The tutorial Use OpenCL in Android camera preview based CV application show us how we can use the Transparent API to dramatically increase the performance of some expensive operations.
The first step in order to be able to execute the tutorial example is to re-compile opencv with the correct flags:
# Export your NDK, it will be looked for OpenCV to compile your project. In my case
export ANDROID_NDK=~/graffter/libs/android-ndk-r10d/
# Download the necessary code