diff --git a/README.txt b/README.txt
--- a/README.txt
+++ b/README.txt
0. FEATURES
-----------
0. FEATURES
-----------
-fits2jpeg is a tiny program to read FITS Images and convert them
-to jpeg, which is more popular. This software supports various
-type of intensity scaling and image enhancements. fits2jpeg do not
-support coordinate axes overlay. fits2jpeg supports batch mode
-operations - for instance, converting several fits files to jpeg
-at once.
+fits2jpeg is a tiny program to read FITS Images and convert them to jpeg, which
+is more popular. This software supports various type of intensity scaling and
+image enhancements. fits2jpeg do not support coordinate axes overlay. fits2jpeg
+supports batch mode operations - for instance, converting several fits files to
+jpeg at once.
1. BUILD/INSTALL
1. BUILD/INSTALL
http://heasarc.gsfc.nasa.gov/docs/software/fitsio/fitsio.html
b) JPEGLIB
http://heasarc.gsfc.nasa.gov/docs/software/fitsio/fitsio.html
b) JPEGLIB
- jpeg library and headers. libjpeg is installed by default on most
- platforms, but we need the header files too. Once you have cfitsio
- and jpeglib installed, you may proceed with compiling jpeg2fits.
+ jpeg library and headers. libjpeg is installed by default on most platforms,
+ but we need the header files too. Once you have cfitsio and jpeglib
+ installed, you may proceed with compiling jpeg2fits.
+
Follow these 4 steps:
Follow these 4 steps:
2. Type `make' to compile the package.
3. Type `make install' to install the programs and any data files and
2. Type `make' to compile the package.
3. Type `make install' to install the programs and any data files and
- documentation. By default, the binary is copied to /usr/local/bin.
- You may change this destination by passing on the following
- argument to configure:
+ documentation. By default, the binary is copied to /usr/local/bin. You may
+ change this destination by passing on the following argument to configure:
--prefix=/your/chosen/destination
Which would result in the binary in /your/chosen/destination/bin
You may need to ensure that in $PATH to run the program.
--prefix=/your/chosen/destination
Which would result in the binary in /your/chosen/destination/bin
You may need to ensure that in $PATH to run the program.
- 4. You can remove the program binaries and object files from the
- source code directory by typing `make clean'.
+ 4. You can remove the program binaries and object files from the source code
+ directory by typing `make clean'.
-You may read more about configure script and others in the accompanying
-file named `INSTALL.txt'.
+You may read more about configure script and others in the accompanying file
+named `INSTALL.txt'.
2.USAGE
-------
2.USAGE
-------
- fits2jpeg [options] <fits_file>
+ Usage: fits2jpeg [options] <fits_file>
+ You need to specify a fits image file <fits_file> for this program to
+ work. Everything else is optional. A brief description of them are
+ listed below:
- Options are:
-h help
-h help
+ Prints out a usage-help message, much like this section.
-s <scale_type>
-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
-
- -e <operation>
- Imaghe enhancement operations. Valid arguments are:
-
- equalize perform histogram equalization
- normalize perform a linear contrast stretch
- (use cutoffs at 1% and 99% for image data)
+ normalize for linear histogram stretch
+ equalize for histogram equalization
+
+ -n
+ Negate the image
+
+ -q <value>
+ quality factor. Defines the jpeg encoding quality
+ Valid range: 0-100, default value: 100, which means
+ best quality and largest file-size.
+
+ -d <path/to/output/directory>
+ Write jpeg file to this specified directory. Will
+ create it if needed. Default is to write jpeg in the
+ same directory of fits image file
+
+ -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
+
+ -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
+ Allowed range: 0.01 to 4.0
+ NOTE: Zooming will be carried out after all other
+ operations, before writing out jpeg image
+
+ fits2jpeg uses a bilinear interpolation based algorithm
+ to scale the image. Allowed range: 0.01 to 4.0
+ NOTE: Anything outside the allowed range will be clipped
+ to this range.
Output will be written to <fits_file_root>.jpg. For eg.,
Output will be written to <fits_file_root>.jpg. For eg.,
writes output to jpeg file 30dor.jpg
writes output to jpeg file 30dor.jpg
- Wild card entries allowed in <fits_file>. For eg: *.fits,
- m31*.fits ngc???.fits etc.
+ Wild card entries allowed in <fits_file>. For eg: *.fits, m31*.fits
+ ngc???.fits etc.
- More examples:
- i. fits2jpeg -s cubic sirius.fits
+3.1 Examples:
+-------------
+ 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
- Converts all fits files in the directory to jpegs, with
- 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.
+ Converts all fits files in the directory to jpegs, with square-root scaling
+ of flux/intensity - Good for very high dynamic range images
+
+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.
+
+ v. fits2jpeg -s equalize -r 200: -d/path/to/mydir NGS253*.fits
+
+ Reads all fits files in the present directory that matches the filename
+ patterm, performs a histogram equalization, drops pixel values below 200
+ and write out all the corresponding jpeg files to directory /path/to/mydir
+ Will create the destination directory tree if it does not exist.
+
+
+3.1. Sequence of operations
+---------------------------
+Here is the sequence of operations, after reading the fits file:
+
+ i. clip the image to user specified pixel limits, if it was requested
+ ii. Squeeze image pixel values to jpeg limits (0 - 255)
+ iii. image scaling function, default being linear pixel scale
+ iv. Negate the image, if requested
+ v. Image zoom - magnify or shrink the image
+ vi. Write out jpeg file
3. DOCUMENTATION
----------------
3. DOCUMENTATION
----------------
-An extensive coverage of how this program works along with line
-by line account of the happenings within the code, are dealt with
-in the user manual, which is yet to be written :(
+An extensive coverage of how this program works along with line by line account
+of the happenings within the code, are dealt with in the user manual, which is
+yet to be written :(
4. LICENSE: GPL [See the file COPYING.txt for details]
4. LICENSE: GPL [See the file COPYING.txt for details]
5. DISCLAIMER
-------------
5. DISCLAIMER
-------------
-You may encounter bugs in this software. If you do, please
-report them. Your bug reports are valuable contributions,
-since they allow us to notice and fix problems on
-machines/platforms we don't have, and/or remained un-noticed.
+You may encounter bugs in this software. If you do, please report them. Your bug
+reports are valuable contributions, since they allow us to notice and fix
+problems on machines/platforms we don't have, and/or remained un-noticed.
6. REPORTING BUGS
6. REPORTING BUGS
Either way, please include as many details as possible.
Either way, please include as many details as possible.
+
-----------------------------------------------------------
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