FSHARP

Description

Applies an edge-sharpening filter to image data. This filter improves the detail and contrast of an image.

Parameters

Name	Type	Length	Value range
Input: Input raster channels *	Raster port	1 - 1024
Output: Output filtered image channels *	Raster port	1 - 1024
Mask: Area mask	Bitmap port	0 - 1
Port Settings: Resample mode	Raster port	1 - 1024	Nearest | Bilinear | Cubic Default: Nearest
Filter X Size	Integer	0 - 1	1 | 3 | 5 | 7 | 9 | 11 | 13 | 15 | 17 | 19 | 21 | 23 | 25 | 27 | 29 | 31 | 33 Default: 3
Filter Y Size	Integer	0 - 1	1 | 3 | 5 | 7 | 9 | 11 | 13 | 15 | 17 | 19 | 21 | 23 | 25 | 27 | 29 | 31 | 33 Default: 3

* Required parameter

Parameter descriptions

Input: Input raster channels

Specifies the input channels to filter.

Output: Output filtered image channels

Specifies the output channels to receive the filtered result.

The output channels (DBOC) can be the same as the input channels (DBIC). If a mask is specified, only the area under the mask is written to the output channels.

Mask: Area mask

Optionally specifies the bitmap that defines the area to be processed within the input raster. If this parameter is not specified, the entire layer is used by default.

To define a bitmap mask, you must specify the bitmap segment that you want to use. All of the pixels within the specified segment, having a pixel value of 1, define the area to be processed.

Only the area under the mask is written to the output. Pixels that are outside the mask but within the filter size window will be used to determine the output pixel values.

Port Settings: Resample mode

Specifies the type of image resampling desired.

Filter X Size

Optionally specifies the horizontal size of the filter, in pixel units. This value must be an odd integer between 1 and 33. The default value is 3 pixels.

Filter Y Size

Optionally specifies the vertical size of the filter, in pixel units. This value must be an odd integer between 1 and 33. The default value is 3 pixels.

Details

FSHARP applies an edge-sharpening filter to image data. FSHARP uses a subtractive smoothing method to sharpen an image. An average filter is first applied to the image. The averaged image retains all low spatial-frequency information, but attenuates the high-frequency features, such as edges and lines. Consequently, the averaged image is subtracted from the original and the resulting difference image substantially retains only the edges and lines. When the edges are determined in this manner, the difference image is returned to the original to provide an edge-enhanced image. The resulting image has a clearer high-frequency detail, although there is a tendency for enhanced noise.

The dimensions of the filter window (FLSZ) must be odd. The minimum filter size is 1x3 and the maximum allowed filter size is 1001x1001. The filter window need not be square.

The input channel (DBIC) can be the same as the output channel (DBOC). For 8-bit channels, if the result is less than zero, it is truncated to zero. If the result is more than 255, it is truncated to 255.