *pixOpen() PIX *pixClose() PIX *pixCloseSafe() PIX *pixOpenGeneralized() PIX *pixCloseGeneralized() Binary morphological (raster) ops with brick Sels PIX *pixDilateBrick() PIX *pixErodeBrick() PIX *pixOpenBrick() PIX *pixCloseBrick() PIX *pixCloseSafeBrick() Binary composed morphological (raster) ops with brick Sels l_int32 selectComposableSels() l_int32 selectComposableSizes() PIX *pixDilateCompBrick() PIX *pixErodeCompBrick() PIX *pixOpenCompBrick() PIX *pixCloseCompBrick() PIX *pixCloseSafeCompBrick() Functions associated with boundary conditions void resetMorphBoundaryCondition() l_int32 getMorphBorderPixelColor() Static helpers for arg processing static PIX *processMorphArgs1() static PIX *processMorphArgs2() You are provided with many simple ways to do binary morphology. In particular, if you are using brick Sels, there are six convenient methods, all specially tailored for separable operations on brick Sels. A "brick" Sel is a Sel that is a rectangle of solid SEL_HITs with the origin at or near the center. Note that a brick Sel can have one dimension of size 1. This is very common. All the brick Sel operations are separable, meaning the operation is done first in the horizontal direction and then in the vertical direction. If one of the dimensions is 1, this is a special case where the operation is only performed in the other direction. These six brick Sel methods are enumerated as follows: (1) Brick Sels: pix*Brick(), where * = {Dilate, Erode, Open, Close}. These are separable rasterop implementations. The Sels are automatically generated, used, and destroyed at the end. You can get the result as a new Pix, in-place back into the src Pix, or written to another existing Pix. (2) Brick Sels: pix*CompBrick(), where * = {Dilate, Erode, Open, Close}. These are separable, 2-way composite, rasterop implementations. The Sels are automatically generated, used, and destroyed at the end. You can get the result as a new Pix, in-place back into the src Pix, or written to another existing Pix. For large Sels, these are considerably faster than the corresponding pix*Brick() functions. N.B.: The size of the Sels that are actually used are typically close to, but not exactly equal to, the size input to the function. (3) Brick Sels: pix*BrickDwa(), where * = {Dilate, Erode, Open, Close}. These are separable dwa (destination word accumulation) implementations. They use auto-gen'd dwa code. You can get the result as a new Pix, in-place back into the src Pix, or written to another existing Pix. This is typically about 3x faster than the analogous rasterop pix*Brick() function, but it has the limitation that the Sel size must be less than 63. This is pre-set to work on a number of pre-generated Sels. If you want to use other Sels, the code can be auto-gen'd for them; see the instructions in morphdwa.c. (4) Same as (1), but you run it through pixMorphSequence(), with the sequence string either compiled in or generated using sprintf. All intermediate images and Sels are created, used and destroyed. You always get the result as a new Pix. For example, you can specify a separable 11 x 17 brick opening as "o11.17", or you can specify the horizontal and vertical operations explicitly as "o11.1 + o1.11". See morphseq.c for details. (5) Same as (2), but you run it through pixMorphCompSequence(), with the sequence string either compiled in or generated using sprintf. All intermediate images and Sels are created, used and destroyed. You always get the result as a new Pix. See morphseq.c for details. (6) Same as (3), but you run it through pixMorphSequenceDwa(), with the sequence string either compiled in or generated using sprintf. All intermediate images and Sels are created, used and destroyed. You always get the result as a new Pix. See morphseq.c for details. If you are using Sels that are not bricks, you have two choices: (a) simplest: use the basic rasterop implementations (pixDilate(), ...) (b) fastest: generate the destination word accumumlation (dwa) code for your Sels and compile it with the library. For an example, see flipdetect.c, which gives implementations using hit-miss Sels with both the rasterop and dwa versions. For the latter, the dwa code resides in fliphmtgen.c, and it was generated by prog/flipselgen.c. Both the rasterop and dwa implementations are tested by prog/fliptest.c. A global constant MORPH_BC is used to set the boundary conditions for rasterop-based binary morphology. MORPH_BC, in morph.c, is set by default to ASYMMETRIC_MORPH_BC for a non-symmetric convention for boundary pixels in dilation and erosion: All pixels outside the image are assumed to be OFF for both dilation and erosion. To use a symmetric definition, see comments in pixErode() and reset MORPH_BC to SYMMETRIC_MORPH_BC, using resetMorphBoundaryCondition(). Boundary artifacts are possible in closing when the non-symmetric boundary conditions are used, because foreground pixels very close to the edge can be removed. This can be avoided by using either the symmetric boundary conditions or the function pixCloseSafe(), which adds a border before the operation and removes it afterwards. The hit-miss transform (HMT) is the bit-and of 2 erosions: (erosion of the src by the hits) & (erosion of the bit-inverted src by the misses) The 'generalized opening' is an HMT followed by a dilation that uses only the hits of the hit-miss Sel. The 'generalized closing' is a dilation (again, with the hits of a hit-miss Sel), followed by the HMT. Both of these 'generalized' functions are idempotent. These functions are extensively tested in prog/binmorph1_reg.c, prog/binmorph2_reg.c, and prog/binmorph3_reg.c.
