Orientation & Mobility

A blind pedestrian is using a guide dog and five technologies for navigation. This figure illustrates the need for an integrated navigational system.

  • The guide dog aids with mobility and obstacle avoidance.

  • The compass provides the user with heading information when stationary.

  • The GPS receiver integrates with a GIS database (digital map) to provide position and heading information during outdoor navigation.

  • The talking signs receiver gives orientation cues by identifying the direction and location of important landmarks in the environment.

  • The digital sign system (DSS) receiver picks up barcodes from signs and sends them to a database to facilitate indoor navigation.

  • The BrailleNote accessible computer, the hub, represents the ‘‘brain’’ of the system, allowing Braille input and speech and Braille output.

Source: Blind Navigation and the Role of Technology

Assistive Technology for Orientation and Mobility

Moving in a 3D space requires orientation and navigation capabilities. For that purpose, we are able to gather, interpret and build up knowledge about our environment in a multifaceted skill. The set of skills, techniques and strategies used by blind people to travel independent and safely are known as Orientation and Mobility (O&M).

Though closely related, there is crucial difference between orientation and mobility:

  • Orientation means to know where he (she) is in space and where he (she) wants to go

  • Mobility is to be able to carry out a plan to get there

The function of any sensory aid is to detect and locate objects and provide information that allows user to determine (within acceptable tolerances) range, direction, and dimension and height of objects. It makes non-contact trailing and tracking possible, enabling the traveler to receive directional indications from physical structures that have strategic locations in the environment with additional object identification if possible.

The assistive technology solutions for pedestrians with visual impairment and reveals that most of the existing solutions address a specific part of the travel problem. Technology-centered approach with limited focus on the user needs is one of the major concerns in the design of most of the systems. State-of-the-art sensor technology and processing techniques are being used to capture details of the surrounding environment. The real challenge is in conveying this information in a simplified and understandable form especially when the alternate senses of hearing, touch, and smell have much lesser perception bandwidth than that of vision. A lot of systems are at prototyping stages and need to be evaluated and validated by the real users. Conveying the required information promptly through the preferred interface to ensure safety, orientation, and independent mobility.

Since 1960s evolving technology helped many researchers built electronic devices for navigation. These can be categorized as follows:

  1. Vision Enhancement involves input from a camera, process the information, and output on a visual display. In its simplest form it may be a miniature head-mounted camera with the output on a head-mounted visual display.

  2. Vision Replacement involves displaying the information directly to the visual cortex of the human brain or via the optic nerve.

  3. Vision Substitution is similar to vision enhancement but with the output being nonvisual, typically tactual or auditory or some combination of the two and since the senses of touch and hearing have a much lower information capacity than vision, it is essential to process the information to a level that can be handled by the user.

O & M devices are broadly categorized as:

  1. Electronic Travel Aids (ETAs): devices that transform information about the environment that would normally be relayed through vision into a form that can be conveyed through another sensory modality.

  2. Electronic Orientation Aids (EOAs): devices that provide orientation prior to, or during the travel. They can be external to the user and/or can be carried by the user (for example, infrared light transmitters and handheld receivers).

  3. Mixed EO&TAs

About this Page

We present a glimpse of the orientation and mobility aids in the following sections:

  • Dogs and Canes - Friends of the Blind: Guide dog and Canes (often White Cane) have been the most popular friend of the users for O&M. Yet debate continues.

  • Electronic Travel Aids and Electronic Orientation Aids: ETAs: Various ETAs and EOAs, commonly called ETAs together, have evolved from simple White Cane to various levels of mechanical, electro-mechanical, and IT-and-AI enabled smart wearable aids.

Torch-like ETAs were some of the first prototypes; more specifically, ultrasounds based ETAs. The problem with the torch-like devices is that one hand of the user is employed to handle the ETA. Moreover, blind users hardly renounce to the white cane, since it is the most reliable device to prevent from falling. So, both arms and hands are occupied by different tools. Because of that, cane-like products started to appear, being the laser cane the first of them. The main problem of many mobility devices is the occupation of the hands to use them. Thus, some other implementations have been proposed, where sensors are mounted on a belt, while the computation unit is carried in a bag. In order to make the ETAs less ostensive, researchers have tried other wearable ETA possibilities like the head, the chest, the tongue, simply worn in the vests, or in the shoes. Several ETAs carried by the users simultaneously use pre-installed hardware in the environment like GPS, Mobile Network or Indoor Positioning Systems.

