Update BoxFilter.cpp

Author: BBuf

ImageFiltering/Box Filter.cpp

@@ -0,0 +1,90 @@
+#include "opencv2/opencv.hpp"
+#include "iostream"
+#include "algorithm"
+#include "vector"
+#include "stdio.h"
+using namespace std;
+using namespace cv;
+
+void BoxFilter(const Mat &src, Mat &dst, int ksize){
+    CV_Assert(src.channels()==1 || src.channels() == 3); //只处理单通道或者三通道图像
+    //生成一维的
+    double *matrix = new double[ksize];
+    double sum = 0;
+    int origin = ksize / 2;
+    for(int i = 0; i < ksize; i++){
+        double g =1.0;
+        sum += g;
+        matrix[i] = g;
+    }
+    for(int i = 0; i < ksize; i++) matrix[i] /= sum;
+    int border = ksize / 2;
+    copyMakeBorder(src, dst, border, border, border, border, BORDER_CONSTANT);
+    int channels = dst.channels();
+    int rows = dst.rows - border;
+    int cols = dst.cols - border;
+    //水平方向
+    for(int i = border; i < rows; i++){
+        for(int j = border; j < cols; j++){
+            double sum[3] = {0};
+            for(int k = -border; k<=border; k++){
+                if(channels == 1){
+                    sum[0] += matrix[border + k] * dst.at<uchar>(i, j+k);
+                }else if(channels == 3){
+                    Vec3b rgb = dst.at<Vec3b>(i, j+k);
+                    sum[0] += matrix[border+k] * rgb[0];
+                    sum[1] += matrix[border+k] * rgb[1];
+                    sum[2] += matrix[border+k] * rgb[2];
+                }
+            }
+            for(int k = 0; k < channels; k++){
+                if(sum[k] < 0) sum[k] = 0;
+                else if(sum[k] > 255) sum[k] = 255;
+            }
+            if(channels == 1)
+                dst.at<Vec3b>(i, j) = static_cast<uchar>(sum[0]);
+            else if(channels == 3){
+                Vec3b rgb = {static_cast<uchar>(sum[0]), static_cast<uchar>(sum[1]), static_cast<uchar>(sum[2])};
+                dst.at<Vec3b>(i, j) = rgb;
+            }
+        }
+    }
+    //竖直方向
+    for(int i = border; i < rows; i++){
+        for(int j = border; j < cols; j++){
+            double sum[3] = {0};
+            for(int k = -border; k<=border; k++){
+                if(channels == 1){
+                    sum[0] += matrix[border + k] * dst.at<uchar>(i+k, j);
+                }else if(channels == 3){
+                    Vec3b rgb = dst.at<Vec3b>(i+k, j);
+                    sum[0] += matrix[border+k] * rgb[0];
+                    sum[1] += matrix[border+k] * rgb[1];
+                    sum[2] += matrix[border+k] * rgb[2];
+                }
+            }
+            for(int k = 0; k < channels; k++){
+                if(sum[k] < 0) sum[k] = 0;
+                else if(sum[k] > 255) sum[k] = 255;
+            }
+            if(channels == 1)
+                dst.at<Vec3b>(i, j) = static_cast<uchar>(sum[0]);
+            else if(channels == 3){
+                Vec3b rgb = {static_cast<uchar>(sum[0]), static_cast<uchar>(sum[1]), static_cast<uchar>(sum[2])};
+                dst.at<Vec3b>(i, j) = rgb;
+            }
+        }
+    }
+    delete [] matrix;
+}
+
+int main(){
+    Mat src = imread("../beauty.jpg");
+    Mat dst(src.rows, src.cols, CV_8UC3);
+    BoxFilter(src, dst, 5);
+    imshow("origin", src);
+    imshow("origin", dst);
+    waitKey(0);
+    imwrite("../result.jpg", dst);
+    return 0;
+}

ImageFiltering/README.md

@@ -4,3 +4,4 @@
 - Gaussian Filter.cpp C++实现了高斯滤波，支持一个通道和3个通道的高斯滤波。原理请看：https://blog.csdn.net/just_sort/article/details/84305585
 - Guided Filter.cpp C++实现了何凯明提出的引导滤波，可以用于暗通道去雾加速。原理请看：https://blog.csdn.net/just_sort/article/details/84324239
 - BilateralFilter.cpp C++实现了双边滤波，在滤除噪声的同时可以对原图的边缘细节进行保留。原理请看：https://blog.csdn.net/just_sort/article/details/84957533
+- BoxFilter.cpp C++实现了方框滤波(盒滤波)，用于平滑图像。原理为滤波器值全为(1/滤波器元素个数)在原图进行滑动。