Index: branches/czw_branch/20101203/psLib/src/fits/psFits.h
===================================================================
--- branches/czw_branch/20101203/psLib/src/fits/psFits.h	(revision 30118)
+++ branches/czw_branch/20101203/psLib/src/fits/psFits.h	(revision 30119)
@@ -50,4 +50,9 @@
     PS_FITS_SCALE_STDEV_NEGATIVE,       ///< Auto-scale to sample stdev, place mean at upper limit
     PS_FITS_SCALE_STDEV_BOTH,           ///< Auto-scale to sample stdev, place mean at middle
+    PS_FITS_SCALE_LOG_RANGE,            ///< Take logarithm, Auto-scale to preserve dynamic range
+    PS_FITS_SCALE_LOG_STDEV_POSITIVE,   ///< Take logarithm, Auto-scale to sample stdev, place mean at lower limit
+    PS_FITS_SCALE_LOG_STDEV_NEGATIVE,   ///< Take logarithm, Auto-scale to sample stdev, place mean at upper limit
+    PS_FITS_SCALE_LOG_STDEV_BOTH,       ///< Take logarithm, Auto-scale to sample stdev, place mean at middle
+
     PS_FITS_SCALE_MANUAL                ///< Manual scaling (use specified BSCALE and BZERO)
 } psFitsScaling;
Index: branches/czw_branch/20101203/psLib/src/fits/psFitsScale.c
===================================================================
--- branches/czw_branch/20101203/psLib/src/fits/psFitsScale.c	(revision 30118)
+++ branches/czw_branch/20101203/psLib/src/fits/psFitsScale.c	(revision 30119)
@@ -100,4 +100,5 @@
 }
 
+    
 // Determine appropriate BSCALE and BZERO for an image, mapping the standard deviation to the nominated number
 // of bits
@@ -237,4 +238,176 @@
 }
 
+
+static bool logscaleStdev(double *bscale, // Scaling, to return
+			  double *bzero, // Zero point, to return
+			  const psImage *image, // Image to scale
+			  const psImage *mask, // Mask image
+			  psImageMaskType maskVal, // Value to mask
+			  const psFitsOptions *options // FITS options
+    )
+{
+    psAssert(bscale, "impossible");
+    psAssert(bzero, "impossible");
+    psAssert(image, "impossible");
+    psAssert(options, "impossible");
+
+    psTrace("psLib.fits", 3, "Scaling image by logarithm statistics");
+    int numCols = image->numCols, numRows = image->numRows; // Size of image
+    
+    double offset = 99e99;
+
+    // Determine the minimum value on this image.
+    switch (image->type.type) {
+    case PS_TYPE_F32: 
+      for (int y = 0; y < numRows; y++) {
+	for (int x = 0; x < numCols; x++) {
+	  psF32 value = image->data.F32[y][x];
+	  if (!isfinite(value)) {
+	    if (value < offset) {
+	      offset = value;
+	    }
+	  }
+	}
+      }
+      break;
+    case PS_TYPE_F64:
+      for (int y = 0; y < numRows; y++) {
+	for (int x = 0; x < numCols; x++) {
+	  psF64 value = image->data.F64[y][x];
+	  if (!isfinite(value)) {
+	    if (value < offset) {
+	      offset = value;
+	    }
+	  }
+	}
+      }
+      break;
+    default:
+      psError(PS_ERR_BAD_PARAMETER_VALUE, true, "Target type is not a float: %d",image->type.type);
+      return NULL;
+      break;
+    }
+    // We only need to offset images that go negative.
+    if (offset > 0.0) {
+      offset = 0.0;
+    }
+    // Write offset to header
+    // How?
