average

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Name

average - computes the average of several bands in an input image

Syntax

average [<option>] <inimage> [<inimage>...] <outimage>

Description

Computes the average image of two or several bands of one or more images. Grey levels of the output average image will be multiplied by a scale factor.

 (inimage[1]+inimage[2]+........+inimage[n])/n * scale

The output image will be of pixeltype double.

The size of the output image depends on the options -max and -min (see below)

Options

-scale factor
Scale factor in calculation. Default: 1.0.

-max
Size of the output image = N x M where N and M are
 N=MAX(Ixsize(inimage[1]),...,Ixsize(inimage[n]))
 M=MAX(Iysize(inimage[1]),...,Iysize(inimage[n]))
In this case, if the output image size is larger than an input image band, then zeros will be added to the rest of the output image.

-min
Size of the output image = N x M where N and M are
 N=MIN(Ixsize(inimage[1]),...,Ixsize(inimage[n]))
 M=MIN(Iysize(inimage[1]),...,Iysize(inimage[n]))
In this case, all the pixels having co-ordinates (x,y), where x > N and y > M, will not be considered in the calculation.

Restrictions

Input bands should not have pixels of type "complex".

Return value

 0 => OK
 1 => Illegal number of arguments
 2 => Can't find input image
 3 => Only one band in input image
 4 => Error in calculation of average value

Author

Yogesan, BLAB, Ifi, UiO

Examples

 average <inimage> <outimage>
 average <inimage1> <inimage2> <outimage>
 average -max <inimage> <outimage>
 average <inimage> <outimage> -scale 2.5
 average -max -scale 2 <inimage> <outimage>

Id

$Id: average.c,v 1.31 1997/05/27 14:47:19 svein Exp $