Problems when running "tutorial-apriltag-detector-live.exe"

[The-Magic-Sword]

I completed the installation according to Tutorial: Installation from source for Windows 11 with Visual C++ 2022 (vc17).
When I tested it, the object recognition for the "tutorial-apriltag-detector.exe" worked fine, but for the -live.exe, I had to install a 3rd party dedicated to frame grabbing.

I have installed third-party libraries such as opencv. Do I need to make other settings during CMake configuration?

[The-Magic-Sword]

It is a problem with opencv configuration. From the printed configuration information, opencv is not installed.
General configuration information for ViSP 3.6.1

Version control: v3.6.0-2036-ge3dfc17d4

Platform:
Timestamp: 2025-01-20T06:09:08Z
Host: Windows 10.0.26100 AMD64
CMake: 3.31.4
CMake generator: Visual Studio 17 2022
CMake build tool: E:/Application/Visual Studio 2022/program/IDE/MSBuild/Current/Bin/amd64/MSBuild.exe
MSVC: 1942

System information:
Number of CPU logical cores: 22
Number of CPU physical cores: 16
Total physical memory (in MiB): 32173
OS name: Windows
OS release: Personal
OS version: (Build 26100)
OS platform: AMD64
CPU name: Pentium III (0.18 micron) With 1 Or 2 MB On-Die L2 Cache
Is the CPU 64-bit? yes
Does the CPU have FPU? yes
CPU optimization: SSE2 SSE3 SSSE3 SSE4_1 SSE4_2

C/C++:
Built as dynamic libs?: yes
C++ Compiler: E:/Application/Visual Studio 2022/program/IDE/VC/Tools/MSVC/14.42.34433/bin/Hostx64/x64/cl.exe (ver 19.42.34436.0)
C++ flags (Release): /DWIN32 /D_WINDOWS /W3 /GR /EHsc /MP22 /EHa -openmp /Gy /bigobj /MD /O2 /Ob2 /DNDEBUG
C++ flags (Debug): /DWIN32 /D_WINDOWS /W3 /GR /EHsc /MP22 /EHa -openmp /Gy /bigobj /MDd /Zi /Ob0 /Od /RTC1
C Compiler: E:/Application/Visual Studio 2022/program/IDE/VC/Tools/MSVC/14.42.34433/bin/Hostx64/x64/cl.exe
C flags (Release): /DWIN32 /D_WINDOWS /W3 /MP22 /EHa -openmp /MD /O2 /Ob2 /DNDEBUG
C flags (Debug): /DWIN32 /D_WINDOWS /W3 /MP22 /EHa -openmp /MDd /Zi /Ob0 /Od /RTC1
Linker flags (Release): /machine:x64 /INCREMENTAL:NO
Linker flags (Debug): /machine:x64 /debug /INCREMENTAL /ignore:4099
Use cxx standard: 17

ViSP modules:
To be built: core dnn_tracker gui imgproc io java_bindings_generator klt me sensor ar blob robot visual_features vs vision detection mbt tt tt_mi
Disabled: -
Disabled by dependency: -
Unavailable: java
Enable visp namespace: no
Enable explicit keyword: no

Windows RT support: no

Python 3:
Interpreter: C:/Users/14941/AppData/Local/Microsoft/WindowsApps/python3.11.exe (ver 3.11.9)

Java:
ant: no
JNI: no

Python3 bindings: no
Requirements:
Python version > 3.7.0: ok (ver 3.11.9)
Python in Virtual environment or conda:
failed
Pybind11 found: failed
CMake > 3.19.0: ok (3.31.4)
C++ standard > 201703L: ok (201703L)

Build options:
Build deprecated: yes
Build with moment combine: no

OpenCV:
Version: n/a

YARP:
Version: n/a

Mathematics:
Blas/Lapack: yes
- Use MKL: no
- Use OpenBLAS: no
- Use Atlas: no
- Use Netlib: no
- Use GSL: no
- Use Lapack (built-in): yes (ver 3.2.1)
Use Eigen3: yes (ver 3.4.0)
Use OpenCV: no

Simulator:
Ogre simulator:
- Use Ogre3D: no
- Use OIS: no
Coin simulator:
- Use Coin3D: no
- Use SoWin: no
- Use SoXt: no
- Use SoQt: no
- Use Qt5: no
- Use Qt4: no
- Use Qt3: no
Panda3D: no

Media I/O:
Use JPEG: no
Use PNG: no
- Use ZLIB: no
Use OpenCV: no
Use stb_image (built-in): yes (ver 2.30.0)
Use TinyEXR (built-in): yes (ver 1.0.9)
Use simdlib (built-in): yes (ver 4.9.109)
Use npz I/O (built-in): yes

