Diagnosing imread failure

richardst · February 1, 2021, 2:43pm

imread() is failing silently on my system. The returned image is always empty().

I am an absolute beginner with OpenCV.

My system is:
Windows 10
Visual Studio 2017
OpenCV 4.5.1

I am building against: ...OpenCV_4_5_1\opencv\build\x64\vc15\lib\opencv_world451.lib and
...OpenCV_4_5_1\opencv\build\x64\vc15\bin\opencv_world451.dll .

I have tried the obvious:

The images are ordinary 1054 x 1004 pixel .bmp, .png or .jpg files. They open normally in other Windows programs.
My program can open the files with <fstream>, so it is not a path or access issue.

#include <opencv2/core.hpp>
#include <opencv2/imgcodecs.hpp>
#include <opencv2/highgui.hpp>
#include <iostream>
#include <fstream>

int main(int argc, char** argv)
{
	cv::String sFilename = cv::String(argv[1]);

	std::cout << "Image to display is: " << sFilename.c_str() << std::endl;

	// check that the file can be opened.
	std::fstream fsIn(sFilename.c_str(), std::fstream::in);
	if( fsIn.is_open() )
	{
		std::cout << " Opened: '" << argv[1] << "'" << std::endl;
		fsIn.close();
	}
	else {
		std::cout << " Couldn't open: '" << argv[1] << "'" << std::endl;
	}
		
	
	// read the image in OpenCV
	cv::Mat image;
	image = cv::imread( sFilename ); // Read the file
	if (image.empty()) // Check for invalid input
	{
		std::cout << "imread() failed to open the image." << std::endl;
		return -1;
	}
	cv::namedWindow("Display window", cv::WINDOW_AUTOSIZE); // Create a window for display.
	cv::imshow("Display window", image); // Show our image inside it.
	cv::waitKey(0); // Wait for a keystroke in the window
	return 0;
}

visualbill · February 1, 2021, 3:56pm

I think you need to load and link imgcodecs library. Look at class definition for opencv imread…

richardst · February 1, 2021, 3:58pm

Thanks, visualbill. I will look into that.

laurent.berger · February 1, 2021, 4:06pm

can you add in your program

cout << cv::getBuildInformation()<< endl;

and show us result
and what does it mean “imread() is failing silently on my system”?

Do you run your program in windows command or you double click on icon?

crackwitz · February 1, 2021, 4:18pm

no you don’t have to do that. if you link against world, that contains everything. if you didn’t, you would have to make sure to link imgcodecs

richardst · February 1, 2021, 5:13pm

Hello Laurent and other commentators,

Thank you very much your help

I am running the program in Visual Studio’s debugger.

To my utter astonishment, simply adding `cout << cv::getBuildInformation()<< endl;’ made the program work.

Ah! The other thing I did (and thought I’d tested) was to ensure the Debug build had
just `opencv_world451d.lib’ in the Additional Dependencies and the Release build had just the non-debug include library. Let’s see if I can break it again… Yup, Can do.

Got it!
I must have had both opencv_world451.lib and opencv_world451**d**.lib in the Additional Dependencies. Silly me. How curious that the effect was that ‘imread()’ failed although the program built and linked OK.

For reference, the console output is now:

Image to display is: C:\Users\[my_username]\Pictures\DSC_6455_d4.bmp
 Opened: 'C:\Users\[my_username]\Pictures\DSC_6455_d4.bmp'

General configuration for OpenCV 4.5.1 =====================================
  Version control:               4.5.1

  Platform:
    Timestamp:                   2020-12-22T00:43:18Z
    Host:                        Windows 10.0.19041 AMD64
    CMake:                       3.16.4
    CMake generator:             Visual Studio 15 2017
    CMake build tool:            C:/Program Files (x86)/Microsoft Visual Studio/2017/Professional/MSBuild/15.0/Bin/MSBuild.exe
    MSVC:                        1916

  CPU/HW features:
    Baseline:                    SSE SSE2 SSE3
      requested:                 SSE3
    Dispatched code generation:  SSE4_1 SSE4_2 FP16 AVX AVX2 AVX512_SKX
      requested:                 SSE4_1 SSE4_2 AVX FP16 AVX2 AVX512_SKX
      SSE4_1 (15 files):         + SSSE3 SSE4_1
      SSE4_2 (1 files):          + SSSE3 SSE4_1 POPCNT SSE4_2
      FP16 (0 files):            + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 AVX
      AVX (4 files):             + SSSE3 SSE4_1 POPCNT SSE4_2 AVX
      AVX2 (29 files):           + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 FMA3 AVX AVX2
      AVX512_SKX (4 files):      + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 FMA3 AVX AVX2 AVX_512F AVX512_COMMON AVX512_SKX

