How to use Vivante for face recognition on imx6q Saber Lite board?

[ivanskl]

I want to use OpenCL for face recognition enhancement.

I am using code OpenCV-2.x from OpenCV documentation:

VideoCapture vcap(...);
ocl::OclCascadeClassifier fd("haar_ff.xml");
ocl::oclMat frame, frameGray;
Mat frameCpu;
vector<Rect> faces;
for(;;){
// processing loop
vcap >> frameCpu;
frame = frameCpu;
ocl::cvtColor(frame, frameGray, BGR2GRAY);
ocl::equalizeHist(frameGray, frameGray);
fd.detectMultiScale(frameGray, faces, ...);
// draw rectangles
// show image

That code compiles well, but program don't work with error:

OpenCV Error: Assertion failed (localThreads[0] * localThreads[1] * localThreads[2] <= kernelWorkGroupSize) in openCLVerifyKernel,
file /root/Downloads/opencv-2.4.9/modules/ocl/src/cl_operations.cpp, line 349
terminate called after throwing an instance of 'cv::Exception'
what(): /root/Downloads/opencv-2.4.9/modules/ocl/src/cl_operations.cpp:349:
error: (-215) localThreads[0] * localThreads[1] * localThreads[2] <= kernelWorkGroupSize in function openCLVerifyKernel

My board is imx6q Saber Lite with Ubuntu Xenial for i.MX6/7 boards  August 2016 (kernel 4.1.15) image.

I can't find how to resolve this problem. And if it's not possible at all to use OpenCL, there is a question: how can I speed up a face recognition on imx6q Saber Lite?

[Bio_TICFSL]

Hi Ivan,

Looks like OpenCV is not using floating point, needs to install again, OpenCV works on Sabre board.

[ivanskl]

OpenCV works, only that code doesn't work.

I recompiled Ot with options in qmake.conf:

IMX6_CFLAGS             = -mthumb -O3 -march=armv7-a -mcpu=cortex-a9 -mtune=cortex-a9 -mvectorize-with-neon-quad -mfpu=neon -mfloat-abi=hard -DLINUX=1 -DEGL_API_FB=1

And I recompiled OpenCV with options:

cmake CMAKE_BUILD_TYPE=RELEASE -DWITH_TBB=ON -DWITH_OPENGL=ON -DENABLE_NEON=ON -DENABLE_VFPV3=ON

But the same error.

I found out operation frame=frameCpu in code gives error.

[mtx512]

imx6q only supports OpenCL 1.1 Embedded Profile not the Full Profile therefore it cant' be enabled for OpenCV. Ideally OpenCV  requires a SOC with OpenCL 1.2 Full Profile support. If you can move to imx6q plus then OpenGL 1.2 support should be available.

The only optimization would be  to ENABLE_NEON=ON and ENABLE_VFPV3=ON .