Android API level 21 brings a new Camera2 API that provides much more control over the camera settings and usage modes, it allows several targets for preview frames and OpenGL texture in particular.

Starting Android API level 11 (Android 3.0) Camera API allows use of OpenGL texture as a target for preview frames. In particular let's try two ways: direct calls to OpenCL API and recently introduced OpenCV T-API (aka Transparent API) - implicit OpenCL accelerations of some OpenCV algo-s. Let's consider how we can use OpenCL in this scenario. The most popular CV application scenario for an Android operated device is starting camera in preview mode, applying some CV algo to every frame and displaying the preview frames modified by that CV algo. Recently it has become possible on Android OS. image filtering) run much faster on a GPU than on a CPU. Using GPGPU via OpenCL for applications performance enhancements is quite a modern trend now.

The related source code is located within OpenCV samples at opencv/samples/android/tutorial-4-opencl directory.

This tutorial also assumes you have an Android operated device with OpenCL enabled. If you need help with anything of the above, you may refer to our Introduction into Android Development guide. It also assumes that you are familiar with Android Java and JNI programming basics. This tutorial assumes you have the following installed and configured: It was written for Eclipse-based ADT tools (deprecated by Google now), but it easily can be reproduced with Android Studio. This guide was designed to help you in use of OpenCL ™ in Android camera preview based CV application. Prev Tutorial: Android Development with OpenCV

Android studio preview view