computes average RGB color rather than perceptual color

[drjasonharrison-vp-eio]

You may want to use Lab, HLS or distance measures to compute the average color.
https://stackoverflow.com/questions/649454/what-is-the-best-way-to-average-two-colors-that-define-a-linear-gradient

[mitjap]

Just transform to linear RGB where you do all the calculations. Then map the final results back to sRGB.
https://en.wikipedia.org/wiki/SRGB#Transformation.

I'm attaching two images. One is black (#000) and white (#FFF) grid which is perceived as light gray when looked at. Other image is gray (#7F7F7F) as calculated by your app. Actual calculated value should be #B4B4B4 or something simmilar. Depend on what gamma value you choose and how strict (accurate) your conversion is.

[drjasonharrison]

Linear RGB is not a uniform perceptual color space. You have a function to transform RGB to HSL, performing the averaging in HSL would be more accurate than using RGB. Also more work as HSL has more boundary conditions.

This answer on StackOverflow has code that you can run in your browser to see the different outcomes of several color averaging algorithms. https://stackoverflow.com/a/73287322/54745