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Echolocation Bionic System for Blind People State‐of‐the‐Art Search Report

I. Introduction and Summary

Based on bat’s echolocation as a unique sensory strategy of projecting and receiving ultrasonic signals to perceive the environment, the project has been named “Echolocation Bionic System for Blind People”.

-Bionic System= system that mimics nature.

-Echolocation = Locating objects in space by the echo produced by sound calls (acoustic radiation).

-for Blind People = the target user group for the developed system.

A State‐of‐the‐Art search has been conducted to identify patents and published applications (hereinafter, patent publications) and non-patent literature (e.g. journal articles, theses, products/projects information, news,…) in the field of echolocation to build an hypothetical device that would improve the accessibility for visually impaired people to the physical environment through haptic feedback.

An initial look at the findings reveals that much research has been done worldwide on support systems for the visually impaired as support systems to recognize objects in a user's surroundings using a tactile display and synthetic voice. Research projects on a walking guide robot and on walking support systems have also been developed. However, there are still many problems in representing the real-time information that is changing around a user.

For this reason the purpose of this report is to illustrate state of the technology and research relevant to integrate systems based on ultrasonic obstacle detecting device, bone conduction stimulation, beep sound or vibration warning, combined with a real-time human-computer interaction based on a hand data glove.

Echolocation Bionic System for Blind People State‐of‐the‐Art Search Report

II. Methodology

The methodology adopted for this search involved the following set of activities:

1. Identifying relevant patent/non-patent databases and other information resources.

2. A keyword-based search was conducted on selected patent and non-patent databases to obtain sets of results relevant to the chosen subject of study.

3. Using patent classification codes for worldwide search in the following areas of International Patent Classification (IPC): A61F, A61H and G01S.

4. Extracting search results and conducting prior art search from related citations and bibliographic references of retrieved documents that were relevant to the project.

Search Assumptions:

1. All patent searches were conducted using public patent databases, and all non-patent searches were conducted on non-patent databases or other web search engines.

2. The patent search publications included the published as well as issued/granted patents and utility models.

3. The scope of the search was limited to international (WIPO) / national patents also including the “patent family” if the language of the priority patent document wasn’t English.

4. The results relevant to the chosen field and published without using the publication date filter have been presented in the sheets entitled as 'Patent Search Results' and 'Non Patent Search Results.'

5. Only 'one member per patent family' was used for the purpose of analysis.

6. Only English language documents were analyzed (incl. the abstract of foreign patent documents available in English).

7. The selection criteria of patent publications was based on their title, abstract, and claims.

Echolocation Bionic System for Blind People State-of-the-Art Search Report

III. Patent Search Results:

TouchSight, a new startup company launched by Manufacturing Engineering Tripos (MET) students Pete Davies, Karan Keswani, Samaan Rahman and Jessi Baker, won first prize at the Next Generation Entrepreneur Forum (NGEF) competition in Monaco (2007) due to a new unique mobility aid for blind and partially-sighted people ([1], [2] & [3]). The glove-based system, known as TouchSight Vision Mitt, enables the user to ‘sense’ his surroundings using ultrasonic sensors and vibration feedback, providing a low-cost alternative or supplement to guide dogs or white sticks. Products with electronic sensing systems for the blind do exist but very few have achieved widespread popular appeal and most are instantly noticeable and potentially stigmatise the user. The students came up with this revolutionary glove based system, which combines ultra-sound with sensory feedback.

The glove uses ultra-sound to detect the environment, similar to a bat. It includes a small vibrator that turns this signal into a physical sensation that the wearer can feel. The nearer you are to an object, the stronger the feedback. Trials with blind users have resulted in extremely positive feedback and a demand for the product to be taken all the way to market.

For more information, see Patent GB2448166 (see table above and click on title, p.4).

This small device is a project designed by Calin Giubega, from Gothenburg, Sweden, that aims to improve everyday life of people who are visually impaired, enhancing their mobility by creating gestures using the hand’s sensory capacities such as the recognition of pressure and spatial acuity factors in relation with the user’s mental model [4].

"Munivo" uses a simple and accessible technology, based on ultrasound technology (Remote sensing). Distance sensors make measurements on two axes, "X" and "Y", between the subject and potential obstacles, sending this information to the electronic control unit. Then, the control unit processes the signals received from sensors and sends control signals to actuators placed in the silicon film in direct contact with the skin of the palm. Finally, the spherical actuators transmit signals to the user, moving on two axes, creating familiar gestures. Through gestures, the user is able to perceive obstacles and delimitations of the environment, creating thus a haptic communication system.

