/*====================================================================* - Copyright (C) 2001 Leptonica. All rights reserved. - - Redistribution and use in source and binary forms, with or without - modification, are permitted provided that the following conditions - are met: - 1. Redistributions of source code must retain the above copyright - notice, this list of conditions and the following disclaimer. - 2. Redistributions in binary form must reproduce the above - copyright notice, this list of conditions and the following - disclaimer in the documentation and/or other materials - provided with the distribution. - - THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS - ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT - LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR - A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL ANY - CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, - EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, - PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR - PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY - OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING - NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS - SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. *====================================================================*/ #ifndef LEPTONICA_DEWARP_H #define LEPTONICA_DEWARP_H /* * dewarp.h * * Data structure to hold arrays and results for generating * horizontal and vertical disparity arrays based on textlines. * Each disparity array is two-dimensional. The vertical disparity * array gives a vertical displacement, relative to the lowest point * in the textlines. The horizontal disparty array gives a horizontal * displacement, relative to the minimum values (for even pages) * or maximum values (for odd pages) of the left and right ends of * full textlines. Horizontal alignment always involves translations * away from the book gutter. * * We have intentionally separated the process of building models * from the rendering process that uses the models. For any page, * the building operation either creates an actual model (that is, * a model with at least the vertical disparity being computed, and * for which the 'success' flag is set) or fails to create a model. * However, at rendering time, a page can have one of two different * types of models. * (1) A valid model is an actual model that meets the rendering * requirements, including whether a full model (horizontal * and vertical disparity) is required, and limits on model * curvatures. See dewarpaTestForValidModel() for details. * Valid models are identified by dewarpaInsertRefModels(), which * sets the 'valid' field. Only valid models are used for rendering. * (2) A reference model is used by a page that doesn't have * a valid model, but has a nearby valid model of the same * parity (even/odd page) that it can use. The range to search * for a valid model is given by the 'maxdist' field. * A page may have neither a valid nor a reference model, in * which case rendering simply copies the input image. * By default, only the vertical disparity is required for * an actual model ('fullmodel' = 0). The 'maxdist' parameter is * input when the dewarpa is created. The other rendering parameters * have default values given in dewarp.c. All parameters used by * rendering can be set (or reset) using accessors. * * After dewarping, use of the vertical disparity will cause all * points on each altered curve to have a y-value equal to the * minimum. Use of horizontal disparity will cause the left * and right edges of the textlines to be vertically aligned if * they had been typeset flush-left and flush-right, respectively. * * The sampled disparity arrays are expanded to full resolution, * using linear interpolation, and this is further expanded * by slope continuation to the right and below if the image * is larger than the full resolution disparity arrays. Then * the disparity correction can be applied to the input image. * If the input pix are 2x reduced, the expansion from sampled * to full res uses the product of (sampling) * (redfactor). * * The most accurate results are produced at full resolution, and * this is generally recommended. */ /* Note on versioning of the serialization of this data structure: * The dewarping utility and the stored data can be expected to change. * In most situations, the serialized version is ephemeral -- it is * not needed after being used. No functions will be provided to * convert between different versions. */ #define DEWARP_VERSION_NUMBER 2 struct L_Dewarpa { l_int32 nalloc; /* size of dewarp ptr array */ l_int32 maxpage; /* maximum page number in array */ struct L_Dewarp **dewarp; /* array of ptrs to page dewarp */ struct Numa *namodels; /* list of page numbers for pages */ /* with page models */ struct Numa *napages; /* list of page numbers with either */ /* page models or ref page models */ l_int32 redfactor; /* reduction factor of input: 1 or 2 */ l_int32 sampling; /* disparity arrays sampling factor */ l_int32 minlines; /* min number of long lines required */ l_int32 maxdist; /* max distance for getting ref pages */ l_int32 min_medcurv; /* minimum median abs line curvature, */ /* in micro-units */ l_int32 max_medcurv; /* maximum median abs line curvature, */ /* in micro-units */ l_int32 max_leftcurv; /* maximum left edge line curvature, */ /* in micro-units */ l_int32 max_rightcurv; /* maximum right edge line curvature, */ /* in micro-units */ l_int32 fullmodel; /* both disparity arrays required */ l_int32 modelsready; /* invalid models have been removed */ /* and refs built against valid set */ }; typedef struct L_Dewarpa L_DEWARPA; struct L_Dewarp { struct Pix *pixs; /* source pix, 1 bpp */ struct Pix *pixd; /* dewarped pix; 1, 8 or 32 bpp */ struct FPix *sampvdispar; /* sampled vert disparity array */ struct FPix *samphdispar; /* sampled horiz disparity array */ struct FPix *fullvdispar; /* full vert disparity array */ struct FPix *fullhdispar; /* full horiz disparity array */ struct Numa *naflats; /* sorted flat location of each line */ struct Numa *nacurves; /* sorted curvature of each line */ l_int32 w; /* width of source image */ l_int32 h; /* height of source image */ l_int32 pageno; /* page number; important for reuse */ l_int32 sampling; /* sampling factor of disparity arrays */ l_int32 redfactor; /* reduction factor of pixs: 1 or 2 */ l_int32 minlines; /* min number of long lines required */ l_int32 nlines; /* number of long lines found */ l_int32 medcurv; /* median abs curvature in micro-units */ l_int32 leftcurv; /* left edge curvature in micro-units */ l_int32 rightcurv; /* right edge curvature in micro-units */ l_int32 nx; /* number of sampling pts in x direction */ l_int32 ny; /* number of sampling pts in y direction */ l_int32 hasref; /* 0 if normal; 1 if has a refpage */ l_int32 refpage; /* page with disparity model to use here */ l_int32 success; /* sets to 1 if model build succeeds */ l_int32 valid; /* sets to 1 if model is valid */ l_int32 debug; /* sets to 1 if debug output requested */ }; typedef struct L_Dewarp L_DEWARP; #endif /* LEPTONICA_DEWARP_H */