I believe it’s a “rate of change” from pixel to pixel. Which is why it triggers on the car and any light reflections within the detection zone, moving much faster than your neighbor across the FOV.
Regardless of whether I’m right technically, or whether either of us truly understands, I guess it comes down to whether you have the ability to move your device or not. You may. Or you may choose not to. If that’s the case, this probably is demonstrably not a product that will work for your application. I hope you’re able to get what you need somewhere. I’ve got 18 of them in an array and another 16 in an array at a commercial location, and have already worked through lots of what you’ve described. So these suggestions are based on experienced application. And a few years working the bugs out. Also, I do coding professionally, and optics semi-professionally.
Not everyone is able to choose their camera location optimally. I hope you’re able to find something that works for you. Merry Christmas, and best wishes.