Leptonica  1.54
Файл src/pixarith.c
#include <string.h>
#include <math.h>
#include "allheaders.h"

Функции

l_int32 pixAddConstantGray (PIX *pixs, l_int32 val)
l_int32 pixMultConstantGray (PIX *pixs, l_float32 val)
PIXpixAddGray (PIX *pixd, PIX *pixs1, PIX *pixs2)
PIXpixSubtractGray (PIX *pixd, PIX *pixs1, PIX *pixs2)
PIXpixThresholdToValue (PIX *pixd, PIX *pixs, l_int32 threshval, l_int32 setval)
PIXpixInitAccumulate (l_int32 w, l_int32 h, l_uint32 offset)
PIXpixFinalAccumulate (PIX *pixs, l_uint32 offset, l_int32 depth)
PIXpixFinalAccumulateThreshold (PIX *pixs, l_uint32 offset, l_uint32 threshold)
l_int32 pixAccumulate (PIX *pixd, PIX *pixs, l_int32 op)
l_int32 pixMultConstAccumulate (PIX *pixs, l_float32 factor, l_uint32 offset)
PIXpixAbsDifference (PIX *pixs1, PIX *pixs2)
PIXpixAddRGB (PIX *pixs1, PIX *pixs2)
PIXpixMinOrMax (PIX *pixd, PIX *pixs1, PIX *pixs2, l_int32 type)
PIXpixMaxDynamicRange (PIX *pixs, l_int32 type)
l_float32makeLogBase2Tab (void)
l_float32 getLogBase2 (l_int32 val, l_float32 *logtab)

Функции

l_float32 getLogBase2 ( l_int32  val,
l_float32 logtab 
)
PIX* pixAbsDifference ( PIX pixs1,
PIX pixs2 
)

pixAbsDifference()

Input: pixs1, pixs2 (both either 8 or 16 bpp gray, or 32 bpp RGB) Return: pixd, or null on error

Notes: (1) The depth of pixs1 and pixs2 must be equal. (2) Clips computation to the min size, aligning the UL corners (3) For 8 and 16 bpp, assumes one gray component. (4) For 32 bpp, assumes 3 color components, and ignores the LSB of each word (the alpha channel) (5) Computes the absolute value of the difference between each component value.

l_int32 pixAccumulate ( PIX pixd,
PIX pixs,
l_int32  op 
)

pixAccumulate()

Input: pixd (32 bpp) pixs (1, 8, 16 or 32 bpp) op (L_ARITH_ADD or L_ARITH_SUBTRACT) Return: 0 if OK; 1 on error

Notes: (1) This adds or subtracts each pixs value from pixd. (2) This clips to the minimum of pixs and pixd, so they do not need to be the same size. (3) The alignment is to the origin (UL corner) of pixs & pixd.

l_int32 pixAddConstantGray ( PIX pixs,
l_int32  val 
)

pixAddConstantGray()

Input: pixs (8, 16 or 32 bpp) val (amount to add to each pixel) Return: 0 if OK, 1 on error

Notes: (1) In-place operation. (2) No clipping for 32 bpp. (3) For 8 and 16 bpp, if val > 0 the result is clipped to 0xff and 0xffff, rsp. (4) For 8 and 16 bpp, if val < 0 the result is clipped to 0.

PIX* pixAddGray ( PIX pixd,
PIX pixs1,
PIX pixs2 
)

pixAddGray()

Input: pixd (<optional>; this can be null, equal to pixs1, or different from pixs1) pixs1 (can be == to pixd) pixs2 Return: pixd always

Notes: (1) Arithmetic addition of two 8, 16 or 32 bpp images. (2) For 8 and 16 bpp, we do explicit clipping to 0xff and 0xffff, respectively. (3) Alignment is to UL corner. (4) There are 3 cases. The result can go to a new dest, in-place to pixs1, or to an existing input dest: * pixd == null: (src1 + src2) --> new pixd * pixd == pixs1: (src1 + src2) --> src1 (in-place) * pixd != pixs1: (src1 + src2) --> input pixd (5) pixs2 must be different from both pixd and pixs1.

PIX* pixAddRGB ( PIX pixs1,
PIX pixs2 
)

pixAddRGB()

Input: pixs1, pixs2 (32 bpp RGB, or colormapped) Return: pixd, or null on error

Notes: (1) Clips computation to the minimum size, aligning the UL corners. (2) Removes any colormap to RGB, and ignores the LSB of each pixel word (the alpha channel). (3) Adds each component value, pixelwise, clipping to 255. (4) This is useful to combine two images where most of the pixels are essentially black, such as in pixPerceptualDiff().

