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Leptonica
1.82.0
Image processing and image analysis suite
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#include "allheaders.h"
Go to the source code of this file.
Macros | |
#define | DEBUG_SPLIT 0 |
Functions | |
static l_int32 | pixSearchForRectangle (PIX *pixs, BOX *boxs, l_int32 minsum, l_int32 skipdist, l_int32 delta, l_int32 maxbg, l_int32 sideflag, BOXA *boxat, NUMA *nascore) |
PIX * | pixMaskConnComp (PIX *pixs, l_int32 connectivity, BOXA **pboxa) |
PIX * | pixMaskBoxa (PIX *pixd, PIX *pixs, BOXA *boxa, l_int32 op) |
PIX * | pixPaintBoxa (PIX *pixs, BOXA *boxa, l_uint32 val) |
PIX * | pixSetBlackOrWhiteBoxa (PIX *pixs, BOXA *boxa, l_int32 op) |
PIX * | pixPaintBoxaRandom (PIX *pixs, BOXA *boxa) |
PIX * | pixBlendBoxaRandom (PIX *pixs, BOXA *boxa, l_float32 fract) |
PIX * | pixDrawBoxa (PIX *pixs, BOXA *boxa, l_int32 width, l_uint32 val) |
PIX * | pixDrawBoxaRandom (PIX *pixs, BOXA *boxa, l_int32 width) |
PIX * | boxaaDisplay (PIX *pixs, BOXAA *baa, l_int32 linewba, l_int32 linewb, l_uint32 colorba, l_uint32 colorb, l_int32 w, l_int32 h) |
PIXA * | pixaDisplayBoxaa (PIXA *pixas, BOXAA *baa, l_int32 colorflag, l_int32 width) |
BOXA * | pixSplitIntoBoxa (PIX *pixs, l_int32 minsum, l_int32 skipdist, l_int32 delta, l_int32 maxbg, l_int32 maxcomps, l_int32 remainder) |
BOXA * | pixSplitComponentIntoBoxa (PIX *pix, BOX *box, l_int32 minsum, l_int32 skipdist, l_int32 delta, l_int32 maxbg, l_int32 maxcomps, l_int32 remainder) |
BOXA * | makeMosaicStrips (l_int32 w, l_int32 h, l_int32 direction, l_int32 size) |
l_ok | boxaCompareRegions (BOXA *boxa1, BOXA *boxa2, l_int32 areathresh, l_int32 *pnsame, l_float32 *pdiffarea, l_float32 *pdiffxor, PIX **ppixdb) |
BOX * | pixSelectLargeULComp (PIX *pixs, l_float32 areaslop, l_int32 yslop, l_int32 connectivity) |
BOX * | boxaSelectLargeULBox (BOXA *boxas, l_float32 areaslop, l_int32 yslop) |
Boxa/Boxaa painting into pix PIX *pixMaskConnComp() PIX *pixMaskBoxa() PIX *pixPaintBoxa() PIX *pixSetBlackOrWhiteBoxa() PIX *pixPaintBoxaRandom() PIX *pixBlendBoxaRandom() PIX *pixDrawBoxa() PIX *pixDrawBoxaRandom() PIX *boxaaDisplay() PIXA *pixaDisplayBoxaa()
Split mask components into Boxa BOXA *pixSplitIntoBoxa() BOXA *pixSplitComponentIntoBoxa() static l_int32 pixSearchForRectangle()
Represent horizontal or vertical mosaic strips BOXA *makeMosaicStrips()
Comparison between boxa l_int32 boxaCompareRegions()
Reliable selection of a single large box BOX *pixSelectLargeULComp() BOX *boxaSelectLargeULBox()
See summary in pixPaintBoxa() of various ways to paint and draw boxes on images.
Definition in file boxfunc3.c.
