Apriltags

.circleci/config.yml

@@ -6,38 +6,93 @@ jobs:
     steps:
       - run: apt-get update -qq && apt-get install -qq git
       - checkout
-      - run: DEBIAN_FRONTEND=noninteractive ./InstallPackagesUbuntu.sh
-      - run: make
+      - run:
+          name: "Install dependencies"
+          command: |
+            DEBIAN_FRONTEND=noninteractive ./InstallPackagesUbuntu.sh
+      - run:
+          name: "Build"
+          command: make
   build-v4l:
     docker:
-        - image: ubuntu:18.04
+      - image: ubuntu:18.04
     steps:
       - run: apt-get update -qq && apt-get install -qq git
       - checkout
-      - run: DEBIAN_FRONTEND=noninteractive ./InstallPackagesUbuntu.sh
-      - run: mkdir -p build && cd build && cmake -DUSE_V4L=true .. && cd ..
-      - run: make
+      - run:
+          name: "Install dependencies"
+          command: |
+            DEBIAN_FRONTEND=noninteractive ./InstallPackagesUbuntu.sh
+      - run:
+          name: "Configure"
+          command: |
+            mkdir -p build
+            cmake -B build -DUSE_V4L=true .
+      - run:
+          name: "Build"
+          command: make
   build-splitter:
     docker:
       - image: ubuntu:18.04
     steps:
       - run: apt-get update -qq && apt-get install -qq git
       - checkout
-      - run: DEBIAN_FRONTEND=noninteractive ./InstallPackagesUbuntu.sh
-      - run: mkdir -p build && cd build && cmake -DUSE_SPLITTER=true .. && cd ..
-      - run: cmake -B build -DUSE_SPLITTER=true .
-      - run: make
+      - run:
+          name: "Install dependencies"
+          command: |
+            DEBIAN_FRONTEND=noninteractive ./InstallPackagesUbuntu.sh
+      - run:
+          name: "Configure"
+          command: |
+            mkdir -p build
+            cmake -B build -DUSE_SPLITTER=true .
+      - run:
+          name: "Build"
+          command: make
   build-qt5:
     docker:
       - image: ubuntu:18.04
     steps:
       - run: apt-get update -qq && apt-get install -qq git
       - checkout
-      - run: DEBIAN_FRONTEND=noninteractive ./InstallPackagesUbuntu.sh
-      - run: apt-get install -qq qtdeclarative5-dev
-      - run: mkdir -p build && cd build && cmake -DUSE_QT5=true .. && cd ..
-      - run: cmake -B build -DUSE_QT5=true .
-      - run: make
+      - run:
+          name: "Install dependencies"
+          command: |
+            DEBIAN_FRONTEND=noninteractive ./InstallPackagesUbuntu.sh
+            apt-get install -qq qtdeclarative5-dev
+      - run:
+          name: "Configure"
+          command: |
+            mkdir -p build
+            cmake -B build -DUSE_QT5=true .
+      - run:
+          name: "Build"
+          command: make
+  build-apriltag:
+    docker:
+      - image: ubuntu:18.04
+    steps:
+      - run: apt-get update -qq && apt-get install -qq git
+      - checkout
+      - run:
+          name: "Install dependencies"
+          command: |
+            DEBIAN_FRONTEND=noninteractive ./InstallPackagesUbuntu.sh
+      - run:
+          name: "Install april tag"
+          command: |
+            git clone https://github.com/AprilRobotics/apriltag.git
+            cd apriltag
+            cmake .
+            make install
+      - run:
+          name: "Configure"
+          command: |
+            mkdir -p build
+            cmake -B build -DUSE_APRILTAG=true .
+      - run:
+          name: "Build"
+          command: make
 
 workflows:
   version: 2
@@ -47,3 +102,4 @@ workflows:
       - build-v4l
       - build-splitter
       - build-qt5
+      - build-apriltag

.gitignore

@@ -5,4 +5,8 @@
 /backup
 /test-data/**
 /.idea
+/.dir-locals.el
+.ccls-cache
+*~
 cmake-build*
+/compile_commands.json

CMakeLists.txt

@@ -8,6 +8,7 @@ set(USE_PYLON FALSE CACHE BOOL "Compile with pylon driver (Basler cameras)")
 set(USE_FLYCAP FALSE CACHE BOOL "Compile with flycap driver (FLIR cameras, predecessor of Spinnaker)")
 set(USE_V4L FALSE CACHE BOOL "Compile with Video4Linux support (generic webcams)")
 set(USE_SPLITTER FALSE CACHE BOOL "Compile with Camera splitter support (virtual cameras with part of a full image)")
+set(USE_APRILTAG FALSE CACHE BOOL "Compile with apriltag detection for robots")
 
 if(USE_DC1394 AND USE_mvIMPACT)
 	message(FATAL_ERROR "DC1394 and mvImpact are not compatible: mvImpact crashes when creating device manager")
@@ -190,6 +191,15 @@ else()
 	message(STATUS "Camera splitter disabled")
 endif()
 
