如何在 python 中检测 png 中某些像素的 rgb 值？

Question

My code takes a screenshot, (should) test if any of the pixels in the screenshot are a general rgb value (in my example they are in the range of: r_min, r_max and g_min, g_max. Also, the end_time is there to make sure that there is enough time to scan all the pixels, since it will then screenshot another photo, and check for the pixels in the other one, until it finds the specific pixels, after that, it changes the value of variable (fish_found) from 0 to 1, and gets through the if statement.

This is the code that I came up with:

    fish_found = 0
    im = screenshot('check.png')
    def find_fish(image_name):

        r_min = 140
        r_max = 190
        g_min = 85
        g_max = 185
        fish_found = 0
        img = Image.open(image_name)
        rgb = img.convert('RGB')
        for x in range(img.size[0]):
            for y in range(img.size[1]):
                r, g, b = rgb.getpixel((x, y))
                if r >= r_min and r <= r_max and g >= g_min and g <= g_max:
                    fish_found = fish_found + 1

    while True:
        im = screenshot('check.png', region=(990,415,20,20))
        end_time = datetime.now() + timedelta(seconds=0.5)
        while datetime.now() < end_time:
            find_fish('check.png')
        print(fish_found)
        if fish_found > 0:
            print("You found a fish")

Answer 1

Okay, update for anyone needing it: the whole code was a mess, and I found a better way to find out if the pixels match:

def function():
    pic = screenshot('screen.png', region=(985, 420, 30, 30))
    width, height = pic.size

    for x in range(0, width, 2):
        #modify the last digit to take greater steps, if you don't want to check every 
        #pixel
        for y in range(0, height, 2):
            #same thing, change the 2 to any value you want

            r, g, b = pic.getpixel((x, y))
            #this gets the actual rgb value of the pixel

            if r in range(250, 256) and g in range(195, 215) and b in range(28, 38):
                #put the range of values of r g b up here ^
                #down here you place your code (after you find out if they match, what do 
                #you do should be right here.
#after all of that, just call your function when you want to.
function()