example: T265 apriltag detection on host #4340

honpong · 2019-07-01T13:07:10Z

@dorodnic I wrote a simple example of t265 apriltag detection running on host. Here we assume the apriltag detection library has been installed in the default path, e.g /usr/local/lib, and cmake find library from there. If no apriltag library found, this sample will simply not be added to the solution.

If this is not the expected way of cmake configuration, please suggest how to properly link a thirdparty library (Apriltag detection) in a librealsense example, the best if you can provide us a blank cmake template.

cc @dorian3d @bfulkers-i @harville

…S COMPLIANCE)

add apriltag lib dependency notice.

dorian3d · 2019-07-03T19:47:05Z

examples/pose-apriltag/rs-pose-apriltag.cpp

+        if(frame_number % 4 == 0)
+        {
+            fisheye_frame.keep();
+            std::async(std::launch::async, [img=fisheye_frame,fn=frame_number,pose=camera_pose,&tag_manager](){


Initialization in lambda captures is a C++14 feature. You may need to stick to C++11 unless it is ok for libRealSense to change the standard in a single sample.

If the latter, set_target_properties(rs-pose-apriltag PROPERTIES CXX_STANDARD 14) has to be added to cmake.

updated to use std::bind()

dorian3d · 2019-07-03T19:47:36Z

examples/pose-apriltag/rs-pose-apriltag.cpp

+        }
+        A[col*9 + 8] = (A[col*9 + 8] - sum)/A[col*9 + col];
+    }
+   return matd_create_data(3, 3, (double[]) { A[8], A[17], A[26], A[35], A[44], A[53], A[62], A[71], 1 });


g++ complains here about taking the address of a temporary array.

updated to direct memory assignement

dorian3d · 2019-07-03T19:51:16Z

examples/pose-apriltag/CMakeLists.txt

+    find_path(APRILTAG_INC NAMES apriltag.h PATH_SUFFIXES apriltag)
+    find_library(APRILTAG_LIB apriltag)
+    include(FindPackageHandleStandardArgs)
+    find_package_handle_standard_args(apriltag DEFAULT_MSG APRILTAG_INC APRILTAG_LIB)


In my setup, I installed the apriltag library in a custom directory. The only way of making it work was to set APRILTAG_INC=mypath/install/include/apriltag and APRILTAG_LIB=mypath/install/lib/libapriltag.so in cmake. Note that I had to specify the inner subdirectory in include/apriltag and the library file libapriltag.so. Setting CMAKE_PREFIX_PATH didn't help, or I didn't do it correctly.

Is this behavior expected?

@dorian3d, CMAKE_PREFIX_PATH should work. Make sure to kill your build directory if you forgot to set CMAKE_PREFIX_PATH the first time, or run cmake -UAPRILTAG_INC -UAPRILTAG_LIB . to force the auto-detection to happen again.

Starting from scratch helped and CMAKE_PREFIX_PATH works 👍

…itialization as C++14 functionality.

rs-pose-apriltag specifies Apriltag library version used

Readme.md adds link to tag image pdf and the original tag images directory.

sample tag size in the pdf is 0.144m

…igh confidence

add comment about homography in undistorted image coordinate handling

ev-mp

Please add it to the demos list here

ev-mp · 2019-07-10T14:05:18Z

examples/pose-apriltag/readme.md

+
+## Dependency
+
+This sample requires the [Apriltag library 3.1.1](https://github.com/AprilRobotics/apriltag/tree/3.1.1)  installed in the default location suggested by the library or a path specified in cmake variable `CMAKE_PREFIX_PATH`.


In order for the demo to be built into distribution images (both Win and Linux) all the dependencies should be embedded into the project's Cmake ( see Libusb dependency, for instance).
So for now it will be available via the manual build only.

@ev-mp I think we are okay via manual build at this moment.

rs-pose-apriltag: add item in the readme index page of examples

honpong · 2019-07-11T06:05:02Z

Please add it to the demos list here

@ev-mp added

ev-mp

@honpong, thanks for the demo!

mickeyouyou · 2019-07-21T14:49:55Z

where this update went?

honpong · 2019-07-21T22:27:47Z

@mickeyouyou it has been merged into the development branch.

mickeyouyou · 2019-07-22T07:52:28Z

yeah thank you so much for your contribution.

patrickpoirier51 · 2019-08-06T12:28:58Z

So I guess we use this one ?
https://github.com/AprilRobotics/apriltag

bfulkers-i · 2019-08-06T12:43:34Z

@patrickpoirier51 correct, this example uses https://github.com/AprilRobotics/apriltag. Check the example readme at https://github.com/IntelRealSense/librealsense/tree/master/examples/pose-apriltag for instructions including how to install the Apriltag library locally and get CMake to find it.

