PRE2017 3 Groep13

Problem statement

People with visual impairments have trouble navigating through space due to the absence of clear sight. Nowadays, they have to trust on their dog who is guiding them across the streets. This people have also a blind stick to feel what object are in their close environment. However, they can not feel if there is a doorstep or a lamppost at the same time, what can cause a insecure feeling. They have to walk slowly because of their short field of view. This problems make it intensive to walk outside. It also occurs that blind people don’t like dogs or even are allergic for them. Improvements for the way blind people are detecting the environment can be made. By means of this project a possibility for improvement will be examined.

Users

The users are people with visual impairments. If possible we will contact a person with visual impairments, so a potential user can influence the design of the product. The goal is to make a user-centered design.

Require

A device that helps people with visual impairments to navigate through space. The specific requirements are given in the table.

Deliverable

A prototype of the device will be made. Also a report of the project will be updated weekly on wiki.

Objective

Making a device that makes it more easy and less intensive for blind people to navigate through space.

Approach

An user-centered design (if possible) of a device that helps blind people navigating through space. This can be done by making a device that gives more information about the close environment of the user. The user have to get information about obstacles by their feet and head/other body parts at the same time. A point for orientation is needed so the user knows in which direction he/she walks. To know what the best options are to make device easy and comfortable to use a blind person will be contacted. After designing a device that meets the requirements a prototype of this device will be made. For this, the following milestones have to be achieved:

Milestones

- Literature study

- Finishing the design of the prototype

- Components for prototype are arrived

- Device is built and the software is made

- The device works and functions well (functioning testing)

- The device is usable (usability testing)

Who’s doing what and roles

Eline : Designing, usability testing, literature study - point of contact

Stefan: Programming, literature study - checks the planning

Tom: Assembling, selecting products, literature study - prepare meetings

Bruno: Assembling, selecting products, literature study - making minutes

Evianne: Human-machine interactions, designing, usability testing, literature study - checks wiki

Literature research

The topics needed for the project are split up. Everybody have a direction at which he/she gathers information.

Eline: - usability testing, universal design

Evianne: - Just Noticeable Difference, human skin, ethics

Bruno: - electromagnetics, hall effect (car sensors)

Tom: - mechanics compass, optical sensors

Stefan:- (digital) compass, infrarood

Spatial discrimination of the human skin

Surfaced have often to be smooth, i.e. food textures have to feel smooth for users. Healthy human are tested in roughness sensation. Obtained results showed that human’s capability of roughness discrimination reduces with increased viscosity of the lubricant, where the influence of the temperature was not found to be significant. Moreover, the increase in the applied force load showed an increase in the sensitivity of roughness discrimination. (Tugba Aktar)

Pain in the skin can be localized with an accuracy of 10-20 mm. Mechanically-induced pain can be localized more precisely then heat or a non-painful touch. Possible due to two different sensory channels. The spatial discrimination capacities of the tactile and nociceptive system are about equal. (Tanja Schlereth)

There are two categories for thermal discrimination. A rising or a falling temperature and temperatures above or below the neutral temperature of the skin. Sensing temperature happens by myelinated fibers in nerves. (Iggo A)

The homing behaviour of Eptesicus fuscus, known as the big brown bat, can be altered by artificially shifting the Earth's magnetic field, indicating that these bats rely on a magnetic compass to return to their home roost. Homing pigeons use also the magnetic field for navigation (Richard A. Holland).

Localization

Indoor localization can be achieved using a beacon system of ultrasonic sensors and a digital compass. Although ultrasonic sensors are very sensitive to noise or shocks these disadvantages can be mitigated by using a band pass filter (H. Kim, J. Choi 2008). Generally the use of an Unscented Kalman Filter further improves accuracy of measurements.

The use of the digital compass inside a smartphone can be used to track head movement. Then that can be used to reproduce a virtual surround sound field using headphones (S. You, Y. Wu 2017). Applying such a system to blind people could help them navigating by producing sounds which come from a certain direction without other people hearing it.

It is shown that a digital compass can give accurate readings using a RC circuit, ADC and a Atmega16L MCU (S. Qu, L. Nie, W. Li 2011). Furthermore by slowly rotating the compass to measure the magnetic field inference can further improve accuracy. S. Qu, Li. Nie and W. Li showed the entire design of such a compass.

If it is known in which plane the compass is being turned, it can be used to further reduce errors (Z. Lijie, C. Ji, 2011). However these solutions were applied to micro-unmanned air vehicle which do require very precise readings. Applications helping blind people might not need these precise readings.

An application of digital compasses might be the orientation of a robotic arm. C. Marcu, G. Lazea, D. Bordencea, D. Lupea and H. Valean showed how an entire system using digital compasses could be built, addressing multiple issues mainly on a high-level without going too much into the details. They showed how to convert the coordinates using the readings of the compass.

Usability testing and universal design To implement User-Centered Design, it is important to define the term usability. Usability has been interpreted in many different ways, but Alonso-Ríos, Vázquez-García, Mosqueira-Rey, & V. Moret-Bonillo defined a clear and extensive usability taxonomy (2009).

Usability Testing is effective in helping developers produce more usable products (Lewis, 2012), which comes in handy in this project. This chapter explains types to do Usability Testing, like thinking aloud which is quite easy but gives a lot of information. Furthermore, several examples are presented.

Especially when involved with people with impairments, it is important to make a universal design. As Story, Mueller, & Mace mention in chapter 2 of their book, there are a lot of things to consider if a design should be universal. (1998)

In chapter 3 of their book, Story, Mueller, & Mace state seven principles (1998). When these principles are followed, the design will be universally usable. Also, a lot of examples are provided in this chapter.

