emphasize

Herror ::emphasize ( Hobject Image, Hobject *ImageEmphasize, const HTuple &MaskWidth, const HTuple &MaskHeight, const HTuple &Factor ) HImage HImage::Emphasize ( const HTuple &MaskWidth, const HTuple &MaskHeight, const HTuple &Factor ) const HImageArray HImageArray::Emphasize ( const HTuple &MaskWidth, const HTuple &MaskHeight, const HTuple &Factor ) const

Enhance contrast of the image.

The operator ::emphasize emphasizes high frequency areas of the image (edges and corners). The resulting images appears sharper.

First the procedure carries out a filtering with the low pass (::mean_image). The resulting gray values (res) are calculated from the obtained gray values (mean) and the original gray values (orig) as follows: res := round((orig - mean) * Factor) + orig

Parameters

`Image` (input_object)	(multichannel-)image(-array) `->` Hobject: HImage(Array) ( byte )
Image to be enhanced.

`ImageEmphasize` (output_object)	(multichannel-)image(-array) `->` Hobject : HImage(Array)* ( byte )
contrast enhanced image.

`MaskWidth` (input_control)	extent.x `->` HTuple.long
Width of low pass mask.
Default value: 7
Suggested values: 3, 5, 7, 9, 11, 15, 21, 25, 31, 39
Typical range of values: `3 <= MaskWidth <= 201`
Minimum increment: 2
Recommended increment: 2

`MaskHeight` (input_control)	extent.y `->` HTuple.long
Height of the low pass mask.
Default value: 7
Suggested values: 3, 5, 7, 9, 11, 15, 21, 25, 31, 39
Typical range of values: `3 <= MaskHeight <= 201`
Minimum increment: 2
Recommended increment: 2

`Factor` (input_control)	real `->` HTuple.double
Intensity of contrast emphasis.
Default value: 1.0
Suggested values: 0.3, 0.5, 0.7, 1.0, 1.4, 1.8, 2.0
Typical range of values: `0.0 <= Factor <= 20.0` (sqrt)
Minimum increment: 0.01
Recommended increment: 0.2
Restriction: `(0 < Factor) && (Factor < 20)`

Example

read_image(&Image,"meer_rot");
disp_image(Image,WindowHandle);
draw_region(&Region,WindowHandle);
reduce_domain(Image,Region,&Mask);
emphasize(Mask,&Sharp,7,7,2.0);
disp_image(Sharp,WindowHandle);

Result

If the parameter values are correct the operator ::emphasize returns the value H_MSG_TRUE The behavior in case of empty input (no input images available) is set via the operator ::set_system('no_object_result',<Result>). If necessary an exception handling is raised.

Possible Successors

::disp_image

Alternatives

::mean_image, ::sub_image, ::laplace, ::add_image

See also

::mean_image, ::highpass_image

Module

Image filters