#! /bin/sh

## Exposure-blend
## Copyright (C) 2007 by Peter J. Gawthrop

## Merges three photos taken using exposure bracketing
if [ -z "$4" ]; then
  echo Usage: Merge normal_image under_exposed_image over_exposed_image  merged_image 
  exit
fi

normal=$1
under=$2
over=$3
merged=$4

echo "Creating $merged from $normal, $under and $over."

## Merge under exposure
convert -type Grayscale $under _mask.tif    #Create mask
convert $normal $under _mask.tif +matte -composite _normal_over.tif # Merge

## Merge over exposure
convert -negate -type Grayscale $over _mask.tif #Create mask
convert _normal_over.tif $over _mask.tif +matte -composite $merged # Merge

## Clean
rm -f _mask.tif _under_masked.tif  _normal_over.tif

## Insert Tags
##comment="HDR image created using Blend  on `date` from: $normal $under $over"
##Exiftool $normal ${merged} "$comment"