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441 lines
14 KiB
441 lines
14 KiB
/*M/////////////////////////////////////////////////////////////////////////////////////// |
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// |
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// IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING. |
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// |
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// By downloading, copying, installing or using the software you agree to this license. |
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// If you do not agree to this license, do not download, install, |
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// copy or use the software. |
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// |
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// |
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// Intel License Agreement |
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// For Open Source Computer Vision Library |
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// |
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// Copyright (C) 2000, Intel Corporation, all rights reserved. |
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// Third party copyrights are property of their respective owners. |
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// |
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// Redistribution and use in source and binary forms, with or without modification, |
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// are permitted provided that the following conditions are met: |
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// |
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// * Redistribution's of source code must retain the above copyright notice, |
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// this list of conditions and the following disclaimer. |
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// |
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// * Redistribution's in binary form must reproduce the above copyright notice, |
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// this list of conditions and the following disclaimer in the documentation |
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// and/or other materials provided with the distribution. |
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// |
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// * The name of Intel Corporation may not be used to endorse or promote products |
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// derived from this software without specific prior written permission. |
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// |
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// This software is provided by the copyright holders and contributors "as is" and |
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// any express or implied warranties, including, but not limited to, the implied |
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// warranties of merchantability and fitness for a particular purpose are disclaimed. |
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// In no event shall the Intel Corporation or contributors be liable for any direct, |
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// indirect, incidental, special, exemplary, or consequential damages |
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// (including, but not limited to, procurement of substitute goods or services; |
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// loss of use, data, or profits; or business interruption) however caused |
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// and on any theory of liability, whether in contract, strict liability, |
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// or tort (including negligence or otherwise) arising in any way out of |
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// the use of this software, even if advised of the possibility of such damage. |
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// |
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//M*/ |
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#include "precomp.hpp" |
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typedef struct |
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{ |
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int bottom; |
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int left; |
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float height; |
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float width; |
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float base_a; |
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float base_b; |
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} |
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icvMinAreaState; |
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#define CV_CALIPERS_MAXHEIGHT 0 |
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#define CV_CALIPERS_MINAREARECT 1 |
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#define CV_CALIPERS_MAXDIST 2 |
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/*F/////////////////////////////////////////////////////////////////////////////////////// |
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// Name: icvRotatingCalipers |
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// Purpose: |
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// Rotating calipers algorithm with some applications |
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// |
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// Context: |
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// Parameters: |
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// points - convex hull vertices ( any orientation ) |
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// n - number of vertices |
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// mode - concrete application of algorithm |
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// can be CV_CALIPERS_MAXDIST or |
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// CV_CALIPERS_MINAREARECT |
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// left, bottom, right, top - indexes of extremal points |
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// out - output info. |
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// In case CV_CALIPERS_MAXDIST it points to float value - |
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// maximal height of polygon. |
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// In case CV_CALIPERS_MINAREARECT |
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// ((CvPoint2D32f*)out)[0] - corner |
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// ((CvPoint2D32f*)out)[1] - vector1 |
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// ((CvPoint2D32f*)out)[0] - corner2 |
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// |
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// ^ |
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// | |
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// vector2 | |
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// | |
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// |____________\ |
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// corner / |
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// vector1 |
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// |
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// Returns: |
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// Notes: |
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//F*/ |
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/* we will use usual cartesian coordinates */ |
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static void |
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icvRotatingCalipers( CvPoint2D32f* points, int n, int mode, float* out ) |
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{ |
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float minarea = FLT_MAX; |
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float max_dist = 0; |
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char buffer[32] = {}; |
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int i, k; |
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CvPoint2D32f* vect = (CvPoint2D32f*)cvAlloc( n * sizeof(vect[0]) ); |
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float* inv_vect_length = (float*)cvAlloc( n * sizeof(inv_vect_length[0]) ); |
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int left = 0, bottom = 0, right = 0, top = 0; |
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int seq[4] = { -1, -1, -1, -1 }; |
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/* rotating calipers sides will always have coordinates |
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(a,b) (-b,a) (-a,-b) (b, -a) |
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*/ |
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/* this is a first base bector (a,b) initialized by (1,0) */ |
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float orientation = 0; |
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float base_a; |
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float base_b = 0; |
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float left_x, right_x, top_y, bottom_y; |
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CvPoint2D32f pt0 = points[0]; |
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left_x = right_x = pt0.x; |
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top_y = bottom_y = pt0.y; |
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for( i = 0; i < n; i++ ) |
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{ |
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double dx, dy; |
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if( pt0.x < left_x ) |
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left_x = pt0.x, left = i; |
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if( pt0.x > right_x ) |
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right_x = pt0.x, right = i; |
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if( pt0.y > top_y ) |
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top_y = pt0.y, top = i; |
