An integrated system generates a model of a three-dimensional object. A scanning laser device scans the three-dimensional object and generates a point cloud. The points of the point cloud each indicate a location of a corresponding point on a surface of the object. A first model is generated, responsive to the point cloud, that generates a first model representing constituent geometric shapes of the object. A data file is generated, responsive to the first model, that can be inputted to a computer-aided design system.

Integrated system for quickly and accurately imaging and modeling three-dimensional objects

The digitization of the 3D shape of real objects is a rapidly expanding field, with applications in entertainment, design, and archaeology. We propose a new 3D model acquisition system that permits the user to rotate an object by hand and see a continuously-updated model as the object is scanned. This tight feedback loop allows the user to find and fill holes in the model in real time, and determine when the object has been completely covered. Our system is based on a 60 Hz. structured-light rangefinder, a real-time variant of ICP (iterative closest points) for alignment, and point-based merging and rendering algorithms. We demonstrate the ability of our prototype to scan objects faster and with greater ease than conventional model acquisition pipelines.

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Real-time 3D model acquisition

An imaging device formed as a monolithic complementary metal oxide semiconductor integrated circuit in an industry standard complementary metal oxide semiconductor process, the integrated circuit including a focal plane array of pixel cells, each one of the cells including a photogate overlying the substrate for accumulating photo-generated charge in an underlying portion of the substrate, a readout circuit including at least an output field effect transistor formed in the substrate, and a charge coupled device section formed on the substrate adjacent the photogate having a sensing node connected to the output transistor and at least one charge coupled device stage for transferring charge from the underlying portion of the substrate to the sensing node.

/pdf/active-pixel-sensor-with-intra-pixel-charge-transfer-387ug1605r.pdf

Active pixel sensor with intra-pixel charge transfer

This paper presents a color structured light technique for recovering object shape from one or more images. The technique works by projecting a pattern of stripes of alternating colors and matching the projected color transitions with observed edges in the image. The correspondence problem is solved using a novel, multi-pass dynamic programming algorithm that eliminates global smoothness assumptions and strict ordering constraints present in previous formulations. The resulting approach is suitable for generating both high-speed scans of moving objects when projecting a single stripe pattern and high-resolution scans of static scenes using a short sequence of time-shifted stripe patterns. In the latter case, space-time analysis is used at each sensor pixel to obtain inter-frame depth localization. Results are demonstrated for a variety of complex scenes.

/pdf/rapid-shape-acquisition-using-color-structured-light-and-47540clupl.pdf

Rapid shape acquisition using color structured light and multi-pass dynamic programming

A forward-facing vision system for a vehicle includes a forward-facing camera disposed in a windshield electronics module attached at a windshield of the vehicle and viewing through the windshield. A control includes a processor that, responsive to processing of captured image data, detects taillights of leading vehicles during nighttime conditions and, responsive to processing of captured image data, detects lane markers on a road being traveled by the vehicle. The control, responsive to lane marker detection and a determination that the vehicle is drifting out of a traffic lane, may control a steering system of the vehicle to mitigate such drifting, with the steering system manually controllable by a driver of the vehicle irrespective of control by the control. The processor, based at least in part on detection of lane markers via processing of captured image data, determines curvature of the road being traveled by the vehicle.

Vision system for vehicle

The authors present experimental results from an array of cells, each of which contains a photodiode and the analog signal-processing circuitry needed for light-stripe range finding. Prototype circuits were fabricated through MOSIS in a 2- mu m CMOS p-well double-metal, double-poly process. This design builds on some of the ideas that have been developed for ICs that integrate signal-processing circuitry with photosensors. In the case of light-stripe range finding, the increase in cell complexity from sensing only to sensing and processing makes the modification of the operational principle of range finding practical, which in turn results in a dramatic improvement in performance. The IC array of photosensor and analog signal processor cells that acquires 1000 frames of light-stripe range data per second-two orders of magnitude faster than conventional light-stripe range-finding methods. The highly parallel range-finding algorithm used requires that the output of each photosensor site be continuously monitored. Prototype high-speed range-finding systems have been built using a 5*5 array and a 28*32 array of these sensing elements. >

/pdf/integrated-sensor-and-range-finding-analog-signal-processor-8rh1a5cqob.pdf

Integrated sensor and range-finding analog signal processor

The authors present a very fast lightstripe rangefinder based on an IC array of photoreceptor and analog signal processor cells which acquires 1000 frames of range image per second-two orders of magnitude faster than currently available rangefinding methods. Unlike a conventional lightstripe range-finder, which obtains a frame of range image by the step-and-repeat process of projecting a stripe and grabbing and analyzing a camera image, the VLSI sensor array of this rangefinder gathers range data in parallel as a scene is swept continuously by a moving stripe. Each cell continuously monitors the output of its photoreceptor, and detects and remembers the time at which it observed the peak incident light intensity during the sweep of the stripe. Prototype rangefinding systems have been built using a 28*32 array of these sensing elements. >

A very fast VLSI rangefinder

VLSI technology makes possible a powerful new sensing methodology--the smart sensor. In a smart sensor, transducers are integrated with processing circuitry so that desired information can be intelligently extracted at the point of sensing. Physical limitations force traditional systems to artificially partition sensing and processing functions. By eliminating such partitioning, VLSI smart sensing adds a new dimension to the design of both sensors and sensing algorithms.
In this research, a high-performance VLSI range-image sensor has been built using the smart sensing methodology. This sensor measures range via light-stripe triangulation, a mature technology widely used in robotic systems. VLSI-based smart sensing made practical a cell-parallel implementation of the light-stripe method. Experiments with the cell-parallel sensor show that its performance is substantially better than that of traditional light-stripe systems. Range image acquisition time is decreased by two orders of magnitude. Furthermore, the range measurement process is qualitatively different, providing more robust and more accurate 3-D measurements. The success of the cell-parallel sensor can be attributed directly to the use of smart sensing and convincingly demonstrates the power of the technique.
One of the most distinguishing features of this work is that it is not just a re-implementation of established algorithms using VLSI. Rather, this thesis demonstrates that intelligent data acquisition makes possible new approaches to sensing that can significantly improve sensor performance.

A VISI Smart Sensor For Fast Range Imaging

A light-stripe rangefinding system consisting of a 6*10 array of pixels is described. Each pixel contains a photodiode to detect the light stripe and a primarily analog signal processor to determine and store the time at which the light stripe crosses that photodiode. Incorporating signal processing into each pixel makes it possible to modify the light-stripe rangefinding algorithm to achieve a frame rate over two orders of magnitude faster than conventional light-stripe rangefinding methods; i.e. over 100 frames/s. The novelty of this approach is its use of smart sensors, ones which provide signal processing at the point of sensing. In this case, the increase in cell complexity from sensing-only to sensing-and-processing makes the modification of the operational principle of rangefinding practical, which in turn results in a dramatic improvement in performance. >

/pdf/integrated-sensor-and-rangefinding-analog-signal-processor-a8sd65xklv.pdf

Andrew Gruss

Papers

Integrated sensor and range-finding analog signal processor

A very fast VLSI rangefinder

A VISI Smart Sensor For Fast Range Imaging

Integrated sensor and rangefinding analog signal processor

A VLSI sensor based rangefinding system