findCirclesGrid hangs in c++ but not python

1

I posted something about this on Stack Overflow: opencv's findCirclesdGrid behaves differently in C++ than in python? - Stack Overflow, but to paraphrase, I mocked some opencv stuff up in python and now that I am porting it to c++ I get a hang on findCirclesGrid.

As far as I can tell, I should be calling exactly the same routines with exactly the same parameters in my C++ code as I do in the python version. Please see the SO post for the whole story. I would appreciate any insight as I am completely stumped and this has been blocking me for at least 1/2 a day.

2

How do you check that python and C++ input are the same?

3

I know the original file is the same, because it’s the same file. I check that the ‘preprocessed’ image—after I blur and grey scale it— is identical by saving it in each implementation and then using beyond compare on the 2 outputs. They are identical.

4

I checked that the params used for the blob detector constructor are the same by stepping through in debug mode in each language and verifying that each field has the same value—to within numerical precision they are also identical.

5

Thanks for the swift response, by the way!

6

File are without compression? no jpeg file
May be you can check opencv version using
print(cv.getBuildInformation())
and
cout<<getBuildInformation();

7

The file is a png. I also save the blurred, grey-scaled images as pngs. As I said, both are linking to 4.6.0. They are different builds, however. I got the python modules via pip and I built the C++ bindings myself. Below is a dump of the getBuildInformation calls. I don’t see any glaring differences.

8

Python:
General configuration for OpenCV 4.6.0 =====================================
Version control: 4.6.0

Platform:
Timestamp: 2022-06-07T10:17:42Z
Host: Windows 10.0.17763 AMD64
CMake: 3.22.5
CMake generator: Visual Studio 14 2015
CMake build tool: MSBuild.exe
MSVC: 1900
Configuration: Debug Release

CPU/HW features:
Baseline: SSE SSE2 SSE3
requested: SSE3
Dispatched code generation: SSE4_1 SSE4_2 FP16 AVX AVX2
requested: SSE4_1 SSE4_2 AVX FP16 AVX2 AVX512_SKX
SSE4_1 (16 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 (31 files): + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 FMA3 AVX AVX2

C/C++:
Built as dynamic libs?: NO
C++ standard: 11
C++ Compiler: C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/x86_amd64/cl.exe (ver 19.0.24245.0)
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 /MP /MT /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 /MP /MTd /Zi /Ob0 /Od /RTC1
C Compiler: C:/Program Files (x86)/Microsoft Visual Studio 14.0/VC/bin/x86_amd64/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 /MP /MT /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 /MP /MTd /Zi /Ob0 /Od /RTC1
Linker flags (Release): /machine:x64 /NODEFAULTLIB:atlthunk.lib /INCREMENTAL:NO /NODEFAULTLIB:libcmtd.lib /NODEFAULTLIB:libcpmtd.lib /NODEFAULTLIB:msvcrtd.lib
Linker flags (Debug): /machine:x64 /NODEFAULTLIB:atlthunk.lib /debug /INCREMENTAL /NODEFAULTLIB:libcmt.lib /NODEFAULTLIB:libcpmt.lib /NODEFAULTLIB:msvcrt.lib
ccache: NO
Precompiled headers: YES
Extra dependencies: wsock32 comctl32 gdi32 ole32 setupapi ws2_32
3rdparty dependencies: libprotobuf ade ittnotify libjpeg-turbo libwebp libpng libtiff libopenjp2 IlmImf zlib quirc ippiw ippicv

