In a blog comment earlier this summer, someone asked how to find "which labeled regions have a bright spot greater than some threshold?" That's a good question. It can be done efficiently... read more >>

In my August 7th post on upslope area, I showed how to construct and solve the flow matrix to determine the upslope area for every pixel in a digital elevation model (DEM). In addition,... read more >>

I saw an application recently where someone wanted to handle NaNs in an image differently depending on whether they were "interior." In other words, a set of connected NaN pixels... read more >>

One the measurements provided by regionprops is 'Centroid'. Here's an example of labeling binary objects, computing the centroid of each object, and plotting the centroid location on top... read more >>

The functions bwlabel and regionprops are very useful for measuring the properties of shapes in a binary image. There are documentation examples and product demos showing how to do this,... read more >>

I'd like to introduce guest blogger Stan Reeves. Stan is a professor in the Department of Electrical and Computer Engineering at Auburn University. He serves as an associate ... read more >>

About twelve years ago, I was implementing the algorithm that became roifill in the Image Processing Toolbox. In this algorithm, a specified set of pixels is replaced (or filled in) such that... read more >>

Didja know? You can fill holes, or pits, in grayscale images by using the Image Processing Toolbox function imfill. The other day I was rereading the Tarboton paper on upslope area,... read more >>

In March 2006 I wrote about how to overlay a specified color onto specified pixels of a grayscale or RGB image. I put a utility function (imoverlay) for performing this... read more >>

In part 4 of this series I classified DEM plateaus into: ... read more >>