I really need to pin down what the yinrih's range of visible frequencies is. They have a concept of light and dark, so they shouldn't be able to see microwaves, since most things above absolute zero radiate in that range or above. They can see body heat, so infrared is visible. There are formulas for finding out the frequency range emitted by an object given its temperature. I should probably mess around with those.
Using Wien's law and assuming the object is a blackbody with a temperature of 37 Celsius (average human body temp), the wavelength it radiates the strongest is 78.32 micrometers, or 3.828 terahertz.
Oops, humans radiate at around 12 micrometers after accounting for skin temp and losses due to clothing. Let's assume yinrih are similar, with fur serving instead of clothes. I never did establish any lore regarding the upper end of yinrih vision other than giving rough numbers, and I have a ton of lore about yinrih seeing below the human visible range. Let's say they can see down to 12 micrometers on the low end and 315 nanometers on the high end, so they can see body heat emitted by warm-blooded animals up to UV-A radiation, since UV-A isn't blocked by the ozone layer.
If we assume a single pair of bandpass membranes covers a fourth of that range, that still over four times the size of the human visible spectrum, so let's say neural signal processing takes care of that. They have more granular control over where and how wide this secondary passband is.
I've depicted yinrih with their eyes fully open as often as not, exposing their black nantenna patches. Their vision would appear as a blown-out image, so let's say that when a yinrih does this they rely on other senses. It isn't painful for them but it does make them effectively blind.
The visual qualia they experience ends up having properties akin to human color, but the perceived color of an object shifts along with the visual passband. If they look at an object that's brightest outside their current passband, it appears gray or black.
Color words in yinrih language are all analogies to objects so colored, and those objects may look very different to them than to us. Tod's red fur appears similar to the color of a redfruit (either the good or poisonous kind), but probably doesn't look red in the same way humans would regard red. It just happens that Tod's fur and the redfruit appear red when viewed with human eyes.