低成本高速眼動儀之建構

Abstract

本研究提出了一種低成本高速眼動儀的建構方法，僅需要新台幣3000元的硬體製作成本，即完成一套取樣率為184Hz的眼動儀。過程中嘗試了數種硬體的組裝且不斷進行改良，並將控制端軟體中的眼動追蹤演算法與硬體驅動間調適及整合至最佳化，使硬體得以發揮最高效能。此外，本研究自製眼動儀系統除一般電腦螢幕上應用與實驗外，尚可透過影格率為75FPS的實景攝影機藉由同時錄製實景影像與紀錄眼動數據來進行真實場景中的相關應用與實驗。由於本研究掌握眼動儀硬體底層至軟體高階應用全方面關鍵技術，在高取樣率的眼動追蹤與高影格數的影片錄製間能有效控制運算時，資源消耗與調度。應用軟體方面，本研究自製眼動儀曾投入實際眼動實驗中，為配合實驗需求，分別有支援靜態圖片與動態影像的實驗介面；分析軟體上，開發有圖形呈現為主的ScanPath、HotZone、SelectROI；數據統計分析為主的Fixation Analysis、Saccade Analysis。

本研究自製眼動儀在ISO9241-Part 9指標性裝置評估驗證中具有反應速度快與準確率高的表現；在25點精準度實驗中也展現誤差的小於0.5˚的亮眼成果。This research presents a detailed approach to build an eye-tracker with low-cost and satisfied performance. Basically, an eye-tracker uses cameras to monitor the pupil movements of the eyes and to predict the gaze positions on the computer screen. The images displayed on the screen may either come from the computer itself or from the screen cameras, if attached around the eyes, with the maximum frame capturing rate of 75 frames per second (fps). The pupil monitoring cameras of the eye-tracker using infrared light are the main hardware devices which should be precisely controlled by the comprehensive software for the proper image capturing and processing. The commercial eye-trackers are very expensive just because such rather complicated technologies of hardware and software integrations are involved.

Our low-cost approach started form the widely surveys of both the web-cams to be modified as infrared monitoring cameras, and the basic open core control software released for sale increase of the related products or for helping the software developments of the relative research as well as applications. Finally, after undergoing many trial and error experiments of hardware and software integrations, our eye-trackers incorporated the modified infrared camera from Sony PS3 Eye-Cam with proper tuned and modified control software from CL Eye Platform Driver [18]are constructed. Each constructed eye-tracker cost around US$ 100 and demonstrated 184 Hz sample rate. Comparing to the commercial eye-tracker Tobii which cost above US$ 5000 and run at 30 Hz, our eye-tracker is 16 times less in cost and 6 times faster in frame capturing. Furthermore, our eye-tracker also exhibited the best performances under the ISO9241-Part 9 TEST in the items of “Response time” and “Correct response rate” when compared with two other eye-trackers including the commercial Tobii.

In additions to the hardware and software system integrations achieved, some software programs are also developed for the practical applications such as the graphic interfaces of ScanPath, HotZone and SelectROI, as well as the data analysis of Fixation and Saccade.