NASA Technical Reports Server (NTRS) 20110003014: Method and System for Temporal Filtering in Video Compression Systems

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by  NASA Technical Reports Server (NTRS)

positive strain at a certain direction with- constant can be alternated by varying underwater detection. The performance
out increasing the applied voltage. The the size of each component, the degree of this innovation can be enhanced by
difference of this innovation from the of the pre-curvature of the positive strain improving the piezoelectric properties.
HYBAS is that all the elements can be components, the thickness of each layer This work was done by Ji Su of Langley Re-
made from one-of-a-kind materials. in the multilayer stacks, and the piezo- search Center, Xiaoning Jiang of TSR Tech-
Stacked HYBATS can provide an ex- electric constant of the material used. nologies, and Tian-Bing Zu of the National
tremely effective piezoelectric constant Because all of the elements are piezo- Institute of Aerospace. Further information is
at both resonance and off resonance fre- electric components, Stacked HYBATS contained in a TSP (see page 1). LAR-
quencies. The effective piezoelectric can serve as projector and receiver for 17671-1
Active Flow Effectors for Noise and Separation Control
These variable effectors provide enhanced vehicle and aeroelastic control.
Langley Research Center, Hampton, Virginia
New flow effector technology for separa- static chevrons, that cannot be optimized erate a thermal moment and def1ect the
tion control and enhanced mixing is based for airframe installation effects or variable structure out of plane when heated. The
upon shape memory alloy hybrid compos- operating conditions and cannot be re- force developed in the host structure
ite (SMAHC) technology. The technology tracted for off-design or fail-safe conditions. during def1ection and the aerodynamic
allows for variable shape control of aircraft Benefits include: load is used for returning the structure
structures through actively deformable sur- (cid:129) Increased vehicle control, overall effi- to the retracted position. The chevron
faces. The flow effectors are made by em- ciency, and reduced noise throughout design is highly scalable and versatile,
bedding shape memory alloy actuator ma- all f1ight regimes, and easily affords active and/or auton-
terial in a composite structure. When (cid:129) Reduced flow noise, omous (environmental) control.
thermally actuated, the flow effector (cid:129) Reduced drag, The technology offers wide-ranging
def1ects into or out of the flow in a pre- (cid:129) Simplicity of design and fabrication, market applications, including aero-
scribed manner to enhance mixing or in- (cid:129) Simplicity of control through direct cur- space, automotive, and any application
duce separation for a variety of applica- rent stimulation, autonomous res ponse that requires flow separation or noise
tions, including aeroacoustic noise to environmental heating, fast res ponse, control.
reduction, drag reduction, and f1ight con- and a high degree of geometric stability. This work was done by Travis L. Turner of
trol. The active flow effectors were devel- The concept involves embedding pre- Langley Research Center. For further informa-
oped for noise reduction as an alternative strained SMA actuators on one side of tion, contact the Langley Innovative Partner-
to fixed-configuration effectors, such as the chevron neutral axis in order to gen- ships Office at [phone]. LAR-17332-1
Method and System for Temporal Filtering in Video
Compression Systems
This filtering improvement increases efficiency for visual signal components for
low-power applications.
Stennis Space Center, Mississippi
Three related innovations combine tion vector between the first pixel posi- tation, estimates the conditional statis-
improved non-linear motion estima- tion in the first image and the second tics of at least one vector of space-fre-
tion, video coding, and video compres- pixel position in the second image, the quency coefficients with similar fre-
sion. The first system comprises a second pixel position in the second quencies, and is conditioned on
method in which side information is image, and the third pixel position in previously encoded data. It estimates an
generated using an adaptive, non-linear the third image using a non-linear encoding rate based on the conditional
motion model. This method enables ex- model; and determining a position of statistics and applies a Slepian-Wolf
trapolating and interpolating a visual the fourth pixel in a fourth image based code with the computed encoding rate.
