OpenCV4.5 报错error：‘ CV_* ’was not declared in this scope 解决解决办法总结

在学习视觉SLAM十四讲过程中，好多地方的opencv需要更改，查阅了一些资料，在这里做一下总结

1. CV_LOAD_IMAGE_UNCHANGED和CV_LOAD_IMAGE_COLOR

错误内容：

‘CV_LOAD_IMAGE_UNCHANGED‘ : undeclared identifier
error: ‘CV_LOAD_IMAGE_COLOR’ was not declared in this scope

解决办法：

//添加头文件
#include "opencv2/imgcodecs/legacy/constants_c.h" 

2. CV_AA

错误内容：

error: ‘CV_AA’ was not declared in this scope

解决办法：

//添加头文件
#include 

3. CV_CALIB_CB_ADAPTIVE_THRESH

错误内容：

error: ‘CV_CALIB_CB_ADAPTIVE_THRESH’ was not declared in this scope

解决办法：

//添加头文件
 #include 

4. CV_GRAY2BGR

错误内容：

error: ‘CV_GRAY2BGR’ was not declared in this scope

解决办法：

1. 更改代码

//代码改为
cv::COLOR_GRAY2BGR

2. 添加头文件

//添加头文件
#include 

5. CV_THRESH_BINARY_INV / CV_CHAIN_APPROX_SIMPLE / CV_RETR_CCOMP / CV_FONT_HERSHEY_SIMPLEX

错误内容：

error: ‘CV_THRESH_BINARY_INV’ was not declared in this scope
error: ‘CV_CHAIN_APPROX_SIMPLE’ was not declared in this scope
error: ‘CV_RETR_CCOMP’ was not declared in this scope
error: ‘CV_FONT_HERSHEY_SIMPLEX’ was not declared in this scope

解决办法：

//代码改为
cv::THRESH_BINARY_INV
cv::CHAIN_APPROX_SIMPLE
cv::RETR_CCOMP
cv::FONT_HERSHEY_SIMPLEX

6. CV_LOAD_IMAGE_GRAYSCALE

错误内容：

error: ‘CV_LOAD_IMAGE_GRAYSCALE’ was not declared in this scope

解决办法：

//代码改为
cv::IMREAD_COLOR

7. CV_FM_8POINT

错误内容：

error: ‘CV_FM_8POINT’ was not declared in this scope

解决办法：

1. 更改代码

//更改前
CV_FM_8POINTT
//更改后
FM_8POINT

2. 添加头文件

#include