Why? UnboundLocalError: local variable 'red' referenced before assignment

[nongnaeja]

I don't know ,why it's error
This my code

from PIL import Image

def ch_red(tmp):

    R = tmp[0]
    G = tmp[1]
    B = tmp[2]

    if 60 <= R <= 99 and G <= 50 and B <= 50:
        red = red + 1

    elif 100 <= R <= 139 and G <= 100 and B <= 150 :
        red = red + 1

    elif 140 <= R <= 229 and G <= 160 and B <= 225 :
        red = red + 1

    elif 230 <= R <= 249 and G <= 210 and B <= 210 :
        red = red + 1  

    elif 250 <= R <= 255 and G <= 240 and B <= 240 :
        red = red + 1  

    return red

def ck_color(s):

    for i in range(0,s.size[0]):

        for j in range(0,s.size[1]):

            tmp = s.getpixel((i,j))

            red = ch_red(tmp)

    return red

p = Image.open("c:\pypro\color\crop(150_100_270_130)\111854\111854(1).jpg")

m = ck_color(p)

print m

when I run .It show

UnboundLocalErr or: local variable 'red' referenced before assignment

Then I fx them to add

'global red '

in ch_red(tmp):
But it show error again

NameError: global name 'red' is not defined

I don't know, How I fix it?
Please.
Thank You.
Nae

[bvdet]

Variable red is not defined until this statement:

red = ch_red(tmp)

Variable red is also local to functions ch_red() and ck_color(). The script will fail even if you declare red to be global in both functions. Can you tell us what you are trying to do?

-BV