## Happenings – 2012 May 19

Well, the past week has been quiet, in more ways than one.

There have been only 2 earthquakes in my immediate vicinity from last Saturday through yesterday… for the month of May, this brings the total to 10.

I made a little progress on the next regression post – the 1st of 2 about the underlying assumptions – but only a little progress. Actually, I’ve probably got all the mathematics done, but the pieces are still disorganized.

As for rings, I’m not sure whether I’m making progress or going backwards. Well, I’ve pretty much got the theory laid out… and I played with the “abstract algebra” package… and now I’m struggling to figure out what examples to add to the theory.

I did take a quick look through my operations research books to check out their chapters on dynamic programming… they have several interesting problems I could look at… but they weren’t interesting enough to distract me from my current overwhelming list of active topics. I also took a look on the Internet, and I found a published excerpt from Richard Bellman’s autobiography, focusing on the beginnings of dynamic programming.

The main thing I’ve been doing is playing with color. Mathematically my week has been quiet because I wasn’t trying to do a half dozen different things. What I want to show you from chapter 1 of Kang’s “computational color technology” will take only a few paragraphs… but what I decided to do with the illustrative example has already spilled over into a 2nd post.

All I wanted was one example at hand while I looked at Kang’s work, but there were all these things I’ve figured out how to do, and shown you… but I’ve never done all of them in one post.

What I decided to do was to pull together all the things we’ve done so far with a set of tristimulus values. All I needed was one example of computing tristimulus values from a spectrum… but once we have the tristimulus values, we can

• compute the chromaticity coordinates… and display them on the CIE chromaticity chart.
• Convert them to RGB on my monitor… and display the color.
• convert the RGB to HSV on my monitor.
• Display the color on the artists’ color wheel.
• Convert the tristimulus values to CIE lab.

And there were a few other things I played with along the way.

On the up side, I found a way to have Mathematica create a grid of different S,B colors for a fixed hue H – instead of doing it by hand. That, as you might guess, created the picture in this post.

On the down side, I discovered that ColorSync is inconsistent. Yes, I’ll show that to you, too.

And on the edge, I’ve seen that computing complementary colors leads to significantly different results, depending on how we do it. I wasn’t really surprised… I guess I knew I would be opening a can of worms.

And that’s enough chatter for this week.

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