I think this actually works posting in case it's useful to someone.

24-0313-color-tracking-3.pd

Both the red and blue objects show up as highly saturated (bottom left). Bottom right shows the hue values, "pix_curve"-d so that only a narrow range of colors comes through strongly: there are two saturated spots, but only the left-hand one (blue) comes through.

No attempt to clean up the background in this version, but this already does a good chunk of it.

hjh

Nice!
What's the use of [pix_offset] here?
I also found [pix_colorclassify] that could be helpful to separate channels easily

@60hz said:

What's the use of [pix_offset] here?

Currently not used. (I thought I deleted it, oops.)

It could be used for one case, though: red seems to be at the end of the hue cycle, 0 and 1. The current approach will match either slightly-yellowish or slightly-purplish reds, but not both in one range. I think (but haven't tested) you could put "0.5 0 0" into pix_offset's right inlet, shifting red away from the wraparound boundary, and then match a continuous range of reds (by pretending they're a different color).

I also found [pix_colorclassify] that could be helpful to separate channels easily

I tried it but found the results difficult to interpret. If you colorclassify and then extract the red channel, it will be sensitive to yellows as well (and there's that brown for "uncertain" which shows up also in all channels).

hjh