I have just done something similar using opencv.js on esp32, I tried to do it on an amb82-mini, but I couldn’t find a way of filtering the image. the the amb82 is much better in just about every way other than software support. it would be nice if opencv.js worked, its basically just serving a webpage so i dont see why it wouldnt as all the processing is done on the browser.
im using a modified version of this, it uses an rgb filter to track a colour range, the tracking range changes based on how wide the path it detects is and how close it gets to the edge of the screen. then tracks the centre of that mass and steers towards it.