25 research outputs found
Invariant surface characteristics for 3D object recognition in range images
In recent years there has been a tremendous increase in computer vision research using range images (or depth maps) as sensor input data. The most attractive feature of range images is the explicitness of the surface information. Many industrial and navigational robotic tasks will be more easily accomplished if such explicit depth information can be efficiently obtained and interpreted. Intensity image understanding research has shown that the early processing of sensor data should be data-driven. The goal of early processing is to generate a rich description for later processing. Classical differential geometry provides a complete local description of smooth surfaces. The first and second fundamental forms of surfaces provide a set of differential-geometric shape descriptors that capture domain-independent surface information. Mean curvature and Gaussian curvature are the fundamental second-order surface characteristics that possess desirable invariance properties and represent extrinsic and intrinsic surface geometry respectively. The signs of these surface curvatures are used to classify range image regions into one of eight basic viewpoint-independent surface types. Experimental results for real and synthetic range images show the properties, usefulness, and importance of differential-geometric surface characteristics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26326/1/0000413.pd
BigStitcher: reconstructing high-resolution image datasets of cleared and expanded samples.
Light-sheet imaging of cleared and expanded samples creates terabyte-sized datasets that consist of many unaligned three-dimensional image tiles, which must be reconstructed before analysis. We developed the BigStitcher software to address this challenge. BigStitcher enables interactive visualization, fast and precise alignment, spatially resolved quality estimation, real-time fusion and deconvolution of dual-illumination, multitile, multiview datasets. The software also compensates for optical effects, thereby improving accuracy and enabling subsequent biological analysis
Human Remains from the Pleistocene-Holocene Transition of Southwest China Suggest a Complex Evolutionary History for East Asians
BACKGROUND: Later Pleistocene human evolution in East Asia remains poorly understood owing to a scarcity of well described, reliably classified and accurately dated fossils. Southwest China has been identified from genetic research as a hotspot of human diversity, containing ancient mtDNA and Y-DNA lineages, and has yielded a number of human remains thought to derive from Pleistocene deposits. We have prepared, reconstructed, described and dated a new partial skull from a consolidated sediment block collected in 1979 from the site of Longlin Cave (Guangxi Province). We also undertook new excavations at Maludong (Yunnan Province) to clarify the stratigraphy and dating of a large sample of mostly undescribed human remains from the site. METHODOLOGY/PRINCIPAL FINDINGS: We undertook a detailed comparison of cranial, including a virtual endocast for the Maludong calotte, mandibular and dental remains from these two localities. Both samples probably derive from the same population, exhibiting an unusual mixture of modern human traits, characters probably plesiomorphic for later Homo, and some unusual features. We dated charcoal with AMS radiocarbon dating and speleothem with the Uranium-series technique and the results show both samples to be from the Pleistocene-Holocene transition: ∼14.3-11.5 ka. CONCLUSIONS/SIGNIFICANCE: Our analysis suggests two plausible explanations for the morphology sampled at Longlin Cave and Maludong. First, it may represent a late-surviving archaic population, perhaps paralleling the situation seen in North Africa as indicated by remains from Dar-es-Soltane and Temara, and maybe also in southern China at Zhirendong. Alternatively, East Asia may have been colonised during multiple waves during the Pleistocene, with the Longlin-Maludong morphology possibly reflecting deep population substructure in Africa prior to modern humans dispersing into Eurasia
Surfaces in early range image understanding
http://deepblue.lib.umich.edu/bitstream/2027.42/3565/5/anf5969.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/3565/4/anf5969.0001.001.tx
Segmentation through symbolic surface descriptions
http://deepblue.lib.umich.edu/bitstream/2027.42/3568/5/anf4239.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/3568/4/anf4239.0001.001.tx
Surface characterization for three-dimensional object recognition in depth maps
http://deepblue.lib.umich.edu/bitstream/2027.42/3569/5/anf5944.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/3569/4/anf5944.0001.001.tx
An overview of three-dimensional recogition
http://deepblue.lib.umich.edu/bitstream/2027.42/3567/5/anf5939.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/3567/4/anf5939.0001.001.tx
Automatic visual solder joint inspection
http://deepblue.lib.umich.edu/bitstream/2027.42/3566/5/anf5938.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/3566/4/anf5938.0001.001.tx
Objective dimensionality reduction using out-of-class covariance
http://deepblue.lib.umich.edu/bitstream/2027.42/3570/5/anf5941.0001.001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/3570/4/anf5941.0001.001.tx