This is the first of several blogs about the algorithm behind poly2mask and roipoly. poly2mask takes a set of polygon vertices and produces a binary mask image. The binary mask has 1s for... read more >>

Last time I showed off custom data cursors with a little utility function that displays object labels as data cursors: My code used label2rgb to display a "colorized" label... read more >>

A post in comp.soft-sys.matlab this week (see the third post in this thread) asked how to display graphically the numerical labels associated with each labeled object. In this blog I'll show a... read more >>

Reader JP asked me about my recent blog post on the Hough transform. Specifically, she wanted to know exactly how the rho-theta coordinate system was defined. When I answered her question, ... read more >>

Image display was added in version 4 of MATLAB, sometime around 1990. Many observant users noticed that the low-level image display object had default pixel values. In other... read more >>

The morphological operator dilation acts like a local maximum operator. Erosion acts like a local minimum operator. You can use them together to compute something called the... read more >>

Someone here recently puzzled over the output of the Hough transform functions in the Image Processing Toolbox. The Hough transform is used to detect line segments, typically in binary... read more >>

Thanks to Kimo Johnson and Perttu Ranta-aho for responding to my custom spatial transformation challenge. Contents Kimo's submission ... read more >>

Blog reader David A. asked me a while back about how to transform an image based on some mathematical function. For example, the online paper "Visualizing complex analytic functions... read more >>

The function imtransform has several optional parameters that allow you to fine-tune its behavior. Today's topic is about the parameters that let you control where the input... read more >>