PIX* boxaaDisplay | ( | PIX * | pixs, |
BOXAA * | baa, | ||
l_int32 | linewba, | ||
l_int32 | linewb, | ||
l_uint32 | colorba, | ||
l_uint32 | colorb, | ||
l_int32 | w, | ||
l_int32 | h | ||
) |
[in] | pixs | [optional] 1 bpp |
[in] | baa | boxaa, typically from a 2d sort |
[in] | linewba | line width to display outline of each boxa |
[in] | linewb | line width to display outline of each box |
[in] | colorba | color to display boxa |
[in] | colorb | color to display box |
[in] | w | width of outupt pix; use 0 if determined by pixs or baa |
[in] | h | height of outupt pix; use 0 if determined by pixs or baa |
Notes: (1) If pixs exists, this renders the boxes over an 8 bpp version of it. Otherwise, it renders the boxes over an empty image with a white background. (2) If pixs exists, the dimensions of pixd are the same, and input values of w and h are ignored. If pixs is NULL, the dimensions of pixd are determined by
Definition at line 637 of file boxfunc3.c.
References boxaaGetExtent(), pixConvertTo8(), and pixGetDimensions().
l_ok boxaCompareRegions | ( | BOXA * | boxa1, |
BOXA * | boxa2, | ||
l_int32 | areathresh, | ||
l_int32 * | pnsame, | ||
l_float32 * | pdiffarea, | ||
l_float32 * | pdiffxor, | ||
PIX ** | ppixdb | ||
) |
[in] | boxa1,boxa2 | |
[in] | areathresh | minimum area of boxes to be considered |
[out] | pnsame | true if same number of boxes |
[out] | pdiffarea | fractional difference in total area |
[out] | pdiffxor | [optional] fractional difference in xor of regions |
[out] | ppixdb | [optional] debug pix showing two boxa |
Notes: (1) This takes 2 boxa, removes all boxes smaller than a given area, and compares the remaining boxes between the boxa. (2) The area threshold is introduced to help remove noise from small components. Any box with a smaller value of w * h will be removed from consideration. (3) The xor difference is the most stringent test, requiring alignment of the corresponding boxes. It is also more computationally intensive and is optionally returned. Alignment is to the UL corner of each region containing all boxes, as given by boxaGetExtent(). (4) Both fractional differences are with respect to the total area in the two boxa. They range from 0.0 to 1.0. A perfect match has value 0.0. If both boxa are empty, we return 0.0; if one is empty we return 1.0. (5) An example input might be the rectangular regions of a segmentation mask for text or images from two pages.
Definition at line 1390 of file boxfunc3.c.
References boxaDestroy(), boxaGetArea(), boxaGetCount(), boxaGetExtent(), boxaSelectByArea(), boxaTransform(), boxDestroy(), boxGetGeometry(), L_INSERT, L_NEG_SLOPE_LINE, L_POS_SLOPE_LINE, L_SELECT_IF_GTE, L_SET_PIXELS, makePixelSumTab8(), pixaAddPix(), pixaCreate(), pixaDestroy(), pixaDisplayTiledInRows(), pixAnd(), pixCountPixels(), pixCreate(), pixDestroy(), pixMaskBoxa(), pixPaintThroughMask(), pixRenderHashBoxaBlend(), pixSetAll(), and pixXor().
[in] | boxas | 1 bpp |
[in] | areaslop | fraction near but less than 1.0 |
[in] | yslop | number of pixels in y direction |
Notes: (1) See usage notes in pixSelectLargeULComp().
Definition at line 1575 of file boxfunc3.c.
References boxaAddBox(), boxaCreate(), boxaDestroy(), boxaGetBox(), boxaGetBoxGeometry(), boxaGetCount(), boxaSort(), L_COPY, L_INSERT, L_SORT_BY_AREA, L_SORT_BY_Y, L_SORT_DECREASING, and L_SORT_INCREASING.
Referenced by pixSelectLargeULComp().
BOXA* makeMosaicStrips | ( | l_int32 | w, |
l_int32 | h, | ||
l_int32 | direction, | ||
l_int32 | size | ||
) |
[in] | w,h | |
[in] | direction | L_SCAN_HORIZONTAL or L_SCAN_VERTICAL |
[in] | size | of strips in the scan direction |
Notes: (1) For example, this can be used to generate a pixa of vertical strips of width 10 from an image, using: pixGetDimensions(pix, &w, &h, NULL); boxa = makeMosaicStrips(w, h, L_SCAN_HORIZONTAL, 10); pixa = pixClipRectangles(pix, boxa); All strips except the last will be the same width. The last strip will have width w % 10.
