"""aebovl -- overlay bracketed exposures to create a composite image
Usage:
aebovl -l<val> [-d<val> -a<val> -m -h] <normal> <under> <over>
Where:
-l <val> light limit (0-255). Pixels lighter than this value are considered
to be too light. Default: 127
-d <val> dark limit (0-255). Pixels darker than this values are considered
to be too dark. Optional. If omitted, the dark limit is set to
255 - light limit.
-a <val> alpha. Adjusts level of blending between images. Optional, range
1 - 255, default is 1. 1 means use all of the light or dark image, 255
means use all of the normal image. Values in between give a blend.
-f <val> apply a filter. Optional. Default: no filter. Filters are:
BLUR, CONTOUR, DETAIL, EDGE_ENHANCE, EDGE_ENHANCE_MORE, EMBOSS,
FIND_EDGES, SMOOTH, SMOOTH_MORE, and SHARPEN.
-b Blur masks. Blur the light and dark masks to soften the overlays and help
smooth transitions.
-m Save mask image. A composite of the masks is saved for reference as
overlay-cm.jpg. Optional. The composite mask shows light areas
as white, normal areas as gray and dark areas as black.
-h Help
<normal> Normally exposed image. Required.
<under> Under-exposed (dark) image. Required.
<over> Over-exposed (light) image. Required.
Output:
Results are saved as overlay*.JPG in the current directory
Notes:
Generally it is easiest to focus on getting the largest uniform section of the
image right (e.g. the sky), then fine tuning from there. Try using -l120 -m
initially, and reduce -l by 10 until the sky is uniformaly darkened. Then set
-d to 255-l, and continue to adjust -l independantly of -d until you are happy
with the rest of the image. Try high and low values of -l. Finally add -b and
see if this improves the effect.
Example work flow:
Start:
aebovl -l120 -m normal.jpg under.jpg over.jpg
Adjust in increments of 10 until sky looks good, perhaps something like:
aebovl -l70 -m normal.jpg under.jpg over.jpg
Fix -d at 255-70:
aebovl -l80 -d185 -m normal.jpg under.jpg over.jpg
Continue to adjust -l until main subject is how you want it:
aebovl -l35 -d185 -m normal.jpg under.jpg over.jpg
Now try -b, and see if it helps:
aebovl -l35 -d185 -b normal.jpg under.jpg over.jpg
"""
import sys
import Image, ImageFilter
import getopt
from getopt import GetoptError
VALID_FILTERS = ["BLUR", "CONTOUR", "DETAIL", "EDGE_ENHANCE",
"EDGE_ENHANCE_MORE", "EMBOSS", "FIND_EDGES", "SMOOTH",
"SMOOTH_MORE", "SHARPEN"]
def abort(code, msg):
sys.stderr.write(msg + '\n')
sys.stderr.write('Run expovl -h for help\n')
sys.exit(code)
def main():
# Get command line parameters
getoptstring = 'bhml:d:a:f:'
try:
opts, args = getopt.getopt(sys.argv[1:], getoptstring)
except GetoptError:
abort(2, "Invalid or missing command line option")
llimit = 127
dlimit = None
alpha = 1
savemasks = False
filter = None
blurmasks = False
help = False
outfilename = "overlay.jpg"
for opt, val in opts:
if opt == "-l": llimit = int(val)
if opt == "-d": dlimit = int(val)
if opt == "-m": savemasks = True
if opt == "-h": help = True
if opt == "-a": alpha = int(val)
if opt == "-b": blurmasks = True
if opt == "-f": filter = val.upper()
if help:
print __doc__
sys.exit(0)
if dlimit is None: dlimit = 255 - llimit
if len(args) != 3:
abort(1, "Three input image files required.")
if filter is not None and filter not in VALID_FILTERS:
abort(3, "Invalid filter specified")
midimgfile, darkimgfile, lightimgfile = args
print "Loading images ..."
midimg = Image.open(midimgfile).convert("RGB")
darkimg = Image.open(darkimgfile).convert("RGB")
lightimg = Image.open(lightimgfile).convert("RGB")
gsimg = midimg.convert("L")
print "Processing images ..."
lightmask = gsimg.point(lambda i: ((i < llimit) * alpha) or 255)
darkmask = gsimg.point(lambda i: ((i > dlimit) * alpha) or 255)
if blurmasks:
lightmask = lightmask.filter(ImageFilter.BLUR)
darkmask = darkmask.filter(ImageFilter.BLUR)
resimg = Image.composite(midimg, lightimg, lightmask)
resimg = Image.composite(resimg, darkimg, darkmask)
if filter is not None:
resimg = resimg.filter(getattr(ImageFilter, filter))
print "Saving image file(s) ..."
resimg.save("overlay.JPG")
if savemasks:
# Recreate the masks without using the alpha factor, so the composite
# mask is composed of white, mid-gray and black, not shades in between
lightmask = gsimg.point(lambda i: (i < llimit) or 255)
darkmask = gsimg.point(lambda i: (i > dlimit) or 255)
if blurmasks:
lightmask = lightmask.filter(ImageFilter.BLUR)
darkmask = darkmask.filter(ImageFilter.BLUR)
gimg = Image.new("L", midimg.size, 128)
wimg = Image.new("L", midimg.size, 0)
bimg = Image.new("L", midimg.size, 255)
compmask = Image.composite(gimg, wimg, lightmask)
compmask = Image.composite(compmask, bimg, darkmask)
compmask.save("overlay-cm.JPG")
print "Results saved as overlay*.JPG"
main()