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if( pt0.y < bottom_y ) |
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bottom_y = pt0.y, bottom = i; |
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CvPoint2D32f pt = points[(i+1) & (i+1 < n ? -1 : 0)]; |
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dx = pt.x - pt0.x; |
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dy = pt.y - pt0.y; |
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vect[i].x = (float)dx; |
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vect[i].y = (float)dy; |
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inv_vect_length[i] = (float)(1./sqrt(dx*dx + dy*dy)); |
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pt0 = pt; |
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} |
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//cvbInvSqrt( inv_vect_length, inv_vect_length, n ); |
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/* find convex hull orientation */ |
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{ |
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double ax = vect[n-1].x; |
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double ay = vect[n-1].y; |
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for( i = 0; i < n; i++ ) |
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{ |
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double bx = vect[i].x; |
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double by = vect[i].y; |
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double convexity = ax * by - ay * bx; |
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if( convexity != 0 ) |
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{ |
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orientation = (convexity > 0) ? 1.f : (-1.f); |
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break; |
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} |
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ax = bx; |
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ay = by; |
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} |
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assert( orientation != 0 ); |
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} |
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base_a = orientation; |
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/*****************************************************************************************/ |
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/* init calipers position */ |
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seq[0] = bottom; |
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seq[1] = right; |
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seq[2] = top; |
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seq[3] = left; |
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/*****************************************************************************************/ |
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/* Main loop - evaluate angles and rotate calipers */ |
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/* all of edges will be checked while rotating calipers by 90 degrees */ |
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for( k = 0; k < n; k++ ) |
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{ |
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/* sinus of minimal angle */ |
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/*float sinus;*/ |
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/* compute cosine of angle between calipers side and polygon edge */ |
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/* dp - dot product */ |
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float dp0 = base_a * vect[seq[0]].x + base_b * vect[seq[0]].y; |
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float dp1 = -base_b * vect[seq[1]].x + base_a * vect[seq[1]].y; |
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float dp2 = -base_a * vect[seq[2]].x - base_b * vect[seq[2]].y; |
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float dp3 = base_b * vect[seq[3]].x - base_a * vect[seq[3]].y; |
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float cosalpha = dp0 * inv_vect_length[seq[0]]; |
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float maxcos = cosalpha; |
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/* number of calipers edges, that has minimal angle with edge */ |
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int main_element = 0; |
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/* choose minimal angle */ |
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cosalpha = dp1 * inv_vect_length[seq[1]]; |
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maxcos = (cosalpha > maxcos) ? (main_element = 1, cosalpha) : maxcos; |
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cosalpha = dp2 * inv_vect_length[seq[2]]; |
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maxcos = (cosalpha > maxcos) ? (main_element = 2, cosalpha) : maxcos; |
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cosalpha = dp3 * inv_vect_length[seq[3]]; |
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maxcos = (cosalpha > maxcos) ? (main_element = 3, cosalpha) : maxcos; |
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/*rotate calipers*/ |
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{ |
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//get next base |
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int pindex = seq[main_element]; |
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float lead_x = vect[pindex].x*inv_vect_length[pindex]; |
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float lead_y = vect[pindex].y*inv_vect_length[pindex]; |
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switch( main_element ) |
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{ |
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case 0: |
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base_a = lead_x; |
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base_b = lead_y; |
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break; |
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case 1: |
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base_a = lead_y; |
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base_b = -lead_x; |
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break; |
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case 2: |
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base_a = -lead_x; |
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base_b = -lead_y; |
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break; |
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case 3: |
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base_a = -lead_y; |
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base_b = lead_x; |
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break; |
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default: assert(0); |
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} |
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} |
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/* change base point of main edge */ |
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seq[main_element] += 1; |
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seq[main_element] = (seq[main_element] == n) ? 0 : seq[main_element]; |
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switch (mode) |
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{ |
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case CV_CALIPERS_MAXHEIGHT: |
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{ |
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/* now main element lies on edge alligned to calipers side */ |
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/* find opposite element i.e. transform */ |
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/* 0->2, 1->3, 2->0, 3->1 */ |
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int opposite_el = main_element ^ 2; |
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float dx = points[seq[opposite_el]].x - points[seq[main_element]].x; |
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float dy = points[seq[opposite_el]].y - points[seq[main_element]].y; |
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float dist; |
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if( main_element & 1 ) |
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dist = (float)fabs(dx * base_a + dy * base_b); |
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else |
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dist = (float)fabs(dx * (-base_b) + dy * base_a); |
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if( dist > max_dist ) |
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max_dist = dist; |
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break; |
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} |
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case CV_CALIPERS_MINAREARECT: |
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/* find area of rectangle */ |
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{ |
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float height; |
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float area; |
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/* find vector left-right */ |
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float dx = points[seq[1]].x - points[seq[3]].x; |
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float dy = points[seq[1]].y - points[seq[3]].y; |
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/* dotproduct */ |
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float width = dx * base_a + dy * base_b; |
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/* find vector left-right */ |
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dx = points[seq[2]].x - points[seq[0]].x; |
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dy = points[seq[2]].y - points[seq[0]].y; |
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/* dotproduct */ |
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height = -dx * base_b + dy * base_a; |
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area = width * height; |