l_uint32 getMorphBorderPixelColor ( l_int32 type, l_int32 depth )
getMorphBorderPixelColor() Input: type (L_MORPH_DILATE, L_MORPH_ERODE) depth (of pix) Return: color of border pixels for this operation
PIX * pixClose ( PIX *pixd, PIX *pixs, SEL *sel )
pixClose() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) sel Return: pixd Notes: (1) Generic morphological closing, using hits in the Sel. (2) This implementation is a strict dual of the opening if symmetric boundary conditions are used (see notes at top of this file). (3) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (4) For clarity, if the case is known, use these patterns: (a) pixd = pixClose(NULL, pixs, ...); (b) pixClose(pixs, pixs, ...); (c) pixClose(pixd, pixs, ...); (5) The size of the result is determined by pixs.
PIX * pixCloseBrick ( PIX *pixd, PIX *pixs, l_int32 hsize, l_int32 vsize )
pixCloseBrick() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) hsize (width of brick Sel) vsize (height of brick Sel) Return: pixd, or null on error Notes: (1) Sel is a brick with all elements being hits (2) The origin is at (x, y) = (hsize/2, vsize/2) (3) Do separably if both hsize and vsize are > 1. (4) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (5) For clarity, if the case is known, use these patterns: (a) pixd = pixCloseBrick(NULL, pixs, ...); (b) pixCloseBrick(pixs, pixs, ...); (c) pixCloseBrick(pixd, pixs, ...); (6) The size of the result is determined by pixs.
PIX * pixCloseCompBrick ( PIX *pixd, PIX *pixs, l_int32 hsize, l_int32 vsize )
pixCloseCompBrick() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) hsize (width of brick Sel) vsize (height of brick Sel) Return: pixd, or null on error Notes: (1) Sel is a brick with all elements being hits (2) The origin is at (x, y) = (hsize/2, vsize/2) (3) Do compositely for each dimension > 1. (4) Do separably if both hsize and vsize are > 1. (5) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (6) For clarity, if the case is known, use these patterns: (a) pixd = pixCloseCompBrick(NULL, pixs, ...); (b) pixCloseCompBrick(pixs, pixs, ...); (c) pixCloseCompBrick(pixd, pixs, ...); (7) The dimensions of the resulting image are determined by pixs. (8) CAUTION: both hsize and vsize are being decomposed. The decomposer chooses a product of sizes (call them 'terms') for each that is close to the input size, but not necessarily equal to it. It attempts to optimize: (a) for consistency with the input values: the product of terms is close to the input size (b) for efficiency of the operation: the sum of the terms is small; ideally about twice the square root of the input size. So, for example, if the input hsize = 37, which is a prime number, the decomposer will break this into two terms, 6 and 6, so that the net result is a dilation with hsize = 36.
PIX * pixCloseGeneralized ( PIX *pixd, PIX *pixs, SEL *sel )
pixCloseGeneralized() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) sel Return: pixd Notes: (1) Generalized morphological closing, using both hits and misses in the Sel. (2) This does a dilation using the hits, followed by a hit-miss transform. (3) This operation is a dual of the generalized opening. (4) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (5) For clarity, if the case is known, use these patterns: (a) pixd = pixCloseGeneralized(NULL, pixs, ...); (b) pixCloseGeneralized(pixs, pixs, ...); (c) pixCloseGeneralized(pixd, pixs, ...); (6) The size of the result is determined by pixs.
