Image resize/scaling is now partially working

[fits2jpeg.git] / README.txt

diff --git a/README.txt b/README.txt
index 2164ec0..df79f4a 100644 (file)
--- a/README.txt
+++ b/README.txt
@@ -80,26 +80,42 @@ file named `INSTALL.txt'.
 2.USAGE
 -------
 
-  fits2jpeg [options] <fits_file>
+ Usage: fits2jpeg [options] <fits_file>
+
+ Options are:
 
-  Options are:
     -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
+         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.,
 
@@ -112,7 +128,7 @@ file named `INSTALL.txt'.
 
   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
@@ -120,12 +136,13 @@ file named `INSTALL.txt'.
      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
@@ -159,4 +176,4 @@ Either way, please include as many details as possible.
 
 -----------------------------------------------------------
 Reks, 28 June 2012 <reks_at_iiap.res.in>
-      Last modified: 28 June 2012
+      Last modified: 10 July 2012