This device is designed to be simple, both in terms of construction and functionality aiming towards a full use of the hand in daily activities. Thus, the shape of Munivo is the result of combining several factors such as function, ergonomics, comfort, functional aesthetics and manufacturing costs. [See also Annex I]

The inventor Steve Hoefer has developed a “Hand-Mounted Haptic Feedback Sonar Obstacle Avoidance Assistance Device” to let the blind remotely feel the world around them ([5] & [6]).

“It’s an open source device that measures distance to surroundings with ultrasonic pulses and translates that to pressure on the wearer's wrist. So it’s set around the wrist and allows to sense objects from about 1 inch (2 cm) to 10 feet (3.5m). It has a generally fast response time (fractions of a second) in order to quickly navigate complex environments. Mounted to the back of the hand, the force feedback means it doesn’t interfere with other assistance devices that mount elsewhere and use audio feedback cues.”

This prototype developed as a wrist mounted detecting device (see figure below) uses two ultrasonic range sensors for detection and two servomotors for haptic feedback. There is a sensor-servo pair on each side of the hand to help indicating direction. The servos motions increase in frequency with closer distances, i.e. a nearby object would elicit a bigger response from the servos. Servos were chosen because they are quiet and can be fine tuned to different positions. Since the hand has so many degrees of freedom, attaching the device to it allows the user to easily point it in the desired direction. Additionally, it doesn’t prevent the user from using a white cane or a guide dog and can be worn on either hand. [See also Annex II]

As a separate project from Tacit, Michael Frink has designed a wrist-mounted piece of electronics for the blind [7]. It is a sleeve that fitted onto a user’s hand, collects information about the world and feeds it back to the user with vibrating pulses on the wrist.

According to the author, the aim of this project is to create a low cost, hand mounted device which analyses the surrounding environment, thus providing environmental data to the user through the use of haptic feedback in order to aid navigation for the visually impaired.

The navigation system is based primarily on the pioneering work of J.M. Loomis and his team's research into spatial analysis for the visually impaired. His work focused primarily on instrumentation which collected data in a 360 degree radius around the user, which was then fed into computer systems which provided vibrational feedback to the user based on the range of obstacles in all directions. The limitation of such systems is the cost since they require large amounts of instrumentation; the vest that the user must wear is both heavy and unfashionable; the potential of false positives due to movement of the user’s limbs; and the excessive power consumption from the data analysis and involved instrumentation.

The prototype that Michael Frink is proposing uses the same concept of haptic feedback from data collected from instrumentation, but limits the flaws inherent in the systems designed by Loomis. Given that the data collection system consists in a pair of ultrasonic range sensors mounted to the back of the user’s hand, the device would be lightweight, its power consumption is kept to a minimum, and works in a manner similar to navigating with a cane, a skill that most visually impaired people have grown accustomed to.

HandSight is a prototype glove developed by Lee Stearns and Darren Smith to aid the blind that senses the lightness or darkness of a surface with tactile feedback from a vibration motor for each individual finger [8]. It can also sense distance from physical objects or obstructions and indicate direction and distance with the same vibration feedback .It supports additional modes, and the possibilities are nearly endless. The glove can connect over Bluetooth to switch modes and visualize the sensor readings.

This instructable was made as part of the final project requirement in the CS graduate course "Tangible Interactive Computing" at the University of was made as part of the final project requirement in the CS graduate course "Tangible Interactive Computing" at the University of Maryland, College Park taught by Professor Jon Froehlich. See more details http://cmsc838f-f12.wikispaces.com/HandSight

Thuong N. Hoang and Bruce H. Thomas, of the Wearable Computer Lab of the University of South Australia, are working on a set of distance-based interaction techniques for modeling and manipulation, enabled by a new input device called the ultrasonic gloves [9].

The ultrasonic gloves are built upon the original design of the pinch glove device for virtual reality systems with a tilt sensor and a pair of ultrasonic transducers in the palms of the gloves. The transducers are distance-ranging sensors that allow the user to specify a range of distances by natural gestures such as facing the palms towards each other or towards other surfaces. The user is able to create virtual models of physical objects by specifying their dimensions with hand gestures. It allows combine the reported distance with the tilt orientation data to construct virtual models and also map the distance data to create a set of affine transformation techniques, including relative and fixed scaling, translation, and rotation, so these techniques can be generalized to different sensor technologies.

