In this tutorial, you will learn how to compute image histograms using OpenCV and the cv2.calcHist function. Histograms are prevalent in nearly every aspect of computer vision. We use grayscale histograms for thresholding. We use histograms for white balancing. We…

In this tutorial, you will learn how to perform automatic color correction with OpenCV using a color matching/balancing card. Last week we discovered how to perform histogram matching. Using histogram matching, we can take the color distribution of one image…

In this tutorial, you will learn how to perform histogram matching using OpenCV and scikit-image. Last week we discussed histogram equalization, a basic image processing technique that can improve the contrast of an input image. But what if you wanted…

In this tutorial, you will learn to perform both histogram equalization and adaptive histogram equalization with OpenCV. Histogram equalization is a basic image processing technique that adjusts the global contrast of an image by updating the image histogram’s pixel intensity…

Let’s face it. Trying to search for images based on text and tags sucks. Whether you are tagging and categorizing your personal images, searching for stock photos for your company website, or simply trying to find the right image for…

So you’ve extracted color histograms from a set of images… But how are you going to compare them for similarity? You’ll need a distance function to handle that. But which one? How you choose? And how do you compare histograms…