/** \brief Checks if a patch at a specific image location is still within the reference image.
*
* @param img - Reference Image.
* @param c - Coordinates of the patch in the reference image.
* @param withBorder - Check, using either the patch-patchSize of Patch::patch_ (withBorder = false) or the patch-patchSize
* of the expanded patch Patch::patchWithBorder_ (withBorder = true).
* @return true, if the patch is completely located within the reference image.
*/
static bool isPatchInFrame(const cv::Mat& img,const FeatureCoordinates& c,const bool withBorder = false){
if(c.isInFront() && c.com_warp_c()){
const int halfpatch_size = patchSize/2+(int)withBorder;
if(c.isNearIdentityWarping()){
if(c.get_c().x < halfpatch_size || c.get_c().y < halfpatch_size || c.get_c().x > img.cols-halfpatch_size || c.get_c().y > img.rows-halfpatch_size){
return false;
} else {
return true;
}
} else {
for(int x = 0;x<2;x++){
for(int y = 0;y<2;y++){
const float dx = halfpatch_size*(2*x-1);
const float dy = halfpatch_size*(2*y-1);
const float wdx = c.get_warp_c()(0,0)*dx + c.get_warp_c()(0,1)*dy;
const float wdy = c.get_warp_c()(1,0)*dx + c.get_warp_c()(1,1)*dy;
const float c_x = c.get_c().x + wdx;
const float c_y = c.get_c().y + wdy;
if(c_x < 0 || c_y < 0 || c_x > img.cols || c_y > img.rows){
return false;
}
}
}
return true;
}
} else {
return false;
}
}
/** \brief Extracts a patch from an image.
*
* @param img - Reference Image.
* @param c - Coordinates of the patch in the reference image (subpixel coordinates possible).
* @param withBorder - If false, the patch object is only initialized with the patch data of the general patch (Patch::patch_).
* If true, the patch object is initialized with both, the patch data of the general patch (Patch::patch_)
* and the patch data of the expanded patch (Patch::patchWithBorder_).
*/
void extractPatchFromImage(const cv::Mat& img,const FeatureCoordinates& c,const bool withBorder = false){
assert(isPatchInFrame(img,c,withBorder));
const int halfpatch_size = patchSize/2+(int)withBorder;
const int refStep = img.step.p[0];
// Get Pointers
uint8_t* img_ptr;
float* patch_ptr;
if(withBorder){
patch_ptr = patchWithBorder_;
} else {
patch_ptr = patch_;
}
if(c.isNearIdentityWarping()){
const int u_r = floor(c.get_c().x);
const int v_r = floor(c.get_c().y);
// compute interpolation weights
const float subpix_x = c.get_c().x-u_r;
const float subpix_y = c.get_c().y-v_r;
const float wTL = (1.0-subpix_x)*(1.0-subpix_y);
const float wTR = subpix_x * (1.0-subpix_y);
const float wBL = (1.0-subpix_x)*subpix_y;
const float wBR = subpix_x * subpix_y;
for(int y=0; y<2*halfpatch_size; ++y){
img_ptr = (uint8_t*) img.data + (v_r+y-halfpatch_size)*refStep + u_r-halfpatch_size;
for(int x=0; x<2*halfpatch_size; ++x, ++img_ptr, ++patch_ptr)
{
*patch_ptr = wTL*img_ptr[0];
if(subpix_x > 0) *patch_ptr += wTR*img_ptr[1];
if(subpix_y > 0) *patch_ptr += wBL*img_ptr[refStep];
if(subpix_x > 0 && subpix_y > 0) *patch_ptr += wBR*img_ptr[refStep+1];
}
}
} else {
for(int y=0; y<2*halfpatch_size; ++y){
for(int x=0; x<2*halfpatch_size; ++x, ++patch_ptr){
const float dx = x - halfpatch_size + 0.5;
const float dy = y - halfpatch_size + 0.5;
const float wdx = c.get_warp_c()(0,0)*dx + c.get_warp_c()(0,1)*dy;
const float wdy = c.get_warp_c()(1,0)*dx + c.get_warp_c()(1,1)*dy;
const float u_pixel = c.get_c().x+wdx - 0.5;
const float v_pixel = c.get_c().y+wdy - 0.5;
const int u_r = floor(u_pixel);
const int v_r = floor(v_pixel);
const float subpix_x = u_pixel-u_r;
const float subpix_y = v_pixel-v_r;
const float wTL = (1.0-subpix_x) * (1.0-subpix_y);
const float wTR = subpix_x * (1.0-subpix_y);
const float wBL = (1.0-subpix_x) * subpix_y;
const float wBR = subpix_x * subpix_y;
img_ptr = (uint8_t*) img.data + v_r*refStep + u_r;
*patch_ptr = wTL*img_ptr[0];
if(subpix_x > 0) *patch_ptr += wTR*img_ptr[1];
if(subpix_y > 0) *patch_ptr += wBL*img_ptr[refStep];
if(subpix_x > 0 && subpix_y > 0) *patch_ptr += wBR*img_ptr[refStep+1];
}
}
}
if(withBorder){
extractPatchFromPatchWithBorder();
}
validGradientParameters_ = false;
}