A goniometer is a device used to measure the angular range of motion of various human joints and muscle groups, such as the elbow, knee or waist. However, the majority of mechanical goniometers are heavy, provide inaccurate measurements and are affected by dust or stains. Electronic and optical fiber-based goniometers demonstrate better capability than their mechanical equivalents; however, due to their higher costs and complicated setup requirements, their usage is not viable. Optical-based encoder patterns were GC-ARE previously proposed and discussed in some studies. Such optical-based encoder patterns achieve the same angular resolution as traditional Gray code encoder patterns with many shortcomings, such as a high error rate and low tolerance, which arise as a result of the encoding method. This paper presents a design for a reliable and non-intrusive phase shift code absolute rotary encoder (PSC-ARE), which is based on an optical sensor, providing a low-cost, high-precision absolute rotary encoder system. An inexpensive optical mouse sensor is used to capture the code image and the phase shift code transforming time-domain data into frequency domain, which is used to decode the corresponding absolute angle. The PSC-ARE proposed in this study shows a performance improvement over conventional designs owing to the reduced interference from dust and other environmental particles and provides lower sensitivity to calibration errors. Furthermore, the proposed design is not only more compact and portable than the traditional goniometer, and it can also provide a longer lifespan as no stepper motor is included. Finally, the proposed design demonstrates high tolerance to “unintentional defocus” effects and noise effects.

测角仪是一种用于测量各种人体关节和肌肉群（例如肘部，膝盖或腰部）运动角度范围的设备。但是，大多数机械式测角仪很重，测量不准确，并且会受到灰尘或污渍的影响。基于电子和光纤的测角仪显示出比其机械等效物更好的性能。但是，由于它们的成本较高和复杂的安装要求，因此无法使用它们。基于光学的编码器模式是先前提出并在一些研究中讨论过的GC-ARE。这种基于光学的编码器图案实现了与传统格雷码编码器图案相同的角分辨率，但存在许多缺点，例如由于编码方法而导致的高错误率和低容差。本文提出了一种基于光学传感器的可靠，非侵入式相移码绝对旋转编码器（PSC-ARE）的设计，可提供一种低成本，高精度的绝对旋转编码器系统。廉价的光学鼠标传感器用于捕获代码图像和将时域数据转换为频域的相移代码，用于解码相应的绝对角度。这项研究中提出的PSC-ARE显示出由于减少了灰尘和其他环境颗粒的干扰而使性能比常规设计有所提高，并且对校准误差的敏感性较低。此外，提出的设计不仅比传统的测角仪更紧凑和便携，而且由于不包括步进电机，因此可以提供更长的使用寿命。最后，