�ݺ�ߣ

· www.polytec.com · © Polytec
Anthony Brock, Applications Engineer
info@polytec.com
949-943-3033
www.polytec.com
The Acoustic Camera: Noise of Hummingbirds

The Acoustic Camera Family
Ring Array
Recommended for
acoustic frequencies for
use in acoustic labs.
Acoustic imaging of 2D
surface.
Sphere Array
Ideal for overlaying
acoustic image in 3D
space. Typically used
for inside cabin noise in
automotive or mapping
room noise.
Star Array
Great for larger areas
with greater standoff
distances.
September 2017 2
Fibonacci Array
with Holography
and Custom
Arrays
Data recorder
A standard modular
data recorder and
software works with
any array type.

Hummingbirds of central California
Anna's humming birds are a local humming bird
species in coastal central California living in the
region year round. A few migratory species such
as the Allen's hummingbird migrate through the
region spending winter in Central America and
summer further north. The birds are very
territorial and will fight for the best food sources.
A hummingbird feeder in the backyard is an
unlimited source of easy food that is worth
fighting for (so long as the human residents
keep filling it).
September 2017 3

The Acoustic Camera setup
Fights can get aggressive between rival
hummingbirds, but typically a sequence
of chirps and sometimes a game of chase
is all that is needed for one bird to flee
and another to gain dominance over a
territory. The chirps are in the frequency
range of 6-10kHz and can often be heard
while a bird approaches the food source.
The Acoustic Camera provided by
Polytec and GFAI is used to capture
these chirps as the hummingbirds fly
through the air and to the feeder.
September 2017 4

Hummingbird Feeding: real time video
This movie shows a
hummingbird flying to the
feeder. Turn the volume
up to hear the chirps.
Note: Download the
Presentation to view
the videos in the next
few slides.
September 2017 5

Hummingbird Feeding: sound map overlay
The movie from the
previous slide is shown
here with the sound map of
the chirps and the wing
movement of the
hummingbird overlaid. The
dog barks and background
wind noise are removed
through processing. The
image is rendered to show
just lines and whitespace to
visualize the noise color
map more easily.
September 2017 6
Download the presentation to view the video

Hummingbird Feeding: slow motion
The movie from the
previous slide is shown
slowed down. Now the
sound sources of the
chirps can be seen coming
from the hummingbird and
reflecting off the back wall.
Additionally sound from
individual wing “flap”
movements can be
visualized.
September 2017 7

Hummingbird Chirp
By zooming in on the images at the exact time of a chirp, the sound source of the
chirp as it is produced by the hummingbird is visualized.
September 2017 8

Hummingbird Wings
The hummingbird wings
move in a figure 8 pattern
rather than a typical
flapping motion. This
allows them to hover and
move forward and
backward easily. This
video shows a zoomed in
visualization of the sound
produced by the wings
during hover. This is
slowed down so the
audio with this video
sounds off.
September 2017 9

Hummingbird Wings
Looking at the motion of the wings as individual frames, it is seen that as the wing is
extended backward from the body of the humming bird, the sound is only visualized
on the wings behind the hummingbird’s body.
September 2017 10

Hummingbird Chirp
Similarly, when the wings are extended outward, the sound source is visualized on
each of the wings to the side of the hummingbird’s body.
September 2017 11

�ݺ�ߣ

The Acoustic Camera: Noise of Hummingbirds

More Related Content

The Acoustic Camera: Noise of Hummingbirds