The ultrasonic gloves can be used as a versatile input device that supports modeling interaction within a wearable AR system due to a modeling by measurement technique that supports gesture-based capturing of physical dimensions of real world objects and affine transformation techniques with translation, rotation, and scaling of virtual objects, offering this way the first within arms reach direct manipulation approach to modeling for wearable outdoor/indoor AR system.

Project HALO is a haptic feedback device that uses a series of rangefinders that would take input from sensors and output feedback to pulse vibration motors placed on the head to help a visually impaired person navigate and avoid obstacles in a space, since when this person gets closer to an object the intensity and frequency of the vibration increase directly proportional to the distance of an object. If a region was lacking feedback, then it would be safe to proceed in that direction [10].

It is an open source Low-Fi rapid prototyped project which main aim is to utilize inexpensive components and sensors to build an assistive technology. It seems that most of the development time was given to writing and developing the code to connect the sensors to the output. On a video demonstration of the HALO project, it was clearly apparent that a person is able to navigate around an enclosed space without hitting anything due to sensors placed on the head that are able to detect objects that come close to that height.

Douglas G. Richards & Martin Lenhardt, of the Dept. of Biomedical Engineering, Virginia Commonwealth University, are developing an innovative echolocation device to serve a large population of blind infants who at present have few alternatives to enhance their sensory capabilities and facilitate motor development [11].

This project under commercial development is an “echolocator”, which is an adaptation of bat-like auditory processing for the visually impaired using patented ultrasound technology. According to the authors, it’s the only sensory substitution device for the blind that uses the human ability to perceive bone conducted high audio (10-20 kHz) and ultrasound (20-100 kHz), thus making use of the natural capacity for echolocation, rather than relying on processed sound, potentially facilitating the learning process, and making a more natural sensory substitution. Moreover, since it presents the sounds in the high audio and ultrasonic regions through bone conduction, it does not interfere with hearing of speech or environmental sounds.

The project will specifically demonstrate feasibility by a performance evaluation of the sonar parameters relevant to use by a blind infant, e.g. field of view, size and distance of object detection, and of the output to existing data on bone conduction thresholds and frequency discrimination.

The figure shows that moving the object a distance of 30 cm across the field of view resulted in a clear movement of the signal strength in the two microphones, allowing binaural echolocating localization of the object. The figure shows two trials (solid and dotted lines) with the object moved at 5 cm intervals. At 10 cm to either side of center, there is a clear difference in intensity at the two microphones of about 10-15 dB.

For more information, see Patent US5047994 related to "Ultrasonic echolocating device for blind infants".

At the University of Michigan, Johann Borenstein has developed a new travel aid for the blind, called the Navbelt [12][13]. The Navbelt consists of a belt, a portable computer, and ultrasonic sensors. In this system, the computer processes the signals that arrive from the sensors, and applies an obstacle avoidance algorithm. The resulting information is relayed to the user by stereophonic headphones. The direction to an obstacle is indicated by the perceived spatial direction of the signal, and the distance is represented by the signal's volume.

NavBelt system is worn by the user like a belt around the waistline and through a set of stereo earphones to provide acoustic signals which direct the user around obstacles. However, the NavBelt system suffers from certain limitations such as the difficulty of conveying information to the user to allow rapid walking, on the other hand the NavBelt must be used together with white cane .

IV.2. Articles, Papers & News

A literature study was conducted on three main topics: visually impaired people, blind navigation, wearable system, haptic device, tactile display, sonar, echolocation and/or ultrasound bone conduction. The main findings are presented below.

· Design of a Sonar System for Visually Impaired Humans

Cameron Morland & David Mountain have created a device which makes echolocation more effective and easier to learn, while being audible only to the user [14]. The prototype sonar system designed emits ultrasonic sounds around 40 kHz through a piezoelectric transducer. These signals reflect off objects in the world and return to the user, where they are picked up by miniature microphones mounted near the ears. Digital processing converts the received signal into the audible range, which is then presented using special earphones. The device works by very specific, but limited, processing of the received echo signal to retain the spatial cues.

For more information, see Patent US2009122648 in the table with the list of patents (p.4).

Korean researchers have developed a vest type of wearable guide system in which all the components of system are located as it is shown in figures above. Once the user has put on the vest, it's ready to acquire the information about obstacles and direction for walking. Further, they can use white cane together if they want [15].

