Surgery – Diagnostic testing – Detecting nuclear – electromagnetic – or ultrasonic radiation
Reexamination Certificate
1999-08-30
2001-11-20
Lateef, Marvin M. (Department: 3737)
Surgery
Diagnostic testing
Detecting nuclear, electromagnetic, or ultrasonic radiation
C600S477000, C356S432000, C356S039000, C356S040000, C356S041000, C356S340000, C250S339030, C250S341300, C250S351000, C250S352000
Reexamination Certificate
active
06321110
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a device for controlling equipment by detecting signals reflecting a brain function of a living body by using visible or near-infrared rays and for controlling the equipment by the signals, and in particular to an improvement on the accuracy of the controlling device.
For operation of game machines or computers there have been used input devices provided with a joy stick, a handle or a keyboard operated by muscles in accordance with the command from the brain of a living body.
On the other hand, methods of inputting commands into game machines by using brain waves have been disclosed by Japanese Patent Application Laid-Open Hei 6-296757 and Japanese Patent Application Laid-Open Hei 7-124331. But there is a problem with the methods of inputting commands into game machines by using brain waves that they handle very small electrical currents, and they are easily influenced by electrical noise signal occurring when muscles are moved, or other external noises.
To solve this problem, Japanese Patent Application Laid-Open Hei 9-149894 discloses a method of optically measuring the change of the flow of blood in the brain reflecting the activity of the brain, and using the obtained information on the degree of the brain activation for the purpose of inputting commands into various kinds of equipment.
When a keyboard or a handle is used for operating a game machine or a computer or inputting data into the game machine or the computer, it is easy to confirm the movement of the body for inputting the command to equipment, or to confirm if the data or the control data has been input into the equipment as intended. Therefore, if the data or the control data was not input into the equipment as intended, they can be corrected immediately.
On the other hand, the information on the degree of the brain activation is used for inputting data or as controlling signals, and it was difficult to confirm immediately if the data or the control data has been input into the equipment as intended. The prior art device is not configured such that change in the degree of the brain activation was not perceived by the possessor of the brain.
When light was used to extract characteristics of the brain as signals, it was difficult to separate the intended signals from the other signals because the source for the intended signals are surrounded by some structures or organs of the living body, and consequently the obtained signals could not be used directly as data into equipment or as a controlling signal for the equipment.
Further the blood flow in the brain optically measured as the information on the degree of the brain activation is susceptible to heart beats or the autonomic nervous system, and signals corresponding to the change of the blood flow in the skin caused by thermoregulation are superposed on the signals corresponding to the degree of the brain activation. In the method by measuring the change of the blood flow in the brain, the signals reflecting the degree of the brain activation is superposed with unwanted signals produced by the change of the blood flow other than the blood flow in the brain. The unwanted signals are an obstacle to obtaining the actual signals for the degree of the brain activation and cause malfunction of the equipment supplied with the unwanted signals. The prior art device is not configured such that change in the degree of the brain activation was not perceived by the possessor of the brain.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a brain function signal input device capable of inputting accurate brain function signals to various kinds of external equipment by reducing noise other than the actual brain function signals based upon activity of the brain.
It is another object of the present invention to provide a brain function signal input device having immunity against the change of the body or heart beats occurring during the operation of inputting the brain function signals.
It is still another object of the present invention to improve the ease of operation of a brain function signal input device by configuring the brain function signal input device such that change in the degree of the brain activation can be perceived by the possessor of the brain.
It is still another object of the present invention to provide an equipment controlling device or a data input device having improved reliability in control by the brain function signal which is an example of signals from a living body, so as to improve performance of the equipment controlling device based upon the brain function signal.
In an embodiment of a brain function signal input device according to the present invention, initially influences of drift and fluctuations originating in signals from a living body are reduced in the measured change of the blood flow in the brain as a brain function signal, as a preliminary processing. Then noise components in the brain function signals is eliminated by processing the brain function signals based upon at least three different signal threshold levels.
The following explains a concrete means and a concrete method of eliminating the drift and fluctuations.
A brain function signal input device comprises: light projecting means for projecting near-infrared rays from a light source onto a head, light measuring means for measuring said near-infrared rays having passed through the head, data processing means for processing an output signal from said light measuring means to obtain a brain function signal, displaying means for displaying the brain function signal, and control signal generating means for generating a control signal to be supplied to an external equipment based upon the brain function signal.
The data processing means takes in the output signals from said light measuring means at a predetermined interval, calculate an average of the output signals at an interval of a predetermined number of the output signals, calculate a difference between the average and an average of the output signals a predetermine time earlier, and outputs the difference as a brain function signal.
By the above data processing, noise originating from heart beats or the change of the body and contained in the output signals from said light measuring means are eliminated, and the brain function signal having a high signal-to-noise ratio and based upon the actual brain function is obtained. Therefore the above-mentioned malfunction of equipment due to the noise is prevented.
Provision of the displaying means for displaying the brain function signal enables an operator of the brain function signal input device, i.e. the sender of the brain function signal, to operate the brain function signal input device, as he confirms the intensity of the brain function signal. Consequently, since the operator can perform the proper operation as he watches the controlled state of the equipment, the ease in the operation of the equipment is improved.
This displaying means can display the brain function signal and threshold levels in the brain function signal intensity used as the criterion for judging whether to generate the above-mentioned control signal, on the same display screen at the same time.
Further the displaying means can be provided with a function for displaying the state of the control signals generated by the control signal generating means.
The means for displaying the measured signal intensity and the controlled state gives the operator information serving as a measure for increasing or decreasing the degree of activation of the brain in controlling the equipment according to the displayed brain function signal.
By using this displayed information, the operator can control equipment as he watches the signals generated by his own brain, and therefore he can reduce wrong operation or mistaken control of the equipment control device based upon signals from the brain.
In processing the signals from the living body, at three different threshold levels are established, then a time at which the signals trav
Ito Yoshitoshi
Koizumi Hideaki
Maki Atsushi
Yamamoto Tsuyoshi
Yamashita Yuichi
Antonelli Terry Stout & Kraus LLP
Hitachi , Ltd.
Lateef Marvin M.
Lin Jeoyuh
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