OpenCV中的CascadeClassifier会生成错误

Question

我正在尝试开发一个简单的应用程序来检测给定图像中的面部和眼睛:

from cv2 import *
face_cascade = CascadeClassifier('haarcascade_frontalface_default.xml')
eye_cascade = CascadeClassifier('haarcascade_eye.xml')

img = imread("123.jpg")
gray = cvtColor(img, COLOR_BGR2GRAY)
rows,cols = gray.shape
gray = getRotationMatrix2D((cols/2,rows/2),-90,1)

faces = face_cascade.detectMultiScale(gray, 1.3, 5, 0)
print faces

for (x,y,w,h) in faces:
    img = rectangle(img, (x,y), ((x+w),(x+h)), (255,0,0), 2)
    #gray = rectangle(gray, (x,y), ((x+w), (x+y)), (0, 255, 0), 4)
    roi_gray = gray[y:y+h, x:x+w]
    roi_color = img[y:y+h, x:x+w]
    eyes = eye_cascade.detectMultiScale(roi_grey)
    for (ex,ey, ew, eh) in eyes:
        roi_color = rectangle(roi_color, (x,y), ((x+w), (y+h)), (50, 50, 50), 3)

imshow("img", img)
waitKey(9)
destroyAllWindows()

(注意:旋转是必要的,因为在使用该cvtColor功能后,输出图像以逆时针旋转90度生成.)

我收到以下错误:

回溯(最近一次调用最后一次):文件"/home/namit/Codes/wow.py",第10行,在faces = face_cascade.detectMultiScale(灰色,1.3,5,0)错误:/ home/namit/OpenCV/opencv -2.4.9/modules/objdetect/src/cascadedetect.cpp:1081:错误:(-215)scaleFactor> 1 && image.depth()== CV_8U函数detectMultiScale

Answer 1

错误消息的原因是图像gray是float64while时face_cascade.detectMultiScale需要unigned的整数.解决这个问题的方法是uint8在调用`face_cascade.detectMultiScale``之前将图像转换为:

import numpy as np
gray = np.array(gray, dtype='uint8')

还有其他问题.一个,cv2.rectangle不返回图像; 相反,它会修改传递给它的图像.以下适用于我:

from cv2 import *
import numpy as np
face_cascade = CascadeClassifier('haarcascade_frontalface_default.xml')
eye_cascade = CascadeClassifier('haarcascade_eye.xml')

fname='123.jpg'
img = imread(fname)
gray = imread(fname, CV_LOAD_IMAGE_GRAYSCALE)
rows,cols = gray.shape

gray = np.array(gray, dtype='uint8')
faces = face_cascade.detectMultiScale(gray, 1.3, 5, 0)
print 'faces=', faces

for (x,y,w,h) in faces:
    rectangle(img, (x,y), ((x+w),(x+h)), (255,0,0), 2)
    roi_gray = gray[y:y+h, x:x+w]
    roi_color = img[y:y+h, x:x+w]
    eyes = eye_cascade.detectMultiScale(roi_gray)
    for (ex,ey, ew, eh) in eyes:
        rectangle(roi_color, (x,y), ((x+w), (y+h)), (50, 50, 50), 3)
    imshow('eyes=%s' % (eyes,), roi_color)

imshow("img", img)
waitKey(0)
destroyAllWindows()

我没有观察到图像旋转的问题,所以我删除了旋转代码.