研發結合聲覺圖像與超音波測距之電子導盲輔具

摘要

本系統研發一電子導盲輔具以幫助並改善視覺障礙者的生活起居與行動自主；結合視訊與超音波距離所生成聲覺圖像之音訊，搭配使用原來視障者所熟悉的白手杖，以增長能探測的距離與角度之能力。

擷取視訊作圖像轉換聲音的演算處理，以十六程度的灰階作音量之變化，並以十二平均律作音頻分配，將聲波疊加成一段複合的立體音訊回饋至耳中，透過超音波探測前方物體之反射距離，結合成為含有環境的方位、形狀、材質與距離等聲覺圖像之音訊。

人類大腦擅長記憶以聲音為標識的序列訊號變化，這與人們很容易記住音樂的曲調類似，視障者可以學習識別該複合音代表的物體特徵訊息，即便轉換至陌生環境，仍可經由前方的聲覺圖像與身旁所圍繞的聲音，而以經驗判斷並於腦中迅速建構出周遭環境的狀況。

視障朋友通常每天行經固定路段與目標地點，裝置的GPS與電子羅盤模組，能記錄多組目的地之座標位置，並於盲友需要時以語音報知自身或目標之方位角度與座標位置；隨時可確知自己身在何處、所欲前往的目的地，並能獨力且安全地到達。

此外，系統結合學習式的智慧遙控器，利用紅外線接收感測器迅速取樣與記錄遙控訊號碼，並以韌體還原生成可變載波且和紅外線控制碼，重建該紅外線遙控發射訊號；使用者可依需求錄製各家電之紅外線遙控訊號，達到無線遙控多樣化資訊家電的便利功能。

關鍵字：視覺障礙者、電子式行進輔具、聲覺圖像、超音波測距、全球定位系統、電子羅盤、學習式紅外線遙控

The Development of an Electronic Travel Aid which Integrates Auditory Images and an Ultrasonic Sensor for the Blind

ABSTRACT

An electronic travel aid (ETA) for the blind is proposed to help the blind improve the quality of their lives. The proposed ETA can help the blind perceive long-distance obstacles, travel to the desired destination, listen to an auditory watch, and control their home appliances (e.g. TV and air conditioner, etc).

The most pervasive travel aid for the blind is the white cane, which only allows them to ensure that a close front path is clear and to locate any possible near obstacle by using the white cane to touch the ground and the obstacle. Therefore, it is a demanding task to develop an easy-to-use ETA to improve the lives of the visually disabled by helping them perceive long-distance obstacles. The goal of the proposed ETA is not to replace the white cane but to complement it by helping the blind to quickly have a sketch of an unfamiliar environment in front of them. The information of the environment (e.g., the orientations, the distances, and sizes of obstacles) is extracted from an image acquired from one camera. An image-to-sound mapping algorithm is implemented to create auditory images of the obstacles ahead of the blind. The image captured by the camera is scanned from the leftist column to the rightist column and every pixel in the column is used to excite an associated sinusoidal oscillator in the audible frequency range such as 12 musical notes. The measurements from an ultrasonic sensor are used to enhance the correctness of the distance information provided by the auditory images. The environmental information is delivered to the user via an earphone. This ETA explores ways to help the blind with white canes to navigate more actively and confidently.

For long-distance travels, a GPS and an electronic compass are utilized to guide the blind to the desired destination. The time information from the GPS is used to implement an auditory watch. In addition to the aforementioned functionalities, the proposed ETA provides the blind with an intelligent universal remote controller to control their home appliances such as TV, air conditioner, etc.

Keywords：blind, electronic travel aid, auditory image, ultrasonic sensor, global positioning system, electronic compass, learning infrared remote control