---
name: "im_eye"
section: "3"
platform: "linux"
package: "libvips-dev"
version: "7.20.7-1+b3"
release: "Debian 6.0 (Squeeze)"
platforms: ["linux"]
url: "https://new.carta.tech/im_eye"
---

# im\_eye(3)

creates a pattern which shows the spatial response of the human visual system

## NAME

im\_eye, im\_feye - creates a pattern which shows the spatial response of the human visual system

## SYNOPSIS

**#include \<vips/vips.h\>**

**int im\_eye(image, xsize, ysize, factor)**\
 **IMAGE \*image;**\
 **int xsize, ysize;**\
 **double factor;**

**int im\_feye(image, xsize, ysize, factor)**\
 **IMAGE \*image;**\
 **int xsize, ysize;**\
 **double factor;**

## DESCRIPTION

**im\_feye()** creates an one band float image with pels in \[-1,+1\] of a pattern which has  the following properties:\
 \- the spatial frequency increases from left to right.\
 \- the grey level intensity decreases from top to bottom.\
 The sizes of the produced image are determined by the entered arguments xsize and ysize.  The variable factor which should be between 0 and 1, determines the number of maximum spatial frequencies present along the horizontal direction.

**im\_eye()** behaves exactly as im\_feye(), but scales the output to \[0,255\].

## RETURN VALUE

The function returns 0 on success and -1 on error.

## SEE ALSO

[im\_grey(3)](/im_grey/3.md), [im\_zone(3)](/im_zone/3.md).

## COPYRIGHT

N. Dessipris

## AUTHOR

N. Dessipris - 10/05/1991