scratch/check_green.py

from PIL import Image

img = Image.open("scratch/tmp/frame_last.jpg")
img = img.convert("RGB")
w, h = img.size
green_count = 0
for x in range(w):
    for y in range(h):
        r, g, b = img.getpixel((x, y))
        if g > 200 and r < 50 and b < 50:
            green_count += 1
print(f"Green ratio: {green_count / (w*h):.2f}")