Definition at line 1311 of file boxfunc3.c.
References boxaAddBox(), boxaCreate(), boxCreate(), L_INSERT, L_SCAN_HORIZONTAL, and L_SCAN_VERTICAL.
[in] | pixas | any depth, can be cmapped |
[in] | baa | boxes to draw on input pixa |
[in] | colorflag | L_DRAW_RED, L_DRAW_GREEN, etc |
[in] | width | thickness of lines |
Notes: (1) All pix in pixas that are not rgb are converted to rgb. (2) Each boxa in baa contains boxes that will be drawn on the corresponding pix in pixas. (3) The color of the boxes drawn on each pix are selected with colorflag: * For red, green or blue: use L_DRAW_RED, etc. * For sequential r, g, b: use L_DRAW_RGB * For random colors: use L_DRAW_RANDOM
Definition at line 719 of file boxfunc3.c.
References boxaaGetBoxa(), boxaaGetCount(), boxaDestroy(), boxaGetBox(), boxaGetCount(), boxDestroy(), composeRGBPixel(), extractRGBValues(), L_CLONE, L_COPY, L_DRAW_BLUE, L_DRAW_GREEN, L_DRAW_RANDOM, L_DRAW_RED, L_DRAW_RGB, L_INSERT, pixaAddPix(), pixaCreate(), pixaGetCount(), pixaGetPix(), and pixRenderBoxArb().
[in] | pixs | any depth; can be cmapped |
[in] | boxa | of boxes, to blend/paint |
[in] | fract | of box color to use |
Notes: (1) pixs is converted to 32 bpp. (2) This differs from pixPaintBoxaRandom(), in that the colors here are blended with the color of pixs. (3) We use up to 254 different colors for painting the regions. (4) If boxes overlap, the final color depends only on the last rect that is used.
Definition at line 438 of file boxfunc3.c.
References boxaGetBox(), boxaGetCount(), boxDestroy(), composeRGBPixel(), L_CLONE, pixBlendInRect(), pixcmapCreateRandom(), pixcmapDestroy(), pixcmapGetColor(), pixConvertTo32(), and pixCopy().
[in] | pixs | any depth; can be cmapped |
[in] | boxa | of boxes, to draw |
[in] | width | of lines |
[in] | val | rgba color to draw |
Notes: (1) If pixs is 1 bpp or is colormapped, it is converted to 8 bpp and the boxa is drawn using a colormap; otherwise, it is converted to 32 bpp rgb.
Definition at line 499 of file boxfunc3.c.
References boxaGetCount(), and pixCopy().
[in] | pixs | any depth, can be cmapped |
[in] | boxa | of boxes, to draw |
[in] | width | thickness of line |
Notes: (1) If pixs is 1 bpp, we draw the boxa using a colormap; otherwise, we convert to 32 bpp. (2) We use up to 254 different colors for drawing the boxes. (3) If boxes overlap, the later ones draw over earlier ones.
Definition at line 563 of file boxfunc3.c.
References boxaGetCount(), and pixCopy().
[in] | pixd | [optional] may be NULL |
[in] | pixs | any depth; not cmapped |
[in] | boxa | of boxes, to paint |
[in] | op | L_SET_PIXELS, L_CLEAR_PIXELS, L_FLIP_PIXELS |
Notes: (1) This can be used with: pixd = NULL (makes a new pixd) pixd = pixs (in-place) (2) If pixd == NULL, this first makes a copy of pixs, and then bit-twiddles over the boxes. Otherwise, it operates directly on pixs. (3) This simple function is typically used with 1 bpp images. It uses the 1-image rasterop function, rasteropUniLow(), to set, clear or flip the pixels in pixd. (4) If you want to generate a 1 bpp mask of ON pixels from the boxes in a Boxa, in a pix of size (w,h): pix = pixCreate(w, h, 1); pixMaskBoxa(pix, pix, boxa, L_SET_PIXELS);
Definition at line 151 of file boxfunc3.c.
