怎么在python中利用opencv3.4.0实现一个人脸检测功能
怎么在python中利用opencv3.4.0实现一个人脸检测功能?很多新手对此不是很清楚,为了帮助大家解决这个难题,下面小编将为大家详细讲解,有这方面需求的人可以来学习下,希望你能有所收获。
import cv2 import numpy as np import random def load_images(dirname, amout = 9999): img_list = [] file = open(dirname) img_name = file.readline() while img_name != '': # 文件尾 img_name = dirname.rsplit(r'/', 1)[0] + r'/' + img_name.split('/', 1)[1].strip('\n') img_list.append(cv2.imread(img_name)) img_name = file.readline() amout -= 1 if amout <= 0: # 控制读取图片的数量 break return img_list # 从每一张没有人的原始图片中随机裁出10张64*128的图片作为负样本 def sample_neg(full_neg_lst, neg_list, size): random.seed(1) width, height = size[1], size[0] for i in range(len(full_neg_lst)): for j in range(10): y = int(random.random() * (len(full_neg_lst[i]) - height)) x = int(random.random() * (len(full_neg_lst[i][0]) - width)) neg_list.append(full_neg_lst[i][y:y + height, x:x + width]) return neg_list # wsize: 处理图片大小,通常64*128; 输入图片尺寸>= wsize def computeHOGs(img_lst, gradient_lst, wsize=(128, 64)): hog = cv2.HOGDescriptor() # hog.winSize = wsize for i in range(len(img_lst)): if img_lst[i].shape[1] >= wsize[1] and img_lst[i].shape[0] >= wsize[0]: roi = img_lst[i][(img_lst[i].shape[0] - wsize[0]) // 2: (img_lst[i].shape[0] - wsize[0]) // 2 + wsize[0], \ (img_lst[i].shape[1] - wsize[1]) // 2: (img_lst[i].shape[1] - wsize[1]) // 2 + wsize[1]] gray = cv2.cvtColor(roi, cv2.COLOR_BGR2GRAY) gradient_lst.append(hog.compute(gray)) # return gradient_lst def get_svm_detector(svm): sv = svm.getSupportVectors() rho, _, _ = svm.getDecisionFunction(0) sv = np.transpose(sv) return np.append(sv, [[-rho]], 0) # 主程序 # 第一步:计算HOG特征 neg_list = [] pos_list = [] gradient_lst = [] labels = [] hard_neg_list = [] svm = cv2.ml.SVM_create() pos_list = load_images(r'G:/python_project/INRIAPerson/96X160H96/Train/pos.lst') full_neg_lst = load_images(r'G:/python_project/INRIAPerson/train_64x128_H96/neg.lst') sample_neg(full_neg_lst, neg_list, [128, 64]) print(len(neg_list)) computeHOGs(pos_list, gradient_lst) [labels.append(+1) for _ in range(len(pos_list))] computeHOGs(neg_list, gradient_lst) [labels.append(-1) for _ in range(len(neg_list))] # 第二步:训练SVM svm.setCoef0(0) svm.setCoef0(0.0) svm.setDegree(3) criteria = (cv2.TERM_CRITERIA_MAX_ITER + cv2.TERM_CRITERIA_EPS, 1000, 1e-3) svm.setTermCriteria(criteria) svm.setGamma(0) svm.setKernel(cv2.ml.SVM_LINEAR) svm.setNu(0.5) svm.setP(0.1) # for EPSILON_SVR, epsilon in loss function? svm.setC(0.01) # From paper, soft classifier svm.setType(cv2.ml.SVM_EPS_SVR) # C_SVC # EPSILON_SVR # may be also NU_SVR # do regression task svm.train(np.array(gradient_lst), cv2.ml.ROW_SAMPLE, np.array(labels)) # 第三步:加入识别错误的样本,进行第二轮训练 # 参考 http://masikkk.com/article/SVM-HOG-HardExample/ hog = cv2.HOGDescriptor() hard_neg_list.clear() hog.setSVMDetector(get_svm_detector(svm)) for i in range(len(full_neg_lst)): rects, wei = hog.detectMultiScale(full_neg_lst[i], winStride=(4, 4),padding=(8, 8), scale=1.05) for (x,y,w,h) in rects: hardExample = full_neg_lst[i][y:y+h, x:x+w] hard_neg_list.append(cv2.resize(hardExample,(64,128))) computeHOGs(hard_neg_list, gradient_lst) [labels.append(-1) for _ in range(len(hard_neg_list))] svm.train(np.array(gradient_lst), cv2.ml.ROW_SAMPLE, np.array(labels)) # 第四步:保存训练结果 hog.setSVMDetector(get_svm_detector(svm)) hog.save('myHogDector.bin')
以下是测试代码:
import cv2 import numpy as np hog = cv2.HOGDescriptor() hog.load('myHogDector.bin') cap = cv2.VideoCapture(0) while True: ok, img = cap.read() rects, wei = hog.detectMultiScale(img, winStride=(4, 4),padding=(8, 8), scale=1.05) for (x, y, w, h) in rects: cv2.rectangle(img, (x, y), (x + w, y + h), (0, 0, 255), 2) cv2.imshow('a', img) if cv2.waitKey(1)&0xff == 27: # esc键 break cv2.destroyAllWindows()
看完上述内容是否对您有帮助呢?如果还想对相关知识有进一步的了解或阅读更多相关文章,请关注行业资讯频道,感谢您对亿速云的支持。