[Greg McKaskle]

Since the LEDs are very bright and very small, the auto-exposure algorithms tend to overlook them and collect too much light in those areas. The result is that the LEDs that look yellow to your eyes will appear white on the computer screen. You can adjust the exposure by lowering the brightness parameter or manually calibrating the exposure. You may then be able to see the yellow LEDs using the camera, but at that point the rest of the image will be quite dark.

If you can set the exposure low enough, you can process it based on the color of yellow detected by the camera. Another approach is to process it using the brightness and ignore color.

As mentioned, this is certainly a valid way to look for the target. It doesn't require a ring light, but since you don't provide the light, you will likely find it to be less robust. But by all means, experiment.

Greg McKaskle