Leptonica
1.54
|
#define DEBUG_CORRELATION_SCORE 0 |
#define DEBUG_PLOT_CC 0 |
#define L_BUF_SIZE 512 |
#define MAX_ALLOWED_DILATION 14 |
typedef struct JbFindTemplatesState JBFINDCTX |
static l_int32 finalPositioningForAlignment | ( | PIX * | pixs, |
l_int32 | x, | ||
l_int32 | y, | ||
l_int32 | idelx, | ||
l_int32 | idely, | ||
PIX * | pixt, | ||
l_int32 * | sumtab, | ||
l_int32 * | pdx, | ||
l_int32 * | pdy | ||
) | [static] |
finalPositioningForAlignment()
Input: pixs (input page image) x, y (location of UL corner of bb of component in pixs) idelx, idely (compensation to match centroids of component and template) pixt (template, with JB_ADDED_PIXELS of padding on all sides) sumtab (for summing fg pixels in an image) &dx, &dy (return delta on position for best match; each one is in the set {-1, 0, 1}) Return: 0 if OK, 1 on error
static void findSimilarSizedTemplatesDestroy | ( | JBFINDCTX ** | pcontext | ) | [static] |
static JBFINDCTX * findSimilarSizedTemplatesInit | ( | JBCLASSER * | classer, |
PIX * | pixs | ||
) | [static] |
findSimilarSizedTemplatesInit()
Input: classer pixs (instance to be matched) Return: Allocated context to be used with findSimilar*
static l_int32 findSimilarSizedTemplatesNext | ( | JBFINDCTX * | state | ) | [static] |
findSimilarSizedTemplatesNext()
Input: state (from findSimilarSizedTemplatesInit) Return: Next template number, or -1 when finished
We have a hash table mapping template area to a list of template numbers with that area. We wish to find similar sized templates, so we first look for templates with the same width and height, and then with width + 1, etc. This walk is guided by the two_by_two_walk array, above.
We don't want to have to collect the whole list of templates first because (we hope) to find it quickly. So we keep the context for this walk in an explictit state structure and this function acts like a generator.
PIXA* jbAccumulateComposites | ( | PIXAA * | pixaa, |
NUMA ** | pna, | ||
PTA ** | pptat | ||
) |
Input: pixaa (one pixa for each class) &pna (<return> number of samples used to build each composite) &ptat (<return> centroids of bordered composites) Return: pixad (accumulated sum of samples in each class), or null on error
Input: jbclasser pixs (of input page) Return: 0 if OK; 1 on error
Input: jbclasser pixs (of input page) boxas (b.b. of components for this page) pixas (components for this page) Return: 0 if OK; 1 on error
Notes: (1) If there are no components on the page, we don't require input of empty boxas or pixas, although that's the typical situation.
l_int32 jbAddPages | ( | JBCLASSER * | classer, |
SARRAY * | safiles | ||
) |
Input: jbclasser safiles (of page image file names) Return: 0 if OK; 1 on error
Note: (1) jbclasser makes a copy of the array of file names. (2) The caller is still responsible for destroying the input array.
JBCLASSER* jbClasserCreate | ( | l_int32 | method, |
l_int32 | components | ||
) |
Input: method (JB_RANKHAUS, JB_CORRELATION) components (JB_CONN_COMPS, JB_CHARACTERS, JB_WORDS) Return: jbclasser, or null on error
void jbClasserDestroy | ( | JBCLASSER ** | pclasser | ) |
l_int32 jbClassifyCorrelation | ( | JBCLASSER * | classer, |
BOXA * | boxa, | ||
PIXA * | pixas | ||
) |
Input: jbclasser boxa (of new components for classification) pixas (of new components for classification) Return: 0 if OK; 1 on error
l_int32 jbClassifyRankHaus | ( | JBCLASSER * | classer, |
BOXA * | boxa, | ||
PIXA * | pixas | ||
) |
Input: jbclasser boxa (of new components for classification) pixas (of new components for classification) Return: 0 if OK; 1 on error
JBCLASSER* jbCorrelationInit | ( | l_int32 | components, |
l_int32 | maxwidth, | ||
l_int32 | maxheight, | ||
l_float32 | thresh, | ||
l_float32 | weightfactor | ||
) |
Input: components (JB_CONN_COMPS, JB_CHARACTERS, JB_WORDS) maxwidth (of component; use 0 for default) maxheight (of component; use 0 for default) thresh (value for correlation score: in [0.4 - 0.98]) weightfactor (corrects thresh for thick characters [0.0 - 1.0]) Return: jbclasser if OK; NULL on error
Notes: (1) For scanned text, suggested input values are: thresh ~ [0.8 - 0.85] weightfactor ~ [0.5 - 0.6] (2) For electronically generated fonts (e.g., rasterized pdf), a very high thresh (e.g., 0.95) will not cause a significant increase in the number of classes.
