英语翻译1.IntroductionIn optical 3D sensing,techniques based on

英语翻译
1.Introduction
In optical 3D sensing,techniques based on pattern-projected methods have the properties of nondestructive detection,high depth accuracy,fast measurement speed,and full-field inspection.It consists of a pattern projection system and an image acquisition system.The inspected surface is illuminated by a pattern from the projection system.Pattern distorted by the surface is recorded by the image acquisition system at a different viewpoint.With triangulation methods or suitable calibrations,distribution of the projected pattern is analyzable to retrieve the 3D shape.
One of the major studies for 3D profile measurements is the application to complicated objects,such as the inspection of a dynamic object with large depth discontinuities.Improvement of the existing projection techniques is one of the desirable solutions.The projection technique can be either the so-called structured light encoded method [1-5] or the fringe projection method [6-8].However,both existing methods have advantages and drawbacks.
In the method of fringe projection,the distorted fringes on the tested object are evaluated to retrieve the 3D shape.Phase of the fringes can be carried out by the phase-shifting technique [8-11] or Fourier transform method [7].In general,the phase-shifting technique takes more than three frames to evaluate the phases and therefore is more accurate than the Fourier transform method.Depth accuracy better than one part in ten thousandth of the field of view can be achieved [12-14].Unfortunately,the longer measurement procedure makes it inefficient to detect dynamic objects.The Fourier transform method is advantageous to perform dynamic inspection since only one single-shot measurement is required.However,compared with the phase-shifting technique,the accuracy is relatively worse.In addition,both the phase-shifting technique and Fourier transform method involve the arctangent operation.
Thus,the extracted phases have principle values ranging from –π and π,and have discontinuities with 2π phase jumps.A so-called phase unwrapping process to recover the absolute phase is inevitable.When objects of interest have large discontinuous height steps,the height steps hinder the unique assignment of fringe order,resulting in ambiguity of phase unwrapping.
求大哥大姐们无聊的时候帮下忙,分不多~
最好不是软件翻译的~起码要读的通呀- -

1.引言
在光学三维传感中,基于图案投影的技术拥有无损检测、测深精度高、测量速度快和全局域检查的优点,它由一个图案投影系统和一个图像采集系统组成.投影系统将一个图案照射至待测表面,图像采集系统从不同的视角记录被表面扭曲的图案.通过三角测量法或合适的校准,投影图案的分布可分析重构三维形状.
三维轮廓测量的主要研究内容之一是用于分析复杂的目标,如检查拥有很强深度不连续性的动态目标,合适的解决方案之一是改善现有的投影技术.投影技术可以是结构光编码法 [1-5]或边缘投影方法[6-8].但现有方法既有优点也有缺点.
在边缘投影法中,计算被测目标的失真边缘,以重构三维形状,通过相移技术[8-11]或傅立叶变换[7]可算出边缘的相位.通常,相移技术需要超过3帧图像计算相位,因此比傅立叶变换更准确,深度精确度可达视场的万分之一[12-14].但较长的测量步骤降低了检测动态目标的效率.由于只需要一帧图像,傅立叶变换法适用于动态检查,但与相移技术相比,精确度较低.此外,相移技术和傅立叶变换法均涉及反正切计算.
因此,计算出的相位主值范围为-π至π,而且存在不连续的2π相位跳变,不可避免地需要称为相位展开的过程以获得绝对相位值.如果感兴趣的目标具有较大的不连续高度梯度,将妨碍边缘阶度的赋值唯一性,导致相位展开非单值.
cnki翻译助手打不开,有些术语不知对不对.