Friday, November 23, 2007
Follow-up on previous post (Documenting Odors)
Following additional research, I have found some articles on "Odor Recorders", devices for recording smells for later play back. I am posting two of them here. Some of the issues addressed include the complexity of odors, as well as the dynamics of odors and the factors included such as drift and aging; and environmental factors such as temperature change and humidity change:
1.
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Device records smells to play back later
29 June 2006
NewScientist.com news service
Paul Marks
IMAGINE being able to record a smell and play it back later, just as you can with sounds or images.
Engineers at the Tokyo Institute of Technology in Japan are building an odour recorder capable of doing just that. Simply point the gadget at a freshly baked cookie, for example, and it will analyse its odour and reproduce it for you using a host of non-toxic chemicals.
The device could be used to improve online shopping by allowing you to sniff foods or fragrances before you buy, to add an extra dimension to virtual reality environments and even to assist military doctors treating soldiers remotely by recreating bile, blood or urine odours that might help a diagnosis.
While a number of companies have produced aroma generators designed to enhance computer games or TV shows, they have failed commercially because they have been very limited in the range of smells they can produce, says Pambuk Somboon of the Tokyo team.
So he has done away with pre-prepared smells and developed a system that records and later reproduces the odours. It's no easy task: "In video, you just need to record shades of red, green and blue," he says. "But humans have 347 olfactory sensors, so we need a lot of source chemicals."
Somboon's system will use 15 chemical-sensing microchips, or electronic noses, to pick up a broad range of aromas. These are then used to create a digital recipe from a set of 96 chemicals that can be chosen according to the purpose of each individual gadget. When you want to replay a smell, drops from the relevant vials are mixed, heated and vaporised. In tests so far, the system has successfully recorded and reproduced the smell of orange, lemon, apple, banana and melon. "We can even tell a green apple from a red apple," Somboon says.
Smell researchers are interested in the institute's work. "It would be interesting to know just what range of smells this new system can detect and recreate," says Stephen Brewster, a computer scientist at the University of Glasgow, UK, who is studying whether smell can be used to help people quickly identify digital photos without opening them. "This could be an interesting delivery system for our work."
From issue 2558 of New Scientist magazine, 29 June 2006, page 32
____________________________________________________________________________
2.(minus technical graphs)
____________________________________________________________________________
Chem. Senses 30 (suppl 1): i254–i255, 2005 doi:10.1093/chemse/bjh211
Chemical Senses vol. 30 suppl 1 © Oxford University Press 2005; all rights reserved.
Correspondence to be sent to: Takamichi Nakamoto, e-mail: nakamoto@mn.ee.titech.ac.jp
Key words: MIMO feedback control, odor recorder, odor sensing system, quartz resonator gas sensor, real-time reference method, robustness
Introduction:
Although techniques of recording and reproduction of visual and
auditory information are nowadays well established, a corresponding
technique for olfaction is still not mature. However, the
study of recording and reproduction techniques for smells is
becoming more popular in the field of chemical sensors as well as
that of virtual reality (Kaye, 2004).
An odor sensor called an ‘electronic nose’ (Pearce et al., 2003) can
be used for olfactory recording. In addition to the odor sensor, a
smell reproduction technique is required. We have developed a
system called an ‘odor recorder’ for reproducing the smell recorded
using an odor sensor (Nakamoto et al., 2001). The recipe of the smell
is obtained using the odor recorder and the smell can then be reproduced
based upon the obtained recipe.
We have successfully determined the eight-component recipe of
apple flavor using our odor recorder (Yamanaka and Nakamoto,
2003). Although a constant recipe was obtained in most of our
previous studies, the actual odor in the atmosphere changes continuously
and dynamically. In this paper, a study of the odor recorder for
dynamical changes of odors is described.
Principle of the odor recorder:
An odor sensing system recognizes the output pattern of a sensor
array composed of multiple sensors. The same sensing system is used
in the odor recorder.First, the target odor to be recorded is introduced
into a sensor array and its output pattern is memorized. Then, the
responses of the sensors to the blended odor, made up of multiple
component odors, are measured and are compared with those to the
target odor. The recipe of the target odor is obtained from that of
the blended odor in the case that the sensor-array output pattern of
the blended odor agrees with that of the target odor. Otherwise, the
recipe of the blended odor is iteratively modified so that the sensorarray
output pattern of the blended odor can approach that of the
target odor using adaptive MIMO (multi-input multi-output) feedback
control theory. The recipe of the target odor is obtained after
the convergence.