  • Innovations: Way beyond the era of dogs and canes, continuous innovations continue to take the horizon of O&M aids forward. These are at various stages of preparedness - ranging from individual skill to laboratory prototype to early commercialization. We cover a few promising ones including SmartCane, Tongue Click Sonar, Canetroller, EyeCane, and VL Eyes using LiFi. We also outline DIY projects for smart glasses.

  • Technology: Provides a brief overview of visual assistive technology for O&M.

Dogs and Canes - Friends of the Blind

The only, absolute and best friend that a man has, in this selfish world, the only one that will not betray or deny him, is his DOG.

- King Frederick of Prussia, 1789

Dog naturally comes to great help for people with blindness or low vision, They are the guide dogs. In contrast, a cane - colored, suitably designed - can provide a different type of independence. The debate continues on which support is better, or should both be used (like the cover picture of the page)? VisionAware takes a non-committal approach, saying: Choose the Option That Is Best for You?, while others continue to debate.

We present some facts.

Source

Advantages of Cane Travel

  • A cane is easily replaceable and affordable. With a cost between free to $40, you can have a spare on hand in case of emergencies.

  • Canes give you tactile information about your environment. You can stop and smell the flowers when you know exactly where the flower box planter is on the sidewalk.

  • You can learn your environment faster and more thoroughly. The tactile information you gain from the cane finding fixed landmarks helps you understand the terrain you are exploring and provides concrete objects to ensure your orientation is correct.

Disadvantages of a White Cane

  • Increased interference from the public wanting to assist – kindhearted people always want to help by grabbing your arm, cane or clothing but sometimes their help isn’t helpful. (Hint: Always ask first!)

  • Cane travel can be more cumbersome and not as fluid. A cane gets stuck in cracks and you get a poke in the stomach – ouch!

  • Weather impacts cane travelers. A 6" or more snowfall with a cane can really wreak havoc getting around, as it is difficult to tap or sweep the cane and some landmarks may not be available to check orientation.

Cane User (Left) vs Dog User (Right)

Advantages of Guide Dog Travel

  • Faster and more graceful travel in general—with a dog you breeze by people and obstacles without much change in pace or direction.

  • A guide dog can be a bridge to the general public opening opportunities for conversation and making new connections. People have made many new friends talking “dogs” with my fellow commuters and folks who are interested in learning about guide dogs.

  • Guide dogs can be a deterrent to potential personal attacks. While guide dogs are not trained to attack, a thief may think twice before trying to take your purse, wallet or smart phone.

Disadvantages of Guide Dog Travel

  • Time and responsibility of daily care for a guide dog – feeding, watering, relieving, grooming and playtime are all a part of a guide dog handler’s day.

  • 2-3 week commitment to train with a new guide dog – it may be nice to get away from it all and have your meals prepared and your room cleaned, but it is still time away from work, family and other responsibilities.

  • Expenses incurred with a guide dog – big dogs eat lots and vet bills are not inexpensive.

  • Dog attacks are increasing and can ruin a dog’s confidence and ability to work. With the increase in pet-friendly hotels and apartments, therapy dogs, emotional support dogs and the like; we are running into more and more dogs in our daily travels. Dog encounters can be a dangerous situation with one serious act of aggression ending a dog’s working life.

  • Dog hair on clothing and in home – lots of grooming and a lint brush and tips for getting dog hair off fabric surfaces is a must.

Guide dogs

Also known as seeing eye dogs, these are assistance dogs trained to lead blind or visually impaired people around obstacles. Although dogs can be trained to navigate various obstacles, they are red-green color blind and incapable of interpreting street signs.

The human does the directing, based on skills acquired through previous mobility training. The handler might be likened to an aircraft's navigator, who must know how to get from one place to another, and the dog is the pilot, who gets them there safely.

Breeds

Guide dog breeds are chosen for temperament and trainability. The most popular breed used globally today is the Labrador Retriever. This breed has a good range of size, is easily kept due to its short coat, is generally healthy and has a gentle but willing temperament. Crosses such as the Goldador (Golden Retriever/Labrador), combine the sensitivity of the Golden Retriever and the tolerance of the Labrador Retriever.

White Cane

A white cane is a device used by many people who are blind or visually impaired.

