【问题标题】:Segmentation fault error for face detection python code in OpenCV 2.2OpenCV 2.2中人脸检测python代码的分段错误错误
【发布时间】:2011-09-04 01:12:38
【问题描述】:

我最近使用http://www.samontab.com/web/2011/06/installing-opencv-2-2-in-ubuntu-11-04/ 提供的说明在我的 Ubuntu 11 机器上安装了 OpenCV v2.2。我也能够运行示例 C 程序和一些示例 python 程序。但是运行 python facedetect.py ~/img.jpg 给了我“Segmentation Fault”。

什么可能导致此问题,我该如何解决?下面是 facedetect.py 的代码。

#!/usr/bin/python
"""
This program is demonstration for face and object detection using haar-like features.
The program finds faces in a camera image or video stream and displays a red box around them.

Original C implementation by:  ?
Python implementation by: Roman Stanchak, James Bowman
"""
import sys
import cv
from optparse import OptionParser

# Parameters for haar detection
# From the API:
# The default parameters (scale_factor=2, min_neighbors=3, flags=0) are tuned 
# for accurate yet slow object detection. For a faster operation on real video 
# images the settings are: 
# scale_factor=1.2, min_neighbors=2, flags=CV_HAAR_DO_CANNY_PRUNING, 
# min_size=<minimum possible face size

min_size = (20, 20)
image_scale = 2
haar_scale = 1.2
min_neighbors = 2
haar_flags = 0

def detect_and_draw(img, cascade):
    # allocate temporary images
    gray = cv.CreateImage((img.width,img.height), 8, 1)
    small_img = cv.CreateImage((cv.Round(img.width / image_scale),
                   cv.Round (img.height / image_scale)), 8, 1)

    # convert color input image to grayscale
    cv.CvtColor(img, gray, cv.CV_BGR2GRAY)

    # scale input image for faster processing
    cv.Resize(gray, small_img, cv.CV_INTER_LINEAR)

    cv.EqualizeHist(small_img, small_img)

    if(cascade):
        t = cv.GetTickCount()
        faces = cv.HaarDetectObjects(small_img, cascade, cv.CreateMemStorage(0),
                                     haar_scale, min_neighbors, haar_flags, min_size)
        t = cv.GetTickCount() - t
        print "detection time = %gms" % (t/(cv.GetTickFrequency()*1000.))
        if faces:
            for ((x, y, w, h), n) in faces:
                # the input to cv.HaarDetectObjects was resized, so scale the 
                # bounding box of each face and convert it to two CvPoints
                pt1 = (int(x * image_scale), int(y * image_scale))
                pt2 = (int((x + w) * image_scale), int((y + h) * image_scale))
                cv.Rectangle(img, pt1, pt2, cv.RGB(255, 0, 0), 3, 8, 0)

    cv.ShowImage("result", img)

if __name__ == '__main__':

    parser = OptionParser(usage = "usage: %prog [options] [filename|camera_index]")
    parser.add_option("-c", "--cascade", action="store", dest="cascade", type="str", help="Haar cascade file, default %default", default = "../data/haarcascades/haarcascade_frontalface_alt.xml")
    (options, args) = parser.parse_args()

    cascade = cv.Load(options.cascade)

    if len(args) != 1:
        parser.print_help()
        sys.exit(1)

    input_name = args[0]
    if input_name.isdigit():
        capture = cv.CreateCameraCapture(int(input_name))
    else:
        capture = None

    cv.NamedWindow("result", 1)

    if capture:
        frame_copy = None
        while True:
            frame = cv.QueryFrame(capture)
            if not frame:
                cv.WaitKey(0)
                break
            if not frame_copy:
                frame_copy = cv.CreateImage((frame.width,frame.height),
                                            cv.IPL_DEPTH_8U, frame.nChannels)
            if frame.origin == cv.IPL_ORIGIN_TL:
                cv.Copy(frame, frame_copy)
            else:
                cv.Flip(frame, frame_copy, 0)

            detect_and_draw(frame_copy, cascade)

            if cv.WaitKey(10) >= 0:
                break
    else:
        image = cv.LoadImage(input_name, 1)
        detect_and_draw(image, cascade)
        cv.WaitKey(0)

    cv.DestroyWindow("result")

请帮忙 谢谢你

【问题讨论】:

    标签: python opencv


    【解决方案1】:

    同样的问题。我已经将其追踪到级联上的 cv.Load 。我在 OS X 10.6、OpenCV 2.3.1 和 Python 2.6 上。这是转储:

    Exception Type:  EXC_BAD_ACCESS (SIGSEGV)
    Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000000
    Crashed Thread:  0  Dispatch queue: com.apple.main-thread
    
    Thread 0 Crashed:  Dispatch queue: com.apple.main-thread
    0   libopencv_objdetect.2.2.dylib   0x00000001007b2899 cv::RTTIImpl<cv::HOGDescriptor>::isInstance(void const*) + 41
    1   libopencv_core.2.2.dylib        0x000000010113b65f cvTypeOf + 47
    2   cv.so                           0x00000001004ba12e pycvLoad(_object*, _object*, _object*) + 206
    3   org.python.python               0x00000001000b8d48 PyEval_EvalFrameEx + 28696
    4   org.python.python               0x00000001000b9af5 PyEval_EvalCodeEx + 2197
    5   org.python.python               0x00000001000b9c16 PyEval_EvalCode + 54
    6   org.python.python               0x00000001000dea6e PyRun_FileExFlags + 174
    7   org.python.python               0x00000001000ded29 PyRun_SimpleFileExFlags + 489
    8   org.python.python               0x00000001000ee40c Py_Main + 2764
    9   org.python.python               0x0000000100000f14 0x100000000 + 3860
    

    我又四处寻找,发现https://code.ros.org/trac/opencv/ticket/983,这似乎表明这是由于OpenCV 无法找到该文件。因此,请仔细检查“../data/haarcascades/haarcascade_frontalface_alt.xml”相对于您执行它的位置是否存在。

    【讨论】:

    • 嗯,你是对的。这很奇怪,因为我安装了 2.3.1,但也许它是以前的安装。无论如何,一旦我得到了正确的文件,我的工作就可以了!
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