diff --git a/README.txt b/README.txt
--- a/README.txt
+++ b/README.txt
2.USAGE
-------
2.USAGE
-------
- fits2jpeg [options] <fits_file>
+ Usage: fits2jpeg [options] <fits_file>
+
+ Options are:
- Options are:
-h help
-s <scale_type>
-h help
-s <scale_type>
- scale for output image intensity. Valid arguments are:
-
- linear for linear scaling, default
+ scale for output image, where <scale_type> can be:
+ linear Linear scale, default
sqroot for square root scale
square for quadratic scale
cubic for cubic scale
log for log scale
sqroot for square root scale
square for quadratic scale
cubic for cubic scale
log for log scale
+ normalize for linear histogram stretch
+ equalize for histogram equalization
+
+ -r <min>:<max>
+ Clip output image to min-max range. Eg:
+ 0:100 Use only values in the range 0-100
+ 100:0 Same as above, but negative image
+ :10 Clip everything above 10
+ 10: Clip everything below 10
+
+ -n
+ Negate the image.
+
+ -q <value>
+ jpeg quality factor. Defines the jpeg encoding quality
+ Valid range: 0-100, default value: 100, which is for
+ best quality (and largest file size).
- -e <operation>
- Imaghe enhancement operations. Valid arguments are:
+ -z <zoomfactor>
+ Resize/Scale output image by <zoomfactor>. Eg:
+ 0.5 Shrink output to half of input
+ 2.0 Magnify output to double the size
- equalize perform histogram equalization
- normalize perform a linear contrast stretch
- (use cutoffs at 1% and 99% for image data)
Output will be written to <fits_file_root>.jpg. For eg.,
Output will be written to <fits_file_root>.jpg. For eg.,
More examples:
More examples:
- i. fits2jpeg -s cubic sirius.fits
+ i. fits2jpeg -s log sirius.fits
will write out sirius.jpg, flux/intensity in log scale
ii. fits2jpeg -s sqroot *.fits
will write out sirius.jpg, flux/intensity in log scale
ii. fits2jpeg -s sqroot *.fits
square-root scaling of flux/intensity - Good for very
high dynamic range images
square-root scaling of flux/intensity - Good for very
high dynamic range images
-iii. fits2jpeg -e normalize ngc4151.fits
- Converts ngc4151.fits to ngc4151.jpg, contrast stretched.
+iii. fits2jpeg -n ngc4151.fits
+ Converts ngc4151.fits to ngc4151.jpg, negative image.
-NOTE: You can perform scaling + enhancing on an image. Scaling will
- always be performed first. In most cases combining these two
- would lead to un-usable images :)
+iv. fits2jpeg -s square -n -r 10:2000 m31.fits
+ Write out m31.jpg, after square scaling of flux/intensity,
+ negate image and clip pixel values in the range 10 to 2000
+ units.
3. DOCUMENTATION
3. DOCUMENTATION
-----------------------------------------------------------
Reks, 28 June 2012 <reks_at_iiap.res.in>
-----------------------------------------------------------
Reks, 28 June 2012 <reks_at_iiap.res.in>
- Last modified: 28 June 2012
+ Last modified: 10 July 2012