Augmented Reality Simple Shape Detector using OpenCV 4 for Android

Attention: This app was created in 2016. I was a beginner to Android development and Computer Vision back then. So don't expect a perfect code please. Over the years I updated the dependencies and converted it to Kotlin, while the business logic remained unchanged.

Note: Originally I targeted min SDK 15 (Android 4), more architectures ("mips", "mips64", "armeabi") and OpenCV 3 with this project. Nowadays the repo uses newer versions. If you need to support older devices, then you can look back in the repo's Git history (app version 1.2 / Git tag 3)

What is this repository for?

• Uses the camera image to recognize triangles, rectangles and circles. It can also be configured to only detect a certain color (red). If a specific shape is detected the information can be shown on top of each shape as a label describing it (multiple shapes at the same time) or as an image respresenting the shape on top of the camera (only one shape is detected). Additionally also a sound depending on the detected shape can be played.
• More computer vision projects at https://michaeltroger.com/computervision/

How do I get set up?

• IDE: Android Studio (tested with 2023.3.1)
• Android SDK
• Images location: res/drawable | Sounds location: res/raw
• Mode (label/image): Flag in MainActivity (default labels)
• Mode (all colors / red only): Flag in MainActivity (default all colors)

Test images

Author

Michael Troger

Credits

• The shape detection is based on Nash's shape detection https://github.com/bsdnoobz/opencv-code/blob/master/shape-detect.cpp His version is based on OpenCV 2 for the PC and usable for static images files. He extracted the code from the OpenCV tutorials http://opencv-code.com back then - that website is no longer available though.
• The red color detection is based on Sol's OpenCV red circle detection. See https://github.com/sol-prog/OpenCV-red-circle-detection and https://solarianprogrammer.com/2015/05/08/detect-red-circles-image-using-opencv/