Multi-view 3D data acquisition using a single uncoded light pattern

This work is part of the project ’3D-Head’ funded by the Malta Council for Science and Technology under Research Grant No. RTDI-2004-034.This research concerns the acquisition of 3-dimensional data from images for the purpose of modeling a person's head. This paper proposes an approach for acquiring the 3-dimensional reconstruction using a multiple stereo camera vision platform and a combination of passive and active lighting techniques. The proposed one-shot active lighting method projects a single, binary dot pattern, hence ensuring the suitability of the method to reconstruct dynamic scenes. Contrary to the conventional spatial neighborhood coding techniques, this approach matches corresponding spots between image pairs by exploiting solely the redundant data available in the multiple camera images. This produces an initial, sparse reconstruction, which is then used to guide a passive lighting technique to obtain a dense 3-dimensional representation of the object of interest. The results obtained reveal the robustness of the projected pattern and the spot matching algorithm, and a decrease in the number of false matches in the 3-dimensional dense reconstructions, particularly in smooth and textureless regions on the human face.peer-reviewe

Flexible real-time natural 2D color and 3D shape measurement

The majority of existing real-time 3D shape measurement systems only generate non-nature texture (i.e., having illumination other than ambient lights) that induces shadow related issues. This paper presents a method that can simultaneously capture natural 2D color texture and 3D shape in real time. Specifically, we use an infrared fringe projection system to acquire 3D shapes, and a secondary color camera to simultaneously capture 2D color images of the object. Finally, we develop a flexible and simple calibration technique to determine the mapping between the 2D color image and the 3D geometry. Experimental results demonstrate the success of the proposed technique

Improving 4-D shape measurement by using projector defocusing

This paper presents a real-time 3-D, or 4-D, shape measurement technique that can reach the speed limit of a digital fringe projection system without significantly increasing the system cost. Instead of generating sinusoidal fringe patterns by a computer directly, they are produced by defocusing binary structured patterns. By this means, with a relatively inexpensive camera, the 3-D shape measurement system can double the previously maximum achievable speed, and reaches the refreshing rate of a digital-light-processing (DLP) projector: 120 Hz

Simultaneous geometry and color texture acquisition using a single-chip color camera

Capturing 3-D geometry and the perfectly aligned color texture simultaneously is crucial for diverse fields including entertainment, target recognition, and computer graphics. However, it is very challenging for a conventional technique because of a number of problems related to color. Previous researchers rely heavily on using two cameras: a black-and-white(B/W) camera to measure the geometry, and a color camera to capture the color texture. However, aligning the color image with the 3-D geometry point by point remains difficult. In this research, we propose a novel technique that uses a single-chip color camera to capture both geometry and color texture simultaneously. A projector projects B/W fringe patterns onto the object, and a color camera captures the raw fringe images with Bayer mosaic patterns. A phase-shifting algorithm is used for our system because of one of its merits: retrieving phase pixel-by-pixel. Therefore, the intensity variations between neighboring pixels do not significantly affect the measurement. Moreover, the same set of fringe images is also used to calculate the B/W texture image, which is further converted into a color image using a demosaicing algorithm. Therefore, the same set of fringe images are used to generate the 3-D geometry as well as the color texture image simultaneously. A hardware system was developed to verify the performance of the proposed technique. Experiments demonstrated that this technique can successfully measure both geometry and color texture of the color objects

High-resolution, high-speed three-dimensional shape measurement using projector defocusing

We present a high-resolution, high-speed three-dimensional (3-D) shape measurement technique that can reach the speed limit of a digital fringe projection system without significantly increasing the system cost. Instead of generating sinusoidal fringe patterns by a computer directly, they are produced by defocusing binary ones. By this means, with a relatively inexpensive camera, the 3-D shape measurement system can double the previously maximum achievable speed and reach the refreshing rate of a digital-light-processing projector: 120 Hz

Underwater 3D Scanner Using RGB Laser Pattern

For efficiency surveying fishery resource, the authors developed the scanner which measure the target shape at once time. The scanner based on the structured light method irradiated the laser patter coded on De Bruijn for high resolution the measurement under water. The evaluation experiment results showed that the scanner can measure the target shape less than 1.4 % error for the measurement range.2021 IEEE/SICE International Symposium on System Integration (SII 2021), January 11-14, 2021, Iwaki, Fukushima, Japan (Virtual Conference

A Coded Structured Light System Based on Primary Color Stripe Projection and Monochrome Imaging

Coded Structured Light techniques represent one of the most attractive research areas within the field of optical metrology. The coding procedures are typically based on projecting either a single pattern or a temporal sequence of patterns to provide 3D surface data. In this context, multi-slit or stripe colored patterns may be used with the aim of reducing the number of projected images. However, color imaging sensors require the use of calibration procedures to address crosstalk effects between different channels and to reduce the chromatic aberrations. In this paper, a Coded Structured Light system has been developed by integrating a color stripe projector and a monochrome camera. A discrete coding method, which combines spatial and temporal information, is generated by sequentially projecting and acquiring a small set of fringe patterns. The method allows the concurrent measurement of geometrical and chromatic data by exploiting the benefits of using a monochrome camera. The proposed methodology has been validated by measuring nominal primitive geometries and free-form shapes. The experimental results have been compared with those obtained by using a time-multiplexing gray code strategy