static JBCLASSER * jbCorrelationInitInternal | ( | l_int32 | components, |
l_int32 | maxwidth, | ||
l_int32 | maxheight, | ||
l_float32 | thresh, | ||
l_float32 | weightfactor, | ||
l_int32 | keep_components | ||
) | [static] |
JBCLASSER* jbCorrelationInitWithoutComponents | ( | l_int32 | components, |
l_int32 | maxwidth, | ||
l_int32 | maxheight, | ||
l_float32 | thresh, | ||
l_float32 | weightfactor | ||
) |
jbCorrelationInitWithoutComponents()
Input: same as jbCorrelationInit Output: same as jbCorrelationInit
Note: acts the same as jbCorrelationInit(), but the resulting object doesn't keep a list of all the components.
void jbDataDestroy | ( | JBDATA ** | pdata | ) |
JBDATA* jbDataRead | ( | const char * | rootname | ) |
Input: rootname (for template and data files) Return: jbdata, or NULL on error
PIXA* jbDataRender | ( | JBDATA * | data, |
l_int32 | debugflag | ||
) |
Input: jbdata debugflag (if TRUE, writes into 2 bpp pix and adds component outlines in color) Return: pixa (reconstruction of original images, using templates) or null on error
JBDATA* jbDataSave | ( | JBCLASSER * | classer | ) |
Input: jbclasser latticew, latticeh (cell size used to store each connected component in the composite) Return: jbdata, or null on error
Notes: (1) This routine stores the jbig2-type data required for generating a lossy jbig2 version of the image. It can be losslessly written to (and read from) two files. (2) It generates and stores the mosaic of templates. (3) It clones the Numa and Pta arrays, so these must all be destroyed by the caller. (4) Input 0 to use the default values for latticew and/or latticeh,
l_int32 jbDataWrite | ( | const char * | rootout, |
JBDATA * | jbdata | ||
) |
Input: rootname (for output files; everything but the extension) jbdata Return: 0 if OK, 1 on error
Notes: (1) Serialization function that writes data in jbdata to file.
l_int32 jbGetComponents | ( | PIX * | pixs, |
l_int32 | components, | ||
l_int32 | maxwidth, | ||
l_int32 | maxheight, | ||
BOXA ** | pboxad, | ||
PIXA ** | ppixad | ||
) |
Input: pixs (1 bpp) components (JB_CONN_COMPS, JB_CHARACTERS, JB_WORDS) maxwidth, maxheight (of saved components; larger are discarded) &pboxa (<return> b.b. of component items) &ppixa (<return> component items) Return: 0 if OK, 1 on error
l_int32 jbGetLLCorners | ( | JBCLASSER * | classer | ) |
Input: jbclasser Return: 0 if OK, 1 on error
Notes: (1) This computes the ptall field, which has the global LL corners, adjusted for each specific component, so that each component can be replaced by the template for its class and have the centroid in the template in the same position as the centroid of the original connected component. It is important that this be done properly to avoid a wavy baseline in the result. (2) It is computed here from the corresponding UL corners, where the input templates and stored instances are all bordered. This should be done after all pages have been processed. (3) For proper substitution, the templates whose LL corners are placed in these locations must be UN-bordered. This is available for a realistic jbig2 encoder, which would (1) encode each template without a border, and (2) encode the position using the LL corner (rather than the UL corner) because the difference between y-values of successive instances is typically close to zero.
l_int32 jbGetULCorners | ( | JBCLASSER * | classer, |
PIX * | pixs, | ||
BOXA * | boxa | ||
) |
Input: jbclasser pixs (full res image) boxa (of c.c. bounding rectangles for this page) Return: 0 if OK, 1 on error
Notes: (1) This computes the ptaul field, which has the global UL corners, adjusted for each specific component, so that each component can be replaced by the template for its class and have the centroid in the template in the same position as the centroid of the original connected component. It is important that this be done properly to avoid a wavy baseline in the result. (2) The array fields ptac and ptact give the centroids of those components relative to the UL corner of each component. Here, we compute the difference in each component, round to nearest integer, and correct the box->x and box->y by the appropriate integral difference. (3) The templates and stored instances are all bordered.
