I define an array of 2 values, and try to use the imgproc module's resize function to resize it to 10 elements with linear interpolation as interpolation method.
cv::Mat input = cv::Mat(1, 2, CV_32F);
input.at<float>(0, 0) = 0.f;
input.at<float>(0, 1) = 1.f;
cv::Mat output = cv::Mat(1, 11, CV_32F);
cv::resize(input, output, output.size(), 0, 0, cv::INTER_LINEAR);
for(int i=0; i<11; ++i)
{
std::cout<< output.at<float>(0, i) << " ";
}
The output I would have expected is:
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
What I get however is:
0 0 0 0.136364 0.318182 0.5 0.681818 0.863636 1 1 1
Clearly, my understanding of how resize works is wrong at a fundamental level. Can someone please tell me what I am doing wrong? Admittedly, OpenCV is an overkill for such simple linear interpolation, but please do help me with what is wrong here.
It's really simple. OpenCV is an image processing library. So you should remember that we are working on images.
Take a look at the output when we have only 8 pixels in destination image
0 0 0.125 0.375 0.625 0.875 1 1
If you take a look at this image it's very straightforward to understand resize behaviour
As you can see in this link you're using a Image transformation library: "The functions in this section perform various geometrical transformations of 2D images"
You want this results
but it will not interpolate properly the original 2 pixels image
来源：https://stackoverflow.com/questions/18104609/interpolating-1-dimensional-array-using-opencv