This guide system for the blind is designed to find out the obstacles in front of the user using ultrasound sensors and notify the information of it using bone conduction vibrator with beep sound and TTS voice announcement. A PDA is used as the main controller and provides the warning and guide information sound to the blind. In addition, a voice recognition method is employed for the user convenience. The bone conduction method is applied as the information transfer method to allow the blind to hear both the guide sound and the environmental sound which is an essential cue for them for walking.

· Ultrasonic earphone system combined with audible band bone conduction vibration.

This paper describes a ultrasound earphone based on the phenomenon with which, when a listener's tragus is vibrated by ultrasound with amplitude modulation of audible sound, an audible sound is perceived. The authors consider that audible sound can be produced by the ultrasound transmitted from an actuator to the external auditory canal. This earphone reproduces a sufficiently loud high-frequency band sound. On the other hand, it cannot reproduce low-frequency band sound. A bone conduction earphone that actuates over facial bones by audible band vibration easily leaks sound to the air in the high-frequency band.

Thus, Japanese researchers Manabu Okamoto, Masato Miyoshi, Akitoshi Kataoka and Shin'ichiro Iwamiya [16] have proposed a hybrid earphone system combined with audible band bone conduction vibration. This system enables an earphone to transmit sound that is not close to a listener's ears, and sound leakage is small.

This paper describes the development of a system that uses a portable Pocket PC to generate 3D spatialized sounds, based on the readings from a multidirectional sonar system that detects obstacles around a blind person [17].

The distances from the user position to the closest objects in six directions are continuously determined using six sonar range meters. The information is used by the Pocket PC to create a 3D sound environment that represents the obstacles in these directions through the simulation of six spatialized sound sources. The dynamic spatialization of the sounds is achieved through the use of previously computed Head Related Transfer Functions, taking into consideration the distance to the obstacles, and the direction the person is heading.

· A sonar system modeled after spatial hearing and echolocating bats for blind mobility aid

In this paper, an ultrasonic blind mobility aid device is achieved by mimicking both the human ears configuration and the echolocating bats, and by implementing a technique to convert inaudible ultrasound echoes into audible sounds [18].

Bitjoka Laurent and Takougang Noupowou Alain Christian, from The University of Ngaoundéré, Cameroon, have designed the sonar system composed of three transducers, one transmitter which plays the role of the mouth of the bat that transmits echolocating signal and two receivers located respectively near the left ear and the right ear so as to mimic human ears configuration. It delivers two audible Doppler signals conveyed binaurally to the user through stereophonic earphones. The amplitude of the audible Doppler signal delivered by this sonar system depends on the reflecting properties of the objects detected and their location.

Kyle Curham and Adam Wolfe, from REED Lab at the University of South Florida, have developed a haptic device based off of the Tacit, structurally similar to this device with sonar sensors and vibrotactors for feedback [19].

The sonar sensors are used to gather information about the environment, and then feedback delivered to the user by varying vibration stimuli. The vibrotactors are mounted on a glove to allow the user to point the device in any direction. This has the advantage of having as many degrees of freedom as the hand and requires fewer actuators and sensors compared to a head-mounted display.

· Development and evaluation of an open source wearable navigation aid for visually impaired users (CYCLOPS)

The Cyclops project (http://cyclops-eye.yolasite.com/) involved the design, assembly and characterization of a wearable computing device capable of assisting pedestrian navigation for blind people. The device is a regular glove with the addition of electronic sensors, actuators and an Arduino Uno controller board, sporting an Atmel ATmega328 microcontroller chip. Design emphasis was placed on producing an intuitive and discreet navigational aid, the technology being shaped around user needs.

This paper presents a model of 'Embedded Glove' to aid the visually impaired people , a hand mounted tactile (vibration mechanism) feedback sonar (Sound Navigation And Ranging) obstacle avoidance system, by warning through vibration motors for visually impaired to whom traveling in indoor/outdoor environments is really a difficult task [21].

