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使用OpenCV和Python查找圖片差異
flyfish
方法1 均方誤差的算法(Mean Squared Error , MSE)
下面的一些表達(dá)與《TensorFlow - 協(xié)方差矩陣》式子表達(dá)式一樣的
擬合 誤差平方和( sum of squared errors)
residual sum of squares (RSS), also known as the sum of squared residuals (SSR) or the sum of squared errors of prediction (SSE),
also known as 就我們所說(shuō)的
RSS, SSR ,SSE表達(dá)的是一個(gè)意思
def mse(imageA, imageB): # the 'Mean Squared Error' between the two images is the # sum of the squared difference between the two images; # NOTE: the two images must have the same dimension err = np.sum((imageA.astype("float") - imageB.astype("float")) ** 2) err /= float(imageA.shape[0] * imageA.shape[1]) # return the MSE, the lower the error, the more "similar" # the two images are return err
方法2 SSIM
structural similarity index measurement (SSIM) system
一種衡量?jī)煞鶊D像結(jié)構(gòu)相似度的新指標(biāo),其值越大越好,最大為1。
新建一個(gè)Python文件,命名為 image_diff.py
原文
Image Difference with OpenCV and Python
原理
根據(jù)參數(shù)讀取兩張圖片并轉(zhuǎn)換為灰度:
使用SSIM計(jì)算兩個(gè)圖像之間的差異,這種方法已經(jīng)在scikit-image 庫(kù)中實(shí)現(xiàn)
在兩個(gè)圖像之間的不同部分繪制矩形邊界框。
代碼如下 已編譯通過(guò)
from skimage.measure import compare_ssim #~ import skimage as ssim import argparse import imutils import cv2 # construct the argument parse and parse the arguments ap = argparse.ArgumentParser() ap.add_argument("-f", "--first", required=True, help="first input image") ap.add_argument("-s", "--second", required=True, help="second") args = vars(ap.parse_args()) # load the two input images imageA = cv2.imread(args["first"]) imageB = cv2.imread(args["second"]) ''' imageA = cv2.imread("E:\\1.png") imageB = cv2.imread("E:\\2.png") ''' # convert the images to grayscale grayA = cv2.cvtColor(imageA, cv2.COLOR_BGR2GRAY) grayB = cv2.cvtColor(imageB, cv2.COLOR_BGR2GRAY) # compute the Structural Similarity Index (SSIM) between the two # images, ensuring that the difference image is returned #structural similarity index measurement (SSIM) system一種衡量?jī)煞鶊D像結(jié)構(gòu)相似度的新指標(biāo),其值越大越好,最大為1。 (score, diff) = compare_ssim(grayA, grayB, full=True) diff = (diff * 255).astype("uint8") print("SSIM: {}".format(score)) # threshold the difference image, followed by finding contours to # obtain the regions of the two input images that differ thresh = cv2.threshold(diff, 0, 255, cv2.THRESH_BINARY_INV | cv2.THRESH_OTSU)[1] cnts = cv2.findContours(thresh.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE) cnts = cnts[0] if imutils.is_cv2() else cnts[1] # loop over the contours for c in cnts: # compute the bounding box of the contour and then draw the # bounding box on both input images to represent where the two # images differ (x, y, w, h) = cv2.boundingRect(c) cv2.rectangle(imageA, (x, y), (x + w, y + h), (0, 0, 255), 2) cv2.rectangle(imageB, (x, y), (x + w, y + h), (0, 0, 255), 2) # show the output images cv2.imshow("Original", imageA) cv2.imshow("Modified", imageB) cv2.imshow("Diff", diff) cv2.imshow("Thresh", thresh) cv2.waitKey(0)
使用方法
python image_diff.py –first original.png –second images/modified.png
如果不想使用參數(shù)將參數(shù)代碼部分直接變成
imageA = cv2.imread(“E:\1.png”) imageB = cv2.imread(“E:\2.png”)
以上這篇利用OpenCV和Python實(shí)現(xiàn)查找圖片差異就是小編分享給大家的全部?jī)?nèi)容了,希望能給大家一個(gè)參考,也希望大家多多支持億速云。
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