c++ - valgrind:opencv 中的 cvCvtColor 错误

Question

这是我非常简单的代码:

#include <opencv/highgui.h>
#include <opencv/cv.h>
#include <iostream>
using namespace std;
using namespace cv;
int main(int argc, char** argv)
{
    for(int i=0;i<2;i++){
        ostringstream tmp;
        tmp << "/vol/test1/" << i << ".jpg";

        IplImage * img = cvLoadImage(tmp.str().c_str());                  //line #12
        IplImage* imgc = cvCreateImage(cvGetSize(img), img->depth,3);
        cvCvtColor(img, imgc, CV_BGR2Lab);                                //line #14
        cvReleaseImage(&img);
        img = imgc;
        cvReleaseImage(&img);
    }
    return 0;
}

该程序仅加载 2 个图像，并将它们转换为 CIELab 空间。但是，Valgrind 会抛出以下错误:

==31879== LEAK SUMMARY:
==31879==    definitely lost: 0 bytes in 0 blocks
==31879==    indirectly lost: 0 bytes in 0 blocks
==31879==      possibly lost: 0 bytes in 0 blocks
==31879==    still reachable: 14,456 bytes in 6 blocks
==31879==         suppressed: 0 bytes in 0 blocks
==31879== 
==31879== ERROR SUMMARY: 903892 errors from 3 contexts (suppressed: 2 from 2)

进一步检查 -g --show-reachable=yes 给我泄漏的详细信息( block 1-4 的报告与 block 5 相同，所以我没有发布它此处):

==31879== 2,072 bytes in 1 blocks are still reachable in loss record 5 of 6
==31879==    at 0x4C2B6CD: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==31879==    by 0x10B3DF5A: ??? (in /usr/lib/x86_64-linux-gnu/libpixman-1.so.0.30.2)
==31879==    by 0x10B40D3F: ??? (in /usr/lib/x86_64-linux-gnu/libpixman-1.so.0.30.2)
==31879==    by 0x10B03A68: ??? (in /usr/lib/x86_64-linux-gnu/libpixman-1.so.0.30.2)
==31879==    by 0x400F305: call_init.part.0 (dl-init.c:85)
==31879==    by 0x400F3DE: _dl_init (dl-init.c:52)
==31879==    by 0x40016E9: ??? (in /lib/x86_64-linux-gnu/ld-2.15.so)
==31879== 
==31879== 4,096 bytes in 1 blocks are still reachable in loss record 6 of 6
==31879==    at 0x4C2B6CD: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==31879==    by 0x64870B7: libjpeg_general_init (in /usr/lib/x86_64-linux-gnu/libjpeg.so.8.0.2)
==31879==    by 0x400F305: call_init.part.0 (dl-init.c:85)
==31879==    by 0x400F3DE: _dl_init (dl-init.c:52)
==31879==    by 0x40016E9: ??? (in /lib/x86_64-linux-gnu/ld-2.15.so)

由于内存泄漏“仍然可以到达”，我想我可以安全地忽略它。但让我担心的是 903892 错误的错误摘要。我使用 --track-origins=yes 重新运行 valgrind:

==31879== ERROR SUMMARY: 903892 errors from 3 contexts (suppressed: 2 from 2)
==31879== 
==31879== 301229 errors in context 1 of 3:
==31879== Use of uninitialised value of size 8
==31879==    at 0x55219F0: cv::CvtColorLoop_Invoker<cv::RGB2Lab_b>::operator()(cv::Range const&) const (in /vol/Toolkits/opencv-2.4.10/release/lib/libopencv_imgproc.so.2.4.10)
==31879==    by 0x5536152: cv::cvtColor(cv::_InputArray const&, cv::_OutputArray const&, int, int) (in /vol/Toolkits/opencv-2.4.10/release/lib/libopencv_imgproc.so.2.4.10)
==31879==    by 0x55403A8: cvCvtColor (in /vol/Toolkits/opencv-2.4.10/release/lib/libopencv_imgproc.so.2.4.10)
==31879==    by 0x400DEB: main (main.cpp:14)
==31879==  Uninitialised value was created by a heap allocation
==31879==    at 0x4C2B6CD: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==31879==    by 0x64ABA74: ??? (in /usr/lib/x86_64-linux-gnu/libjpeg.so.8.0.2)
==31879==    by 0x64ABD02: ??? (in /usr/lib/x86_64-linux-gnu/libjpeg.so.8.0.2)
==31879==    by 0x649EFF9: jinit_d_main_controller (in /usr/lib/x86_64-linux-gnu/libjpeg.so.8.0.2)
==31879==    by 0x64A22BB: jinit_master_decompress (in /usr/lib/x86_64-linux-gnu/libjpeg.so.8.0.2)
==31879==    by 0x64991D4: jpeg_start_decompress (in /usr/lib/x86_64-linux-gnu/libjpeg.so.8.0.2)
==31879==    by 0x4E64621: cv::JpegDecoder::readData(cv::Mat&) (in /vol/Toolkits/opencv-2.4.10/release/lib/libopencv_highgui.so.2.4.10)
==31879==    by 0x4E4AC8C: cv::imread_(std::string const&, int, int, cv::Mat*) (in /vol/Toolkits/opencv-2.4.10/release/lib/libopencv_highgui.so.2.4.10)
==31879==    by 0x4E4B13B: cvLoadImage (in /vol/Toolkits/opencv-2.4.10/release/lib/libopencv_highgui.so.2.4.10)
==31879==    by 0x400D9D: main (main.cpp:12)

(上下文 2 和 3 的报告与上下文 1 相同，因此我不会在此处发布)。这些错误似乎来 self 代码中的第 12 行和第 14 行。怎么了？还是我在这里遗漏了什么？

旁注:如果我扫描更 multimap 像，内存泄漏报告是相同的，但 Error Summary 中的错误数量呈线性增加。我的程序在扫描 ~3000 张图像后运行到 segmentation fault。

Answer 1

请避免所有已弃用的 IplImages，并改用 cv::Mat 和 c++ api。

#include <opencv2/opencv.hpp> // c++ headers
#include <iostream>
using namespace std;
using namespace cv;
int main(int argc, char** argv)
{
    for(int i=0;i<2;i++){
        ostringstream tmp;
        tmp << "/vol/test1/" << i << ".jpg";

        Mat img = imread(tmp.str().c_str());              
        Mat imgc; // no pre-allocation nessecary
        cvtColor(img, imgc, CV_BGR2Lab);                  
        // no manual release nessecary        
    }
    return 0;
}