SYNOPSIS

fitspng [options] file

DESCRIPTION

Fitspng is an utility intended to convert of images in astronomical FITS format to computer graphics PNG format.

The primary goal of fitspng is to transform of the high dynamic images to a limited numerical range of PNG format. The transformation uses global tone mapping by a set of tone functions with machine estimated or user provided scaling parameters.

The detailed description can be found at homepage: http://integral.physics.muni.cz/fitspng

OPTIONS

-f [linear|asinh|log|gamma|normal|sqrt|sqr|logistic|atan]

Scale output intensities by specified profile: linearly, asinh, log, gamma (as in sRGB), normal (Gauss cumulative distribution function [5]), square root, square, logistic (emulating classical photography sensitivity [6]), atan and ratio (x/1+x).

-f0 f

Specifies scale of output profile: f*Func(i).

-fz z

Specifies zero (black level) of output profile: Func(i) + z.

-fr u,v

Output intensities, in case of color depth 8 bites, are scaled according this formula: (output intensities) = Func((input intensities - (med - u*mad))/(mad/v)) where med is median of every 10 pixel in the image, mad is mean of positive deviations from the median of every 10 pixel (same frequency). If the pixel is out of level range from 0 to 255, than value is replaced by 0 and 255 respectively. The default is u = 3, v = 1/3.

-fl t,s

Output intensities, in case of color depth 8 bites, are scaled according this formula: (output intensities) = Func((input intensities - t)/s). The setup completely disable internal parameter estimation.

-fs x

The color saturation is multiplied by the given ratio (for color FITS only).

-fw x,y

Set coordinates of white point.

-fn st,ss

When used, switch-on mode which emulates humans night vision. It is useful only for color FITS.

-cs sRGB or AdobeRGB

Select the colorspace of output image.

-s s

Scale down the size of image by the specified factor s as a (non-zero) positive integer number. If the s factor is greater of one, any output pixel is constructed as the arithmetical mean of s*s input pixels.

-o

Output image name. Default value is fitspng.png.

-B [8|16]

8 bites per pixel of color (gray) depth of output. This is default. 16 bites per pixel of color (gray) depth of output. There is frequently problem with additional rendering. Most of utilities doesn't work with this color depth correctly. On the other side, 16 bit per pixel images has saved photometric content more precisely.

-v

Print additional informations during processing.

--help

Show summary of options.

--version

Display software version.

EXAMPLES

Convert an image from FITS to PNG:
    bash$ fitspng gray.fits -o gray.png

Emulate human's night vision:
    bash$ fitspng color.fits -o color.png -fn 100,10

Emulate classical photography sensitivity function (density curve):
    bash$ fitspng color.fits -o color.png -f logistic

Create semi-gray image:
    bash$ fitspng color.fits -o color.png -fs 0.2

Select the specified band from color FITS (with help of FITS file name extension):
    bash$ fitspng color.fits[3] -o green.png

Create thumbnails:
    bash$ for A in *.fits; do fitspng -s 10 $A -o ${A%fits}png; done

AUTHOR

Filip Hroch ([email protected])