Expanding the Detection of Traversable Area with RealSense for the Visually Impaired

Abstract

The introduction of RGB-Depth (RGB-D) sensors into the visually impaired people (VIP)-assisting area has stirred great interest of many researchers. However, the detection range of RGB-D sensors is limited by narrow depth field angle and sparse depth map in the distance, which hampers broader and longer traversability awareness. This paper proposes an effective approach to expand the detection of traversable area based on a RGB-D sensor, the Intel RealSense R200, which is compatible with both indoor and outdoor environments. The depth image of RealSense is enhanced with IR image large-scale matching and RGB image-guided filtering. Traversable area is obtained with RANdom SAmple Consensus (RANSAC) segmentation and surface normal vector estimation, preliminarily. A seeded growing region algorithm, combining the depth image and RGB image, enlarges the preliminary traversable area greatly. This is critical not only for avoiding close obstacles, but also for allowing superior path planning on navigation. The proposed approach has been tested on a score of indoor and outdoor scenarios. Moreover, the approach has been integrated into an assistance system, which consists of a wearable prototype and an audio interface. Furthermore, the presented approach has been proved to be useful and reliable by a field test with eight visually impaired volunteers.

Unifying obstacle detection, recognition, and fusion based on millimeter wave radar and RGB-depth sensors for the visually impaired

“…The RealSense R200 is composed of two infrared cameras (right and left), an infrared laser projector, a color camera and an image processor 5 , as illustrated in Fig. 2(b).…”

“…When the active projecting has no effect, the depth images could also be generated through the passive stereo matching. With the principle of active projecting and passive stereo matching, the performance of RealSense R200 is excellent under indoor and outdoor circumstances 5 . The R200 is quite suitable for VIP navigation because of its environment adaptability, small size and cost-effectiveness.…”

“…The development of the CV has a close relationship with the stereo vision sensor. The RGB-D sensor has also received rising attention and been used widely because of its outstanding performance [5][6][7] . They provide much more information compared the traditional assistive tools, which are able to acquire color information and perceive the environment in three dimensions at video frame rates.…”

“…However, the RGB-D sensors, including light-coding sensors, timeof-flight sensors (TOF camera), and stereo cameras, could not solve the problems of remote obstacle detection and velocity detection perfectly. The detection range of low power light-coding sensors is too small in outdoor environment, especially in sunny environment 5 . The measurement results of TOF camera are sensitive to ambient light and show poor performance in outdoor environments 12 .…”

Insight on Electronic Travel Aids for Visually Impaired People: A Review on the Electromagnetic Technology

“…Different technologies have been used with the aim of creating better devices, the most significant being based on ultrasonic sensors and optical/vision systems [11][12][13][14][15][16][17].…”