Researchers
at
the
University
of
Waterloo
have
developed
a
faster
and
more
accurate
way
to
take
and
merge
photos.
The
result
is
the
ability
to
take
sections
of
each
photo
to
create
a
single
picture
where
all
elements
are
in
focus.
“If
you’re
taking
a
picture
of
a
field
of
flowers
with
mountains
in
the
distance,
you
focus
on
the
flowers
and
take
a
shot,
then
you
focus
out
a
tiny
bit
and
take
another
shot,
and
so
on,"
said
Peter
van
Beek,
a
professor
at
Waterloo’s
David
R.
Cheriton
School
of
Computer
Science.
"You
take
enough
shots
until
you’ve
captured
enough
photos
to
put
them
together
and
create
a
photo
where
every
element
of
that
scene
in
focus.”
The top photograph of flowers is a single image with a narrow plane of focus where only the orange flower at the bottom centre is in sharp focus. The bottom photo is an all-in-focus image created by focus stacking a series of images, each with a slightly different plane of focus, using the algorithm developed by University of Waterloo's Professor Peter van Beek and his students.
The
computational
process
to
combine
the
photos
is
called
photo
stacking.
Many
photo-editing
applications
can
blend
a
series
of
images
into
a
single
composite
picture,
but
images
have
to
be
carefully
selected
one
by
one,
and
the
process
is
manual.
“The
difficulty
in
doing
this
manually
selecting
images
is
that
it’s
slow
and
people
tend
to
take
far
too
many
pictures,”
van
Beek
said.
“Or,
conversely,
sometimes
the
photographer
is
rushed
and
misses
taking
a
few
pictures
that
are
critical
for
the
composite
image
to
be
in
focus.
Taking
too
many
pictures
is
time-consuming
and
taking
too
few
means
the
resulting
image
won’t
be
sharp.”
Many
computer
scientists
have
investigated
this
problem
and
have
mainly
concentrated
on
developing
techniques
that
improve
combining
the
set
of
images
into
a
single
photo.
Van
Beek
and
his
team
of
undergraduate
research
assistants
—
David
Choi,
Aliya
Pazylbekova
and
Wuhan
Zhou
—
have
instead
put
their
efforts
toward
improving
image
capturing
and
selection
processes,
so
fewer
images
need
to
be
taken
to
create
a
single
image
where
everything
is
in
focus.
“You
specify
what
you
want
in
focus,
press
the
shutter,
then
the
algorithm
selects
the
images
to
be
focus
stacked,”
van
Beek
explains.
“Our
algorithm
requires
4.5
times
fewer
images
on
average
—
a
reduction
that
would
significantly
cut
the
time
needed
to
capture
the
set
of
pictures.”
The
study,
Improved
Image
Selection
for
Focus
Stacking
in
Digital
Photography,
was
presented
at
the
24th
IEEE
International
Conference
on
Image
Processing.