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if( area <= minarea ) |
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{ |
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float *buf = (float *) buffer; |
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minarea = area; |
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/* leftist point */ |
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((int *) buf)[0] = seq[3]; |
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buf[1] = base_a; |
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buf[2] = width; |
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buf[3] = base_b; |
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buf[4] = height; |
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/* bottom point */ |
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((int *) buf)[5] = seq[0]; |
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buf[6] = area; |
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} |
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break; |
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} |
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} /*switch */ |
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} /* for */ |
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switch (mode) |
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{ |
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case CV_CALIPERS_MINAREARECT: |
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{ |
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float *buf = (float *) buffer; |
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float A1 = buf[1]; |
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float B1 = buf[3]; |
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float A2 = -buf[3]; |
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float B2 = buf[1]; |
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float C1 = A1 * points[((int *) buf)[0]].x + points[((int *) buf)[0]].y * B1; |
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float C2 = A2 * points[((int *) buf)[5]].x + points[((int *) buf)[5]].y * B2; |
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float idet = 1.f / (A1 * B2 - A2 * B1); |
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float px = (C1 * B2 - C2 * B1) * idet; |
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float py = (A1 * C2 - A2 * C1) * idet; |
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out[0] = px; |
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out[1] = py; |
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out[2] = A1 * buf[2]; |
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out[3] = B1 * buf[2]; |
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out[4] = A2 * buf[4]; |
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out[5] = B2 * buf[4]; |
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} |
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break; |
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case CV_CALIPERS_MAXHEIGHT: |
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{ |
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out[0] = max_dist; |
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} |
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break; |
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} |
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cvFree( &vect ); |
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cvFree( &inv_vect_length ); |
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} |
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CV_IMPL CvBox2D |
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cvMinAreaRect2( const CvArr* array, CvMemStorage* storage ) |
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{ |
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cv::Ptr<CvMemStorage> temp_storage; |
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CvBox2D box; |
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cv::AutoBuffer<CvPoint2D32f> _points; |
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CvPoint2D32f* points; |
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memset(&box, 0, sizeof(box)); |
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int i, n; |
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CvSeqReader reader; |
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CvContour contour_header; |
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CvSeqBlock block; |
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CvSeq* ptseq = (CvSeq*)array; |
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CvPoint2D32f out[3]; |
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if( CV_IS_SEQ(ptseq) ) |
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{ |
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if( !CV_IS_SEQ_POINT_SET(ptseq) && |
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(CV_SEQ_KIND(ptseq) != CV_SEQ_KIND_CURVE || |
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CV_SEQ_ELTYPE(ptseq) != CV_SEQ_ELTYPE_PPOINT )) |
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CV_Error( CV_StsUnsupportedFormat, |
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"Input sequence must consist of 2d points or pointers to 2d points" ); |
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if( !storage ) |
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storage = ptseq->storage; |
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} |
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else |
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{ |
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ptseq = cvPointSeqFromMat( CV_SEQ_KIND_GENERIC, array, &contour_header, &block ); |
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} |
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if( storage ) |
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{ |
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temp_storage = cvCreateChildMemStorage( storage ); |
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} |
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else |
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{ |
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temp_storage = cvCreateMemStorage(1 << 10); |
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} |
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ptseq = cvConvexHull2( ptseq, temp_storage, CV_CLOCKWISE, 1 ); |
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n = ptseq->total; |
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_points.allocate(n); |
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points = _points; |
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cvStartReadSeq( ptseq, &reader ); |
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if( CV_SEQ_ELTYPE( ptseq ) == CV_32SC2 ) |
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{ |
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for( i = 0; i < n; i++ ) |
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{ |
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CvPoint pt; |
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CV_READ_SEQ_ELEM( pt, reader ); |
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points[i].x = (float)pt.x; |
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points[i].y = (float)pt.y; |
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} |
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} |
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else |
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{ |
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for( i = 0; i < n; i++ ) |
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{ |
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CV_READ_SEQ_ELEM( points[i], reader ); |
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} |
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} |
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if( n > 2 ) |
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{ |
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icvRotatingCalipers( points, n, CV_CALIPERS_MINAREARECT, (float*)out ); |
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box.center.x = out[0].x + (out[1].x + out[2].x)*0.5f; |
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box.center.y = out[0].y + (out[1].y + out[2].y)*0.5f; |
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box.size.width = (float)sqrt((double)out[1].x*out[1].x + (double)out[1].y*out[1].y); |
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box.size.height = (float)sqrt((double)out[2].x*out[2].x + (double)out[2].y*out[2].y); |
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box.angle = (float)atan2( (double)out[1].y, (double)out[1].x ); |
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} |
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else if( n == 2 ) |
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{ |
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box.center.x = (points[0].x + points[1].x)*0.5f; |
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box.center.y = (points[0].y + points[1].y)*0.5f; |
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double dx = points[1].x - points[0].x; |
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double dy = points[1].y - points[0].y; |
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box.size.width = (float)sqrt(dx*dx + dy*dy); |
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box.size.height = 0; |
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box.angle = (float)atan2( dy, dx ); |
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} |
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else |
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{ |
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if( n == 1 ) |
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box.center = points[0]; |
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} |
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box.angle = (float)(box.angle*180/CV_PI); |
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return box; |
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} |
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