opencv c++灰度图像阈值处理
时间: 2024-09-30 11:00:54 浏览: 44
在OpenCV库中,C++处理灰度图像的阈值操作通常涉及以下几个步骤:
1. **读取图像**:首先,你需要使用`cv::imread()`函数从文件或内存中加载灰度图像。例如:
```cpp
cv::Mat grayImage = cv::imread("gray_image.jpg", cv::IMREAD_GRAYSCALE);
```
2. **设置阈值**:你可以使用`cv::threshold()`函数对图像进行二值化。这个函数需要输入图像、输出图像、阈值范围以及阈值选择的方式(如高于阈值设为白色,低于设为黑色):
```cpp
cv::Mat binaryImage;
cv::threshold(grayImage, binaryImage, thresholdValue, 255, cv::THRESH_BINARY | cv::THRESH_OTSU); // 自动计算最佳阈值
```
这里的`cv::THRESH_BINARY`表示二进制阈值分割,`cv::THRESH_OTSU`则用于自动确定最佳阈值。
3. **结果分析**:处理后的`binaryImage`是一个二值图像,其中像素值要么是0(黑),要么是255(白)。你可以进一步分析这个图像,比如边缘检测或形状识别。
相关问题
实现灰度图像和彩色图像的迭代阈值分割算法opencv c++代码实现
以下是基于OpenCV的灰度图像和彩色图像迭代阈值分割算法的C++代码实现:
灰度图像迭代阈值分割:
```cpp
#include <opencv2/opencv.hpp>
#include <iostream>
using namespace cv;
using namespace std;
double thresholdValue(Mat& img) {
double T = 0;
double T_last = -1;
int rows = img.rows;
int cols = img.cols;
int total = rows * cols;
while(abs(T - T_last) > 1) {
double sum1 = 0, sum2 = 0, count1 = 0, count2 = 0;
for(int i = 0; i < rows; ++i) {
for(int j = 0; j < cols; ++j) {
if(img.at<uchar>(i, j) > T) {
sum1 += img.at<uchar>(i, j);
count1++;
} else {
sum2 += img.at<uchar>(i, j);
count2++;
}
}
}
T_last = T;
T = (sum1 / count1 + sum2 / count2) / 2;
}
return T;
}
int main() {
Mat img = imread("lena.jpg", IMREAD_GRAYSCALE);
if(img.empty()) {
cout << "Could not read the image" << endl;
return -1;
}
double T = thresholdValue(img);
Mat dst;
threshold(img, dst, T, 255, THRESH_BINARY);
namedWindow("Original Image", WINDOW_NORMAL);
namedWindow("Thresholded Image", WINDOW_NORMAL);
imshow("Original Image", img);
imshow("Thresholded Image", dst);
waitKey(0);
return 0;
}
```
彩色图像迭代阈值分割:
```cpp
#include <opencv2/opencv.hpp>
#include <iostream>
using namespace cv;
using namespace std;
double thresholdValue(Mat& img) {
double T = 0;
double T_last = -1;
int rows = img.rows;
int cols = img.cols;
int total = rows * cols;
while(abs(T - T_last) > 1) {
double sum1 = 0, sum2 = 0, count1 = 0, count2 = 0;
for(int i = 0; i < rows; ++i) {
for(int j = 0; j < cols; ++j) {
Vec3b pixel = img.at<Vec3b>(i, j);
int gray = (pixel[0] + pixel[1] + pixel[2]) / 3;
if(gray > T) {
sum1 += gray;
count1++;
} else {
sum2 += gray;
count2++;
}
}
}
T_last = T;
T = (sum1 / count1 + sum2 / count2) / 2;
}
return T;
}
int main() {
Mat img = imread("lena.jpg");
if(img.empty()) {
cout << "Could not read the image" << endl;
return -1;
}
double T = thresholdValue(img);
Mat dst;
cvtColor(img, dst, COLOR_BGR2GRAY);
threshold(dst, dst, T, 255, THRESH_BINARY);
namedWindow("Original Image", WINDOW_NORMAL);
namedWindow("Thresholded Image", WINDOW_NORMAL);
imshow("Original Image", img);
imshow("Thresholded Image", dst);
waitKey(0);
return 0;
}
```
opencv C++ OTSU阈值分割
以下是使用OpenCV C++实现OTSU阈值分割的示例代码:
```cpp
#include <opencv2/opencv.hpp>
int main()
{
// 读取图像
cv::Mat image = cv::imread("image.jpg", cv::IMREAD_GRAYSCALE);
// 应用OTSU阈值分割
cv::Mat binary;
cv::threshold(image, binary, 0, 255, cv::THRESH_BINARY | cv::THRESH_OTSU);
// 显示结果
cv::imshow("Original Image", image);
cv::imshow("OTSU Thresholding", binary);
cv::waitKey(0);
return 0;
}
```
这段代码首先使用`imread`函数读取一张灰度图像,然后使用`threshold`函数应用OTSU阈值分割。最后,使用`imshow`函数显示原始图像和OTSU阈值分割结果。
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