signal, including determining the first upon the third motion vector. The method for decoding includes gen-
motion vector between the first pixel For the video compression element, erating a side-information vector of fre-
position in a first image to a second the video encoder has low computa- quency coefficients based on previously
pixel position in a second image; deter- tional complexity and high compres- decoded source data and encoder sta-
mining a second motion vector between sion efficiency. The disclosed system tistics and previous reconstructions of
the second pixel position in the second comprises a video encoder and a de- the source frequency vector. It also per-
image and a third pixel position in a coder. The encoder converts the source forms Slepian-Wolf decoding of a
third image; determining a third mo- frame into a space-frequency represen- source frequency vector based on the
NASA Tech Briefs, January 2011 29
generated side-information and the tween the second pixel position and the Inquiries concerning rights for the commer-
Slepian-Wolf code bits. third pixel position, and a fourth pixel cial use of this invention should be addressed
The video coding element includes re- value for a fourth frame based upon a lin- to:
ceiving a first reference frame having a ear or nonlinear combination of the first IBM
first pixel value at a first pixel position, a pixel value, the second pixel value, and 1101 Kitchawan Road
second reference frame having a second the third pixel value. A stationary filter- Yorktown Heights, NY 10598
pixel value at a second pixel position, and ing process determines the estimated Telephone No. [phone]
a third reference frame having a third pixel values. The parameters of the filter E-mail: [email protected]
pixel value at a third pixel position. It de- may be predetermined constants. Refer to SSC-00291/309/310, volume
termines a first motion vector between This work was done by Ligang Lu, Drake and number of this NASA Tech Briefsissue,
the first pixel position and the second He, Ashish Jagmohan, and Vadim Sheinin of and the page number.
pixel position, a second motion vector be- IBM for Stennis Space Center.
Apparatus for Measuring Total Emissivity of Small,
Low-Emissivity Samples
Goddard Space Flight Center, Greenbelt, Maryland
An apparatus was developed for meas- vidually controlled using off-the-shelf PID there is zero heat flow through the wires.
uring total emissivity of small, light- (proportional–integral–der i va tive) con- Thus, all of sample-temperature-control
weight, low-emissivity samples at low trollers, allowing flexibility in the test con- heater power is radiated to the chamber.
temperatures. The entire apparatus fits ditions. The chamber can be controlled at Double-aluminized Kapton (DAK)
inside a small laboratory cryostat. Sam- a higher temperature than the sample, al- emissivity was studied down to 10 K,
ple installation and removal are rela- lowing a direct absorptivity measurement. which was about 25 K colder than any
tively quick, allowing for faster testing. The lightweight sample is suspended previously reported measurements. This
The small chamber surrounding the by its heater and thermometer leads from verified a minimum in the emissivity at
sample is lined with black-painted alu- an isothermal bar external to the cham- about 35 K and a rise as the temperature
minum honeycomb, which simplifies data ber. The wires run out of the chamber dropped to lower values.
analysis. This results in the sample viewing through small holes in its corners, and This work was done by James Tuttle and
a very high-emissivity surface on all sides, the wires do not contact the chamber it- Michael J. DiPirro of Goddard Space Flight
an effect which would normally require a self. During a steady-state measurement, Center. For further information, contact the
much larger chamber volume. The sam- the thermometer and bar are individually Goddard Innovative Partnerships Office at
ple and chamber temperatures are indi- controlled at the same temperature, so [phone]. GSC-15697-1
Multiple-Zone Diffractive Optic Element for Laser
Ranging Applications
This technology can be used on unmanned aerial vehicles, or in collision-avoidance and robotic
control applications in cars, trains, and ships.
Goddard Space Flight Center, Greenbelt, Maryland
A diffractive optic element (DOE) can case, the laser altimeter operating range would simultaneously generate a wide di-
be used as a beam splitter to generate would need to extend from several hun- vergence angle beam using a small por-
multiple laser beams from a single input dred kilometers down to a few meters. tion of the total laser energy for the ap-
laser beam. This technology has been re- The innovator was recently involved in proach and landing portion of the
cently used in LRO’s Lunar Orbiter an investigation how to modify the mission. Only a few percent of the total
Laser Altimeter (LOLA) instrument to LOLA instrument for the OSIRIS aster- laser energy is required for approach
generate five laser beams that measure oid mapping and sample return mission. and landing operations as the return sig-
the lunar topography from a 50-km One approach is to replace the DOE in nal increases as the inverse square of the
nominal mapping orbit (see figure). An the LOLA laser beam expander assembly ranging height. A wide divergence beam
extension of this approach is to use a with a multiple-zone DOE that would could be implemented by making the
multiple-zone DOE to allow a laser al- allow for the simultaneous illumination center of the DOE a diffractive or refrac-
timeter instrument to operate over a of the asteroid with mapping and land- tive negative lens. The beam energy and
wider range of distances. In particular, a ing laser beams. The proposed OSIRIS beam divergence characteristics of a mul-
multiple-zone DOE could be used for multiple-zone DOE would generate the tiple-zone DOE could be easily tailored
applications that require both mapping same LOLA five-beam output pattern for to meet the requirements of other mis-
and landing on a planetary body. In this high-altitude topographic mapping, but sions that require laser ranging data.
30 NASA Tech Briefs, January 2011