Using vxAccessDistribution

Hi everybody,

Now I have a grayscale image, then I want to find histogram in 9 directions into distribution and get elements there as follow:

vx_distribution hogDistribution = vxCreateDistribution(context, 9, 0, 180);

vx_node histogramNode = vxHistogramNode(graph, grayscale, hogDistribution);

vx_status status;
vx_uint32* histogramMatrix;

NVXIO_SAFE_CALL(vxQueryNode(histogramNode, VX_NODE_ATTRIBUTE_STATUS, &status, sizeof(status)));
//Here return status = VX_SUCCESS

status = vxAccessDistribution(hogDistribution, (void**)&histogramMatrix, VX_READ_AND_WRITE);
//Here return status = VX_SUCCESS
//But I can't show data onto the screen for checking.

Who can help me explain why it is? And I should how to repair it in order to it works correctly?

Thanks all.


Do you want to show the image ‘grayscale’?
Or detection results?


I want to display results stored inside histogramMatrix but have nothing there.



Do you want to display distribution with ‘ovxio::Render’ (based on VisionWorks-1.6).
This function can render 2D images and some primitive 2D graphic objects, but no distribution.

I’m not sure if there is a function to display distribution.
But usually we read the data directly.