PIX * pixCloseSafe ( PIX *pixd, PIX *pixs, SEL *sel )
pixCloseSafe() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) sel Return: pixd Notes: (1) Generic morphological closing, using hits in the Sel. (2) If non-symmetric boundary conditions are used, this function adds a border of OFF pixels that is of sufficient size to avoid losing pixels from the dilation, and it removes the border after the operation is finished. It thus enforces a correct extensive result for closing. (3) If symmetric b.c. are used, it is not necessary to add and remove this border. (4) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (5) For clarity, if the case is known, use these patterns: (a) pixd = pixCloseSafe(NULL, pixs, ...); (b) pixCloseSafe(pixs, pixs, ...); (c) pixCloseSafe(pixd, pixs, ...); (6) The size of the result is determined by pixs.
PIX * pixCloseSafeBrick ( PIX *pixd, PIX *pixs, l_int32 hsize, l_int32 vsize )
pixCloseSafeBrick() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) hsize (width of brick Sel) vsize (height of brick Sel) Return: pixd, or null on error Notes: (1) Sel is a brick with all elements being hits (2) The origin is at (x, y) = (hsize/2, vsize/2) (3) Do separably if both hsize and vsize are > 1. (4) Safe closing adds a border of 0 pixels, of sufficient size so that all pixels in input image are processed within 32-bit words in the expanded image. As a result, there is no special processing for pixels near the boundary, and there are no boundary effects. The border is removed at the end. (5) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (6) For clarity, if the case is known, use these patterns: (a) pixd = pixCloseBrick(NULL, pixs, ...); (b) pixCloseBrick(pixs, pixs, ...); (c) pixCloseBrick(pixd, pixs, ...); (7) The size of the result is determined by pixs.
PIX * pixCloseSafeCompBrick ( PIX *pixd, PIX *pixs, l_int32 hsize, l_int32 vsize )
pixCloseSafeCompBrick() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) hsize (width of brick Sel) vsize (height of brick Sel) Return: pixd, or null on error Notes: (1) Sel is a brick with all elements being hits (2) The origin is at (x, y) = (hsize/2, vsize/2) (3) Do compositely for each dimension > 1. (4) Do separably if both hsize and vsize are > 1. (5) Safe closing adds a border of 0 pixels, of sufficient size so that all pixels in input image are processed within 32-bit words in the expanded image. As a result, there is no special processing for pixels near the boundary, and there are no boundary effects. The border is removed at the end. (6) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (7) For clarity, if the case is known, use these patterns: (a) pixd = pixCloseSafeCompBrick(NULL, pixs, ...); (b) pixCloseSafeCompBrick(pixs, pixs, ...); (c) pixCloseSafeCompBrick(pixd, pixs, ...); (8) The dimensions of the resulting image are determined by pixs. (9) CAUTION: both hsize and vsize are being decomposed. The decomposer chooses a product of sizes (call them 'terms') for each that is close to the input size, but not necessarily equal to it. It attempts to optimize: (a) for consistency with the input values: the product of terms is close to the input size (b) for efficiency of the operation: the sum of the terms is small; ideally about twice the square root of the input size. So, for example, if the input hsize = 37, which is a prime number, the decomposer will break this into two terms, 6 and 6, so that the net result is a dilation with hsize = 36.
PIX * pixDilate ( PIX *pixd, PIX *pixs, SEL *sel )
pixDilate() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) sel Return: pixd Notes: (1) This dilates src using hits in Sel. (2) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (3) For clarity, if the case is known, use these patterns: (a) pixd = pixDilate(NULL, pixs, ...); (b) pixDilate(pixs, pixs, ...); (c) pixDilate(pixd, pixs, ...); (4) The size of the result is determined by pixs.
PIX * pixDilateBrick ( PIX *pixd, PIX *pixs, l_int32 hsize, l_int32 vsize )
pixDilateBrick() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) hsize (width of brick Sel) vsize (height of brick Sel) Return: pixd Notes: (1) Sel is a brick with all elements being hits (2) The origin is at (x, y) = (hsize/2, vsize/2) (3) Do separably if both hsize and vsize are > 1. (4) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (5) For clarity, if the case is known, use these patterns: (a) pixd = pixDilateBrick(NULL, pixs, ...); (b) pixDilateBrick(pixs, pixs, ...); (c) pixDilateBrick(pixd, pixs, ...); (6) The size of the result is determined by pixs.