Referenced by boxaCompareRegions().
[in] | pixs | 1 bpp |
[in] | connectivity | 4 or 8 |
[out] | pboxa | [optional] bounding boxes of c.c. |
Notes: (1) This generates a mask image with ON pixels over the b.b. of the c.c. in pixs. If there are no ON pixels in pixs, pixd will also have no ON pixels.
Definition at line 97 of file boxfunc3.c.
[in] | pixs | any depth, can be cmapped |
[in] | boxa | of boxes, to paint |
[in] | val | rgba color to paint |
Notes: (1) If pixs is 1 bpp or is colormapped, it is converted to 8 bpp and the boxa is painted using a colormap; otherwise, it is converted to 32 bpp rgb. (2) There are several ways to display a box on an image: * Paint it as a solid color * Draw the outline * Blend the outline or region with the existing image We provide painting and drawing here; blending is in blend.c. When painting or drawing, the result can be either a cmapped image or an rgb image. The dest will be cmapped if the src is either 1 bpp or has a cmap that is not full. To force RGB output, use pixConvertTo8(pixs, FALSE) before calling any of these paint and draw functions.
Definition at line 220 of file boxfunc3.c.
References boxaGetCount(), and pixCopy().
[in] | pixs | any depth, can be cmapped |
[in] | boxa | of boxes, to paint |
Notes: (1) If pixs is 1 bpp, we paint the boxa using a colormap; otherwise, we convert to 32 bpp. (2) We use up to 254 different colors for painting the regions. (3) If boxes overlap, the later ones paint over earlier ones.
Definition at line 367 of file boxfunc3.c.
References boxaGetCount(), and pixCopy().
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static |
[in] | pixs | 1 bpp |
[in] | boxs | current region to investigate |
[in] | minsum | minimum pixels to trigger propagation |
[in] | skipdist | distance before computing sum for propagation |
[in] | delta | difference required to stop propagation |
[in] | maxbg | maximum number of allowed bg pixels in ref scan |
[in] | sideflag | side to search from |
[in] | boxat | add result of rectangular region found here |
[in] | nascore | add score for this rectangle here |
Notes: (1) See pixSplitComponentIntoBoxa() for an explanation of the algorithm. This does the sweep from a single side. For each iteration in pixSplitComponentIntoBoxa(), this will be called 4 times, for sideflag = {0, 1, 2, 3}. (2) If a valid rectangle is not found, add a score of 0 and input a minimum box.
Definition at line 1062 of file boxfunc3.c.
[in] | pixs | 1 bpp |
[in] | areaslop | fraction near but less than 1.0 |
[in] | yslop | number of pixels in y direction |
[in] | connectivity | 4 or 8 |
Notes: (1) This selects a box near the top (first) and left (second) of the image, from the set of all boxes that have area >= areaslop * (area of biggest box), where areaslop is some fraction; say ~ 0.9. (2) For all boxes satisfying the above condition, select the left-most box that is within yslop (say, 20) pixels of the box nearest the top. (3) This can be used to reliably select a specific one of the largest regions in an image, for applications where there are expected to be small variations in region size and location. (4) See boxSelectLargeULBox() for implementation details.
Definition at line 1534 of file boxfunc3.c.
References boxaDestroy(), boxaGetCount(), boxaSelectLargeULBox(), and pixConnCompBB().
[in] | pixs | any depth, can be cmapped |
[in] | boxa | [optional] of boxes, to clear or set |
[in] | op | L_SET_BLACK, L_SET_WHITE |
Definition at line 286 of file boxfunc3.c.
References boxaGetCount(), and pixCopy().
