基于结构光技术的高反射表面三维测量

Three-Dimensional Measurement of Highly-Reflective Surface Using Structured Light Technique

基于条带边缘的结构光编码策略生成投影图案,提出一种新的结构光技术,用于减少相机捕获图案中的过度饱和区域。在一次测量中,为避免图像饱和,在高、低两种曝光时间下捕获结构光图像。高曝光是为获得黑暗区域的高质量图像,低曝光是为获取饱和区域的高质量图像。此外,在低曝光阶段,通过拟合非线性函数来估计投影图像与捕获图像之间的强度关系,进而自适应调整相机捕获图像中饱和像素对应于投影图像中像素点的强度。将两次曝光采集到的图像融合成一组信噪比较高的条纹图像,并对新图像进行解码,从而实现精确的三维测量。实验结果表明,所提出的结构光技术对反射率变化范围较大的物体表面,甚至对不锈钢表面,具有较高的测量精度。

A novel structured light technique is proposed in which the strip-edge-based structured light coding strategy is used to generate the projection patterns for reducing the area of oversaturation in an image captured using a camera.The structured light images are captured using both long and short exposure time during a single measurement to avoid image saturation.The long exposure time is used to obtain high-quality images of dark areas,whereas the short exposure time is used to obtain high-quality images of saturated areas.Furthermore,in the short exposure stage,the intensity relation between the projected image and the captured image is estimated by fitting a nonlinear function,and the saturated pixels in the captured image are adaptively adjusted to correspond to the pixel intensities in the projected image.Subsequently,the short-and long-exposure images are combined to form a set of fringe images with a high signal-to-noise ratio,and new images are decoded to achieve accurate three-dimensional measurement.The experimental results denote that the proposed structured light technique exhibits high measurement accuracy for object surfaces denoting a large range of reflectivity variation,including stainless steel surfaces.