Educational Supplement to Research Initiaion Award: MachineVision

场景中的点被照亮时，不仅会向传感器方向反射光线，还会在它们之间反射光线。这些交互反射可以明显地改变场景的外观。现有的视觉传感器和算法没有考虑互反射的影响，因此经常产生错误的结果。一项初步调查研究了交互反射对由强度恢复形状的方法(例如，光度立体)恢复的形状信息的影响。人们发现，对于Lambertian曲面，在存在互反射的情况下恢复的错误(伪)形状是唯一的，并且可以在数学上与实际形状相关。已经开发了一种算法，该算法使用物理互反射模型来从伪形状恢复曲面的实际形状。本研究将从以下几个方面展开。(1)非朗伯(如镜面)互反射的分析。这就需要开发非朗伯反射的数学模型，并将其应用于在存在干涉反射的情况下恢复准确形状的问题。(2)检测和纠正现有视觉传感器(斑点扫描仪、光条测距仪、立体声系统)由于干涉反射而产生的误差。对于每个传感器，使用传感器模型来获得物理约束，以帮助分析交互反射。所有分析结果将通过实验室实验进行验证。这项研究将实现(A)相互反射分析的根本进展和(B)视觉传感技术的实质性改进。

Points in scene, when illuminated, reflect light not only in the direction of the sensor but also between themselves. These interreflections can appreciably alter the appearance of the scene. Existing vision sensors and algorithms do not account for the effects of interreflections and hence often produce erroneous results. An initial investigation studied the effects of interreflections on shape information recovered by shape-from- intensity methods (e.g. photometric stereo). It was discovered that, for Lambertian surfaces, the erroneous (pseudo) shape recovered in the presence of interreflections is unique and can be mathematically related to the actual shape. An algorithm has been developed that uses a physical interreflection model to recover the actual shape of the surface from the psuedo shape. The research will be extended in the following directions. (1) The analysis of non-Lambertian (e.g. specular) interreflections. This entails the development of mathematical models for non-Lambertian interreflections as well as their application to the problem of recovering accurate shape in the presence of interreflections. (2) The detection and correction of errors produced by existing vision sensors (spot scanners, light stripe range finders, stereo systems) as a result of interreflections. For each sensor, a sensor model is used to obtain physical constraints that aid the analysis of interreflections. All analytical results will be verified by laboratory experiments. This research should achieve (a) fundamental advances in the analysis of interreflections and (b) substantial improvements in vision sensing technology.