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 ///////////////////////////////////////////////////
18 // AlignFeatures.cpp
19 // S.O. # :
20 // Author(s): zkira, mbansal, bsouthall, narodits
21 // $Id: AlignFeatures.cpp,v 1.20 2011/06/17 13:35:47 mbansal Exp $
22
23 #include <stdio.h>
24 #include <string.h>
25
26 #include "trsMatrix.h"
27 #include "MatrixUtils.h"
28 #include "AlignFeatures.h"
29 #include "Log.h"
30
31 #define LOG_TAG "AlignFeatures"
32
Align()33 Align::Align()
34 {
35 width = height = 0;
36 frame_number = 0;
37 num_frames_captured = 0;
38 reference_frame_index = 0;
39 db_Identity3x3(Hcurr);
40 db_Identity3x3(Hprev);
41 }
42
~Align()43 Align::~Align()
44 {
45 // Free gray-scale image
46 if (imageGray != ImageUtils::IMAGE_TYPE_NOIMAGE)
47 ImageUtils::freeImage(imageGray);
48 }
49
getRegProfileString()50 char* Align::getRegProfileString()
51 {
52 return reg.profile_string;
53 }
54
initialize(int width,int height,bool _quarter_res,float _thresh_still)55 int Align::initialize(int width, int height, bool _quarter_res, float _thresh_still)
56 {
57 int nr_corners = DEFAULT_NR_CORNERS;
58 double max_disparity = DEFAULT_MAX_DISPARITY;
59 int motion_model_type = DEFAULT_MOTION_MODEL;
60 int nrsamples = DB_DEFAULT_NR_SAMPLES;
61 double scale = DB_POINT_STANDARDDEV;
62 int chunk_size = DB_DEFAULT_CHUNK_SIZE;
63 int nrhorz = width/48; // Empirically determined number of horizontal
64 int nrvert = height/60; // and vertical buckets for harris corner detection.
65 bool linear_polish = false;
66 unsigned int reference_update_period = DEFAULT_REFERENCE_UPDATE_PERIOD;
67
68 const bool DEFAULT_USE_SMALLER_MATCHING_WINDOW = false;
69 bool use_smaller_matching_window = DEFAULT_USE_SMALLER_MATCHING_WINDOW;
70
71 quarter_res = _quarter_res;
72 thresh_still = _thresh_still;
73
74 frame_number = 0;
75 num_frames_captured = 0;
76 reference_frame_index = 0;
77 db_Identity3x3(Hcurr);
78 db_Identity3x3(Hprev);
79
80 if (!reg.Initialized())
81 {
82 reg.Init(width, height, motion_model_type, 20, linear_polish, quarter_res,
83 scale, reference_update_period, false, 0, nrsamples, chunk_size,
84 nr_corners, max_disparity, use_smaller_matching_window,
85 nrhorz, nrvert);
86 }
87 this->width = width;
88 this->height = height;
89
90 imageGray = ImageUtils::allocateImage(width, height, 1);
91
92 if (reg.Initialized())
93 return ALIGN_RET_OK;
94 else
95 return ALIGN_RET_ERROR;
96 }
97
addFrameRGB(ImageType imageRGB)98 int Align::addFrameRGB(ImageType imageRGB)
99 {
100 ImageUtils::rgb2gray(imageGray, imageRGB, width, height);
101 return addFrame(imageGray);
102 }
103
addFrame(ImageType imageGray_)104 int Align::addFrame(ImageType imageGray_)
105 {
106 int ret_code = ALIGN_RET_OK;
107
108 // Obtain a vector of pointers to rows in image and pass in to dbreg
109 ImageType *m_rows = ImageUtils::imageTypeToRowPointers(imageGray_, width, height);
110
111 if (frame_number == 0)
112 {
113 reg.AddFrame(m_rows, Hcurr, true); // Force this to be a reference frame
114 int num_corner_ref = reg.GetNrRefCorners();
115
116 if (num_corner_ref < MIN_NR_REF_CORNERS)
117 {
118 return ALIGN_RET_LOW_TEXTURE;
119 }
120 }
121 else
122 {
123 reg.AddFrame(m_rows, Hcurr, false);
124 }
125
126 // Average translation per frame =
127 // [Translation from Frame0 to Frame(n-1)] / [(n-1)]
128 average_tx_per_frame = (num_frames_captured < 2) ? 0.0 :
129 Hprev[2] / (num_frames_captured - 1);
130
131 // Increment the captured frame counter if we already have a reference frame
132 num_frames_captured++;
133
134 if (frame_number != 0)
135 {
136 int num_inliers = reg.GetNrInliers();
137
138 if(num_inliers < MIN_NR_INLIERS)
139 {
140 ret_code = ALIGN_RET_FEW_INLIERS;
141
142 Hcurr[0] = 1.0;
143 Hcurr[1] = 0.0;
144 // Set this as the average per frame translation taking into acccount
145 // the separation of the current frame from the reference frame...