  C/C++:
    Built as dynamic libs?:      YES
    C++ standard:                11
    C++ Compiler:                C:/Program Files (x86)/Microsoft Visual Studio/2017/Professional/VC/Tools/MSVC/14.16.27023/bin/Hostx86/x64/cl.exe  (ver 19.16.27042.0)
    C++ flags (Release):         /DWIN32 /D_WINDOWS /W4 /GR  /D _CRT_SECURE_NO_DEPRECATE /D _CRT_NONSTDC_NO_DEPRECATE /D _SCL_SECURE_NO_WARNINGS /Gy /bigobj /Oi  /fp:precise     /EHa /wd4127 /wd4251 /wd4324 /wd4275 /wd4512 /wd4589 /MP2  /MD /O2 /Ob2 /DNDEBUG
    C++ flags (Debug):           /DWIN32 /D_WINDOWS /W4 /GR  /D _CRT_SECURE_NO_DEPRECATE /D _CRT_NONSTDC_NO_DEPRECATE /D _SCL_SECURE_NO_WARNINGS /Gy /bigobj /Oi  /fp:precise     /EHa /wd4127 /wd4251 /wd4324 /wd4275 /wd4512 /wd4589 /MP2  /MDd /Zi /Ob0 /Od /RTC1
    C Compiler:                  C:/Program Files (x86)/Microsoft Visual Studio/2017/Professional/VC/Tools/MSVC/14.16.27023/bin/Hostx86/x64/cl.exe
    C flags (Release):           /DWIN32 /D_WINDOWS /W3  /D _CRT_SECURE_NO_DEPRECATE /D _CRT_NONSTDC_NO_DEPRECATE /D _SCL_SECURE_NO_WARNINGS /Gy /bigobj /Oi  /fp:precise     /MP2   /MD /O2 /Ob2 /DNDEBUG
    C flags (Debug):             /DWIN32 /D_WINDOWS /W3  /D _CRT_SECURE_NO_DEPRECATE /D _CRT_NONSTDC_NO_DEPRECATE /D _SCL_SECURE_NO_WARNINGS /Gy /bigobj /Oi  /fp:precise     /MP2 /MDd /Zi /Ob0 /Od /RTC1
    Linker flags (Release):      /machine:x64  /INCREMENTAL:NO
    Linker flags (Debug):        /machine:x64  /debug /INCREMENTAL
    ccache:                      NO
    Precompiled headers:         NO
    Extra dependencies:
    3rdparty dependencies:

  OpenCV modules:
    To be built:                 calib3d core dnn features2d flann gapi highgui imgcodecs imgproc ml objdetect photo stitching video videoio world
    Disabled:                    python2 python3
    Disabled by dependency:      -
    Unavailable:                 java ts
    Applications:                apps
    Documentation:               NO
    Non-free algorithms:         NO

  Windows RT support:            NO

  GUI:
    Win32 UI:                    YES
    VTK support:                 NO

  Media I/O:
    ZLib:                        build (ver 1.2.11)
    JPEG:                        build-libjpeg-turbo (ver 2.0.6-62)
    WEBP:                        build (ver encoder: 0x020f)
    PNG:                         build (ver 1.6.37)
    TIFF:                        build (ver 42 - 4.0.10)
    JPEG 2000:                   build (ver 2.3.1)
    OpenEXR:                     build (ver 2.3.0)
    HDR:                         YES
    SUNRASTER:                   YES
    PXM:                         YES
    PFM:                         YES

  Video I/O:
    DC1394:                      NO
    FFMPEG:                      YES (prebuilt binaries)
      avcodec:                   YES (58.91.100)
      avformat:                  YES (58.45.100)
      avutil:                    YES (56.51.100)
      swscale:                   YES (5.7.100)
      avresample:                YES (4.0.0)
    GStreamer:                   NO
    DirectShow:                  YES
    Media Foundation:            YES
      DXVA:                      YES

  Parallel framework:            Concurrency

  Trace:                         YES (with Intel ITT)

  Other third-party libraries:
    Intel IPP:                   2020.0.0 Gold [2020.0.0]
           at:                   C:/build/master_winpack-build-win64-vc15/build/3rdparty/ippicv/ippicv_win/icv
    Intel IPP IW:                sources (2020.0.0)
              at:                C:/build/master_winpack-build-win64-vc15/build/3rdparty/ippicv/ippicv_win/iw
    Eigen:                       NO
    Custom HAL:                  NO
    Protobuf:                    build (3.5.1)

  OpenCL:                        YES (NVD3D11)
    Include path:                C:/build/master_winpack-build-win64-vc15/opencv/3rdparty/include/opencl/1.2
    Link libraries:              Dynamic load

  Python (for build):            C:/utils/soft/python27-x64/python.exe

  Java:
    ant:                         C:/utils/soft/apache-ant-1.9.7/bin/ant.bat (ver 1.9.7)
    JNI:                         C:/Program Files/Java/jdk1.8.0_112/include C:/Program Files/Java/jdk1.8.0_112/include/win32 C:/Program Files/Java/jdk1.8.0_112/include
    Java wrappers:               NO
    Java tests:                  NO

  Install to:                    C:/build/master_winpack-build-win64-vc15/install
-----------------------------------------------------------------

Again, many thanks to all. Let’s hope this helps someone else.
Peace and blessing.

Richard

laurent.berger · February 1, 2021, 5:33pm

Don’t mix debug and release lib that’s it!

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