Real robots:
Use Afma4: no
Use Afma6: no
Use Franka: no
Use Viper650: no
Use Viper850: no
Use ur_rtde: no
Use Kinova Jaco: no
Use aria (Pioneer): no
Use PTU46: no
Use Biclops PTU: no
Use Flir PTU SDK: no
Use MAVSDK: no
Use Parrot ARSDK: no
-Use ffmpeg: no
Use Virtuose: no
Use qbdevice (built-in): yes (ver 2.6.0)
Use takktile2 (built-in): no
Use pololu (built-in): yes (ver 1.0.0)

GUI:
Use X11: no
Use GTK: no
Use OpenCV: no
Use GDI: yes
Use Direct3D: no

Cameras:
Use DC1394-2.x: no
Use CMU 1394: no
Use V4L2: no
Use directshow: no
Use OpenCV: no
Use FLIR Flycapture: no
Use Basler Pylon: no
Use IDS uEye: no

RGB-D sensors:
Use Realsense: no
Use Realsense2: no
Use Occipital Structure: no
Use Kinect: no
- Use libfreenect: no
- Use libusb-1: no
- Use std::thread: yes
Use PCL: no
- Use VTK: no

F/T sensors:
Use atidaq (built-in): no
Use comedi: no
Use IIT SDK: no

Mocap:
Use Qualisys: no
Use Vicon: no

Detection:
Use zbar: no
Use dmtx: no
Use AprilTag (built-in): yes (ver 3.4.2)
- Use AprilTag big family: no

Misc:
Use Clipper (built-in): no
Use pugixml (built-in): yes (ver 1.14.0)
Use libxml2: no
Use json (nlohmann system): yes (ver 3.11.3)

Optimization:
Use OpenMP: yes (ver 2.0)
Use std::thread: yes
Use pthread: no
Use simdlib (built-in): yes (ver 4.9.109)

DNN:
Use CUDA Toolkit: no
Use TensorRT: no

Documentation:
Use doxygen: yes (ver 1.13.2)
- Use mathjax: no

Tests and samples:
Use catch2 (built-in): yes (ver 3.7.1)
Tests: yes
Apps: yes
Demos: yes
Examples: yes
Tutorials: yes
Dataset found: yes (ver 3.7.0 in D:\NUS\semester2\visp-ws\visp-images)

Library dirs:
Eigen3 dir: D:/NUS/semester2/visp-ws/3rdparty/eigen-3.4.0/build-vc17/install/share/eigen3/cmake

Install path: D:/NUS/semester2/visp-ws/visp-build-vc17/install

==========================================================

[fspindle]

I'm pretty sure that OpenCV is not detected by CMake because you didn't follow instructions Complete OpenCV installation that consists in setting OpenCV_DIR env var and also adding the path to OpenCV dll in the Path env var.

[The-Magic-Sword]

I reinstalled opencv according to the tutorial, but cmake still cannot recognize it. The required paths and variables have been added.

The only thing I'm not sure about is that the tutorial note says: OpenCV 4.8.0 win pack installer doesn't contain prebuild OpenCV libraries build with Visual Studio 17 2022. It contains only prebuild libraries build with Visual Studio 16 2019 (vc16). That's why we need to build OpenCV from source.
But when adding the path in the tutorial, it becomes the bin file under vc17: %VISP_WS%\3rdparty\opencv-4.8.0\build\x64\vc17\bin

[fspindle]

Open a new command shell terminal and check using echo %OpenCV_DIR% that OpenCV_DIR env var is set to D:\NUS\semester2\visp-ws\3rdparty\opencv-4.8.0\build

Then close CMake GUI before opening it again, and try a new ViSP configuration. Does USE_OPENCV appear?

Note also that even if it is written in the tutorial that OpenCV 4.8.0 win pack installer doesn't contain prebuild OpenCV libraries build with Visual Studio 17 2022, ViSP should be able to detect and build with OpenCV build with vc16.

[The-Magic-Sword]

I have installed it on Ubuntu, may I ask in servoBbop2.cpp(https://visp-doc.inria.fr/doxygen/visp-daily/servoBebop2_8cpp_source.html) line 250 vpDetectorAprilTag::vpAprilTagFamily tagFamily = vpDetectorAprilTag::TAG_36h11;
Can the detector contain two tags simultaneously, which means I only detect 1 tag but want to include different tags?

[fspindle]

It can detect multiple tags from the same family like in tutorial-apriltag-detector.cpp.

It can also detected multiple tags from different families, but for each family you need to instantiate a new vpDetectorAprilTag object.