Once the recipe is recorded, the smell can be reproduced using the
odor blender. The odor blender, remotely located from the odor
recorder, can be used to generate the smell in the same manner as the
blender inside the odor recorder.
The feedback approach utilized in the odor recorder is essential,
since the linear superposition theorem is not completely valid in the
case of most of the chemical sensor responses. Moreover, it is also
effective in compensating for the drift and aging that are often
encountered in chemical sensors.
Record of dynamical change of odor using the realtime reference method:
Our group attempted for the first time to use a feedback-error
learning neural network to record the dynamically changing odor
(Nakamoto and Hiramatsu, 2002). Then, the real-time reference
method for recording dynamical change of odor was developed
(Yamanaka et al., 2003). This method is useful for recording
dynamical changes of odors, as well as for compensating for environmental
changes such as temperature and humidity.
The comparison of the real-time reference method with conventional
approach is illustrated in Figure 2a,b. Although multiple
component odors and multiple sensors are actually used, only a
single component odor and single sensor are shown here for
simplicity.
In the previous method shown in Figure 2a, the steady-state
response to a target odor with constant concentration is measured
for the first time. Then, the recipe of the blended odor is adjusted so
that the response to the blended odor can match that to the target
odor. Since it takes a few minutes to determine the concentration, the
change during the process of the recipe determination cannot be
detected.
On the other hand, the target and blended odors are alternately
introduced into the sensor array every sampling interval (several
seconds) in the real-time reference method illustrated in Figure 2 (b).
Although the sensor response to the blended odor deviates from that
to the target odor, at first due to the concentration difference, it soon
approaches the response to the target odor. Once convergence
occurs, the blended odor concentration tracks that of the target
odor. The real-time reference method achieves a time resolution of a
few seconds to record dynamical changes of odor.
We now describe the experiment on recording the dynamically
changing odor using the real-time reference method. The concentrations
of four odor components of apple flavor were independently
changed in the experiment. The odor components used here were
trans-2-hexenyl acetate (green note, Comp1), trans-2-hexenal (smell
of grass, Comp2), isobutyric acid (sour sweet, Comp3) and ethyl
valerate (fruity, Comp4). The sensors used here were four quartz
resonators (20 MHz, AT-CUT) coated with polphenyl ether, polyethylene
glycol 1000, tricresyl phosphate and Apiezon L, respectively.
The sampling interval was 4 s.
The temperature and the humidity were intentionally changed
during the experiment since robustness against temperature and
humidity changes was also studied. Changing the air conditioner
mode (DRY/COOL) caused 2.5°C of the temperature change and
20% of the humidity change during the experiment.
The experimental result is shown in Figure 3a,b. The solid and
dashed lines are the concentrations of the component odors in the
target odor and plots are the recorded concentrations of the component
odors. Since the recorded concentrations of each component
odor almost agreed with that of the target odor, it was found that the
real-time reference method achieves a record of dynamical change of
odor even in an environment in which the temperature and the
humidity changed, as is shown in Figure 3b.
Conclusion:
A record of the dynamical change of the odor was successfully made.
The real-time reference method can be speeded up when the blended
odor is measured simultaneously with the target odor using the same
two sensor arrays. Furthermore, recording the dynamical change of
odor together with a movie record will be an interesting topic for
further study.
References:
Kaye, J.J. (2004) Making scents. Interaction, ??, 49.
Nakamoto, T. and Hiramatsu, H. (2002) Study of odor recorder for dynamical
change of odor using QCM sensors and neural network. Sensors Actuators
B, 85, 263.
Nakamoto, T., Nakahira, Y., Hiramatsu, H. and Moriizumi, T. (2001) Odor
recorder using active odor sensing system. Sensors Actuators B, 76, 465.
Pearce, T.C., Schiffman, S.S, Nagle, H.T and Gardner, J.W. (eds) (2003)
Handbook of Machine Olfaction. Wiley-VCH, Weinheim.
Yamanaka, T. and Nakamoto, T. (2003) Real-time reference method in odor
recorder under environmental change. Sensors Actuators B, 93, 51.
Yamanaka, T., Matsumoto. R. and Nakamoto, T. (2003) Fundamental
study of odor recorder for multi-component odor using recipe exploration
based on singular value decomposition. IEEE Sensor J., 3, 468.
