用于智能移动设备的条纹反射法检测系统

条纹反射法是一种结构简单的三维面形检测手段,本文对该方法在智能手机、平板等移动设备中的集成和应用进行了研究。首先,对条纹反射法标定误差以及智能设备的特点进行了分析。然后,在分析实际检测中的关键误差基础上,提出了通过相机非线性定标、改善相移算法、格点位置标定、应对相机自动增益调整等一系列方法和算法,在设备现有硬件条件下提高了测量精度和稳定性;最后,使用iPad Air对直径为105 mm的SiC反射面进行了实验。结果表明,标定精度在毫米量级时,对反射面的检测精度RMS值达到33μm,并且以低频误差为主,在局部高频区域检测结果有明显优势,证实了在不使用其他外部设备前提下,集成于智能平板的条纹反射法具备几十微米量级精度的检测能力。

Deflectometry measurement system for smart mobile devices

Deflectometry is a three-dimension surface measurement method using simple equipment. In this paper, deflectometry based on portable devices such as smart phones and tablets is discussed. First, the calibration error and advantages of mobile devices are proposed. Then, according to analysis of the data and errors in experiments, a series of methods, such as camera non-linear calibration, improved phase shift algorithm, grid position calibration, automatic gain adjustment, are introduced to improve the measurement accuracy and stability. Finally, app launched in an iPad is used to test a 105 mm SiC workpiece. Experimental results indicate that the precision of global surface is 33 μm RMS with millimeter scale calibration accuracy. The error is mostly of low frequency, and the sensitivity is rather high in some areas. It proves that deflectometry integrated in smart tablet has the capability of achieving a measurement accuracy of tens of microns without other external equipment.