the last word

I’m working on material for a presentation this weekend — more on that in a future post — and I decided to print this slit-scan sunset image: But when I looked at it closely, I saw some artifacts near the horizon: I figured the Matlab one-dimensional averaging code that I created for the succulents pictures… [Read More]

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]