+    //    psMetadataAddF32(header,PS_LIST_TAIL,"LOGZERO",0,"Flux offset subtracted before taking logarithm.",offset);
+    // Take the logarithm of the image, applying the offset
+    switch (image->type.type) {
+    case PS_TYPE_F32: 
+      for (int y = 0; y < numRows; y++) {
+	for (int x = 0; x < numCols; x++) {
+	  image->data.F32[y][x] = (log10( image->data.F32[y][x] - offset));
+	}
+      }
+      break;
+    case PS_TYPE_F64:
+	for (int y = 0; y < numRows; y++) {
+	  for (int x = 0; x < numCols; x++) {
+	    image->data.F64[y][x] = (log10( image->data.F64[y][x] - offset));
+	  }
+	}
+      break;
+    default:
+      psError(PS_ERR_BAD_PARAMETER_VALUE, true, "Target type is not a float: %d",image->type.type);
+      return NULL;
+      break;
+    }
+      
+    // Do regular scaling on the logarithm image
+    if (!scaleStdev(bscale, bzero, image, mask, maskVal, options)) {
+      psError(PS_ERR_UNKNOWN, false, "Unable to set BSCALE and BZERO from stdev");
+      return false;
+    }
+    return true;
+}
+
+static bool logscaleRange(double *bscale, // Scaling, to return
+			  double *bzero, // Zero point, to return
+			  const psImage *image, // Image to scale
+			  const psFitsOptions *options // FITS options
+    )
+{
+    psAssert(bscale, "impossible");
+    psAssert(bzero, "impossible");
+    psAssert(image, "impossible");
+    psAssert(options, "impossible");
+
+    psTrace("psLib.fits", 3, "Scaling image by logarithm statistics");
+    int numCols = image->numCols, numRows = image->numRows; // Size of image
+    
+    double offset = 99e99;
+
+    // Determine the minimum value on this image.
+    switch (image->type.type) {
+    case PS_TYPE_F32: 
+      for (int y = 0; y < numRows; y++) {
+	for (int x = 0; x < numCols; x++) {
+	  psF32 value = image->data.F32[y][x];
+	  if (!isfinite(value)) {
+	    if (value < offset) {
+	      offset = value;
+	    }
+	  }
+	}
+      }
+      break;
+    case PS_TYPE_F64:
+      for (int y = 0; y < numRows; y++) {
+	for (int x = 0; x < numCols; x++) {
+	  psF64 value = image->data.F64[y][x];
+	  if (!isfinite(value)) {
+	    if (value < offset) {
+	      offset = value;
+	    }
+	  }
+	}
+      }
+      break;
+    default:
+      psError(PS_ERR_BAD_PARAMETER_VALUE, true, "Target type is not a float: %d",image->type.type);
+      return NULL;
+      break;
+    }
+    // We only need to offset images that go negative.
+    if (offset > 0.0) {
+      offset = 0.0;
+    }
+    // Write offset to header
+    // How?
+    //    psMetadataAddF32(header,PS_LIST_TAIL,"LOGZERO",0,"Flux offset subtracted before taking logarithm.",offset);
+    // Take the logarithm of the image, applying the offset
+    switch (image->type.type) {
+    case PS_TYPE_F32: 
+      for (int y = 0; y < numRows; y++) {
+	for (int x = 0; x < numCols; x++) {
+	  image->data.F32[y][x] = (log10( image->data.F32[y][x] - offset));
+	}
+      }
+      break;
+    case PS_TYPE_F64:
+	for (int y = 0; y < numRows; y++) {
+	  for (int x = 0; x < numCols; x++) {
+	    image->data.F64[y][x] = (log10( image->data.F64[y][x] - offset));
+	  }
+	}
+      break;
+    default:
+      psError(PS_ERR_BAD_PARAMETER_VALUE, true, "Target type is not a float: %d",image->type.type);
+      return NULL;
+      break;
+    }
+      
+    // Do regular scaling on the logarithm image
+    if (!scaleRange(bscale, bzero, image, options)) {
+      psError(PS_ERR_UNKNOWN, false, "Unable to set BSCALE and BZERO from stdev");
+      return false;
+    }
+    return true;
+}
+
+
 //////////////////////////////////////////////////////////////////////////////////////////////////////////////
 // Public functions
@@ -295,4 +468,18 @@
       case PS_FITS_SCALE_STDEV_BOTH:
         if (!scaleStdev(bscale, bzero, image, mask, maskVal, options)) {
+            psError(PS_ERR_UNKNOWN, false, "Unable to set BSCALE and BZERO from stdev");
+            return false;
+        }
+        break;
+    case PS_FITS_SCALE_LOG_RANGE:
+      if (!logscaleRange(bscale,bzero,image,options)) {
+	psError(PS_ERR_UNKNOWN, false, "Unable to set BSCALE and BZERO from range");
+	return false;
+      }
+      break;
+    case PS_FITS_SCALE_LOG_STDEV_POSITIVE:
+    case PS_FITS_SCALE_LOG_STDEV_NEGATIVE:
+    case PS_FITS_SCALE_LOG_STDEV_BOTH:
+      if (!logscaleStdev(bscale, bzero, image, mask, maskVal, options)) {
             psError(PS_ERR_UNKNOWN, false, "Unable to set BSCALE and BZERO from stdev");
             return false;