Research
Methods of “Seeing” for the Blind
For a blind person, there are various options and methods one could use to navigate. There are methods such as echolocation, such as using a cane, or using a seeing dog. Some are more accurate than others, some are more convenient than others, and some methods need to be learned, for example, a blind person may be allergic to dogs, and therefore cannot use a seeing dog, or how a blind person needs to learn how to use echolocation.
What is Echolocation?
Echolocation is the use of sound waves and echoes to determine where objects are. Objects that emit any sound offer a sound reflecting surface. Echolocation works when the user makes a sound such as a tongue click (which is the most used method by humans) or a snap. The user then listens for the echo/sound waves that bounce off of the object to determine the distance between the user and the object. Echolocation is primarily used by animals such as the bat or dolphin, but blind humans are also known to use echolocation as they can detect objects at a longer distance using long durations of sound compared to sighted people, however for this to work equal hearing in both ears are important.
Echolocation for the Blind
As mentioned before, echolocation is used by blind people to determine the distance of objects. A human can also determine the position, distance, size, shape and texture of an object just by echolocating. Dolphins and bats have special body parts just for echolocation, so would a typical human be able to echo locate? The answer indeed is yes. Indeed, humans can learn how to echo locate. It takes years of practice to become a professional echo locater, but even an hour can prove immediate results. To determine how close or far the object is, you listen to the volume of the echo. If the returning click is loud, it means its close because the vibrations of the clicks bounce off the object and depending on the angular position of an object placed, can be detected with high accuracy.An experiment was conducted where to validate the stimuli, they took in-ear recordings during echolocation to determine with accuracy of the angular position of the object (if the object is concave v.s flat) and even if the object was motionary (eg. tree v.s car). This process is called an fMRI.
What is fMRI?
Functional magnetic resonance imaging: It is a form of MRI of the brain that registers blood flow to function areas of brain. As blind humans emit sounds to detect the location of an object, both perceived pitch and loudness of emitted sound change as it fuses reflections from nearby objects. Results show that ability to detect pitch is the main factor of echolocation.
In conclusion, Blind or visually impaired people are better at echolocation compared to sighted people, however it is unclear on whether it is related to better detection to pitch, loudness or both.
Methods of “Seeing” for the Blind
For a blind person, there are various options and methods one could use to navigate. There are methods such as echolocation, such as using a cane, or using a seeing dog. Some are more accurate than others, some are more convenient than others, and some methods need to be learned, for example, a blind person may be allergic to dogs, and therefore cannot use a seeing dog, or how a blind person needs to learn how to use echolocation.
What is Echolocation?
Echolocation is the use of sound waves and echoes to determine where objects are. Objects that emit any sound offer a sound reflecting surface. Echolocation works when the user makes a sound such as a tongue click (which is the most used method by humans) or a snap. The user then listens for the echo/sound waves that bounce off of the object to determine the distance between the user and the object. Echolocation is primarily used by animals such as the bat or dolphin, but blind humans are also known to use echolocation as they can detect objects at a longer distance using long durations of sound compared to sighted people, however for this to work equal hearing in both ears are important.
Echolocation for the Blind
As mentioned before, echolocation is used by blind people to determine the distance of objects. A human can also determine the position, distance, size, shape and texture of an object just by echolocating. Dolphins and bats have special body parts just for echolocation, so would a typical human be able to echo locate? The answer indeed is yes. Indeed, humans can learn how to echo locate. It takes years of practice to become a professional echo locater, but even an hour can prove immediate results. To determine how close or far the object is, you listen to the volume of the echo. If the returning click is loud, it means its close because the vibrations of the clicks bounce off the object and depending on the angular position of an object placed, can be detected with high accuracy.An experiment was conducted where to validate the stimuli, they took in-ear recordings during echolocation to determine with accuracy of the angular position of the object (if the object is concave v.s flat) and even if the object was motionary (eg. tree v.s car). This process is called an fMRI.
What is fMRI?
Functional magnetic resonance imaging: It is a form of MRI of the brain that registers blood flow to function areas of brain. As blind humans emit sounds to detect the location of an object, both perceived pitch and loudness of emitted sound change as it fuses reflections from nearby objects. Results show that ability to detect pitch is the main factor of echolocation.
In conclusion, Blind or visually impaired people are better at echolocation compared to sighted people, however it is unclear on whether it is related to better detection to pitch, loudness or both.