Fast Range-lmage Generator by using Gray coded pattern projection

本课题研究了距离图像的获取方法以及距离图像在三维物体识别中的应用。我们开发了一种新型的基于模式投影的距离成像系统。图案投影仪和CCD（电荷耦合器件）摄像机利用基于三角法的空间编码实现距离测量系统。制作了灰度编码模式光的实验系统和半平面光二值图像积累的实验系统。我们有实验结果。前一种方法不需要在2n个位置依次扫描狭缝光，只需要少量(n)次光投射就能稳定快速地获得精确的距离图像。后一种方法实现了用非常简单的设备构造测距仪。经证实，这些系统可能适用于工业用途，例如形状检测，形状测量和机器人视觉。灰度编码模式投影法需要光掩模的切换。为该系统制作的实验图案投影仪具有机械光掩膜结构。非机械模式投影仪，如LCD（液晶装置）快门，希望在工业上使用。对点阵液晶显示进行了初步实验。结果表明，投影对比度相当好，电极间隙的影响可以忽略不计。范围图像非常方便用于场景分析，包括分割、描述和理解3D物体。为了识别三维物体的形状，研究了以下方法。利用二次曲面逼近法将曲面空间划分为椭球面、抛物面和圆锥面。环算子和曲率算子可以检测距离图像中的特征点。

This project deals with methods to get range picture and applications and utilizations of range picture for Three-dimensional(3D) object recognition. We have developed new type of range-imaging systems using pattern projection. Pattern projector and CCD(Charge Coupled Device) video camera realize the range measurement system utilizing space encoding based on triangulation method. Both the experimental system using Gray coded pattern ligh, and one using binary image accumulation with half-plane light, are produced. We have experimental results. The former approach gets accurate range picture stably and quickly with a few (n) of light projection, instead of scanning a slit light at 2n positions in turn. The latter approach realizes range finder constructed with very simple equipments. It is confirmed that these systems may be suited for the industrial use, for example, shape inspection, shape measurement and also robot vision.Gray coded pattern projection method requires the switching of light-masks. Experimental pattern projector produced for the system have mechanical light-mask structure. Non-mechanical pattern projector, such as LCD(Liquid Crystal Device) shutter, are wished for industrial use. Dot matrix LCD display is experimented elementally. It is confirmed that the contrast of projection is considerable good and the influence of gap of electrode can be ignored.Range picture are very convenient for scene analysis including segmentation, description, and understanding of 3D objects. In order to recognize the shape of 3D objects, the following methodologies have been studied. Quadric surface approximation is applied to classify the spape of surface into some categories, for instance, ellipsoid, paraboloid and cone. Ring operator and curvature operator can detect feature points in range picture.