Good Morning from my Robotics Lab! This is Shadow_8472, and today, I’m working on my Raspberry Pi again to make it chase cats off counters. Let’s get started.
A lot has happened this week, yet it feels like not enough. I had a Python script running OpenCV from the command line last week, and this week, I’ve started work on the dynamic background.
I’d have to say I’m not quite a third of the way to this smaller goal, but in terms of required research, I should be finished with it next week.
Right now, I have the pseudocode for this part of the project, as well as a demo highlighting the difference between the last two frames. To get to that point, I had to buffer frames to a two-frame queue, then compare them.
It is not fun when you have an error search engines don’t recognize. “Src1 is not a valid numerical tuple.” Long story short, it was the way Python arrays work. They need to be declared, then each element, or a placeholder element added. Somehow, after giving up for the night, I halfheartedly tinkered with swapping the order of comparison, and it followed the same element. I traced the bug back through my IO function, and got a buffered video feed.
The other exciting thing was finding the comparison function. The buffer has a pointer to say which is the more recent frame, and reading the most recent frame is fine, but the trick here is to highlight what’s new and changed this frame. It took a bit to find that function, and I played with a few bitwise operators I found next to it. One strangely affected the “raw footage,” and ended up strobing. I had to slow the framerate on that one to see it was inverting everything each frame.
The very next thing to do is to boost those frames to all white, but I haven’t found how to do that yet. After that, I need to figure out how to extract the resolution and get the demo working in low resolution mode by scaling the width and height down by an integer.
With a scaled down resolution, I should be able to build a heatmap as a countdown timer until areas fade into the background. Once I have all that working, I can start researching again for spawning a second thread and analysing the full resolution picture for naughty felines.
Final Question: How many more weekly parts should it take before I have my first working prototype?