RETRO (vipl) functions


LIBRARY ROUTINE

lvtilt - Adds a specified plane to the input image to correct for a tilt in the image luminance.

LIBRARY CALL

int lvtilt(
	xvimage *img1,
	xvimage *img2,
	int mflg,
	float xslope,
	float yslope)

INPUT

OUTPUT

RETURN VALUE

TRUE (1) on success, FALSE (0) on failure

DESCRIPTION

lvtilt adds a specified plane to the input image to correct for a tilt in the image luminance. Often an image will have a skew in the grey level values that represents a plane with a certain slope. The tilt takes the form of a plane which has a X and Y zero crossing at the center of the input image with xslope and yslope as specified in the argument line.

img1 is the input and output xvimage structure. This is done to save space, but you must be careful not to overwrite important data. img2 is the mask image, if mflg is set then the mask image is used to gate the operation. A non-zero mask pixel enables the ouput pixel to contain adjusted values. A zero mask pixel just transfers the value of the corresponding pixel in the input image to the output image. The input images must be of the same data type and size.

xslope and yslope specify the characteristics of the plane and must be given in units per pixel.

The output image data type is the same as the input data type.

ADDITIONAL INFORMATION

none

EXAMPLES

none

SIDE EFFECTS

none

RESTRICTIONS

lvtilt will not operate on COMPLEX or BIT data storage type images.

MODIFICATION

John Rasure, Marcelo Teran, Donna Koechner Mon Jun 11 16:53:44 MDT 1990 Donna Koechner - updated to ghostwriter Fri Jun 28 16:43:19 MDT 1991 Scott Wilson - Fixed bogous pointer increment in float loop with mask

FILES

$RETRO/objects/library/vipl/src/lvtilt.c

SEE ALSO

vipl(3)

COPYRIGHT

Copyright (C) 1993 - 1997, Khoral Research, Inc. ("KRI") All rights reserved.