This function convolves an image with the given kernel matrix.
Declaration:
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AT_ERRCOUNT ACCUAPI IG_FIP_convolve(
HIGEAR hIGear,
LPAT_RECT lpRect,
LPAT_INT lpMatrix,
AT_DIMENSION nMatrixWidth,
AT_DIMENSION nMatrixHeight,
AT_DOUBLE dNormalizer,
AT_BOOL bAddToOrigin
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Arguments:
| Name | Type | Description |
| hIGear | HIGEAR | HIGEAR handle of image to be processed. |
| lpRect | LPAT_RECT | Far pointer to an AT_RECT structure specifying the rectangular portion of the image on which to operate. If NULL, this operation will be performed on the entire image. |
| lpMatrix | LPAT_INT | Array of kernel elements with which to convolve. |
| nMatrixWidth | AT_DIMENSION | Width of kernel matrix. |
| nMatrixHeight | AT_DIMENSION | Height of kernel matrix. |
| dNormalizer | AT_DOUBLE | Normalizer of kernel. |
| bAddToOrigin | AT_BOOL | Whether to add the result of the convolution to the original pixel values, or replace the original pixel values. |
Return Value:
Returns the number of ImageGear errors that occurred during this function call.
Supported Raster Image Formats:
Grayscale - 8, 16, 32 bpp.
Sample:
FreqIP
Example:
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HIGEAR hIGear; /* Handle of the image */ AT_RECT lpRect; /* rectangle to process */ AT_UINT mxConv[] = { 0, 1, 0, 1, 5, 1, 0, 1, 0 }; /* Convolution kernel */ AT_DOUBLE dNormalizer = 0.2; /* Normalizer of the kernel */ AT_BOOL bAddToOrigin; /* TRUE = add to original pix vals */ ... IG_FIP_convolve(hIGear, lpRect, 3, 3, mxConv, dNormalizer, FALSE); ... |
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Remarks:
The convolution is implemented using FFT, based on the Convolution Theorem, which provides improved performance for larger kernel matrix.
The result of the convolution is multiplied by dNormalizer to scale the data. For kernels that sum to zero, the normalizer is usually set to 1.0.