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

Windows RT support: NO

GUI: WIN32UI
Win32 UI: YES
VTK support: NO

Media I/O:
ZLib: build (ver 1.2.12)
JPEG: build-libjpeg-turbo (ver 2.1.2-62)
WEBP: build (ver encoder: 0x020f)
PNG: build (ver 1.6.37)
TIFF: build (ver 42 - 4.2.0)
JPEG 2000: build (ver 2.4.0)
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 (58.134.100)
avformat: YES (58.76.100)
avutil: YES (56.70.100)
swscale: YES (5.9.100)
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: D:/a/opencv-python/opencv-python/_skbuild/win-amd64-3.6/cmake-build/3rdparty/ippicv/ippicv_win/icv
Intel IPP IW: sources (2020.0.0)
at: D:/a/opencv-python/opencv-python/_skbuild/win-amd64-3.6/cmake-build/3rdparty/ippicv/ippicv_win/iw
Lapack: NO
Eigen: NO
Custom HAL: NO
Protobuf: build (3.19.1)

OpenCL: YES (NVD3D11)
Include path: D:/a/opencv-python/opencv-python/opencv/3rdparty/include/opencl/1.2
Link libraries: Dynamic load

Python 3:
Interpreter: C:/hostedtoolcache/windows/Python/3.6.8/x64/python.exe (ver 3.6.8)
Libraries: C:/hostedtoolcache/windows/Python/3.6.8/x64/libs/python36.lib (ver 3.6.8)
numpy: C:/hostedtoolcache/windows/Python/3.6.8/x64/lib/site-packages/numpy/core/include (ver 1.13.3)
install path: python/cv2/python-3

Python (for build): C:/hostedtoolcache/windows/Python/2.7.18/x64/python.exe

Java:
ant: NO
JNI: C:/hostedtoolcache/windows/Java_Temurin-Hotspot_jdk/8.0.332-9/x64/include C:/hostedtoolcache/windows/Java_Temurin-Hotspot_jdk/8.0.332-9/x64/include/win32 C:/hostedtoolcache/windows/Java_Temurin-Hotspot_jdk/8.0.332-9/x64/include
Java wrappers: NO
Java tests: NO

Install to: D:/a/opencv-python/opencv-python/_skbuild/win-amd64-3.6/cmake-install

9

C++:

General configuration for OpenCV 4.6.0 =====================================
Version control: 4.6.0

Platform:
Timestamp: 2022-06-05T15:53:27Z
Host: Windows 10.0.16299 AMD64
CMake: 3.12.18081601-MSVC_2
CMake generator: Visual Studio 15 2017
CMake build tool: C:/Program Files (x86)/Microsoft Visual Studio/2017/BuildTools/MSBuild/15.0/Bin/MSBuild.exe
MSVC: 1916
Configuration: Debug Release

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 (16 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 (31 files): + SSSE3 SSE4_1 POPCNT SSE4_2 FP16 FMA3 AVX AVX2
AVX512_SKX (5 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/BuildTools/VC/Tools/MSVC/14.16.27023/bin/Hostx86/x64/cl.exe (ver 19.16.27048.0)
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 /MP3 /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 /MP3 /MDd /Zi /Ob0 /Od /RTC1
C Compiler: C:/Program Files (x86)/Microsoft Visual Studio/2017/BuildTools/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 /MP3 /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 /MP3 /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 1.2.12)
JPEG: build-libjpeg-turbo (ver 2.1.2-62)
WEBP: build (ver encoder: 0x020f)
PNG: build (ver 1.6.37)
TIFF: build (ver 42 - 4.2.0)
JPEG 2000: build (ver 2.4.0)
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 (58.134.100)
avformat: YES (58.76.100)
avutil: YES (56.70.100)
swscale: YES (5.9.100)
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 (3.19.1)

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-1.10.12/bin/ant.bat (ver 1.10.12)
JNI: C:/utils/soft/jdk1.8.0_333/include C:/utils/soft/jdk1.8.0_333/include/win32 C:/utils/soft/jdk1.8.0_333/include
Java wrappers: NO
Java tests: NO

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

10

So, it seems that findCirclesGrid isn’t hanging it just takes a loooooooooot longer to return via the C++ bindings as it does in the python build. Is there some reason for this? Why is the underlying libs in the python distribution orders of magnitude quicker than the C++ version?

11

Ah, so the issue was simply that I was running in debug mode. Running in Release it goes as fast as python does.