OpenCV写入参数读取访问冲突

Question

A very simple question...why am I getting a read access violation error with this code?

cv::Mat laserSpeckle = Mat::zeros(100,100,CV_8UC1);
imwrite( "C://testimage.jpg", laserSpeckle );

When i attach a debugger and look into it further, it throws the exception at this snippet in grfmt.cpp.

if( params[i] == CV_IMWRITE_JPEG_QUALITY )
        {
            quality = params[i+1];
            quality = MIN(MAX(quality, 0), 100);
        }

It occurs with .png and .tiff too. Im an OpenCV newbie, my apologies if this is something really simple. I am using Qt for what its worth.

Answer 1

Do you build OpenCV yourself? If yes, make sure that the option WITH_JPEG is enabled when you configure your build files:

cmake ... -DWITH_JPEG=ON ...

Answer 2

It should work with bmp format:

cv::Mat laserSpeckle = cv::Mat::zeros(100,100,CV_8UC1);
cv::imwrite( "C://testimage.bmp", laserSpeckle );

Your code also works on my computer. However, it seems that on some systems it works only for bmp images. I saw similar issues reported here and here .

Answer 3

If you want to save image with alpha channel you should use png format. It is described here

Answer 4

问题出在调试器 版本 （x64）上，如果您使用发行 版 （x64）生成代码，则对我来说效果很好。

Answer 5

在我的情况下，c ++代码生成设置错误，应该是多线程调试dll MD