Figure 3 Recorded dynamic concentration change of each component vapor in target odor. Solid line: concentration of each component vapor in target
odor, Plot: recorded concentration of each component odor. (a) Comparison between target and blended odors and (b) temperature and humidity changes
during experiment.
____________________________________________________________________________
1.
____________________________________________________________________________
Device records smells to play back later
29 June 2006
NewScientist.com news service
Paul Marks
IMAGINE being able to record a smell and play it back later, just as you can with sounds or images.
Engineers at the Tokyo Institute of Technology in Japan are building an odour recorder capable of doing just that. Simply point the gadget at a freshly baked cookie, for example, and it will analyse its odour and reproduce it for you using a host of non-toxic chemicals.
The device could be used to improve online shopping by allowing you to sniff foods or fragrances before you buy, to add an extra dimension to virtual reality environments and even to assist military doctors treating soldiers remotely by recreating bile, blood or urine odours that might help a diagnosis.
While a number of companies have produced aroma generators designed to enhance computer games or TV shows, they have failed commercially because they have been very limited in the range of smells they can produce, says Pambuk Somboon of the Tokyo team.
So he has done away with pre-prepared smells and developed a system that records and later reproduces the odours. It's no easy task: "In video, you just need to record shades of red, green and blue," he says. "But humans have 347 olfactory sensors, so we need a lot of source chemicals."
Somboon's system will use 15 chemical-sensing microchips, or electronic noses, to pick up a broad range of aromas. These are then used to create a digital recipe from a set of 96 chemicals that can be chosen according to the purpose of each individual gadget. When you want to replay a smell, drops from the relevant vials are mixed, heated and vaporised. In tests so far, the system has successfully recorded and reproduced the smell of orange, lemon, apple, banana and melon. "We can even tell a green apple from a red apple," Somboon says.
Smell researchers are interested in the institute's work. "It would be interesting to know just what range of smells this new system can detect and recreate," says Stephen Brewster, a computer scientist at the University of Glasgow, UK, who is studying whether smell can be used to help people quickly identify digital photos without opening them. "This could be an interesting delivery system for our work."
From issue 2558 of New Scientist magazine, 29 June 2006, page 32
____________________________________________________________________________
2.(minus technical graphs)
____________________________________________________________________________
Chem. Senses 30 (suppl 1): i254–i255, 2005 doi:10.1093/chemse/bjh211
Chemical Senses vol. 30 suppl 1 © Oxford University Press 2005; all rights reserved.
Correspondence to be sent to: Takamichi Nakamoto, e-mail: nakamoto@mn.ee.titech.ac.jp
Key words: MIMO feedback control, odor recorder, odor sensing system, quartz resonator gas sensor, real-time reference method, robustness
Introduction:
Although techniques of recording and reproduction of visual and
auditory information are nowadays well established, a corresponding
technique for olfaction is still not mature. However, the
study of recording and reproduction techniques for smells is
becoming more popular in the field of chemical sensors as well as
that of virtual reality (Kaye, 2004).
An odor sensor called an ‘electronic nose’ (Pearce et al., 2003) can
be used for olfactory recording. In addition to the odor sensor, a
smell reproduction technique is required. We have developed a
system called an ‘odor recorder’ for reproducing the smell recorded
using an odor sensor (Nakamoto et al., 2001). The recipe of the smell
is obtained using the odor recorder and the smell can then be reproduced
based upon the obtained recipe.
We have successfully determined the eight-component recipe of
apple flavor using our odor recorder (Yamanaka and Nakamoto,
2003). Although a constant recipe was obtained in most of our
previous studies, the actual odor in the atmosphere changes continuously
and dynamically. In this paper, a study of the odor recorder for
dynamical changes of odors is described.
Principle of the odor recorder:
An odor sensing system recognizes the output pattern of a sensor
array composed of multiple sensors. The same sensing system is used
in the odor recorder.First, the target odor to be recorded is introduced
into a sensor array and its output pattern is memorized. Then, the
responses of the sensors to the blended odor, made up of multiple
component odors, are measured and are compared with those to the
target odor. The recipe of the target odor is obtained from that of
the blended odor in the case that the sensor-array output pattern of
the blended odor agrees with that of the target odor. Otherwise, the
recipe of the blended odor is iteratively modified so that the sensorarray
output pattern of the blended odor can approach that of the
target odor using adaptive MIMO (multi-input multi-output) feedback
control theory. The recipe of the target odor is obtained after
the convergence.
