效果圖
未加水印前:
水印掩碼:
透明度爲 0.3
的水印圖片:
透明度爲 1.0
的水印圖片:
實現代碼
感覺我自己寫的這段代碼,效果比opencv官網上給出的例子效果要好,水印中不會夾帶黑色噪點。
# coding=utf-8 import cv2 import numpy as np bottom = cv2.imread('elegent.jpg') mark = cv2.imread('mask.jpg') # 加水印 def waterMark(src, mask, transparency): # 對掩碼:轉爲float型 --> 乘上透明度 --> 地板整數 --> 回到uint8型 mask = np.floor(mask.astype(np.float32) * transparency).astype(np.uint8) dst = cv2.add(src, mask) # 防止溢出像素值域 dst = dst*(dst<=255) + 255*(dst>255) # 回到uint8型 dst = dst.astype(np.uint8) return dst b_rows, b_cols, b_channels = bottom.shape m_rows, m_cols, m_channels = mark.shape # 將圖片右下角矩形塊 替換爲 加過水印的矩形塊 bottom[b_rows-m_rows:b_rows, b_cols-m_cols:b_cols, ] = waterMark(bottom[b_rows-m_rows:b_rows, b_cols-m_cols:b_cols, ], mark, 0.3) # 保存水印圖片 cv2.imwrite('waterMark.jpg', bottom) cv2.imshow('waterMark', bottom) cv2.waitKey(3000) cv2.destroyAllWindows()
對比
OpenCV官網上的類似例程:
具體代碼:
# coding=utf-8 import cv2 img1 = cv2.imread('elegent.jpg') img2 = cv2.imread('mask.jpg') b_rows, b_cols, b_channels = img1.shape m_rows, m_cols, m_channels = img2.shape # I want to put logo on top-left corner, So I create a ROI rows,cols,channels = img2.shape roi = img1[b_rows-m_rows:b_rows, b_cols-m_cols:b_cols, ] # Now create a mask of logo and create its inverse mask also img2gray = cv2.cvtColor(img2,cv2.COLOR_BGR2GRAY) ret, mask = cv2.threshold(img2gray, 10, 255, cv2.THRESH_BINARY) mask_inv = cv2.bitwise_not(mask) # Now black-out the area of logo in ROI img1_bg = cv2.bitwise_and(roi,roi,mask = mask_inv) # Take only region of logo from logo image. img2_fg = cv2.bitwise_and(img2,img2,mask = mask) # Put logo in ROI and modify the main image dst = cv2.add(img1_bg,img2_fg) # img1[0:rows, 0:cols ] = dst # 將圖片右下角矩形塊 替換爲 加過水印的矩形塊 img1[b_rows-m_rows:b_rows, b_cols-m_cols:b_cols, ] = dst cv2.imwrite('res.jpg', img1) cv2.imshow('res',img1) cv2.waitKey(0) cv2.destroyAllWindows()
該例程的實現效果:
劣勢:
由細節放大圖可看出,opencv官網例程的效果不佳,不僅 不能自定義 水印透明度,而且水印中還會 夾帶黑色噪點,有損美觀: