678 research outputs found
Block-Matching Optical Flow for Dynamic Vision Sensor- Algorithm and FPGA Implementation
Rapid and low power computation of optical flow (OF) is potentially useful in
robotics. The dynamic vision sensor (DVS) event camera produces quick and
sparse output, and has high dynamic range, but conventional OF algorithms are
frame-based and cannot be directly used with event-based cameras. Previous DVS
OF methods do not work well with dense textured input and are designed for
implementation in logic circuits. This paper proposes a new block-matching
based DVS OF algorithm which is inspired by motion estimation methods used for
MPEG video compression. The algorithm was implemented both in software and on
FPGA. For each event, it computes the motion direction as one of 9 directions.
The speed of the motion is set by the sample interval. Results show that the
Average Angular Error can be improved by 30\% compared with previous methods.
The OF can be calculated on FPGA with 50\,MHz clock in 0.2\,us per event (11
clock cycles), 20 times faster than a Java software implementation running on a
desktop PC. Sample data is shown that the method works on scenes dominated by
edges, sparse features, and dense texture.Comment: Published in ISCAS 201
Global Migration - Immigration - Multiethnicity: Challenges to the Concept of the Nation-State
Professor Delbriick begins his article by briefly discussing the
history and development of the nation-state, and then examines how
changes in the political and social environment, often international
and cross-cultural in nature, have altered the traditional notion of
the nation-state. He argues that the modern form of the State
should be based on the concept of the Open Republic, rather than
on that of the traditional closed, self-centered, and self-reliant
nation-state. Professor Delbriick demands that his concept of an
Open Republic first be grounded in the form of a republican
State-a constitutional government involving the democratic
participation of all citizens and a marketplace of ideas. He
focuses on a republic geared in nature and character toward an
openness to accepting and assimilating citizens of different
ethnic, religious, or cultural backgrounds, with equal rights for
those diverse citizens. He concludes that such an Open Republic
is suited to preserving a national public interest, while at the same
time meeting the global challenges of the present and future
Global Migration - Immigration - Multiethnicity: Challenges to the Concept of the Nation-State
Professor Delbriick begins his article by briefly discussing the
history and development of the nation-state, and then examines how
changes in the political and social environment, often international
and cross-cultural in nature, have altered the traditional notion of
the nation-state. He argues that the modern form of the State
should be based on the concept of the Open Republic, rather than
on that of the traditional closed, self-centered, and self-reliant
nation-state. Professor Delbriick demands that his concept of an
Open Republic first be grounded in the form of a republican
State-a constitutional government involving the democratic
participation of all citizens and a marketplace of ideas. He
focuses on a republic geared in nature and character toward an
openness to accepting and assimilating citizens of different
ethnic, religious, or cultural backgrounds, with equal rights for
those diverse citizens. He concludes that such an Open Republic
is suited to preserving a national public interest, while at the same
time meeting the global challenges of the present and future
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