遥感影像RGBtoHIS
RGB通过对红®、绿(G)、蓝(B)三个颜色通道的变化以及它们相互之间的叠加来得到各式各样的颜色的，RGB即是代表红、绿、蓝三个通道的颜色。
import cv2
import numpy as np
import sys
import math
def RGBtoHIS(RGBimg): #定义转换函数
rows = int(RGBimg.shape[0])
cols = int(RGBimg.shape[1])
B, G, R = cv2.split(RGBimg)
# 归一化到[0,1]
B = B / 255.0
G = G / 255.0
R = R / 255.0
HISimg = RGBimg.copy()
H, S, I = cv2.split(HISimg)
for i in range(rows):
for j in range(cols):
num = 0.5 * ((R[i, j] - G[i, j]) + (R[i, j] - B[i, j]))
den = np.sqrt((R[i, j] - G[i, j]) ** 2 + (R[i, j] - B[i, j]) * (G[i, j] - B[i, j]))
theta = float(np.arccos(num / den))
if den == 0:
H = 0
elif B[i, j] <= G[i, j]:
H = theta
else:
H = 2 * 3.14169265 - theta
min_RGB = min(min(B[i, j], G[i, j]), R[i, j])
sum = B[i, j] + G[i, j] + R[i, j]
if sum == 0:
S = 0
else:
S = 1 - 3 * min_RGB / sum
H = H / (2 * 3.14159265)
I = sum / 3.0
# 输出HSI图像，扩充到255以方便显示，一般H分量在[0,2pi]之间，S和I在[0,1]之间
HISimg[i, j, 0] = H * 255
HISimg[i, j, 1] = S * 255
HISimg[i, j, 2] = I * 255
return HISimg
filepath=‘D:/VSWorkSpace/PythonSpace/Fusion/MSS_test_resample.tif’ #文件路径
RGBimg=cv2.imread(filepath,1) #使用opencv读取RGB图像
cv2.namedWindow(“MSS”,0)
cv2.resizeWindow(‘MSS’,500,500)
cv2.imshow(‘MSS’,RGBimg)
HISimg=RGBtoHIS(RGBimg) #调用函数RGB to HIS
cv2.namedWindow(“HISimg”,1)
cv2.resizeWindow(‘HISimg’,500,500)
cv2.imshow(‘HISimg’, HISimg)
cv2.imwrite(‘copy.tif’,HISimg, [cv2.IMWRITE_JPEG_QUALITY, 2]) #保存转换结果
print(HISimg.shape)
cv2.waitKey(0)
cv2.destroyAllWindows() # 释放窗口
后续写HIS to RGB，请关注