PIX * pixDilateCompBrick ( PIX *pixd, PIX *pixs, l_int32 hsize, l_int32 vsize )
pixDilateCompBrick() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) hsize (width of brick Sel) vsize (height of brick Sel) Return: pixd, or null on error Notes: (1) Sel is a brick with all elements being hits (2) The origin is at (x, y) = (hsize/2, vsize/2) (3) Do compositely for each dimension > 1. (4) Do separably if both hsize and vsize are > 1. (5) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (6) For clarity, if the case is known, use these patterns: (a) pixd = pixDilateCompBrick(NULL, pixs, ...); (b) pixDilateCompBrick(pixs, pixs, ...); (c) pixDilateCompBrick(pixd, pixs, ...); (7) The dimensions of the resulting image are determined by pixs. (8) CAUTION: both hsize and vsize are being decomposed. The decomposer chooses a product of sizes (call them 'terms') for each that is close to the input size, but not necessarily equal to it. It attempts to optimize: (a) for consistency with the input values: the product of terms is close to the input size (b) for efficiency of the operation: the sum of the terms is small; ideally about twice the square root of the input size. So, for example, if the input hsize = 37, which is a prime number, the decomposer will break this into two terms, 6 and 6, so that the net result is a dilation with hsize = 36.
PIX * pixErode ( PIX *pixd, PIX *pixs, SEL *sel )
pixErode() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) sel Return: pixd Notes: (1) This erodes src using hits in Sel. (2) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (3) For clarity, if the case is known, use these patterns: (a) pixd = pixErode(NULL, pixs, ...); (b) pixErode(pixs, pixs, ...); (c) pixErode(pixd, pixs, ...); (4) The size of the result is determined by pixs.
PIX * pixErodeBrick ( PIX *pixd, PIX *pixs, l_int32 hsize, l_int32 vsize )
pixErodeBrick() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) hsize (width of brick Sel) vsize (height of brick Sel) Return: pixd Notes: (1) Sel is a brick with all elements being hits (2) The origin is at (x, y) = (hsize/2, vsize/2) (3) Do separably if both hsize and vsize are > 1. (4) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (5) For clarity, if the case is known, use these patterns: (a) pixd = pixErodeBrick(NULL, pixs, ...); (b) pixErodeBrick(pixs, pixs, ...); (c) pixErodeBrick(pixd, pixs, ...); (6) The size of the result is determined by pixs.
PIX * pixErodeCompBrick ( PIX *pixd, PIX *pixs, l_int32 hsize, l_int32 vsize )
pixErodeCompBrick() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) hsize (width of brick Sel) vsize (height of brick Sel) Return: pixd, or null on error Notes: (1) Sel is a brick with all elements being hits (2) The origin is at (x, y) = (hsize/2, vsize/2) (3) Do compositely for each dimension > 1. (4) Do separably if both hsize and vsize are > 1. (5) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (6) For clarity, if the case is known, use these patterns: (a) pixd = pixErodeCompBrick(NULL, pixs, ...); (b) pixErodeCompBrick(pixs, pixs, ...); (c) pixErodeCompBrick(pixd, pixs, ...); (7) The dimensions of the resulting image are determined by pixs. (8) CAUTION: both hsize and vsize are being decomposed. The decomposer chooses a product of sizes (call them 'terms') for each that is close to the input size, but not necessarily equal to it. It attempts to optimize: (a) for consistency with the input values: the product of terms is close to the input size (b) for efficiency of the operation: the sum of the terms is small; ideally about twice the square root of the input size. So, for example, if the input hsize = 37, which is a prime number, the decomposer will break this into two terms, 6 and 6, so that the net result is a dilation with hsize = 36.
PIX * pixHMT ( PIX *pixd, PIX *pixs, SEL *sel )
pixHMT() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) sel Return: pixd Notes: (1) The hit-miss transform erodes the src, using both hits and misses in the Sel. It ANDs the shifted src for hits and ANDs the inverted shifted src for misses. (2) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (3) For clarity, if the case is known, use these patterns: (a) pixd = pixHMT(NULL, pixs, ...); (b) pixHMT(pixs, pixs, ...); (c) pixHMT(pixd, pixs, ...); (4) The size of the result is determined by pixs.
PIX * pixOpen ( PIX *pixd, PIX *pixs, SEL *sel )
pixOpen() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) sel Return: pixd Notes: (1) Generic morphological opening, using hits in the Sel. (2) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (3) For clarity, if the case is known, use these patterns: (a) pixd = pixOpen(NULL, pixs, ...); (b) pixOpen(pixs, pixs, ...); (c) pixOpen(pixd, pixs, ...); (4) The size of the result is determined by pixs.