BOXA* pixSplitComponentIntoBoxa | ( | PIX * | pix, |
BOX * | box, | ||
l_int32 | minsum, | ||
l_int32 | skipdist, | ||
l_int32 | delta, | ||
l_int32 | maxbg, | ||
l_int32 | maxcomps, | ||
l_int32 | remainder | ||
) |
[in] | pix | 1 bpp |
[in] | box | [optional] location of pix w/rt an origin |
[in] | minsum | minimum pixels to trigger propagation |
[in] | skipdist | distance before computing sum for propagation |
[in] | delta | difference required to stop propagation |
[in] | maxbg | maximum number of allowed bg pixels in ref scan |
[in] | maxcomps | use 0 for unlimited number of subdivided components |
[in] | remainder | set to 1 to get b.b. of remaining stuff |
Notes: (1) This generates a boxa of rectangles that covers the fg of a mask. It does so by a greedy partitioning of the mask, choosing the largest rectangle found from each of the four directions at each step. (2) The input parameters give some flexibility for boundary noise. The resulting set of rectangles must cover all the fg pixels and, in addition, may cover some bg pixels. Using small input parameters on a noiseless mask (i.e., one that has only large vertical and horizontal edges) will result in a proper covering of only the fg pixels of the mask. (3) The input is assumed to be a single connected component, that may have holes. From each side, sweep inward, counting the pixels. If the count becomes greater than minsum, and we have moved forward a further amount skipdist, record that count ('countref'), but don't accept if the scan contains more than maxbg bg pixels. Continue the scan until we reach a count that differs from countref by at least delta, at which point the propagation stops. The box swept out gets a score, which is the sum of fg pixels minus a penalty. The penalty is the number of bg pixels in the box. This is done from all four sides, and the side with the largest score is saved as a rectangle. The process repeats until there is either no rectangle left, or there is one that can't be captured from any direction. For the latter case, we simply accept the last rectangle. (4) The input box is only used to specify the location of the UL corner of pix, with respect to an origin that typically represents the UL corner of an underlying image, of which pix is one component. If box is null, the UL corner is taken to be (0, 0). (5) The parameter maxcomps gives the maximum number of allowed rectangles extracted from any single connected component. Use 0 if no limit is to be applied. (6) The flag remainder specifies whether we take a final bounding box for anything left after the maximum number of allowed rectangle is extracted. (7) So if maxcomps > 0, it specifies that we want no more than the first maxcomps rectangles that satisfy the input criteria. After this, we can get a final rectangle that bounds everything left over by setting remainder == 1. If remainder == 0, we only get rectangles that satisfy the input criteria. (8) It should be noted that the removal of rectangles can break the original c.c. into several c.c. (9) Summing up: * If maxcomp == 0, the splitting proceeds as far as possible. * If maxcomp > 0, the splitting stops when maxcomps are found, or earlier if no more components can be selected. * If remainder == 1 and components remain that cannot be selected, they are returned as a single final rectangle; otherwise, they are ignored.
Definition at line 947 of file boxfunc3.c.
BOXA* pixSplitIntoBoxa | ( | PIX * | pixs, |
l_int32 | minsum, | ||
l_int32 | skipdist, | ||
l_int32 | delta, | ||
l_int32 | maxbg, | ||
l_int32 | maxcomps, | ||
l_int32 | remainder | ||
) |
[in] | pixs | 1 bpp |
[in] | minsum | minimum pixels to trigger propagation |
[in] | skipdist | distance before computing sum for propagation |
[in] | delta | difference required to stop propagation |
[in] | maxbg | maximum number of allowed bg pixels in ref scan |
[in] | maxcomps | use 0 for unlimited number of subdivided components |
[in] | remainder | set to 1 to get b.b. of remaining stuff |
Notes: (1) This generates a boxa of rectangles that covers the fg of a mask. For each 8-connected component in pixs, it does a greedy partitioning, choosing the largest rectangle found from each of the four directions at each iter. See pixSplitComponentIntoBoxa() for details. (2) The input parameters give some flexibility for boundary noise. The resulting set of rectangles may cover some bg pixels. (3) This should be used when there are a small number of mask components, each of which has sides that are close to horizontal and vertical. The input parameters delta and maxbg determine whether or not holes in the mask are covered. (4) The parameter maxcomps gives the maximum number of allowed rectangles extracted from any single connected component. Use 0 if no limit is to be applied. (5) The flag remainder specifies whether we take a final bounding box for anything left after the maximum number of allowed rectangle is extracted.
Definition at line 838 of file boxfunc3.c.