Machine vision: motion tracking

By
[Audio Version]

Following is another in my series of ad hoc journal entries I've been keeping of my thoughts on machine vision.

I was thinking earlier about something related to the head tilting issue. As I was walking around, I tracked stationary points in space. While my sense is of a stable view of the stationary point, I found that my eyes do actually saccade very rapidly and very subtly to keep the target in the center of my fovea. That is, my gaze is not stable.

My gaze does appear to be predictive, though. It seems as I move, my eye comes to predict where the stationary point will be in the next moment and keeps my eyes moving to keep up. It's a little like shooting skeet. You see the clay pigeon emerge from the launcher and continuously adjust your muscles to keep it in your gun's sights. You could close your eyes and keep moving the gun along the predicted trajectory, but as time goes by, the gun will move farther and farther off target.

As a side note, this may help explain why my eyes sometimes get tired when I rock in my seat while working at my computer. The screen's position relative to my eyes is constantly changing. Surely my eyes have to work harder to keep focused on the screen's contents.

Comments

Post a Comment

Popular posts from this blog

Coherence and ambiguities in problem solving

By
Natural Language Processing (NLP) is a big topic. One I come back to again and again when I have time to explore it. Work has kept me very busy. So has moving. In recent months I've returned to the topic. I made some interesting progress constructing an "NLP pipeline". But as anyone who has done NLP work will tell you, English is full of ambiguities. They may tell you about the approaches they take to reduce the ambiguity and be decisive in the end. But the ambiguities persist and can't simply be guessed away. The problem More importantly though. The ambiguities often require us as humans to look across levels of interpretation to resolve. I generally have not found AI researchers offering a good way of doing this though. To illustrate my problem, consider this sentence: Some guys' shoes' laces are red. As someone literate in English you have no problem interpreting it. But odds are good you can guess where the ambiguity lies. Looked at in isolation, each of t
Read more

Neural network in C# with multicore parallelization / MNIST digits demo

By
Image
I've been working for a couple weeks on building my first fully functional artificial neural network (ANN). I'm not blazing any news trails here by doing so. I'm a software engineer. I can barely follow the mathematical explanations of how ANNs work. For the most part I have turned to the source code others have shared online for inspiration. In most cases I've struggled to understand even that, despite programming for a living. Part of the challenge is that more than a few of those demos have surprised me by being nonfunctional. They did something for sure. They just didn't learn anything or perform significantly better than random chance making correct predictions, no matter how many iterations they went through. Or they had bugs that prevented them from working according to the well-worn basic backpropagation algorithm. I mostly worked from C# examples when I could find them. One thing that was a genuine struggle for me to deal with is my sense that they all
Read more

Mechanical finger

By
Image
I'm a bit surprised I never posted about this sooner. When I was in high school, back around 1990, I designed and built prototypes of a human-shaped finger for a robot. At the time there were already some human-shaped mechanical hands, but I was disappointed by their Erector Set bulkiness and openness. I imagined they would pinch human skin and damage all sorts of things humans are used to interacting with. I was trying to think of a way to solve that problem and came up with the idea of constructing a solid finger out of a sandwich of layers of parts. I built a prototype out of balsa wood and then another out of plastic. Below are some pictures I just took of them and the design sketch for the plastic one. I guess I didn't think much of them because, as the years went by, so many great innovations have come about in this area. Still, I think there's merit in this approach. This is incredibly lightweight. The balsa wood one weighs a few grams.  They each weigh
Read more