+if(USE_APRILTAG)
+  find_package(apriltag REQUIRED)
+  add_definitions(-DAPRILTAG)
+  set(SRCS ${SRCS} src/app/plugins/plugin_apriltag.cpp)
+  message(STATUS "apriltag enabled")
+else()
+  message(STATUS "apriltag disabled")
+endif()
+
 include_directories(${PROJECT_SOURCE_DIR}/src/app)
 include_directories(${PROJECT_SOURCE_DIR}/src/app/gui)
 include_directories(${PROJECT_SOURCE_DIR}/src/app/plugins)
@@ -220,6 +230,7 @@ set (SRCS ${SRCS}
 	src/app/plugins/plugin_detect_balls.cpp
 	src/app/plugins/plugin_detect_robots.cpp
 	src/app/plugins/plugin_find_blobs.cpp
+	src/app/plugins/plugin_greyscale.cpp
 	src/app/plugins/plugin_publishgeometry.cpp
 	src/app/plugins/plugin_legacypublishgeometry.cpp
 	src/app/plugins/plugin_runlength_encode.cpp
@@ -347,6 +358,9 @@ set (libs ${QT_LIBRARIES}
 	${SPINNAKER_LIBS}
 )
 target_link_libraries(sslvision ${libs})
+if(USE_APRILTAG)
+  target_link_libraries(sslvision apriltag)
+endif()
 if(USE_QT5)
 	qt5_use_modules(sslvision Widgets)
 endif()
@@ -356,6 +370,9 @@ set (libs ${libs} sslvision)
 set (target vision)
 add_executable(${target} ${UI_SRCS} ${MOC_SRCS} ${RC_SRCS} ${SRCS})
 target_link_libraries(${target} ${libs})
+if (USE_APRILTAG)
+  target_link_libraries(${target} apriltag)
+endif()
 if(USE_QT5)
 	qt5_use_modules(${target} Widgets OpenGL)
 endif()

README.md

@@ -112,7 +112,44 @@ cmake -DUSE_WHAT_SO_EVER=true ..
 cd ..
 make
 ```
-The `USE_*` parameters are cached, so they do not have to be passed in each time.
+The `USE_*` parameters are cached, so they do not have to be passed in
+each time.
+
+### Apriltags Support
+
+There is experimental support for detecting and tracking robots via
+[Apriltags](https://april.eecs.umich.edu/software/apriltag). The
+standard tag sets in the [Apriltags Imgs
+Repo](https://github.com/AprilRobotics/apriltag-imgs) are all
+supported along with two customized tag sets:
+
+- Custom20h7: 26 unique tags
+
+To generate the custom tag images you must use the
+[Apriltag-Generation
+Repo](https://github.com/AprilRobotics/apriltag-generation). Follow
+the instructions listed in the repo. The tag layouts are as follows:
+
+- Custom20h7
+
+  custom_xxddddxxxwwwwwwxdwbbbbwddwbddbwddwbddbwddwbbbbwdxwwwwwwxxxddddxx
+
+The hamming distance used during generation are as follows:
+
+- Custom20h7: 7
+
+To enable you must set the `USE_APRILTAG` option to `ON`. e.g.:
+
+``` bash
+cd build
+cmake -DUSE_APRILTAG=ON ..
+cd ..
+make
+```
+
+This will add a new plugin to each camera that runs on every frame. At
+the moment the old robot detection patterns are detected in addition
+to the apriltag detection.
 
 ## Running
 
@@ -199,3 +236,40 @@ program refuses to start completely when parsing the XML files
 (this should normally never occur) then simply delete all
 XML files and restart. The program will restore its default
 settings.
+
+#### Apriltags
+
+Unlike the butterfly pattern, there are no colors in the apriltags. So
+you must manually assign tag ids to the different team colors. Under
+Global settings there are two settings list "Blue April Tags" and
+"Yellow April Tags". Expand each list and click "Add Tag" to create a
+new tag entry for the associated team color. Expand the new entry and
+edit the value to a valid tag id in order to begin detection.
+
+You must also configure the apriltag detection settings. The settings
+are per camera under the "AprilTag" settings in each thread. Select
+the tag family and configure the size in mm of the side of the
+Apriltag quad. See the apriltags repository for explanation of the
+other options and how they affect detection accuracy and speed.
+
+Apriltag detection takes place on a greyscale version of the image. To
+see this image enable "greyscale" un the Visualization plugin for the
+appropriate camera. If a tag is not detecting check the greyscale
+image contrast. Verify that the tag doesn't have a glare or a large
+contrast due to shadows.
+
+Under the Visualization plugin you can also enable the "detected
+AprilTags" option. This will draw a cyan border around the quad of the
+tag (i.e. the part you should measure and enter as quad size in the
+detector settings). It will also draw the tag id in magenta over the
+detected tag.
+
+##### Large Distortions
+
+Currently, the tag detection runs on a raw image provided by the
+camera to maximize performance. Fixes for distortion happen *AFTER*
+detection. However, the apriltag detector is designed to work on
+undistorted (aka rectified) images. If your camera lens has a large
+distortion (you can see this by the field lines and other image lines
+being highly curved), then the detection accuracy may be lower or even
+fail.