The model developed by Sankar Kumar and Nithya Lakshmi comprises of a glove strapped to the wrist, embedded with ultrasonic sensors, battery, microcontroller and vibrator motors. Along with being completely reliable, this system also provides to be a cost-effective guidance mechanism for the visually impaired and has been designed to scan a wide area with a set of ultrasonic sensors which also provides a good range and speed in the detection of the obstacle. The detected obstacle is immediately notified to the possessor thereby the presence of obstacle along with its direction is conveyed to the visually impaired person by means of a tactile system. Thus, the ‘embedded glove’ with ultrasonic sensors (transmitter and receiver) for the obstacle detection and distance estimation, is capable to measure the distance by calculating the amount of time taken by a pulse of sound to travel to a destination and return as the reflected echo. The calculated information is given to the visually impaired person via a feedback system (vibratory mechanism or speech synthesizer). The intense of vibration illustrates the proximity of the obstacle from the visually impaired person.

Peter Mihajlik, Maria Guttermuth, Krisztian Seres and Peter Tatai from TSP Lab, Department of Telecommunications and Telematics, Budapest University of Technology and Economics (Hungary) describes in this paper [22] a novel navigation aid for the blind designed at their laboratory. The system detects obstacles in front of the user by the help of ultrasonic echolocation and indicates the distance and horizontal position of the nearest detected object by spatial stereo sound effects.

The simplified block-diagram of the hardware The simplified flow-chart of the software.

Thus, the instrument currently under construction, is a battery operated ultrasonic navigation aid for the blind that comprises a digital signal processor based system is able to determine the distance and the horizontal position of the obstacles in front of the user and to indicate the location of the nearest (most dangerous) one by stereo sound through earphones. The DSP is equipped with suitable interface circuits connected to one ultrasound transmitter and two receivers, which can be mounted on the hat of the blind person.

· CyARM-interactive device for environment recognition using a non-visual modality

Japaneses researchers have developed an interactive device for environment recognition, which uses senses other than vision. The device named CyARM has a mechanism that controls the motion of a visually impaired person's arm according to information about distance gathered by an ultrasonic sensor[23].

CyARM is a sensing device with a unique, intuitive interface for assisting blind people with walking. The user holds CyARM in their hand, and searches the environment by pointing and moving the device. CyARM is connected to the user’s body by a wire and transmits ultrasonic waves to measure the distance to the obstacle. The tension of the wire is controlled according to the measured distance to the obstacle.

Another step involved in developing an advanced technology obstacle avoidance cane encompasses bat echolocation signal processing techniques and ultrasonic technology. The final cane design, originally developed as a concept at the University of Leeds in around 2004, was marketed worldwide as the UltraCane™ by West Yorkshire company Sound Foresight Technology [24].

The UltraCane™ was developed by mimicking the echolocation of bats which use wide ranging ultrasound in order to build a ‘spatial map’ of their surroundings, allowing them to effectively, ‘see’ in the dark.

The patented UltraCane™ works alerting users of obstacles ahead of them, both in their path and at head height. The handle of the white cane is a handset fitted with transmitters and sensors. Buttons in the handle vibrate when the sensors detect a nearby object. The strength of the vibration indicates the proximity of the object, thus helping the user to walk around the obstacle easily and independently. [See also Annex III]

Primpo Co. [25] has developed its revolutionary new cane product for the visually impaired, "iSONIC".

Unlike conventional white canes, with which a user can’t detect obstacles above waist height, the "iSONIC" model can detect obstacles within a range of 25 degrees horizontally and 50 degrees vertically with an integrated supersonic sensor.

The product can also detect obstacles within a distance of 2 meters, as well as very slim objects, narrower than 3 cm. With decreasing distance to an object, the cane's vibrating indicator sends a stronger signal to the user, pinpointing the location of the obstacle. [See also Annex IV]

The 'K' Sonar enables blind people to perceive their environment through ultrasound, increasing their mobility in their need to travel. The 'K' Sonar has been designed to be attached to a long cane [26].

The 'K' Sonar uses KASPA Technology to mimic the bat's sonar capability of gathering rich spatial information about the surrounding environment. In a similar way to a person recognizing the texture of different surfaces through their fingertips, sonar echoes, as heard in miniature headphones, carry object texture information to the brain.

This device is likened to a flashlight that sends out silent ultra high frequency sound signals. The signals bounce off obstacles in the path of the device, returning to the receiver sensor. The unit translates these signals into audible ‘tone complex’ sounds which are then amplified and sent to the user’s earphones.

Kay's Advanced Spatial Perception Aid [27] is a sonar device that enables blind people to see with sound developed by Leslie Kay, of New Zealand's SonicVision Ltd.

The Trisensor, later termed the Sonic Guide and more recently the KASPA, was designed as a “wide-angle binaural” ultrasonic aid. A transmitter and two receivers are mounted on the nosepiece of a pair of glasses. Information from the backscatter of ultrasonic waves is transmitted to the ears binaurally using sonification of the signal such that interaural intensity differences represent directional differences, and pitch indicates the distance to an obstacle. This device is a continuous scanning device that provides tones about all obstacles in the environment regardless of motion of the user or look direction. As the sonified signal is not developed to minimize masking, other aspects of the surroundings cannot easily be heard. An individual using this device cannot readily communicate with those around, limiting the device solely to independent travel situations.

The Sonic Pathfinder is a ultrasonic mobility device designed for outdoor use in conjunction with either a long cane, dog guide or residual vision [28]. The Sonic Pathfinder gives the user advance warning of objects which lie within the travel path. The distance and position of a detected object is signaled via the ear pieces using the eight tones of the musical scale.

According the description given by Tony Heyes, this system has evolved out of the work of the Blind Mobility Research Unit at Nottingham University, England, as a head-mounted pulse-echo sonar system controlled by a microcomputer. The five ultra-sonic transducers which are mounted on the head-band comprise three receivers, one pointing left, one right and one straight ahead, and two transmitters. The two transmitters are angled so as to irradiate the user's pathway with ultra-sonic energy. Echoes from objects lying within this pathway are received by the three receiving transducers and this information is processed by the on-board computer. The output of the device, the display, is fed to one or other of the two ear pieces depending on whether the object is on the left or the right of the user or to both ear pieces if the object lies directly in the travel path.

The headband contains five ultrasonic transducers, three receivers and one transmitter. Echoes from transmitted signals trigger a range of distance alert tones, which are delivered through earphones to the user.

The Miniguide uses ultrasonic echo-location to detect objects [29]. The aid vibrates to indicate the distance to objects - the faster the vibration rate the nearer the object. There is also an earphone socket which can be used to provide sound feedback. A single push button is used to switch the aid on or off and also change settings. The aid can accommodate ranges of between 0.5m and 8m, depending on the chosen mode. The Miniguide has got a transmitter/ receiver pair that should be held one above the other while in operation.

The Miniguide is a small handheld device that uses ultrasonic pulses to echo locate obstacles in its path. It has the advantage of a low current requirement. However, when used indoors, most ultrasonic devices pick up unwanted ambient echoes from adjacent walls, ceilings and surfaces which may corrupt the result. Vibration displays usually draw more current than the rest of the circuit requirement.

The next table summarizes each one of sonar-based devices that use basically ultrasonic technology combined with audio and/or vibro-tactile feedback:

Some of the surveyed systems with audio feedback are based on the echolocation principle and employ several sonar or ultrasonic sensors plus a beeping scheme to warn the user. Other electronic devices with vibro-tactile feedback or with haptic-audio support for non-visual spatial recognition that enables individuals who are blind to expand their knowledge by using an artificial reality built on haptic and audio feedback, also have been investigated.

Moreover, many researches deal with the problem known as auditory localization but now can be resolved with the Stereo Bone Conduction Stimulation. Thereby remain the auditory canal open, which allows hearing both the alarm signal and the environmental sound. Also, there are systems that cannot solve the blind’s ultimate problem of the environment perception due to the characteristics of the ultrasound reflections such that many object can barely be detected.

For this reason, the author’s prototype development programme is, hopefully, a step in the right direction to integrate the state of the art current technologies. Further prototype solutions will follow.

[9] HOANG, Thuong N.; THOMAS, Bruce H. Distance-based modeling and manipulation techniques using ultrasonic gloves. En Mixed and Augmented Reality (ISMAR), 2012 IEEE International Symposium on. IEEE, 2012. p. 287-288.

[11] Richards D.G., Lenhardt M.; “Infant Echolocator”. Abstract of Paper, 80^th Annual Meeting of the Virginia Academy of Science, May 22-24, 2002, Hampton University, Hampton, Virginia.

[12] Borenstein J., "The Navbelt - A Computerized Multi-Sensor Travel Aid for Active Guidance of the Blind," CSUN's Fifth Annual Conference on Technology and Persons with Disabilities, pp. 107-116, Los Angeles, California March 1990.

[14] MORLAND, Cameron; MOUNTAIN, David. Design of a sonar system for visually impaired humans. En Proceedings of the 14th international conference on auditory display, Paris, France. 2008.

