#-*- encoding:utf-8 -*-
'''
python 繪製顏色直方圖
'''
import cv2
import numpy as np
from matplotlib import pyplot as plt

def readImage():
    #讀取圖片 B，G，R，返回一個ndarray型別
    #cv2.IMREAD_COLOR  # 以彩色模式讀入 1
    #cv2.IMREAD_GRAYSCALE  # 以灰色模式讀入 0
    img = cv2.imread('../../data/home.jpg',cv2.IMREAD_COLOR)
    #返回多維矩陣，#(384, 512, 3)，
    print type(img), img.shape, img.size, img.dtype
    #ravel()展平n維矩陣的所有
    print img.ravel(), len(img.ravel())

def cvt():
    '''
    經常用到的顏色轉換BGR->Gray 和BGR->HSV
    '''
    # 讀取圖片 B，G，R，返回一個ndarray型別
    img = cv2.imread('../../data/home.jpg')
    #cv2.COLOR_BGR2GRAY;cv2.COLOR_BGR2HSV
    # 彩色影象轉灰度影象YUV(Y即為灰度圖) Y = 0.299R + 0.587G + 0.114B
    img1 = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    # 彩色影象轉灰度影象YUV(Y->亮度；U,V->色度)
    img2 = cv2.cvtColor(img, cv2.COLOR_BGR2HSV)
    print img1
    print img2

cvt()