直方图的python和opencv2问题

Question

I am having some trouble with histograms and and opencv2 with python. I took some code from here: http://opencvpython.blogspot.com/2012/04/drawing-histogram-in-opencv-python.html

here is the code:

import cv2
import numpy as np

img = cv2.imread('lena.bmp')
h = np.zeros((512,512,3))                                   

bins = np.arange(256).reshape(256,1)
color = [ (255,0,0),(0,255,0),(0,0,255) ]
for ch, col in enumerate(color):
    hist_item = cv2.calcHist([img],[ch],None,[256],[0,255])
    cv2.normalize(hist_item,hist_item,0,255,cv2.NORM_MINMAX)
    hist=np.int32(np.around(hist_item))
    pts = np.column_stack((bins,hist))
    cv2.polylines(h,[pts],False,col)
    print pts

where lena.bmp comes from this link.

Problems are:

1) cv2.polylines(h,[pts],False,col) fails with error:

OpenCV Error: Assertion failed (src.dims <= 2 && esz <= (size_t)32) in transpose

2) printing pts i see that values are different from values i get using gimp to analyze r, g and b histograms. And here i mean that bins have different values.

Any idea?

Answer 1

最终，我使这段代码在另一台计算机上工作，所以代码正确，但是我的环境中缺少某些内容。