Ghiani, Ieporini, & Paternò designed a multimodal mobile application considering museum environments. They extended the vocal output with haptic output in form of vibrations. It was tested if participants prefered discontinuous output or continuous output differing in intensity using a within-subject design. The results implied the participants prefered the discontinuous variant, but the results were non-significant.

mechanics compass, optical sensors

The application of robotics to a mobility aid for the elderly blind The objective of robot mobility aid is to let blind people regain personal autonomy by taking exercise independent of people who care for them. The perceived usefulness rather than usability is the limiting factor in adoption of new technology. Multiple impairments can be tackled at the same time, in the paper the device works as a mobility device and walking support. Preferable is that the user is in control of what happens, or that the robot decides what happens, but not something in between as that leads to confusion. Also users prefer voice feedback over tonal information, perhaps because it is more human-like (Giudice, N. A., Legge, G. E.).

A Tool for Range Sensing and Environment Discovery for the Blind A device is created which uses a laser to calculate distances to objects. This could help the user to decide where to move, but is not sufficient for safe deambulation. The device would work as a virtual white cane, without using the actual invasive sensing method of the white cane. It uses active triangulation to produce reliable local range measurements. Objects can be found, but it is still hard to translate this to the user (Yuan, D., Manduchi, R.).

New Developments in Mobility and Orientation Aids for the Blind. The long cane (white cane) is still the primary mobility aid for the blind. New electronic mobility aids mostly use the transmission of an energy wave and the reception of echoes (echo-location) from objects in or near the user’s path. Optical transmission is another highly used concept. As wavelength is the limiting factor in detection of small objects, optical transmission has advantages. One class of aids is known as the “obstacle detectors”, other aids attempt more than only obstacle detection, by using for example auditory output to show the way. Also incorporating he sensing on the skin has been researched. Lastly there is the area of cortical implants (Brabyn, J.A.).

Blind Navigation and the Role of Technology The most important difference between visual navigation and blind navigation is that visual navigation is more of a perceptual process, whereas blind navigation is more of an effortful endeavor requiring the use of a cognitive and attentional resources. Some technologies work better in other environments. Also aesthetics are of impact on the user. The long cane and guide dog are the most common tools of navigation, other aids are mostly used to complement these tools. Other devices are based on sonar detection, optical technologies, infrared signage, GPS-based devices, sound devices and some tools for indoor navigation (Kay, L.).

An ultrasonic sensing probe as a mobility aid for the blind It is quite hard to get a clear understanding of a possible environment via echo location or ultrasonic sensing. Under specific conditions objects were located with echo location. Different environments give very different amounts of perception. Moreover was it needed for users to learn to use the device. Learning to interpret the sounds did not necessarily improve mobility. Objects could be detected, but users had to still learn how to avoid them. Also, as hearing was used for echo location, normal use of the hearing sense was slightly impaired (Lacey, G., Dawson-Howe, K.M.).

Electromagnetics and sensors Proximity sensors can detect the presence of an object without physical contact. There are many variations of these sensors but 3 basic designs exist: electromagnetic, optical, and ultrasonic. The electromagnetic types are subdivided into inductive and capacitive sensors. However these work with metal. Optical proximity sensors use one of two basic principles, reflection or through-beam. Here shiny surfaces can cause trouble. Ultrasound works similar, in respect that sound also reflect on objects, which can be measured. Here objects that do not reflect it back can cause trouble.

In the article of Benniu, Zhang; Junqian, Zhang; Kaihong, Zhang and Zhixiang, Zhou a non-contact proximity sensor that is able to detect any kind of material with low frequency electromagnetic field.

In the article of M.R.Jackson, R.M.Parkin and B.Tao, a medium range radar sensor is proposed, however this is for a distance too big for our purposes.

Yang‐Sub Lee and Mark F. Hamilton mainly discuss the ideal circumstances for an ultrasonic sensor in air.

State-of-the-art

Bousbia-Salah suggests a system where obstacles on the ground are detected by an ultrasonic sensor integrated into the cane and the surrounding obstacles are detected using sonar sensors coupled on the user shoulders. Shoval et al. proposes a system which consists of a belt, filled with ultrasonic sensors called Navbelt. One limitation of this kind of system is that it is exceedingly difficult for the user to understand the guidance signals in time, which should allow walking fast. Another system using a vision sensor is presented by Sainarayanan et al. to capture the environment in front of the user. The image is processed by a real time image-processing scheme using fuzzy clustering algorithms. The processed image is mapped onto a specially structured stereo acoustic pattern and transferred to stereo earphones. Some authors use stereovision to obtain 3D information of the surrounding environment. Sang-Woong Lee proposes a walking guidance system which uses stereovision to obtain 3D range information and an area correlation method for approximate depth information. It includes a pedestrian detection model trained with a dataset and polynomial functions as kernel functions (Vitor Filipe).

Planning

Week 1: literature study (all), asking experient permission for usability testing (Eline), writing the problem statement (Evianne), make planning (all), determining roles (all), making requirements (all)

Week 2: interviewing user (Eline), making design of the device (Eline and Evianne), making bill of materials (Stefan, Tom, Bruno), updating wiki (all)

Week 3: programming the software (Stefan), building the device (Tom and Bruno), giving the device a beautiful appearance (Eline and Evianne), updating wiki (all)

Week 4: complete tasks of week 3

Week 5: testing functionality of the device (all), finishing prototype (all)

Week 6: completing tasks that are not finished yet (all)

Week 7: usability testing (Eline and Evianne), complete report (all)

Week 8: delivery of product (all), final presentation (Eline)

Coaching Questions Group 13