image-processing - 查找轮廓错误 'support only 8uC1 images'

Question

尝试在二进制图像上运行 findContours”

Mat conv(image.size(), CV_8U);
image.convertTo(conv, CV_8U);
vector<vector<cv::Point> > contours;

findContours(conv, contours, CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE);

引发错误:

OpenCV Error: Unsupported format or combination of formats ([Start]FindContours support only 8uC1 images) in cvStartFindContours, 

有什么想法吗？谢谢

Answer 1

来自 the documentation :

C++: void Mat::convertTo(OutputArray m, int rtype, double alpha=1, double beta=0 ) const
Parameters:

rtype – desired output matrix type or, rather, the depth since the number ofchannels are the same as the input has; if rtype is negative, the output matrix will have the same type as the input.

您看到 convertTo 没有改变 channel 数，这意味着您很可能获得 3 个 channel (r、g 和 b)。但是 findContours 需要单色图像。

您需要将图像转换为黑白图像:

cv::Mat bwImage;
cv::cvtColor(image, bwImage, CV_RGB2GRAY);
vector< vector<cv::Point> > contours;
cv::findContours(bwImage, contours, CV_RETR_LIST, CV_CHAIN_APPROX_SIMPLE);