Espacio Acústico Virtual

In general, the portable prototype consists of a support (glasses) that has two microcameras and earpieces, all it connected to an small computer. The cameras register the images that are in the persons'sfield of view and send that signal to the computer, which is in charge to transform the information of image to 3D sound that is sent to the earpieces. Therefore, on the person who uses the portable prototype is created the illusion with which the objects that surround to him are covered with sonorous sources that they emit continuously, thus recognizing their surroundings by means of locatable sounds in the space.

2.-How much the system weighs?

The portable prototype desing evolution tends to that it is very easy to use and to carry, for which all the system does not have to weigh much more of 500 gr., its volume does not have to be excessive for its practical use and must have fast ignition and accessible controls. At the present time, the prototype which we developed for demonstration and tests weigh 1.5 kg, but facing its future commercialization joint processor + batteries must weigh between 200 and 400 gr., and the glasses about 110 gr.

3.- When the sounds that allow to perceive the space are being listened , is possible to be continued listening to other sounds, like a conversation, a car, etc.?

The answer is fully yes. The earpieces do not prevent to listen to the normal sounds of the place where the n blind person is and, in fact, he can maintain a completely normal conversation. The device has a gain control that is placed at a level where the user is comfortable.

4.-How are the sounds that the user perceives?

The sounds are like clicks (to a rate of 10/sg) that come from the zones of the space where they would be the objects that surround to us. In order to have an idea, there is one that compares them with the sound of the rain drops that we can locate spacially with only hear that sound. An example of this type of sounds can be here.

5.- What are HRTF functions?

HRTF Functions (Head Related Transfer Function) mathematically describe the combined effect of the auricular pavilion, head and torso on the sounds coming from a certain space position. They depend to a great extent on the anatomy of each person and are therefore different for each subject.

6.-How are the HRTF functions measured?

Its measurement is made registering, by means of tiny microphones introduced in the external auditory channel, the sound waves that they bequeath to both ears, in answer to a test signal that emits the loudspeakers located in the positions of the space which they are desired to characterize.

7.- What is the externalization or auralization of sounds?

Once the HRTF functions are measured, with this information and after the equalization of the earpieces, a any sound can be processed and be presented to the volunteer, who will perceive it as originated from the position of the space whose HRTF has been used, although in fact the sounds come from the earpieces. This technique denominates externalization or auralization of sounds.

8.- How many people work in the project?

Actually we are 20 people involved in the project. More data on the team here.

9.- Will be the system commercialized?

Our objective is that thus it is. We hope to be able to commercialize the first units in 2004.

10.- How much will cost each portable unit?

It is anticipated that the price will be of around 1000 euros, considering that the microcameras every time are cheaper to be already very extended in the market, like the earpieces, and that a processor adapted to our necessities and made in great amounts would not have to be very expensive. To those 1000 euros it would be necessary to add the cost of the measurement of transference functions, that are not considered at the moment.

11.- Are There more groups in the world investigating in the same subject?

The investigation in the search of alternatives of perception that help blind people, or with low residual vision, to extend the scope of mobility and, even on a more ambitious form, to perceive the surroundings who surround to them and to orient themselves in it, is developed in three basic fronts: orientation with respect to the general surroundings (cities, etc.), orientation in local surroundings (houses, public buildings, parks, etc.) and detection of dangerous obstacles and search of a safe way. Techniques are investigated that make use of GPS, ecosoundings, laser, ultrasounds... some of them already commercialized. Nevertheless, within the concept that we handled in our project, it does not exist now any commercialized product, although there are some systems with distant similar to ours.

12.- What facilities and resources the project have?

We have facilities in the University Hospital of the Canary Islands, the Technological Institute of the Canary Islands and the Institute of Astrophysics of the Canary Islands. Luckyly, our laboratories are very well equipped and we have all computer science resources, medical and electronic tools that we need to carry out our objectives. Much more detailed information can be found in the Development section.

13.- What is a functional nuclear magnetic resonance?

Functional nuclear magnetic resonance (fMRI) is a radiodiagnosis technique that allows to observe extensive zones of the central nervous system in operation. In our case, we use this technique to know which is the region of the brain that activates with certain sonorous stimuli.

14.-What are the phospenes?

In some of the blind people, certain sounds with which we have been working cause a light sensation (denominated phosphene), as small stars or small points of white light in a dark background, that the person places or perceives simultaneously in the same point from where it seems to him to hear the sonorous source.

15.- What is echolocation?

The echolocation is the technique to use sounds to perceive the surroundings, that spontaneously are taken advantage of by many blind people from the sound and the echoes. Some use the reverberation of their own steps or sounds generated like clicks of fingers, whispers or whistles, etc.

16.- What benefits will contribute the system to the blind people?

The benefits will be to favor the autonomy of the blind person, improvements in the orientation capacity and mobility in surroundings not known being a consequence of the perception of the surroundings and consequently the detection of obstacles in the way, to facilitate social integration in the school, work, cultural and recreational house, activities, etc. In addition, it will allow to the complementation of the techniques and traditional methods of training for orientation, mobility and handling in the daily life. On the other hand, it is expected the development of auditory abilities and benefits of emotional and psychological character derivatives of the previous aspects.

17.- Why it serves the HRTF functions measurements robot?

It allows to measure HRTFs in any space coordinate within the prototype field of view with errors onf positioning of the order of millimeters. It uses a manipulator whom the moves the loudspeaker spins the table that moves to the volunteer.