| 摘要: | 摘 要 本論文主要利用光學質心法配合CMOS影像感測器及其他光源(包括雷射、發光二極體)應用於新型的光電量測系統的研究。光學質心法已被廣泛應用於許多的光電系統上，尤其結合電子影像的光電系統不但可取得所要的量測資料更可同時處理影像，使得擷取的資訊更豐富、更完整。首先探討光學質心法的理論基礎及誤差參數，同時詳述我們應用此方法所發展出來的現代光電量測系統，包括: 工業自動化應用(包含單、雙目標:主動式及被動式測距)、配合紅外線雷射及CMOS影像感測器應用於汽車測距、配合光學設計鏡組所研發出來的電子影像水平儀，利用光學三角測量法及快速傅利葉轉換所研發出來的人類脈搏量測系統。近年來由於半導體製程的進步，CMOS影像感測器的發展日新月異，其體積小、低耗電、價格低廉，並且系統整合於一單晶片上，運用此CMOS影像感測器配合光學質心法研發先進低價的光電量測系統是本論文的目的。 Abstract To design some low cost, practical electro-optical systems with CMOS image sensor, light sources and centroid method is the goal of this dissertation. The centroid method has been applied to many large field applications, including target or star tracking, industrial applications, infrared image tracking, et al. However, Laser triangulation and target tracking are normally used in conjunction with position sensing detectors (PSDs) or with charge coupled devices (CCDs), where the centroid position is found through intensity profile fitting to a similar Gaussian shaped light spot. In this dissertation, a CMOS image sensor is adopted to function as a one-dimensional array position sensing detector (in active range finder and pulse measurement system) or two-dimensional array position detector (in passive range finder and tilt sensor). First, the presented range finders with a CMOS image sensor and different light sources are based on simple triangulation method. By adjusting the exposure time (ET) of the CMOS image sensor, the image processing and triangulation range finder can be integrated in one system. Hence the fields of applications are very versatile, ranging from industrial automation to traffic, aiming system and blind guidance as well. Second, a low cost prototype of a laser range finder using a CMOS image sensor is developed for the automotive field. The system presented here is also based on triangulation. The gravity of the infrared laser spot on CMOS image sensor is converted into pixel coordinates proportional to the distance to be measured. The system is operated in two modes: continuous wave (CW) and pulsed mode. The comparison of these two modes also has been conducted and presented. From the experimental results, it was found that the distance could be estimated with accuracy better than 1.1% within the range of 5 to 45 meters. Third, a low cost, compact electro-optical (EO) leveler using a CMOS image sensor is developed for the purpose of tilt angle measurement. The two lenses optical system is designed to find the tilt information of the total system. ZEMAX was used to design and predict the performance of this optical system. One lens was designed to be bowl shaped and can hold a liquid. The gravity of the light spot on the CMOS image sensor is converted into pixel coordinates proportional to the tilt angle to be measured. The experimental results verified the simulation results. The reading tilt angle can be estimated with a resolution at better than 4.2 sec of arc. Final, a non-invasive, non-contact measurement of pulse waveforms by applying optical triangulation technology on skin surface vibration is developed. The arterial pulsation information can be obtained with this measurement system. An algorithm to evaluate the pulsing activities from center of laser spot intensity on a certain wrist point has been conducted by Fast Fourier Transform (FFT). The amplitude and frequency of vibration of skin can be known by this measurement system. |