  • A white cane primarily allows its user to scan their surroundings for obstacles or orientation marks, but is also helpful for onlookers in identifying the user as blind or visually impaired and taking appropriate care.

  • The latter is the reason for the cane's white color, which in many jurisdictions is mandatory.

Mobility canes are often made from aluminium, graphite-reinforced plastic or other fibre-reinforced plastic, and can come with a wide variety of tips depending upon user preference.

White canes can be either collapsible or straight, with both versions having pros and cons. The National Federation of the Blind in the United States affirms that the lightness and greater length of the straight canes allows greater mobility and safety, though collapsible canes can be stored with more ease, giving them advantage in crowded areas such as classrooms and public events.

Blind people have used canes as mobility tools for centuries, but it was not until after World War I that the white cane was introduced.

In 1921 James Biggs, a photographer from Bristol who became blind after an accident and was uncomfortable with the amount of traffic around his home, painted his walking stick white to be more easily visible.

Variants of White Cane

  • Long cane: Designed primarily as a mobility tool used to detect objects in the path of a user. Cane length depends upon the height of a user, and traditionally extends from the floor to the user's sternum.

Often long canes can be folded.

  • Guide cane: A shorter cane, generally extending from the floor to the user's waist, with more limited potential as a mobility device. It is used to scan for kerbs and steps.

  • Identification (ID) cane: Used primarily to alert others that the user is visually impaired, but not to the extent where they require a long cane or other variant. It has no use as a mobility tool.

  • Support cane: Designed primarily to offer physical stability to a visually impaired user, the cane also works as a means of identification.

  • Kiddie cane: This variant functions exactly the same as an adult's long cane but is designed for use by children.

  • Green cane: Used in some countries, such as Argentina, to designate that the user has low vision, while the white cane designates that a user is completely blind.

  • Red-and-White cane: For deafblindness

Red and White Canes – and persons with deafblindness

White canes are often used by blind pedestrians and/or those with a visual impairment, and this is well known in most countries around the world.

However, persons with deafblindness (with both sight and hearing impairments) use a red and white striped cane to navigate, therefore, it is very important to raise awareness of this symbol.

In some countries the red and white cane is already well recognized, but in some other countries, there is still much work left to do, to increase the recognition by the general public and authorities.

Read the story of Alegria, a Spanish older woman with deafblindness, for the importance of the red and white cane.

Electronic Travel Aids and Electronic Orientation Aids: ETAs

Various ETAs and EOAs, commonly called ETAs together, have evolved from simple White Cane to various levels of mechanical, electro-mechanical, and IT-and-AI enabled smart wearable aids. Multitude of services have also been built around O&M. These are covered below under Torch-like, Cane-like, Wearable, and Infrastructure ETAs.

The key parameters of ETAs are listed below with their Space of possibilities:

  • Energy Management: Active, Passive

  • Technology: Ultrasounds, Incandescent light, Infrared (IR), Laser, Global Position System (GPS), Compass, Mono/Stereo Vision, RFID, WLAN, Gyroscope, GSM/GPRS/UMTS (Mobile Phone Network), Bluetooth, Inertial sensors

  • Hardware Use: Belt, Cane, Chest, Hand, Head Mounted, Neck, Phone, Shoe, Skin, Tongue, Worn, Earphones, External (implemented over the urban space)

  • Information Channel: Tactile Electro Mechanic, Vibration, Sounds (unstructured, stereo or mono), Synthetic Voice, Recorded Voice, Braille, Bone conduction, Mechanical guidance , Direct Stimulation of Brain Cortex

  • Information Structure: Discrete (from binary to 'N' symbols), 1-D, 2-D, 3-D, or n-D

  • Field of Application: Indoor, Outdoor

Also, most ETAs are carried by the user. Avoiding obstacles and providing a safe travel depends on the specific movements of the user. Carried ETAs fit much better for this kind of problem. In the historical review we found that the first ICTs applied to blindness belonged to this group (and so it happens with non-ICT technology such as the canes). As we will see, most of them codifies the information in sounds, what is called sonification.

Source

Torch-like ETAs

Torch-like ETAs were some of the first prototypes; more specifically, ultrasounds based ETAs. We have seen some of these examples in history, such as the G-5 Obstacle detector or the Signal Corps (even if limitations in technology forced to build "bag-like" ETAs). After those devices, Kay developed, in the late 60', the Ultrasonic torch and the Torch, setting up the paradigm of this approach. Now we have a wide range of them.

