Without Function數位影像處理(細線化)程式碼python數位影像處理(二值化，低通，高通，中值濾波器)程式碼python

值方圖等化

import cv2
img=cv2.imread("8.png",0)
cv2.imshow("IMG",img)
dst=cv2.equalizeHist(img)
cv2.imshow("DST",dst)
cv2.waitKey(0)
cv2.destroyAllWindows()

 影像二值化

import cv2
a=cv2.imread("8.png",0)
cv2.imshow("IMG",a)
x=a.shape[0]
y=a.shape[1]
threshold=125
for i in range(x):
    for j in range(y):
        if(a[i][j]>threshold):
            a[i][j]=0
        else:
            a[i][j]=255
cv2.imshow("threshold",a)  
cv2.waitKey(0)
cv2.destroyAllWindows()

調整影像強度

import cv2
a=cv2.imread("8.png",0)
cv2.imshow("IMG",a)
x=a.shape[0]
y=a.shape[1]

for i in range(x):
    for j in range(y):
        a[i][j]=a[i][j]*0.7
cv2.imshow("dark",a)  

b=cv2.imread("8.png",0)
for i in range(x):
    for j in range(y):
        b[i][j]=b[i][j]*1.5
        if(int(b[i][j])>=int(255)):
            b[i][j]=int(255)
cv2.imshow("bright",b)

cv2.waitKey(0)
cv2.destroyAllWindows()

中值濾波

import cv2
import numpy as np
a=cv2.imread("8.png",0)
cv2.imshow("IMG",a)
x=a.shape[0]
y=a.shape[1]
for i in range(1,x):
    for j in range(1,y):
        a[i][j]=np.median(a[i-1:i+2,j-1:j+2])
cv2.imshow("cv2.medianBlur",a)  
cv2.waitKey(0)
cv2.destroyAllWindows()

低通濾波

import cv2
import numpy as np
img=cv2.imread("8.png",0)
cv2.imshow("Ori",img) #原圖
fft1=np.fft.fft2(img) #傅立葉轉頻域
fft2=np.fft.fftshift(fft1) #把低頻訊號放在中間
fft3=np.log(np.abs(fft2))/20 #取絕對值取log不然強度太強
cv2.imshow("fft",fft3) #成功轉成頻域

ifft2=np.fft.ifftshift(fft2) #反傅立葉回來(把低頻移到邊角)
iimg=np.fft.ifft2(ifft2) #反傅立葉回時域
iimg=np.abs(iimg)  #取絕對值取log不然強度太強
cv2.imshow("ifft",iimg/200)

rows,cols = img.shape
mask = np.ones(img.shape,np.uint8)  #創造跟原圖一樣大小都是1的陣列
mask[int(rows/2)-30:int(rows/2)+30,int(cols/2)-30:int(cols/2)+30] = 0
cv2.imshow("mask",mask) #低通遮罩

highpass=mask*fft2 #傅立葉跟低通相乘
highpass1=np.fft.ifftshift(highpass) #反傅立葉回來(把低頻移到邊角)
highpass2=np.fft.ifft2(highpass1) #反傅立葉回時域
highpass3=np.abs(highpass2) #取絕對值取log不然強度太強
cv2.imshow("highpass",highpass3/60)#成功轉成頻域

result=highpass3+img #邊緣跟原圖相加
cv2.imshow("result",result/200) #達到銳化效果

cv2.waitKey(0)
cv2.destroyAllWindows()

高通濾波

import cv2
import numpy as np
img=cv2.imread("8.png",0)
cv2.imshow("Ori",img) #原圖
fft1=np.fft.fft2(img) #傅立葉轉頻域
fft2=np.fft.fftshift(fft1) #把低頻訊號放在中間
fft3=np.log(np.abs(fft2))/20 #取絕對值取log不然強度太強
cv2.imshow("fft",fft3) #成功轉成頻域

rows,cols = img.shape
mask = np.ones(img.shape,np.uint8)  #創造跟原圖一樣大小都是0的陣列
#mask = cv2.circle(mask, (int(rows/2), int(cols/2)), 30, (255, 255, 255), -1) #畫一個園
cv2.imshow("mask",mask) #低通遮罩

lowpass=mask*fft2 #傅立葉跟低通相乘
lowpass1=np.fft.ifftshift(lowpass) #反傅立葉回來(把低頻移到邊角)
lowpass2=np.fft.ifft2(lowpass1) #反傅立葉回時域
lowpass3=np.abs(lowpass2) #取絕對值取log不然強度太強
cv2.imshow("highpass",lowpass3/60000)#成功轉成頻域
cv2.waitKey(0)
cv2.destroyAllWindows()