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dewarp4.c Single page dewarper Reference model (book-level, dewarpa) operations and debugging output Top-level single page dewarper l_int32 dewarpSinglePage() Operations on dewarpa l_int32 dewarpaListPages() l_int32 dewarpaSetValidModels() l_int32 dewarpaInsertRefModels() l_int32 dewarpaStripRefModels() l_int32 dewarpaRestoreModels() Dewarp debugging output l_int32 dewarpaInfo() l_int32 dewarpaModelStats() static l_int32 dewarpaTestForValidModel() l_int32 dewarpaShowArrays() l_int32 dewarpDebug() l_int32 dewarpShowResults()
l_int32 dewarpDebug ( L_DEWARP *dew, const char *subdir, l_int32 index )
dewarpDebug() Input: dew subdir (a subdirectory of /tmp; e.g., "dew1") index (to help label output images; e.g., the page number) Return: 0 if OK, 1 on error Notes: (1) Prints dewarp fields and generates disparity array contour images. The contour images are written to file: /tmp/[subdir]/pixv_[index].png
l_int32 dewarpShowResults ( L_DEWARPA *dewa, SARRAY *sa, BOXA *boxa, l_int32 firstpage, l_int32 lastpage, const char *pdfout )
dewarpShowResults() Input: dewa sarray (of indexed input images) boxa (crop boxes for input images; can be null) firstpage, lastpage pdfout (filename) Return: 0 if OK, 1 on error Notes: (1) This generates a pdf of image pairs (before, after) for the designated set of input pages. (2) If the boxa exists, its elements are aligned with numbers in the filenames in @sa. It is used to crop the input images. It is assumed that the dewa was generated from the cropped images. No undercropping is applied before rendering.
l_int32 dewarpSinglePage ( PIX *pixs, l_int32 thresh, l_int32 adaptive, l_int32 both, PIX **ppixd, L_DEWARPA **pdewa, l_int32 debug )
dewarpSinglePage() Input: pixs (with text, any depth) thresh (for binarization) adaptive (1 for adaptive thresholding; 0 for global threshold) both (1 for horizontal and vertical; 0 for vertical only) &pixd (<return> dewarped result) &dewa (<optional return> dewa with single page; NULL to skip) debug (1 for debugging output, 0 otherwise) Return: 0 if OK, 1 on error (list of page numbers), or null on error Notes: (1) Dewarps pixs and returns the result in &pixd. (2) This uses default values for all model parameters. (3) If pixs is 1 bpp, the parameters @adaptive and @thresh are ignored. (4) If it can't build a model, returns a copy of pixs in &pixd.
l_int32 dewarpaInfo ( FILE *fp, L_DEWARPA *dewa )
dewarpaInfo() Input: fp dewa Return: 0 if OK, 1 on error
l_int32 dewarpaInsertRefModels ( L_DEWARPA *dewa, l_int32 notests, l_int32 debug )
dewarpaInsertRefModels() Input: dewa notests (if 1, ignore curvature constraints on model) debug (1 to output information on invalid page models) Return: 0 if OK, 1 on error Notes: (1) This destroys all dewarp models that are invalid, and then inserts reference models where possible. (2) If @notests == 1, this ignores the curvature constraints and assumes that all successfully built models are valid. (3) If useboth == 0, it uses the closest valid model within the distance and parity constraints. If useboth == 1, it tries to use the closest allowed hvalid model; if it doesn't find an hvalid model, it uses the closest valid model. (4) For all pages without a model, this clears out any existing invalid and reference dewarps, finds the nearest valid model with the same parity, and inserts an empty dewarp with the reference page. (5) Then if it is requested to use both vertical and horizontal disparity arrays (useboth == 1), it tries to replace any hvalid == 0 model or reference with an hvalid == 1 reference. (6) The distance constraint is that any reference model must be within maxdist. Note that with the parity constraint, no reference models will be used if maxdist < 2. (7) This function must be called, even if reference models will not be used. It should be called after building models on all available pages, and after setting the rendering parameters. (8) If the dewa has been serialized, this function is called by dewarpaRead() when it is read back. It is also called any time the rendering parameters are changed. (9) Note: if this has been called with useboth == 1, and useboth is reset to 0, you should first call dewarpRestoreModels() to bring real models from the cache back to the primary array.
