Tech Briefs Magazine - April 2021 - 26

Imaging
bubbles away from the chip and then generate gas bubbles in a new pattern.
The researchers demonstrated how
precisely and variably the new projector
for ultrasound works by writing the
alphabet in a kind of picture show of

sound pressure profiles. To make the letters visible, they caught micro-particles
in the various sound pressure profiles.
Depending on the sound pattern, the
particles arranged themselves into the
individual letters.

The technique could be used not only
for diagnostic and therapeutic purposes
but also in biomedical laboratories.
For more information, contact Prof. Dr.
Peer Fischer at fischer@is.mpg.de; +49 711
689-3560.

Technologies Make 3D Cameras Easier to Use
These technologies help compress 3D camera files and automate focus and exposure settings.
Purdue University, West Lafayette, Indiana

n order to make 3D cameras as easy to
use as one found on a smartphone,
researchers have developed new technologies aimed at making 3D cameras
easier to use. These technologies help
compress 3D camera files and automate
focus and exposure settings.
Using high-end 3D cameras almost
always requires a great deal of training.
To obtain the best image with current
high-end 3D cameras based on structured light technique, the manufacturer
must conduct precise projector and camera focal length and other parameters
calibration and the user must manually
adjust the optimal sensor exposure time.
This leads to a training requirement for
a user to properly operate the camera
and often involves complicated recalibration processes by the manufacturer if the
camera is accidentally disturbed.
The researchers automated the process of profilometry by developing algorithms to rapidly determine the optimal

On the right is a 3D image with auto-exposure control. Researchers have created technology to
make 3D cameras easier to use. (Image: Purdue University)

exposure after understanding the intrinsic constant response function of the
sensor. They also devised a method of
generating highly accurate 3D images

using an autofocusing feature on electronically tunable lenses.
For more information, contact Chris
Adam at cladam@prf.org; 765-588-3341.

Ultra-Miniaturized Microendoscope
The lens-free scope produces higher-quality images at a fraction of the size.
Johns Hopkins University, Baltimore, Maryland

icroendoscopes are designed to
examine neurons as they fire in
the brain and accordingly must be
minuscule in scale yet powerful enough
to produce a clear image. Most standard
microendoscopes are about half a millimeter to a few millimeters in diameter
and require larger, more invasive lenses
to achieve high-quality imaging. While
lensless microendoscopes exist, the optical fiber that scans an area of the brain
pixel-by-pixel frequently bends and loses
imaging ability when moved.
A new lens-free, ultra-miniaturized
endoscope - the width of only a few
human hairs - was developed that,

when compared to a conventional lensbased microendoscope, increases the
amount researchers can see and improves image quality.
To test the device, researchers examined beads in different patterns on a slide
using a coded aperture - a flat grid that
randomly blocks light, creating a projection in a known pattern, akin to randomly poking a piece of aluminum foil and
letting light through all of the small
holes. This creates a messy image but one
that provides a bounty of information
about where the light originates, and that
information can be computationally reconstructed into a clearer image.

www.techbriefs.com

Cov

ToC

Additionally, the microendoscope
doesn't require movement to focus on
objects at different depths; computational refocusing is used to determine where
the light originated from in three dimensions. This allows the endoscope to be
much smaller than traditional versions.
Looking forward, researchers will test
the microendoscope with fluorescent
labeling procedures in which active
brain neurons are tagged and illuminated to determine the endoscope's accuracy in imaging neural activity.
For more information, contact Chanapa
Tantibanchachai at chanapa@jhu.edu; 443997-5056.
Tech Briefs, April 2021

maito:fischer@is.mpg.de maito:cladam@prf.org http://www.techbriefs.com http://www.abpi.net/ntbpdfclicks/l.php?202104TBNAV

Tech Briefs Magazine - April 2021

Table of Contents for the Digital Edition of Tech Briefs Magazine - April 2021