Sascha Haeberling | 8bddf8c | 2013-08-14 11:20:34 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2011 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | /* $Id: db_image_homography.h,v 1.2 2011/06/17 14:03:31 mbansal Exp $ */ |
| 18 | |
| 19 | #ifndef DB_IMAGE_HOMOGRAPHY |
| 20 | #define DB_IMAGE_HOMOGRAPHY |
| 21 | |
| 22 | |
| 23 | |
| 24 | /***************************************************************** |
| 25 | * Lean and mean begins here * |
| 26 | *****************************************************************/ |
| 27 | |
| 28 | #include "db_framestitching.h" |
| 29 | /*! |
| 30 | * \defgroup LMImageHomography (LM) Image Homography Estimation (feature based) |
| 31 | */ |
| 32 | /*\{*/ |
| 33 | /*! |
| 34 | Solve for projective H such that xp~Hx. Prior normalization is not necessary, |
| 35 | although desirable for numerical conditioning |
| 36 | \param H image projective (out) |
| 37 | \param x1 image 1 point 1 |
| 38 | \param x2 image 1 point 2 |
| 39 | \param x3 image 1 point 3 |
| 40 | \param x4 image 1 point 4 |
| 41 | \param xp1 image 2 point 1 |
| 42 | \param xp2 image 2 point 2 |
| 43 | \param xp3 image 2 point 3 |
| 44 | \param xp4 image 2 point 4 |
| 45 | */ |
| 46 | DB_API void db_StitchProjective2D_4Points(double H[9], |
| 47 | double x1[3],double x2[3],double x3[3],double x4[3], |
| 48 | double xp1[3],double xp2[3],double xp3[3],double xp4[3]); |
| 49 | |
| 50 | /*! |
| 51 | Solve for affine H such that xp~Hx. Prior normalization is not necessary, |
| 52 | although desirable for numerical conditioning |
| 53 | \param H image projective (out) |
| 54 | \param x1 image 1 point 1 |
| 55 | \param x2 image 1 point 2 |
| 56 | \param x3 image 1 point 3 |
| 57 | \param xp1 image 2 point 1 |
| 58 | \param xp2 image 2 point 2 |
| 59 | \param xp3 image 2 point 3 |
| 60 | */ |
| 61 | DB_API void db_StitchAffine2D_3Points(double H[9], |
| 62 | double x1[3],double x2[3],double x3[3], |
| 63 | double xp1[3],double xp2[3],double xp3[3]); |
| 64 | |
| 65 | /*! |
| 66 | Solve for rotation R such that xp~Rx. |
| 67 | Image points have to be of unit norm for the least squares to be meaningful. |
| 68 | \param R image rotation (out) |
| 69 | \param x1 image 1 point 1 |
| 70 | \param x2 image 1 point 2 |
| 71 | \param xp1 image 2 point 1 |
| 72 | \param xp2 image 2 point 2 |
| 73 | */ |
| 74 | inline void db_StitchCameraRotation_2Points(double R[9], |
| 75 | /*Image points have to be of unit norm |
| 76 | for the least squares to be meaningful*/ |
| 77 | double x1[3],double x2[3], |
| 78 | double xp1[3],double xp2[3]) |
| 79 | { |
| 80 | double* x[2]; |
| 81 | double* xp[2]; |
| 82 | double scale,t[3]; |
| 83 | |
| 84 | x[0]=x1; |
| 85 | x[1]=x2; |
| 86 | xp[0]=xp1; |
| 87 | xp[1]=xp2; |
| 88 | db_StitchSimilarity3DRaw(&scale,R,t,xp,x,2,1,0,1,0); |
| 89 | } |
| 90 | |
| 91 | /*! |
| 92 | Solve for a homography H generated by a rotation R with a common unknown focal length f, i.e. |
| 93 | H=diag(f,f,1)*R*diag(1/f,1/f,1) such that xp~Hx. |
| 94 | If signed_disambiguation is true, the points are |
| 95 | required to be in front of the camera. No specific normalization of the homogenous points |
| 96 | is required, although it could be desirable to keep x1,x2,xp1 and xp2 of reasonable magnitude. |
| 97 | If a solution is obtained the function returns 1, otherwise 0. If the focal length is desired |
| 98 | a valid pointer should be passed in f |
| 99 | */ |
| 100 | DB_API int db_StitchRotationCommonFocalLength_3Points(double H[9],double x1[3],double x2[3],double x3[3], |