neilyoung · 2019-11-04T16:24:43Z

@honpong Thanks for this neat contribution. Do you know a way in order to make this detection available for a python script?

honpong · 2019-11-05T05:41:00Z

@neilyoung, is this https://github.com/AprilRobotics/apriltag/wiki/AprilTag-User-Guide#python something you may consider?

neilyoung · 2019-11-05T08:46:27Z

@honpong Great reference. Many thanks. May I ask you two easy questions regarding your sample?

honpong · 2019-11-05T08:49:03Z

@neilyoung, yes

neilyoung · 2019-11-05T12:21:07Z

@honpong Many thanks. I first need to check an assumption I made regarding your sample code. Could you confirm this assumption? Please find it here #5184

honpong · 2019-11-06T09:52:33Z

@neilyoung, please see my new comment #5184.

neilyoung · 2019-11-06T11:40:34Z

@honpong Yepp, added yet another comment :)

honpong added 4 commits July 3, 2019 16:03

example: t265 apriltag pose detection

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example: cmake add t265 apriltag example

76f4465

example: cmake add t265 apriltag executable. (TO BE MODIFIED FOR LIBR…

1026466

…S COMPLIANCE)

example: pose-apriltag add readme.md

438bedd

honpong force-pushed the t265-apriltag-host branch from cb2714f to 438bedd Compare July 3, 2019 08:05

radfordi and others added 3 commits July 3, 2019 16:54

rs-pose-apriltag: use newer cmake style

052dd05

rs-pose-apriltag: auto-detect install apriltag library

6589f19

Update readme.md

dffea43

add apriltag lib dependency notice.

dorian3d reviewed Jul 3, 2019

View reviewed changes

honpong added 3 commits July 5, 2019 17:28

example: rs-pose-apriltag remove use of temporary array address.

c999655

example: rs-pose-apriltag use std::bind instead of lambda argument in…

d5c2a94

…itialization as C++14 functionality.

example rs-pose-apriltag readme specify lib version

eb68b6c

rs-pose-apriltag specifies Apriltag library version used

catree mentioned this pull request Jul 5, 2019

Add AprilTag 3 module opencv/opencv_contrib#2143

Closed

bfulkers-i added 8 commits July 8, 2019 15:50

rs-pose-apriltag: Set the C++11 standard correctly

4139124

rs-pose-apriltag: Add a status message if Apriltag is missing

5c51789

rs-pose-apriltag: Make the size of the Apriltag more visible

4d8823d

rs-pose-apriltag: remove extra return statement

527efee

rs-pose-apriltag: add documentation on how to build apriltag library

923001f

rs-pose-apriltag: detect every 6th frame for 5Hz

421b535

rs-pose-apriltag: use more robust pose estimation

e873c9a

rs-pose-apriltag: print when there are no detections

3e36c94

bfulkers-i force-pushed the t265-apriltag-host branch from 95a1272 to 3e36c94 Compare July 8, 2019 15:23

honpong added 6 commits July 9, 2019 14:25

rs-pose-apriltag: add sample apriltag image pdf

a5e9290

readme add link to tag image pdf

f03f7e8

Readme.md adds link to tag image pdf and the original tag images directory.

readme.md specifies sample tag size

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sample tag size in the pdf is 0.144m

rs-pose-apriltag: format spacing

06e091b

rs-pose-apriltag: add comment and alternative to tag pose estimation

69e9407

rs-pose-apriltag: add comment regarding homography

75c22e8

honpong added 2 commits July 9, 2019 15:21

rs-pose-apriltag: only print world tag pose when tracker output has h…

3724ec3

…igh confidence

Readme.md updates about homography

62495c4

add comment about homography in undistorted image coordinate handling

bfulkers-i assigned ev-mp Jul 9, 2019

ev-mp reviewed Jul 10, 2019

View reviewed changes

rs-pose-apriltag: index readme page examples add

bd59f3b

rs-pose-apriltag: add item in the readme index page of examples

ev-mp approved these changes Jul 11, 2019

View reviewed changes

ev-mp merged commit 506b040 into IntelRealSense:development Jul 11, 2019

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example: T265 apriltag detection on host #4340

example: T265 apriltag detection on host #4340

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neilyoung commented Nov 6, 2019


		## Dependency

		This sample requires the [Apriltag library 3.1.1](https://github.com/AprilRobotics/apriltag/tree/3.1.1) installed in the default location suggested by the library or a path specified in cmake variable `CMAKE_PREFIX_PATH`.

example: T265 apriltag detection on host #4340

example: T265 apriltag detection on host #4340

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