Check Color

A simple visual detection method is to check the color of a region of the image. See this topic on how to get a region of the image.

We use image_stats() to extract color stats from an image. An example usage is in PokemonBDSP_MenuDetector.cpp. image_stats() returns a struct ImageStats that stores average per-pixel color, pixel color stddev and pixel count on this image. Then it calls is_white() declared in SolidColorTest.h to check whether the stats reflect the image is all white.

We also commonly use is_solid() in SolidColorTest.h to check whether the image is full of a particular color. For example you can check PokemonLA_DialogDetector.cpp.

Determine Color Thresholds

When doing color check, you need to set thresholds in is_solid() and other functions, like what is the maximum color deviation that can still pass the check. You can first collect a few test images by taking screenshots using the screenshot button on the SerialPrograms executable. Pick some thresholds to pass all your test images. You can add command line tests (See its topic) to run color detection on images directly without temporarily hardcoding tests.

Finally, keep the thresholds a little higher than needed on your test images so that users with different capture card color distortions than yours can still pass the check.

Color Values

We have a Color class in Color.h to represent a 32-bit-precision ARGB pixel color. Each color channel precision is 8-bit uint8. The data in Color is stored as a uint32_t. Some of our color-related functions also take uint32_t as color inputs. See combine_argb() and combine_rgb() in Color.h to know how individual A, R, G, B values form a uint32_t.