| 101 | double xp1[3],double xp2[3],double xp3[3],double *f=0,int signed_disambiguation=1); |
| 102 | |
| 103 | /*! |
| 104 | Find scale, rotation and translation of the similarity that |
| 105 | takes the nr_points inhomogenous 2D points X to Xp, |
| 106 | i.e. for the homogenous equivalents |
| 107 | Xp and X we would have |
| 108 | \code |
| 109 | Xp~ |
| 110 | [sR t]*X |
| 111 | [0 1] |
| 112 | \endcode |
| 113 | If orientation_preserving is true, R is restricted such that det(R)>0. |
| 114 | allow_scaling, allow_rotation and allow_translation allow s,R and t |
| 115 | to differ from 1,Identity and 0 |
| 116 | |
| 117 | Full similarity takes the following on 550MHz: |
| 118 | \code |
| 119 | 0.9 microseconds with 2 points |
| 120 | 1.0 microseconds with 3 points |
| 121 | 1.1 microseconds with 4 points |
| 122 | 1.3 microseconds with 5 points |
| 123 | 1.4 microseconds with 6 points |
| 124 | 1.7 microseconds with 10 points |
| 125 | 9 microseconds with 100 points |
| 126 | 130 microseconds with 1000 points |
| 127 | 1.3 milliseconds with 10000 points |
| 128 | 35 milliseconds with 100000 points |
| 129 | 350 milliseconds with 1000000 points |
| 130 | \endcode |
| 131 | |
| 132 | Without orientation_preserving: |
| 133 | \code |
| 134 | 3 points is minimal for (s,R,t) (R,t) |
| 135 | 2 points is minimal for (s,t) (s,R) (R) |
| 136 | 1 point is minimal for (s) (t) |
| 137 | \endcode |
| 138 | |
| 139 | With orientation_preserving: |
| 140 | \code |
| 141 | 2 points is minimal for (s,R,t) (R,t) (s,t) |
| 142 | 1 point is minimal for (s,R) (R) (s) (t) |
| 143 | \endcode |
| 144 | \param scale (out) |
| 145 | \param R 2D rotation (out) |
| 146 | \param t 2D translation (out) |
| 147 | \param Xp (nr_points x 2) pointer to array of image points |
| 148 | \param X (nr_points x 2 ) pointer to array of image points |
| 149 | \param nr_points number of points |
| 150 | \param orientation_preserving |
| 151 | \param allow_scaling compute scale (if 0, scale=1) |
| 152 | \param allow_rotation compute rotation (if 0, R=[I]) |
| 153 | \param allow_translation compute translation (if 0 t = [0,0]') |
| 154 | */ |
| 155 | DB_API void db_StitchSimilarity2DRaw(double *scale,double R[4],double t[2], |
| 156 | double **Xp,double **X,int nr_points,int orientation_preserving=1, |
| 157 | int allow_scaling=1,int allow_rotation=1,int allow_translation=1); |
| 158 | /*! |
| 159 | See db_StitchRotationCommonFocalLength_3Points(). |
| 160 | \param H Image similarity transformation (out) |
| 161 | \param Xp (nr_points x 2) pointer to array of image points |
| 162 | \param X (nr_points x 2) pointer to array of image points |
| 163 | \param nr_points number of points |
| 164 | \param orientation_preserving |
| 165 | \param allow_scaling compute scale (if 0, scale=1) |
| 166 | \param allow_rotation compute rotation (if 0, R=[I]) |
| 167 | \param allow_translation compute translation (if 0 t = [0,0]') |
| 168 | */ |
| 169 | inline void db_StitchSimilarity2D(double H[9],double **Xp,double **X,int nr_points,int orientation_preserving=1, |
| 170 | int allow_scaling=1,int allow_rotation=1,int allow_translation=1) |
| 171 | { |
| 172 | double s,R[4],t[2]; |
| 173 | |
| 174 | db_StitchSimilarity2DRaw(&s,R,t,Xp,X,nr_points,orientation_preserving, |
| 175 | allow_scaling,allow_rotation,allow_translation); |
| 176 | |
| 177 | H[0]=s*R[0]; H[1]=s*R[1]; H[2]=t[0]; |
| 178 | H[3]=s*R[2]; H[4]=s*R[3]; H[5]=t[1]; |
| 179 | db_Zero2(H+6); |
| 180 | H[8]=1.0; |
| 181 | } |
| 182 | /*\}*/ |
| 183 | #endif /* DB_IMAGE_HOMOGRAPHY */ |