[15] KIM, Chang-Gul; SONG, Byung-Seop. Design of a wearable walking-guide system for the blind. En Proceedings of the 1st international convention on Rehabilitation engineering & assistive technology: in conjunction with 1st Tan Tock Seng Hospital Neurorehabilitation Meeting. ACM, 2007. p. 118-122.

[16] Manabu Okamoto: "Bone conduction earphone using ultrasound vibration" Technical Report of IEICE US2001-104. EA2001-118. 83-88 (2002)

[17] AGUERREVERE, Daniel; CHOUDHURY, Maroof; BARRETO, Armando. Portable 3D sound/sonar navigation system for blind individuals. En The 2nd LACCEI Int. Latin Amer. Caribbean Conf. Eng. Technol. Miami, FL. 2004.

[18] LAURENT, Bitjoka; CHRISTIAN, Takougang Noupowou Alain. A sonar system modeled after spatial hearing and echolocating bats for blind mobility aid.International Journal of Physical Sciences, 2007, vol. 2, no 4, p. 104-111.

[19] CURHAM, Kyle; WOLFE, Adam. Navigation Using a Haptic Hand-Mounted Device For the Visually.Impaired. En Haptics Class Project Paper, University of South Florida, Jun 27, 2012.

[20] SALONIKIDOU, Barbara, et al. Development and evaluation of an open source wearable navigation aid for visually impaired users (CYCLOPS). En Bioinformatics & Bioengineering (BIBE), 2012 IEEE 12th International Conference on. IEEE, 2012. p. 115-120.

[21] KUMAR S, Sankar; ABARNA J; LAVANYA G; LAKSHMI S, Nithya. ‘Embedded Glove’ to aid the visually impaired. International Journal of Electrical, Electronics and Data Communication, ISSN (PRINT): 2320-2084, Volume 1, Issue 1, 2013.

[22] MIHAJLIK, P., et al. Dsp-based ultrasonic navigation aid for the blind. En Instrumentation and Measurement Technology Conference, 2001. IMTC 2001. Proceedings of the 18th IEEE. IEEE, 2001. p. 1535-1540.

[23] OKAMOTO, Makoto, et al. CyARM–Interactive Device for Environment Recognition Using a Non-visual Modality. En Computers Helping People with Special Needs. Springer Berlin Heidelberg, 2004. p. 462-467.

[27] KAY, Leslie. Auditory perception of objects by blind persons, using a bioacoustic high resolution air sonar. The Journal of the Acoustical Society of America, 2000, vol. 107, p. 3266.

Information for building a device that improves the accessibility for visual impaired users who want to access to the physical environment

	Page
I	Introduction and Summary	2
II	Methodology and Search Assumptions	3
III	Patent Search Results	4
IV	Non-Patent Search Results
	IV.1. Projects Research	7
	IV.2. Articles & Papers	16

	IV.3. Commercial Sonar-Based Devices	23

V	Conclusion	27
VI	Bibliography, Links and References	28
VII	Annexes	31

Device	Input Transducer	Output Display	Information Conveyed	Model of Operation	Operating Environment	Aproximate Cost	Developer
Bat ‘K’ Sonar Cane	Sonar	Acoustic	Presence of multiple targets, out to 5 m distance, including drop-offs and over-hangs	Cane-mounted	Indoors or outdoors	$700	Bay Advances Technologies batforblind.co.nz
Kaspa	Sonar	Acoustic, stereo sound	Acoustic image of multiple objects 3-D space (out to 5 m), including over-hangs	Head-mounted	Mainly outdoors	$2,500	Bay Advances Technologies batforblind.co.nz
Sonic Path-finder	Sonar	Acoustic, stereo sound	Objects contacted by a pedestrian in the next 2 seconds (including over-hangs)	Head-mounted	Mainly outdoors	$1,600	Perceptual Alternatives sonicpathfinder.org
Mini-guide	Sonar	Acoustic and vibro-tactile	Object distance (0.5 to 8 m) including over-hangs	Hand-held	Mainly outdoors	$600	GDP Research gdp-research.com.au
UltraCane	Sonar	Acoustic and vibro-tactile	Object distance (1 to 4 m) drop-offs and over-hangs	Cane-mounted	Indoors or outdoors	$800	Sound Foresight ultracane.com
iSonic	Sonar	Acoustic and vibro-tactile	Object color and distance (3 cm to 2 m) drop-offs and over-hangs	Cane-mounted	Indoors or outdoors	$800	PRIMPO Co., Ltd. primpo.com

State of the Art