PIX * pixOpenBrick ( PIX *pixd, PIX *pixs, l_int32 hsize, l_int32 vsize )
pixOpenBrick() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) hsize (width of brick Sel) vsize (height of brick Sel) Return: pixd, or null on error Notes: (1) Sel is a brick with all elements being hits (2) The origin is at (x, y) = (hsize/2, vsize/2) (3) Do separably if both hsize and vsize are > 1. (4) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (5) For clarity, if the case is known, use these patterns: (a) pixd = pixOpenBrick(NULL, pixs, ...); (b) pixOpenBrick(pixs, pixs, ...); (c) pixOpenBrick(pixd, pixs, ...); (6) The size of the result is determined by pixs.
PIX * pixOpenCompBrick ( PIX *pixd, PIX *pixs, l_int32 hsize, l_int32 vsize )
pixOpenCompBrick() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) hsize (width of brick Sel) vsize (height of brick Sel) Return: pixd, or null on error Notes: (1) Sel is a brick with all elements being hits (2) The origin is at (x, y) = (hsize/2, vsize/2) (3) Do compositely for each dimension > 1. (4) Do separably if both hsize and vsize are > 1. (5) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (6) For clarity, if the case is known, use these patterns: (a) pixd = pixOpenCompBrick(NULL, pixs, ...); (b) pixOpenCompBrick(pixs, pixs, ...); (c) pixOpenCompBrick(pixd, pixs, ...); (7) The dimensions of the resulting image are determined by pixs. (8) CAUTION: both hsize and vsize are being decomposed. The decomposer chooses a product of sizes (call them 'terms') for each that is close to the input size, but not necessarily equal to it. It attempts to optimize: (a) for consistency with the input values: the product of terms is close to the input size (b) for efficiency of the operation: the sum of the terms is small; ideally about twice the square root of the input size. So, for example, if the input hsize = 37, which is a prime number, the decomposer will break this into two terms, 6 and 6, so that the net result is a dilation with hsize = 36.
PIX * pixOpenGeneralized ( PIX *pixd, PIX *pixs, SEL *sel )
pixOpenGeneralized() Input: pixd (<optional>; this can be null, equal to pixs, or different from pixs) pixs (1 bpp) sel Return: pixd Notes: (1) Generalized morphological opening, using both hits and misses in the Sel. (2) This does a hit-miss transform, followed by a dilation using the hits. (3) There are three cases: (a) pixd == null (result into new pixd) (b) pixd == pixs (in-place; writes result back to pixs) (c) pixd != pixs (puts result into existing pixd) (4) For clarity, if the case is known, use these patterns: (a) pixd = pixOpenGeneralized(NULL, pixs, ...); (b) pixOpenGeneralized(pixs, pixs, ...); (c) pixOpenGeneralized(pixd, pixs, ...); (5) The size of the result is determined by pixs.
void resetMorphBoundaryCondition ( l_int32 bc )
resetMorphBoundaryCondition() Input: bc (SYMMETRIC_MORPH_BC, ASYMMETRIC_MORPH_BC) Return: void
l_int32 selectComposableSels ( l_int32 size, l_int32 direction, SEL **psel1, SEL **psel2 )
selectComposableSels()
Input: size (of composed sel) direction (L_HORIZ, L_VERT) &sel1 (<optional return> contiguous sel; can be null) &sel2 (<optional return> comb sel; can be null) Return: 0 if OK, 1 on error Notes: (1) When using composable Sels, where the original Sel is decomposed into two, the best you can do in terms of reducing the computation is by a factor: 2 * sqrt(size) / size In practice, you get quite close to this. E.g., Sel size | Optimum reduction factor -------- ------------------------ 36 | 1/3 64 | 1/4 144 | 1/6 256 | 1/8
l_int32 selectComposableSizes ( l_int32 size, l_int32 *pfactor1, l_int32 *pfactor2 )
selectComposableSizes() Input: size (of sel to be decomposed) &factor1 (<return> larger factor) &factor2 (<return> smaller factor) Return: 0 if OK, 1 on error Notes: (1) This works for Sel sizes up to 62500, which seems sufficient. (2) The composable sel size is typically within +- 1 of the requested size. Up to size = 300, the maximum difference is +- 2. (3) We choose an overall cost function where the penalty for the size difference between input and actual is 4 times the penalty for additional rasterops. (4) Returned values: factor1 >= factor2 If size > 1, then factor1 > 1.
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.