l_int32 dewarpaListPages ( L_DEWARPA *dewa )
dewarpaListPages() Input: dewa (populated with dewarp structs for pages) Return: 0 if OK, 1 on error (list of page numbers), or null on error Notes: (1) This generates two numas, stored in the dewarpa, that give: (a) the page number for each dew that has a page model. (b) the page number for each dew that has either a page model or a reference model. It can be called at any time. (2) It is called by the dewarpa serializer before writing.
l_int32 dewarpaModelStats ( L_DEWARPA *dewa, l_int32 *pnnone, l_int32 *pnvsuccess, l_int32 *pnvvalid, l_int32 *pnhsuccess, l_int32 *pnhvalid, l_int32 *pnref )
dewarpaModelStats() Input: dewa &nnone (<optional return> number without any model) &nvsuccess (<optional return> number with a vert model) &nvvalid (<optional return> number with a valid vert model) &nhsuccess (<optional return> number with both models) &nhvalid (<optional return> number with both models valid) &nref (<optional return> number with a reference model) Return: 0 if OK, 1 on error Notes: (1) A page without a model has no dew. It most likely failed to generate a vertical model, and has not been assigned a ref model from a neighboring page with a valid vertical model. (2) A page has vsuccess == 1 if there is at least a model of the vertical disparity. The model may be invalid, in which case dewarpaInsertRefModels() will stash it in the cache and attempt to replace it by a valid ref model. (3) A vvvalid model is a vertical disparity model whose parameters satisfy the constraints given in dewarpaSetValidModels(). (4) A page has hsuccess == 1 if both the vertical and horizontal disparity arrays have been constructed. (5) An hvalid model has vertical and horizontal disparity models whose parameters satisfy the constraints given in dewarpaSetValidModels(). (6) A page has a ref model if it failed to generate a valid model but was assigned a vvalid or hvalid model on another page (within maxdist) by dewarpaInsertRefModel(). (7) This calls dewarpaTestForValidModel(); it ignores the vvalid and hvalid fields.
l_int32 dewarpaRestoreModels ( L_DEWARPA *dewa )
dewarpaRestoreModels() Input: dewa (populated with dewarp structs for pages) Return: 0 if OK, 1 on error Notes: (1) This puts all real models (and only real models) in the primary dewarp array. First remove all dewarps that are only references to other page models. Then move all models that had been cached back into the primary dewarp array. (2) After this is done, we still need to recompute and insert the reference models before dewa->modelsready is true.
l_int32 dewarpaSetValidModels ( L_DEWARPA *dewa, l_int32 notests, l_int32 debug )
dewarpaSetValidModels() Input: dewa notests debug (1 to output information on invalid page models) Return: 0 if OK, 1 on error Notes: (1) A valid model must meet the rendering requirements, which include whether or not a vertical disparity model exists and conditions on curvatures for vertical and horizontal disparity models. (2) If @notests == 1, this ignores the curvature constraints and assumes that all successfully built models are valid. (3) This function does not need to be called by the application. It is called by dewarpaInsertRefModels(), which will destroy all invalid dewarps. Consequently, to inspect an invalid dewarp model, it must be done before calling dewarpaInsertRefModels().
l_int32 dewarpaShowArrays ( L_DEWARPA *dewa, l_float32 scalefact, l_int32 first, l_int32 last )
dewarpaShowArrays() Input: dewa scalefact (on contour images; typ. 0.5) first (first page model to render) last (last page model to render; use 0 to go to end) Return: 0 if OK, 1 on error Notes: (1) Generates a pdf of contour plots of the disparity arrays. (2) This only shows actual models; not ref models
l_int32 dewarpaStripRefModels ( L_DEWARPA *dewa )
dewarpaStripRefModels() Input: dewa (populated with dewarp structs for pages) Return: 0 if OK, 1 on error Notes: (1) This examines each dew in a dewarpa, and removes all that don't have their own page model (i.e., all that have "references" to nearby pages with valid models). These references were generated by dewarpaInsertRefModels(dewa).
Zakariyya Mughal <email@example.com>
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.