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greg |
1.4 |
.\" RCSid "$Id: pextrem.1,v 1.3 2022/02/04 20:11:48 greg Exp $" |
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greg |
1.1 |
.TH PEXTREM 1 11/15/93 RADIANCE |
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.SH NAME |
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pextrem - find minimum and maximum values in RADIANCE picture |
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.SH SYNOPSIS |
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.B pextrem |
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[ |
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greg |
1.3 |
.B "-o | -O" |
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greg |
1.1 |
] |
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[ |
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picture |
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] |
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.SH DESCRIPTION |
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.I Pextrem |
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locates the minimum and maximum values for the input |
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.I picture, |
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and prints their pixel locations and color values. |
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The first line printed contains the x and y pixel location |
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(x measured from the left margin, y measured from the bottom), |
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followed by the red, green and blue values. |
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The second line printed contains the same information for the |
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maximum value. |
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.PP |
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The |
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.I \-o |
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option prints the original (radiance) values, undoing any exposure |
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or color correction done on the picture. |
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greg |
1.3 |
If the input is XYZE, then the second channel is in candelas/meter^2, |
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unless |
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.I \-O |
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is specified, when watts/sr/meter^2 are always reported. |
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greg |
1.1 |
.PP |
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If no input |
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.I picture |
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is given, the standard input is read. |
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greg |
1.4 |
.SH NOTES |
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greg |
1.1 |
The luminance value is used for comparison of pixels, although in |
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certain anomolous cases (ie. highly saturated colors) it is possible that |
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.I pextrem |
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will not pick the absolute minimum or maximum luminance value. |
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This is because a fast integer-space comparison is used. |
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A more reliable floating-point comparison would be slower by |
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an order of magnitude. |
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greg |
1.4 |
.PP |
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Hyperspectral pictures report min/max values as RGB colors for |
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output consistency. |
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.SH AUTHOR |
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Greg Ward |
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greg |
1.1 |
.SH "SEE ALSO" |
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falsecolor(1), getinfo(1), pcomb(1), pcompos(1), pextrem(1), pfilt(1), |
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pflip(1), protate(1), psign(1), rpict(1), ximage(1) |
