---
name: "pextrem"
section: "1"
platform: "linux"
package: "radiance"
version: "4R1+20120125-1+b1"
release: "Debian 7 (Wheezy)"
platforms: ["linux"]
url: "https://new.carta.tech/pextrem"
---

# pextrem(1)

find minimum and maximum values in RADIANCE picture

## NAME

pextrem - find minimum and maximum values in RADIANCE picture

## SYNOPSIS

**pextrem** \[ **-o** \] \[ picture \]

## DESCRIPTION

*Pextrem* locates the minimum and maximum values for the input *picture,* and prints their pixel locations and color values. The first line printed contains the x and y pixel location (x measured from the left margin, y measured from the bottom), followed by the red, green and blue values. The second line printed contains the same information for the maximum value.

The *-o* option prints the original (radiance) values, undoing any exposure or color correction done on the picture.

If no input  *picture* is given, the standard input is read.

## AUTHOR

Greg Ward

## BUGS

The luminance value is used for comparison of pixels, although in certain anomolous cases (ie. highly saturated colors) it is possible that *pextrem* will not pick the absolute minimum or maximum luminance value. This is because a fast integer-space comparison is used. A more reliable floating-point comparison would be slower by an order of magnitude.

## SEE ALSO

[falsecolor(1)](/falsecolor/1.md), [getinfo(1)](/getinfo/1.md), [pcomb(1)](/pcomb/1.md), [pcompos(1)](/pcompos/1.md), [pextrem(1)](/pextrem/1.md), [pfilt(1)](/pfilt/1.md), [pflip(1)](/pflip/1.md), [protate(1)](/protate/1.md), [psign(1)](/psign/1.md), [rpict(1)](/rpict/1.md), [ximage(1)](/ximage/1.md)