4,747 research outputs found
Micro Fourier Transform Profilometry (FTP): 3D shape measurement at 10,000 frames per second
Recent advances in imaging sensors and digital light projection technology
have facilitated a rapid progress in 3D optical sensing, enabling 3D surfaces
of complex-shaped objects to be captured with improved resolution and accuracy.
However, due to the large number of projection patterns required for phase
recovery and disambiguation, the maximum fame rates of current 3D shape
measurement techniques are still limited to the range of hundreds of frames per
second (fps). Here, we demonstrate a new 3D dynamic imaging technique, Micro
Fourier Transform Profilometry (FTP), which can capture 3D surfaces of
transient events at up to 10,000 fps based on our newly developed high-speed
fringe projection system. Compared with existing techniques, FTP has the
prominent advantage of recovering an accurate, unambiguous, and dense 3D point
cloud with only two projected patterns. Furthermore, the phase information is
encoded within a single high-frequency fringe image, thereby allowing
motion-artifact-free reconstruction of transient events with temporal
resolution of 50 microseconds. To show FTP's broad utility, we use it to
reconstruct 3D videos of 4 transient scenes: vibrating cantilevers, rotating
fan blades, bullet fired from a toy gun, and balloon's explosion triggered by a
flying dart, which were previously difficult or even unable to be captured with
conventional approaches.Comment: This manuscript was originally submitted on 30th January 1
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Pictures in Your Mind: Using Interactive Gesture-Controlled Reliefs to Explore Art
Tactile reliefs offer many benefits over the more classic raised line drawings or tactile diagrams, as depth, 3D shape, and surface textures are directly perceivable. Although often created for blind and visually impaired (BVI) people, a wider range of people may benefit from such multimodal material. However, some reliefs are still difficult to understand without proper guidance or accompanying verbal descriptions, hindering autonomous exploration.
In this work, we present a gesture-controlled interactive audio guide (IAG) based on recent low-cost depth cameras that can be operated directly with the hands on relief surfaces during tactile exploration. The interactively explorable, location-dependent verbal and captioned descriptions promise rapid tactile accessibility to 2.5D spatial information in a home or education setting, to online resources, or as a kiosk installation at public places.
We present a working prototype, discuss design decisions, and present the results of two evaluation studies: the first with 13 BVI test users and the second follow-up study with 14 test users across a wide range of people with differences and difficulties associated with perception, memory, cognition, and communication. The participant-led research method of this latter study prompted new, significant and innovative developments
Multi-View Neural Surface Reconstruction with Structured Light
Three-dimensional (3D) object reconstruction based on differentiable
rendering (DR) is an active research topic in computer vision. DR-based methods
minimize the difference between the rendered and target images by optimizing
both the shape and appearance and realizing a high visual reproductivity.
However, most approaches perform poorly for textureless objects because of the
geometrical ambiguity, which means that multiple shapes can have the same
rendered result in such objects. To overcome this problem, we introduce active
sensing with structured light (SL) into multi-view 3D object reconstruction
based on DR to learn the unknown geometry and appearance of arbitrary scenes
and camera poses. More specifically, our framework leverages the
correspondences between pixels in different views calculated by structured
light as an additional constraint in the DR-based optimization of implicit
surface, color representations, and camera poses. Because camera poses can be
optimized simultaneously, our method realizes high reconstruction accuracy in
the textureless region and reduces efforts for camera pose calibration, which
is required for conventional SL-based methods. Experiment results on both
synthetic and real data demonstrate that our system outperforms conventional
DR- and SL-based methods in a high-quality surface reconstruction, particularly
for challenging objects with textureless or shiny surfaces.Comment: Accepted by BMVC 202
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