Archives for 2014

My silence over the last few days has not been because I’m on vacation. On the contrary, I’ve been really busy figuring out how to process the succulent slit-scan images. Doing it all in Matlab offers the most flexibility, but there’s not much interactivity. I create a set of parameters, process a bunch of images… [Read More]

In the last couple of posts, I talked about how to smooth slit-scan photographs in the time direction. For the time being, I consider that a solved problem, at least for the succulents images. These images require a lot of sharpening, because the subject has a lot of low-contrast areas there’s a lot of diffraction,… [Read More]

Median filtering is computationally intensive at large extents, and Matlab is poor at parallelizing this operation. Here’s a graph of some timings for one-dimensional filtering of a 6000×56000 pixel image using both median filtering and averaging with a block filter of the same size as the median filter’s extent: I did a series of analyses… [Read More]

In yesterday’s post, I downsampled images successively, a factor of two at each step, in an attempt to get averaging at the same time. I was working with the images today, and it didn’t look like I was getting the desired effect. Then it hit me. I was doing exactly the wrong thing. Downsamping by… [Read More]

As many of you know, I’ve been doing slit scans of plants, and I’ve been struggling with image artifacts due to subject motion. In the past few days I’ve been working on a Matlab program to deal with the artifacts and at the same time assemble several images into a complete, visually seamless composite. In… [Read More]