PIX* pixFinalAccumulate ( PIX pixs,
l_uint32  offset,
l_int32  depth 
)

pixFinalAccumulate()

Input: pixs (32 bpp) offset (same as used for initialization) depth (8, 16 or 32 bpp, of destination) Return: pixd (8, 16 or 32 bpp), or null on error

Notes: (1) The offset must be >= 0 and should not exceed 0x40000000. (2) The offset is subtracted from the src 32 bpp image (3) For 8 bpp dest, the result is clipped to [0, 0xff] (4) For 16 bpp dest, the result is clipped to [0, 0xffff]

PIX* pixFinalAccumulateThreshold ( PIX pixs,
l_uint32  offset,
l_uint32  threshold 
)

pixFinalAccumulateThreshold()

Input: pixs (32 bpp) offset (same as used for initialization) threshold (values less than this are set in the destination) Return: pixd (1 bpp), or null on error

Notes: (1) The offset must be >= 0 and should not exceed 0x40000000. (2) The offset is subtracted from the src 32 bpp image

PIX* pixInitAccumulate ( l_int32  w,
l_int32  h,
l_uint32  offset 
)

pixInitAccumulate()

Input: w, h (of accumulate array) offset (initialize the 32 bpp to have this value; not more than 0x40000000) Return: pixd (32 bpp), or null on error

Notes: (1) The offset must be >= 0. (2) The offset is used so that we can do arithmetic with negative number results on l_uint32 data; it prevents the l_uint32 data from going negative. (3) Because we use l_int32 intermediate data results, these should never exceed the max of l_int32 (0x7fffffff). We do not permit the offset to be above 0x40000000, which is half way between 0 and the max of l_int32. (4) The same offset should be used for initialization, multiplication by a constant, and final extraction! (5) If you're only adding positive values, offset can be 0.

PIX* pixMaxDynamicRange ( PIX pixs,
l_int32  type 
)

pixMaxDynamicRange()

Input: pixs (4, 8, 16 or 32 bpp source) type (L_LINEAR_SCALE or L_LOG_SCALE) Return: pixd (8 bpp), or null on error

Notes: (1) Scales pixel values to fit maximally within the dest 8 bpp pixd (2) Uses a LUT for log scaling

PIX* pixMinOrMax ( PIX pixd,
PIX pixs1,
PIX pixs2,
l_int32  type 
)

pixMinOrMax()

Input: pixd (<optional> destination: this can be null, equal to pixs1, or different from pixs1) pixs1 (can be == to pixd) pixs2 type (L_CHOOSE_MIN, L_CHOOSE_MAX) Return: pixd always

Notes: (1) This gives the min or max of two images, component-wise. (2) The depth can be 8 or 16 bpp for 1 component, and 32 bpp for a 3 component image. For 32 bpp, ignore the LSB of each word (the alpha channel) (3) There are 3 cases:

  • if pixd == null, Min(src1, src2) --> new pixd
  • if pixd == pixs1, Min(src1, src2) --> src1 (in-place)
  • if pixd != pixs1, Min(src1, src2) --> input pixd
l_int32 pixMultConstAccumulate ( PIX pixs,
l_float32  factor,
l_uint32  offset 
)

pixMultConstAccumulate()

Input: pixs (32 bpp) factor offset (same as used for initialization) Return: 0 if OK; 1 on error

Notes: (1) The offset must be >= 0 and should not exceed 0x40000000. (2) This multiplies each pixel, relative to offset, by the input factor (3) The result is returned with the offset back in place.

l_int32 pixMultConstantGray ( PIX pixs,
l_float32  val 
)

pixMultConstantGray()

Input: pixs (8, 16 or 32 bpp) val (>= 0.0; amount to multiply by each pixel) Return: 0 if OK, 1 on error

Notes: (1) In-place operation; val must be >= 0. (2) No clipping for 32 bpp. (3) For 8 and 16 bpp, the result is clipped to 0xff and 0xffff, rsp.

PIX* pixSubtractGray ( PIX pixd,
PIX pixs1,
PIX pixs2 
)

pixSubtractGray()

Input: pixd (<optional>; this can be null, equal to pixs1, or different from pixs1) pixs1 (can be == to pixd) pixs2 Return: pixd always

Notes: (1) Arithmetic subtraction of two 8, 16 or 32 bpp images. (2) Source pixs2 is always subtracted from source pixs1. (3) Do explicit clipping to 0. (4) Alignment is to UL corner. (5) There are 3 cases. The result can go to a new dest, in-place to pixs1, or to an existing input dest: (a) pixd == null (src1 - src2) --> new pixd (b) pixd == pixs1 (src1 - src2) --> src1 (in-place) (d) pixd != pixs1 (src1 - src2) --> input pixd (6) pixs2 must be different from both pixd and pixs1.

PIX* pixThresholdToValue ( PIX pixd,
PIX pixs,
l_int32  threshval,
l_int32  setval 
)

pixThresholdToValue()

Input: pixd (<optional>; if not null, must be equal to pixs) pixs (8, 16, 32 bpp) threshval setval Return: pixd always

Notes:

  • operation can be in-place (pixs == pixd) or to a new pixd
  • if setval > threshval, sets pixels with a value >= threshval to setval
  • if setval < threshval, sets pixels with a value <= threshval to setval
  • if setval == threshval, no-op