Change value of a variable based off of greyscale texture's luminosity.

Hello, I’ve been looking around and I haven’t been able to find anyone else having asked a question akin to this.

Is it possible, within Blueprints, to not only look at a specific set of greyscaled texture maps, but also use the luminosity of the closest averaged pixels to alter a variable? All of the assets with these texture maps would be pre-made, not procedural.

The end-goal would be to paint heat maps for characters and environment assets (Not a standard Heat-map, but a greyscaled, predetermined, “Heat level” texture map) The luminosity of the closest pixels/ averaged pixels to the User’s body would determine the heat of that section of the asset. After reaching a certain point, the User would catch fire. The luminosity/ brightness of that area of the texture would act as a multiplier for the temperature increase.