Gabor的核函数参考的wiki
使用实数Real的公式计算核函数代码：
Mat getGaborFilter(float lambda, float theta, float sigma2,float gamma, float psi = 0.0f){if(abs(lambda-0.0f)<1e-6){lambda = 1.0f;} float sigma_x = sigma2;float sigma_y = sigma2/(gamma*gamma);int nstds = 3;float sqrt_sigma_x = sqrt(sigma_x);float sqrt_sigma_y = sqrt(sigma_y);int xmax = max(abs(nstds*sqrt_sigma_x*cos(theta)),abs(nstds*sqrt_sigma_y*sin(theta)));int ymax = max(abs(nstds*sqrt_sigma_x*sin(theta)),abs(nstds*sqrt_sigma_y*cos(theta)));int half_filter_size = xmax>ymax ? xmax:ymax;int filter_size = 2*half_filter_size+1;Mat gaber = Mat::zeros(filter_size,filter_size,CV_32F);for(int i=0;i<filter_size;i++){float* f = gaber.ptr<float>(i);for(int j=0;j<filter_size;j++){int x = j-half_filter_size;int y = i-half_filter_size;float x_theta=x*cos(theta)+y*sin(theta);float y_theta=-x*sin(theta)+y*cos(theta);f[x] = exp(-.5*(x_theta*x_theta/sigma_x+y_theta*y_theta/sigma_y));f[x] = f[x]*cos(2*PI*x_theta/lambda+psi);};}return gaber;
}使用得到的Gabor核对一副图像进行卷积的函数：
Mat gaborFilter(Mat& img, Mat& filter){int half_filter_size = (max(filter.rows,filter.cols)-1)/2;Mat filtered_img(img.rows,img.cols,CV_32F);for(int i=0;i<img.rows;i++){uchar* img_p = img.ptr<uchar>(i);float* img_f = filtered_img.ptr<float>(i);for(int j=0;j<img.cols;j++){float filter_value = 0.0f;for(int fi=0;fi<filter.rows;fi++){float* f = filter.ptr<float>(fi);int img_i = i+fi-half_filter_size;img_i = img_i < 0 ? 0 : img_i;img_i = img_i >= img.rows ? (img.rows-1) : img_i;uchar* p = img.ptr<uchar>(img_i);for(int fj=0;fj<filter.cols;fj++){int img_j = j+fj-half_filter_size;img_j = img_j < 0 ? 0 : img_j;img_j = (img_j >= img.cols) ? (img.cols-1) : img_j;float tmp = (float)p[img_j]*f[fj];filter_value += tmp;}}img_f[j] = filter_value;}}return filtered_img;
}对一幅图使用如下核卷积：
Mat gaber = getGaborFilter(0.3,0,4,2);
Gabor算子卷积之后得到很多负值（不知道有没有问题），后面的图是归一化之后显示出来的。
Mat normalizeFilterShow(Mat gaber){Mat gaber_show = Mat::zeros(gaber.rows,gaber.cols,CV_8UC1);float gaber_max = FLT_MIN;float gaber_min = FLT_MAX;for(int i=0;i<gaber.rows;i++){float* f = gaber.ptr<float>(i);for(int j=0;j<gaber.cols;j++){if(f[j]>gaber_max){gaber_max = f[j];}if(f[j]<gaber_min){gaber_min = f[j];}}}float gaber_max_min = gaber_max-gaber_min;for(int i=0;i<gaber_show.rows;i++){uchar* p = gaber_show.ptr<uchar>(i);float* f = gaber.ptr<float>(i);for(int j=0;j<gaber_show.cols;j++){if(gaber_max_min!=0.0f){float tmp = (f[j]-gaber_min)*255.0f/gaber_max_min;p[j] = (uchar)tmp;}else{p[j] = 255;}}}return gaber_show;
}
