Abstract
Conveying image information to the blind or visually impaired (BVI) is an important means to improve their quality of life. The touch screen devices used daily are the potential carriers for BVI to perceive image information through touch. However, touch screen devices also have the disadvantages of limited computing power and lack of rich tactile experience. In order to help BVI to access images conveniently through the touch screen, we built an image contour display system based on vibrotactile feedback. In this paper, an image smoothing algorithm based on convolutional neural network that can run quickly on the touch screen device is first used to preprocess the image to improve the effect of contour extraction. Then, based on the haptic physiological characteristics of human beings, this paper proposes a method of using the improved MH-Pen to guide the BVI to perceive image contour on the touch screen. This paper introduces the extraction and expression methods of image contours in detail, and compares and analyzes the effects of the subjects' perception of image contours in two haptic display modes through two types of user experiments. The experimental results show that the image smoothing algorithm is useful and necessary to help obtain the main contour of the image and to ensure the real-time display of the contour, and the contour expression method based on the motion direction guidance helps the subjects recognize the contour of the image more effectively.
Highlights
F OR a long time, people have been trying to convey image information to blind or visually impaired (BVI) to promote their development in object recognition and spatial cognition
Based on the human’s tactile physiological characteristics, this study proposes a new method for BVI to effectively perceive image contour information by applying deep learning and haptic display techniques to daily-used touch screen devices
This paper first uses convolutional neural network (CNN)-based image smoothing filter to remove detailed features in the image that are unhelpful for contour perception
Summary
F OR a long time, people have been trying to convey image information to blind or visually impaired (BVI) to promote their development in object recognition and spatial cognition. When the touch screen is used as the carrier for BVI to perceive image contour features, it is necessary to provide tactile stimulation with motion direction guidance function for the movement of hands or fingers on the touch screen. Due to the frequent movement of touch screen devices, the touchscreen interaction often lacks a stable external reference frame, which cannot provide BVI with good positioning and guidance functions These defects lead to BVI losing the tracking of the contour and shape of the object in the image during the process of touching the screen. Based on this consideration, this study adopts a pen-type haptic device to provide motion direction guidance for BVI’s movement on the touch screen.
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