Hi, can somebody tell me how to create a histogram from a table of values instead from a image?
I want to compare a histogram with a pattern of a gaussian function with some images.
Greetings
You can create a matrix from you "table of values" and then call cv::calcHist on this matrix, because OpenCV can build histograms for CV_8U and CV_32F types. Here is how you can create a matrix from an array of floats:
float* Idata=new float[480*640*3];
Mat I(480, 640, CV_32FC3, Idata);
More examples in the OpenCV Cheatsheet. And you can always build a Mat on top of std::vector.
Oh, I thought there is some method to create histogram which based on some datas for the bins. (a table from 0-255 with values from 0.0 to 1.0)
not sure if this was what you were asking about with the bins but you can specify whether to have either uniform of custom bins, as a flag in the cv::calcHist method. Then you just input a float array with the lowest inclusive value(will be included), then all of the top exclusive boundaries of your bins(so that bin will not include values from that value).
i.e: float exampleArray[] = {0, 100, 256};
So this will have two bins, the first from 0-99 and the second from 100-255.
Also remember to input the correct number of bins and the non-uniform flag in the cv::calcHist method.
Hope this helps you or others with similar problems.
Asked: 2012-09-29 15:37:36 -0600
Seen: 442 times
Last updated: Sep 30 '12
