OpenCV学习笔记7-图像算术运算

1.图像加法

cv2.add(img1, img2[, dst[, mask[, dtype]]]) -> dst（图像矩阵）

*img1和img2应该是大小相同的两个图像矩阵

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import numpy as npimport cv2img1 = cv2.imread('1.png')img2 = cv2.imread('opencv_logo.jpg')img3 = cv2.add(img1, img2)cv2.imshow('image', img3)cv2.waitKey(0)cv2.destroyAllWindows()

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2.图像加权

cv2.addWeighted(img1, 权重1, img2, 权重2, 常数项[, dst[,dtype]]) -> dst（图像矩阵）

dst = a*img1 + b*img2 + c

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import numpy as npimport cv2img1 = cv2.imread('1.png')img2 = cv2.imread('opencv_logo.jpg')img3 = cv2.addWeighted(img1, 0.7, img2, 0.3, 0)cv2.imshow('image', img3)cv2.waitKey(0)cv2.destroyAllWindows()

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3.位运算(AND/OR/NOT/XOR)

• bitwise_and(src1, src2[, dst[, mask]]) -> dst
• bitwise_or(src1, src2[, dst[, mask]]) -> dst
• bitwise_not(src[, dst[, mask]]) -> dst
• bitwise_xor(src1, src2[, dst[, mask]]) -> dst
• threshold(src, thresh(阈值), maxval, type[, dst]) -> retval, dst #获取二元值的灰度图像

*mask是运算的模版，可认为是控制每个像素点是否进行运算的矩阵

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import numpy as npimport cv2from matplotlib import pyplot as pltimg1 = cv2.imread('Yzy.jpg')img2 = cv2.imread('opencv_logo.jpg')#按照opencv_logo的大小，以及想被放置的位置，从Yzy.jpg中取出ROIrows, cols, channels = img2.shaperoi = img1[0:rows, 0:cols, :]#将opencv_logo灰度图像二值化，获取mask和mask_invimg2gray = cv2.cvtColor(img2, cv2.COLOR_BGR2GRAY)ret, mask = cv2.threshold(img2gray, 175, 255, cv2.THRESH_BINARY)mask_inv = cv2.bitwise_not(mask)#取roi中与mask中不为0的值对应的像素的值，其他值为0，将roi中放置logo的地方标记出来#取img2中与mask_inv中不为0的值对应的像素的值，其他值为0，仅把logo分割出来img1_bg = cv2.bitwise_and(roi, roi, mask=mask)img2_fg = cv2.bitwise_and(img2, img2, mask=mask_inv)#将背景和前景相加dst = cv2.add(img1_bg, img2_fg)img1[0:rows, 0:cols, :] = dstcv2.namedWindow('res', cv2.WINDOW_NORMAL)cv2.imshow('res', img1)#cv2.imshow('1', img1_bg)#cv2.imshow('2', img2_fg)cv2.waitKey(0)cv2.destroyAllWindows()

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