cv :: findContours正在修改源图像OpenCV 2.3 [英] cv::findContours is modifying source image OpenCV 2.3

问题描述

从OpenCV文档中，cv :: findContours中的源图像被视为 const ，但我的应用程序正在发生一些奇怪的事情。我正在使用cv :: inRange函数来获取特定颜色的阈值图像，然后，使用cv :: moments，我可以在阈值图像中获得白色像素的中心，这是正常的。

From OpenCV documentation, source image in cv::findContours is aquired as const, but something strange is going on with my application. I'm using cv::inRange function to get thresholded image over specific color, and after that, using cv::moments, I can get the center of white pixels in thresholded image and this is working ok.

此外，我想实现用于寻找最大轮廓并在该轮廓中定位中心力矩的代码。在代码中添加了cv :: findContours之后，我在输出中发现了奇怪的行为，之后我想使用以下代码检查源图像的内容：

In addition, I would like to implement the code for finding biggest contour and locating central moment in that contour. After adding just cv::findContours in the code, I spotted strange behavior in the output and after that I wanted to check what is going on with source image using this code:

cv::Mat contourImage;
threshedImage.copyTo(contourImage); // threshedImage is the output from inRange
cv::findContours(threshedImage, contours, CV_RETR_LIST, CV_CHAIN_APPROX_NONE, cv::Point(0,0));
cv::Mat temp;
cv::absdiff(threshedImage,contourOutput, temp);
cv::namedWindow("absdiff");
cv::imshow("absdiff",temp);

此后，输出显示threshedImage和contourImage之间存在差异。这怎么可能？有没有人对cv :: findContours有类似的结果？

After this, output is showing that there is a difference between threshedImage and contourImage. How this is possible? Does anyone have similar results with cv::findContours?

推荐答案

错误！ 文档明确指出：

源图像由此函数修改。

所以如果你需要原始图像完整，制作此图像的副本并将副本传递给 cv :: findContours（）。

So if you need the original image intact, make a copy of this image and pass the copy to cv::findContours().

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