[英]ValueError: math domain error (python)
我正在测试数学模块和PIL模块,并尝试在图像上应用盒计数算法。 当我在下面运行该代码时,出现以下错误:
Traceback (most recent call last):
File "C:\Users\Joao\Desktop\Image Size.py", line 48, in <module>
gy.append(math.log(boxCount))
ValueError: math domain error
码:
import Tkinter as tk
from Tkinter import *
from PIL import Image, ImageTk
import os, glob, tkFileDialog
import math
im = Image.open("img1.bmp")
width, height = im.size
print width
print height
imgx = width
imgy = height
pixels = im.load()
theColor = (255, 255, 255)
# fractal dimension calculation using box-counting method
b = 2 # initial box size in pixels
f = 2 # box scaling factor
n = 3 # number of graph points for simple linear regression
gx = [] # x coordinates of graph points
gy = [] # y coordinates of graph points
for ib in range(n):
bs = b * f ** ib # box size in pixels
bnx = int(imgx / bs) # of boxes in x direction of image
bny = int(imgy / bs) # of boxes in y direction of image
boxCount = 0
for by in range(bny):
for bx in range(bnx):
# if there are any pixels in the box then increase box count
foundPixel = False
for ky in range(bs):
for kx in range(bs):
if pixels[bs * bx + kx, bs * by + ky] == theColor:
foundPixel = True
boxCount += 1
break
if foundPixel:
break
gx.append(math.log(1.0 / bs))
gy.append(math.log(boxCount))
我发现,如果将boxcount的值更改为1(而不是零),则完全不会产生错误,但是我需要将boxcount值设置为0。有人可以建议解决方案吗?
由于未定义对数为负数或零,因此请替换:
gy.append(math.log(boxCount))
有了这个 :
gy.append(math.log(boxCount if boxCount>0 else 1))
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