Once the recipe is recorded, the smell can be reproduced using the
odor blender. The odor blender, remotely located from the odor
recorder, can be used to generate the smell in the same manner as the
blender inside the odor recorder.
The feedback approach utilized in the odor recorder is essential,
since the linear superposition theorem is not completely valid in the
case of most of the chemical sensor responses. Moreover, it is also
effective in compensating for the drift and aging that are often
encountered in chemical sensors.
Record of dynamical change of odor using the realtime reference method:
Our group attempted for the first time to use a feedback-error
learning neural network to record the dynamically changing odor
(Nakamoto and Hiramatsu, 2002). Then, the real-time reference
method for recording dynamical change of odor was developed
(Yamanaka et al., 2003). This method is useful for recording
dynamical changes of odors, as well as for compensating for environmental
changes such as temperature and humidity.
The comparison of the real-time reference method with conventional
approach is illustrated in Figure 2a,b. Although multiple
component odors and multiple sensors are actually used, only a
single component odor and single sensor are shown here for
simplicity.
In the previous method shown in Figure 2a, the steady-state
response to a target odor with constant concentration is measured
for the first time. Then, the recipe of the blended odor is adjusted so
that the response to the blended odor can match that to the target
odor. Since it takes a few minutes to determine the concentration, the
change during the process of the recipe determination cannot be
detected.
On the other hand, the target and blended odors are alternately
introduced into the sensor array every sampling interval (several
seconds) in the real-time reference method illustrated in Figure 2 (b).
Although the sensor response to the blended odor deviates from that
to the target odor, at first due to the concentration difference, it soon
approaches the response to the target odor. Once convergence
occurs, the blended odor concentration tracks that of the target
odor. The real-time reference method achieves a time resolution of a
few seconds to record dynamical changes of odor.
We now describe the experiment on recording the dynamically
changing odor using the real-time reference method. The concentrations
of four odor components of apple flavor were independently
changed in the experiment. The odor components used here were
trans-2-hexenyl acetate (green note, Comp1), trans-2-hexenal (smell
of grass, Comp2), isobutyric acid (sour sweet, Comp3) and ethyl
valerate (fruity, Comp4). The sensors used here were four quartz
resonators (20 MHz, AT-CUT) coated with polphenyl ether, polyethylene
glycol 1000, tricresyl phosphate and Apiezon L, respectively.
The sampling interval was 4 s.
The temperature and the humidity were intentionally changed
during the experiment since robustness against temperature and
humidity changes was also studied. Changing the air conditioner
mode (DRY/COOL) caused 2.5°C of the temperature change and
20% of the humidity change during the experiment.
The experimental result is shown in Figure 3a,b. The solid and
dashed lines are the concentrations of the component odors in the
target odor and plots are the recorded concentrations of the component
odors. Since the recorded concentrations of each component
odor almost agreed with that of the target odor, it was found that the
real-time reference method achieves a record of dynamical change of
odor even in an environment in which the temperature and the
humidity changed, as is shown in Figure 3b.
Conclusion:
A record of the dynamical change of the odor was successfully made.
The real-time reference method can be speeded up when the blended
odor is measured simultaneously with the target odor using the same
two sensor arrays. Furthermore, recording the dynamical change of
odor together with a movie record will be an interesting topic for
further study.
References:
Kaye, J.J. (2004) Making scents. Interaction, ??, 49.
Nakamoto, T. and Hiramatsu, H. (2002) Study of odor recorder for dynamical
change of odor using QCM sensors and neural network. Sensors Actuators
B, 85, 263.
Nakamoto, T., Nakahira, Y., Hiramatsu, H. and Moriizumi, T. (2001) Odor
recorder using active odor sensing system. Sensors Actuators B, 76, 465.
Pearce, T.C., Schiffman, S.S, Nagle, H.T and Gardner, J.W. (eds) (2003)
Handbook of Machine Olfaction. Wiley-VCH, Weinheim.
Yamanaka, T. and Nakamoto, T. (2003) Real-time reference method in odor
recorder under environmental change. Sensors Actuators B, 93, 51.
Yamanaka, T., Matsumoto. R. and Nakamoto, T. (2003) Fundamental
study of odor recorder for multi-component odor using recipe exploration
based on singular value decomposition. IEEE Sensor J., 3, 468.
Figure 3 Recorded dynamic concentration change of each component vapor in target odor. Solid line: concentration of each component vapor in target
odor, Plot: recorded concentration of each component odor. (a) Comparison between target and blended odors and (b) temperature and humidity changes
during experiment.
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