Ray Electronic Mobility Aid

Hi-tech mobility for the blind and visually impaired Ray was designed to provide a handheld, lightweight and compact supplement to traditional canes for the blind. It is a small, extremely sensitive electronic mobility aid that senses obstacles and alerts the user by emitting audible or vibrating signals (or both.) Ray features easy 2-button operation and is so compact that it can fit in the palm of your hand, slides into a pocket for fast storage, or worn around neck.

Using an ultrasonic emission similar to the cone of light of a flashlight, Ray can recognize obstacles up to a distance of 2.85m away and announce them to the user via an audible or vibrating signal.

Ray is intended as a complement to traditional canes for the blind, not as a replacement. While Ray recognizes obstacles in your path, it cannot detect drop-offs such as curbs.

A special Escape mode enables the user to locate small gaps such as door entrances or passageways through a crowd of people (again the user can choose between audible or tactile feedback.)

Thermal Vision

This paper evaluates the efficacy of using far infrared thermal imaging with a haptic display to simplify the problem of quickly identifying the presence and location of people relative to a blind user. The idea is to use a haptic display that images the output of an infrared camera. Each pixel of the display is a binary up or down determined by comparing the IR camera output to a threshold set just below human skin temperature.

A prototype device was constructed consisting of a 50x50 tactile array from KGS Corp. and an infrared camera mounted in a textbook-sized frame as seen in Fig. 1. The frame can be held and aimed at a target with hand straps on each side. The prototype device also attaches, via a tether, to a notebook computer. The device was tested by five blind users to establish the efficacy of the system in a variety of real world scenarios.

Prototype device in hand held mode. The infrared camera is mounted on top of the tactile display. The tactile display shows the image of two people in front of the user

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Future hand held device with integrated miniature microbolometer based infrared camera and fingertip tactile array. The device will also include a thermal threshold thumbwheel. The battery and processor will be in a small belt worn box attached via a cord.

MiniGuide

Portable electronic travel device that uses ultrasound to detect objects to provide tactile or auditory feedback by vibrating or chirping sounds more rapidly as the user approaches an object. When used with a cane or dog guide, it can help a blind person avoid obstacles and overhangs, locate landmarks, locate items such as mailboxes or trash cans, and find paths through crowds at ranges from 20 inches to 26 feet. Has two large button controls; five default ranges (ranging from ½ meter to 8 meters); user-friendly advanced settings that allow user to select range presets, change type of auditory feedback, and manage optional remote unit; and a durable plastic case. Optional remote unit for instructors can receive the same tactile feedback as the student.


Virtual White Cane

Obs Avoid using Haptics&Laser is a virtual white cane using a laser rangefinder to scan the environment and a haptic interface to present this information to the user. Using the virtual white cane, the user is able to poke at obstacles several meters ahead and without physical contact with the obstacle. By using a haptic interface, the interaction is very similar to how a regular white cane is used. The length of the virtual cane can be chosen by the user, but it is still limited. The wheel chair will be controlled by Joystick using right hand and sensing the environment will be controlled by Falcon (haptic interface) using the other hand.

This is particularly useful for blind people with motion impairment.

The Novint Falcon, joystick and 2D LiDAR

Cane-like ETAs

The problem with the torch-like devices is that one hand of the user is employed to handle the ETA. Moreover, blind users hardly renounce to the white cane, since it is the most reliable device to prevent from falling. So, both arms and hands are occupied by different tools. Because of that, cane-like products started to appear, being the laser cane the first of them.

UltraCane

Developing safer alternatives since 2010, the UltraCane is a primary electronic mobility aid for use by people who are blind or visually impaired and is THE ONLY electronic mobility aid that utilizes state of the art narrow beam technology, allowing the user to safely avoid obstacles and navigate around them, both in the user's forward path and just as importantly, giving valuable protection at head/chest height. No other electronic mobility aid utilizes this technology.

The UltraCane detects street furniture and other obstacles within 2m or 4m (depending on setting) and it does this by emitting ultrasonic waves from two sensors. It also detects up to 1.5m ahead at chest/head height, giving tactile feedback to the user through two vibrating buttons on the handle over which the user places their thumb.

The two buttons, when vibrating, indicate the direction of the obstacle; the frequency of the vibration lets the user know the proximity of the obstacle.

This type of feedback stimulates a spatial <