146 Hcurr[2] = -average_tx_per_frame *
147 (num_frames_captured - reference_frame_index);
148 Hcurr[3] = 0.0;
149 Hcurr[4] = 1.0;
150 Hcurr[5] = 0.0;
151 Hcurr[6] = 0.0;
152 Hcurr[7] = 0.0;
153 Hcurr[8] = 1.0;
154 }
155
156 if(fabs(Hcurr[2])<thresh_still && fabs(Hcurr[5])<thresh_still) // Still camera
157 {
158 return ALIGN_RET_ERROR;
159 }
160
161 // compute the homography:
162 double Hinv33[3][3];
163 double Hprev33[3][3];
164 double Hcurr33[3][3];
165
166 // Invert and multiple with previous transformation
167 Matrix33::convert9to33(Hcurr33, Hcurr);
168 Matrix33::convert9to33(Hprev33, Hprev);
169 normProjMat33d(Hcurr33);
170
171 inv33d(Hcurr33, Hinv33);
172
173 mult33d(Hcurr33, Hprev33, Hinv33);
174 normProjMat33d(Hcurr33);
175 Matrix9::convert33to9(Hprev, Hcurr33);
176 // Since we have already factored the current transformation
177 // into Hprev, we can reset the Hcurr to identity
178 db_Identity3x3(Hcurr);
179
180 // Update the reference frame to be the current frame
181 reg.UpdateReference(m_rows,quarter_res,false);
182
183 // Update the reference frame index
184 reference_frame_index = num_frames_captured;
185 }
186
187 frame_number++;
188
189 return ret_code;
190 }
191
192 // Get current transformation
getLastTRS(double trs[3][3])193 int Align::getLastTRS(double trs[3][3])
194 {
195 if (frame_number < 1)
196 {
197 trs[0][0] = 1.0;
198 trs[0][1] = 0.0;
199 trs[0][2] = 0.0;
200 trs[1][0] = 0.0;
201 trs[1][1] = 1.0;
202 trs[1][2] = 0.0;
203 trs[2][0] = 0.0;
204 trs[2][1] = 0.0;
205 trs[2][2] = 1.0;
206 return ALIGN_RET_ERROR;
207 }
208
209 // Note that the logic here handles the case, where a frame is not used for
210 // mosaicing but is captured and used in the preview-rendering.
211 // For these frames, we don't set Hcurr to identity in AddFrame() and the
212 // logic here appends their transformation to Hprev to render them with the
213 // correct transformation. For the frames we do use for mosaicing, we already
214 // append their Hcurr to Hprev in AddFrame() and then set Hcurr to identity.
215
216 double Hinv33[3][3];
217 double Hprev33[3][3];
218 double Hcurr33[3][3];
219
220 Matrix33::convert9to33(Hcurr33, Hcurr);
221 normProjMat33d(Hcurr33);
222 inv33d(Hcurr33, Hinv33);
223
224 Matrix33::convert9to33(Hprev33, Hprev);
225
226 mult33d(trs, Hprev33, Hinv33);
227 normProjMat33d(trs);
228
229 return ALIGN_RET_OK;
230 }
231
232