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张图像，并将其转换为CIELab空间。 但是， Valgrind引发以下错误：

==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)

使用-g --show-reachable=yes进一步检查，可以-g --show-reachable=yes泄漏的详细信息（第1-4块的报告与第5块的报告相同，因此不在此处发布）：

==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“仍然可以实现”，我想我可以放心地忽略它。 但是与我相关的是903892错误的错误摘要。 我用--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，因此我不在此发布）。 错误似乎来自我的代码中的第12和14行。 怎么了？ 还是我在这里想念东西？

旁注：如果我扫描更多图像，则泄漏内存的报告相同，但“ Error Summary中的Error Summary数量呈线性增加。 扫描约3000张图像后，我的程序运行segmentation fault 。

Answer 1

请避免使用所有不推荐使用的IplImages，而应使用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;
}