JBCLASSER* jbRankHausInit | ( | l_int32 | components, |
l_int32 | maxwidth, | ||
l_int32 | maxheight, | ||
l_int32 | size, | ||
l_float32 | rank | ||
) |
Input: components (JB_CONN_COMPS, JB_CHARACTERS, JB_WORDS) maxwidth (of component; use 0 for default) maxheight (of component; use 0 for default) size (of square structuring element; 2, representing 2x2 sel, is necessary for reasonable accuracy of small components; combine this with rank ~ 0.97 to avoid undue class expansion) rank (rank val of match, each way; in [0.5 - 1.0]; when using size = 2, 0.97 is a reasonable value) Return: jbclasser if OK; NULL on error
PIXA* jbTemplatesFromComposites | ( | PIXA * | pixac, |
NUMA * | na | ||
) |
Input: pixac (one pix of composites for each class) na (number of samples used for each class composite) Return: pixad (8 bpp templates for each class), or null on error
l_int32 pixHaustest | ( | PIX * | pix1, |
PIX * | pix2, | ||
PIX * | pix3, | ||
PIX * | pix4, | ||
l_float32 | delx, | ||
l_float32 | dely, | ||
l_int32 | maxdiffw, | ||
l_int32 | maxdiffh | ||
) |
Input: pix1 (new pix, not dilated) pix2 (new pix, dilated) pix3 (exemplar pix, not dilated) pix4 (exemplar pix, dilated) delx (x comp of centroid difference) dely (y comp of centroid difference) maxdiffw (max width difference of pix1 and pix2) maxdiffh (max height difference of pix1 and pix2) Return: 0 (FALSE) if no match, 1 (TRUE) if the new pix is in the same class as the exemplar.
Note: we check first that the two pix are roughly the same size. Only if they meet that criterion do we compare the bitmaps. The Hausdorff is a 2-way check. The centroid difference is used to align the two images to the nearest integer for each of the checks. These check that the dilated image of one contains ALL the pixels of the undilated image of the other. Checks are done in both direction. A single pixel not contained in either direction results in failure of the test.
l_int32 pixRankHaustest | ( | PIX * | pix1, |
PIX * | pix2, | ||
PIX * | pix3, | ||
PIX * | pix4, | ||
l_float32 | delx, | ||
l_float32 | dely, | ||
l_int32 | maxdiffw, | ||
l_int32 | maxdiffh, | ||
l_int32 | area1, | ||
l_int32 | area3, | ||
l_float32 | rank, | ||
l_int32 * | tab8 | ||
) |
Input: pix1 (new pix, not dilated) pix2 (new pix, dilated) pix3 (exemplar pix, not dilated) pix4 (exemplar pix, dilated) delx (x comp of centroid difference) dely (y comp of centroid difference) maxdiffw (max width difference of pix1 and pix2) maxdiffh (max height difference of pix1 and pix2) area1 (fg pixels in pix1) area3 (fg pixels in pix3) rank (rank value of test, each way) tab8 (table of pixel sums for byte) Return: 0 (FALSE) if no match, 1 (TRUE) if the new pix is in the same class as the exemplar.
Note: we check first that the two pix are roughly the same size. Only if they meet that criterion do we compare the bitmaps. We convert the rank value to a number of pixels by multiplying the rank fraction by the number of pixels in the undilated image. The Hausdorff is a 2-way check. The centroid difference is used to align the two images to the nearest integer for each of the checks. The rank hausdorff checks that the dilated image of one contains the rank fraction of the pixels of the undilated image of the other. Checks are done in both direction. Failure of the test in either direction results in failure of the test.
PIX* pixWordMaskByDilation | ( | PIX * | pixs, |
l_int32 | maxsize, | ||
l_int32 * | psize | ||
) |
Input: pixs (1 bpp; typ. at 75 to 150 ppi) maxsize (use 0 for default; not to exceed 14) &size (<optional return>=""> size of optimal horiz Sel) Return: pixd (dilated word mask), or null on error
Notes: (1) For 75 to 150 ppi, the optimal dilation should not exceed 7. This is the default size chosen if maxsize <= 0. (2) To run this on images at resolution between 200 and 300, it is advisable to use a larger maxsize, say between 10 and 14. (3) The best size for dilating to get word masks is optionally returned.
const l_int32 JB_ADDED_PIXELS = 6 [static] |
const l_int32 MAX_CHAR_COMP_WIDTH = 350 [static] |
const l_int32 MAX_COMP_HEIGHT = 120 [static] |
const l_int32 MAX_CONN_COMP_WIDTH = 350 [static] |
const l_int32 MAX_DIFF_HEIGHT = 2 [static] |
const l_int32 MAX_DIFF_WIDTH = 2 [static] |
const l_int32 MAX_WORD_COMP_WIDTH = 1000 [static] |
int two_by_two_walk[50] [static] |
{ 0, 0, 0, 1, -1, 0, 0, -1, 1, 0, -1, 1, 1, 1, -1, -1, 1, -1, 0, -2, 2, 0, 0, 2, -2, 0, -1, -2, 1, -2, 2, -1, 2, 1, 1, 2, -1, 2, -2, 1, -2, -1, -2, -2, 2, -2, 2, 2, -2, 2}