FilterSobelBorder

Applies the Sobel filter to the source image and stores the result to the destination image. The border pixel values are determined based on the specified border type and border value parameters. The filter kernel is a 3x3 or 5x5 matrix mask specified by an input parameter. The kernel has the following values, with the anchor located in the center cell.

1 2 1

0 0 0

-1 -2 -1

1 4 6 4 1

2 8 12 8 2

0 0 0 0 0

-2 -8 -12 -8 -2

-1 -4 -6 -4 -1

The function is declared as follows:

HmppResult HMPPI_FilterSobelHorizBorder_32f_C1R(const float* pSrc, int srcStep, float* pDst, int dstStep, HmppiSize roi, HmppiMaskSize maskSize, HmppiBorderType borderType, float borderValue);

HmppResult HMPPI_FilterSobelNegVertBorder_32f_C1R(const float* pSrc, int srcStep, float* pDst, int dstStep, HmppiSize roi, HmppiMaskSize maskSize, HmppiBorderType borderType, float borderValue);

Parameters

Parameter	Description	Value Range	Input/Output
pSrc	Pointer to the source vector	The value cannot be NULL.	Input
srcStep	Distance between starts of consecutive lines in the source image, in bytes	(0, INT_MAX]	Input
pDst	Pointer to the destination vector	The value cannot be NULL.	Output
dstStep	Distance between starts of consecutive lines in the destination image, in bytes	(0, INT_MAX]	Input
roiSize	Size of the ROI of the source and destination images, in pixels	roiSize.width ∈ (0, INT_MAX], roiSize.height ∈ (0, INT_MAX]	Input
maskSize	Predefined mask	HmppMskSize3x3 or HmppMskSize5x5	Input
borderType	Border type	The value is one of the following enumerated values of HmppiBorderType: HMPPI_BORDER_CONST HMPPI_BORDER_REPL HMPPI_BORDER_MIRROR	Input
borderValue	Constant value of the constant border pixel. This parameter is valid only when borderType is set to HMPPI_BORDER_CONST.	Value within the data type range	Input

Return Value

Success: HMPP_STS_NO_ERR
Failure: An error code is returned.

Error Codes

Error Code	Description
HMPP_STS_NULL_PTR_ERR	The value of pSrc or pDst is NULL.
HMPP_STS_SIZE_ERR	The value of roiSize.width or roiSize.height is less than or equal to 0.
HMPP_STS_STEP_ERR	The value of srcStep or dstStep is less than or equal to 0.
HMPP_STS_ROI_ERR	The result of roiSize.width x Number of bytes occupied by the data type is greater than the step.
HMPP_STS_NOT_EVEN_STEP_ERR	The value of srcStep or dstStep cannot be exactly divided by the byte length of the data type to which src or dst belongs.
HMPP_STS_BAD_ARG_ERR	The value of borderType or maskSize is not supported.

Example

#include <stdio.h>
#include "hmppi.h"
#include "hmpp_type.h"
#define SRC_BUFFER_SIZE_T 28
#define DST_BUFFER_SIZE_T 16
int SobelBorderExample()
{
    HmppiSize roi = { 2, 4 };
    const float src[SRC_BUFFER_SIZE_T] = { 9.8375815e-16, 4.5484828e-16, 1.4972698e-14, -1.3397389e+25, 1.9061152e+27, -8.8007769e+17, -217025.86, -6.2768196e+14, 4.4335606e+33, 1.0258707e-13, -9.3150633e-11, -5192.7163, 2.536292e+25, 6.0832354e+15, 8.5712402e+29, -0.15451884, -0.2848247, -2.1714717e+10, 2.7212473e+17, -1.3591454e-22, 7.6473188e+21, -2.2729285e-30, 1129877.1, -1.0089557e-05, -1.1054221e+21, -3.8945858e-19, -6.8345717e-34, 60685416};
    float dst[DST_BUFFER_SIZE_T] = {0};
    int32_t srcStep = 4 * sizeof(int16_t);
    int32_t dstStep = 4 * sizeof(int16_t);
    HmppiMaskSize mskSize = HmppMskSize3x3; 
    HmppResult result = HMPPI_FilterSobelHorizBorder_32f_C1R(src, srcStep, dst, dstStep, roi, mskSize, HMPPI_BORDER_CONST, 0);
    if (result != HMPP_STS_NO_ERR) {
        printf("result error: %d\n", result);
    } else {
        printf("result: %d\n", (int)result);
    }
    printf("dst= ");
    for(int32_t i = 0; i < DST_BUFFER_SIZE_T; i++){
        printf("%e ",dst[i]);
    }
    printf("\n");
    return 0;
}
int main() {
    SobelBorderExample();
    return 0;
}

Output:

result: 0
dst= -1.339739e+25 -2.679478e+25 3.812230e+27 1.906115e+27 1.339739e+25 2.679478e+25 -3.812230e+27 -1.906115e+27 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00 0.000000e+00

Parent topic: Image Filtering