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  • 3.8.1

    • Gaussian Blur

    Gaussian filtering uses a specific filter kernel to convolve the image and is a linear smoothing filter that is widely used in the noise removal process of image processing.

    Operator Effect

    Input ImageParameterOutput Image
    imagekernelSize = 3
    borderType = HB_VP_BORDER_REPLICATE    		image

    Principle

    The 3X3 Gaussian filter kernel is as follows:

    kernel=116[121242121]\begin{aligned}kernel = \frac{1}{16}\begin{bmatrix} 1 & 2 & 1 \\2 & 4 & 2 \\1 & 2 & 1 \end{bmatrix}\end{aligned}

    The 5X5 Gaussian filter kernel is as follows:

    kernel=1256[1464141624164624362464162416414641]\begin{aligned}kernel = \frac{1}{256}\begin{bmatrix}1 & 4 & 6 & 4 & 1 \\4 & 16 & 24 & 16 & 4 \\6 & 24 & 36 & 24 & 6 \\4 & 16 & 24 & 16 & 4 \\1 & 4 & 6 & 4 & 1 \end{bmatrix}\end{aligned}

    API Interface

    int32_t hbVPGaussianBlur(hbUCPTaskHandle_t *taskHandle,,
                         hbVPImage *dstImg,
                         hbVPImage const *srcImg,
                         hbVPGaussianBlurParam const *gaussianParam);

    For detailed interface information, please refer to hbVPGaussianBlur.

    Usage

    // Include the header
#include "hobot/hb_ucp.h"
#include "hobot/vp/hb_vp.h"
#include "hobot/vp/hb_vp_gaussian_blur.h"

// init Image, allocate memory for image data
hbUCPSysMem src_mem;
hbUCPMallocCached(&src_mem, src_stride * src_height, 0);
hbVPImage src_img{HB_VP_IMAGE_FORMAT_Y,
                  HB_VP_IMAGE_TYPE_U8C1,
                  src_width,
                  src_height,
                  src_stride,
                  src_mem.virAddr,
                  src_mem.phyAddr,
                  nullptr,
                  0,
                  0};

hbUCPSysMem dst_mem;
hbUCPMallocCached(&dst_mem, dst_stride * dst_height, 0);
hbVPImage dst_img{HB_VP_IMAGE_FORMAT_Y,
                  HB_VP_IMAGE_TYPE_U8C1,
                  dst_width,
                  dst_height,
                  dst_stride,
                  dst_mem.virAddr,
                  dst_mem.phyAddr,
                  nullptr,
                  0,
                  0};

// init param
hbVPGaussianBlurParam vp_param;
vp_param.kernelSize = 3;
vp_param.borderType = HB_VP_BORDER_REPLICATE;

// init task handle and schedule param
hbUCPTaskHandle_t task_handle{nullptr};
hbUCPSchedParam sched_param;
HB_UCP_INITIALIZE_SCHED_PARAM(&sched_param);
sched_param.backend = HB_UCP_DSP_CORE_0;

// create task
hbVPGaussianBlur(&task_handle, &dst_img, &src_img, &vp_param);

// submit task
hbUCPSubmitTask(task_handle, &sched_param);

// wait for task done 
hbUCPWaitTaskDone(task_handle, 0);

// release task handle
hbUCPReleaseTask(task_handle);

// release memory
hbUCPFree(&src_mem);
hbUCPFree(&dst_mem);