Biological optical measuring instrument

• US 7,187,962 B2
• Filed: 06/28/2002
• Issued: 03/06/2007
• Est. Priority Date: 06/28/2001
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi Medical Corporation (Hitachi, Ltd.)
• Inventors: Shingo, Kawasaki
• Primary Examiner(s): Winakur; Eric F.
• Assistant Examiner(s): Lin; Jack
• Application Number:
  US10/482,579
• Publication Number:
  US 20040242979A1
• Time in Patent Office: 1,712 Days
• Field of Search: 600/323, 600/336, 600/328
• US Class Current: 600/322
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14553 specially adapted for cerebral tissue

Abstract

In a biological optical measuring instrument, when displaying a biological variation in a predetermined region of a subject through irradiating light to the subject and processing light signals obtained by detecting the transmitting light, the light signals of a plurality of sections having a predetermined time interval are extracted, section data are prepared from the respective extracted light signals, the plurality of the prepared section data are added and averaged, prior to preparing averaged section data for the predetermined time interval a light signal section containing noise components is specified from differential values of the extracted light signals and the section data of the light signal containing the noise components is excluded from the averaging operation, thereby, a biological optical measuring instrument is provided which permits to remove the section data containing noise components are automatically removed through computation without relying upon visual observation, to obtain highly reliable measurement result quickly and to display the same.

Claims

1. A biological optical measuring instrument comprising a light generating unit which irradiates light having a predetermined wavelength to a subject, a light detecting unit which detects light which is irradiated from the light generating unit and is transmitted through the subject, and a signal processing unit which analyzes signals detected by the light detecting unit and prepares biological information including blood stream information in the subject, wherein the signal processing unit includes means for detecting spike shaped noise components contained in the detected signals in a form of steep peaks which are due to body movement by the subject, and means for removing a signal portion containing the detected spike shaped noise components from the signals.

2. A biological optical measuring instrument according to claim 1, wherein the means for detecting the spiked shaped noise components judges that the spiked shape noise components are contained in a corresponding portion of the signals, when any of differential values of the signals obtained in a time course, are more than a predetermined threshold value.

3. A biological optical measuring instrument according to claim 1 or 2, wherein the signal processing unit includes means for extracting signals in a plurality of sections having a predetermined time interval from signals obtained along the time axis and for preparing section data from the respective extracted signals, means for detecting and removing section data containing noise components among the extracted and prepared section data, and means for performing adding and averaging process using the not removed section data among the plurality of the section data and for preparing averaged section data having a predetermined time interval.

4. A biological optical measuring instrument according to claim 3, wherein the section having a predetermined time interval includes a time interval, in which a task is executed by the subject.

5. A biological optical measuring instrument according to claim 4, wherein the task executed by the subject is motion and language.

6. A biological optical measuring instrument according to claim 3, wherein the light having a predetermined wavelength is near-infrared light.

7. A biological optical measuring instrument according to claim 1 or 2, wherein the light having a predetermined wavelength is near-infrared light.

8. A biological optical measuring method comprising:

a first step of irradiating light having a predetermined wavelength to a subject from a first position of the subject and measuring the transmitting light at a second position of the subject as transmitting light signal data containing biological information in a plurality of times for a predetermined interval;

a second step of adding the plurality of measured transmitting light signal data for the predetermined time interval and determining an average value of the transmitting light signal data;

a third step of determining differences of the respective transmitting light signal data for the predetermined time interval and the average value of the light transmitting signal data for the predetermined time interval prior to the respective concerned transmitting light signal;

a fourth step of excluding transmitting light signal data for the predetermined time interval, of which a determined difference exceeds a predetermined threshold value, which is indicative of spike shaped noise components contained in the measured light transmitting signal data in the form of steep peaks which are due to body movement by the subject, for later averaging computation of the transmitting light signal data; and

a fifth step of displaying the biological information, which includes blood stream information in the subject, in a form of an image based on processing of the transmitting light signal data in the first through fourth steps.

9. A biological optical measuring method according to claim 8, wherein the light having a predetermined wavelength is near-infrared light.

10. A biological optical measuring method according to claim 8, wherein the section having a predetermined time interval includes a time interval in which a task is executed by the subject.

11. A biological optical measuring method according to claim 8, wherein the transmitting light signal data including biological information is hemoglobin concentration signal data relating to oxygenated hemoglobin, deoxygenated hemoglobin or total hemoglobin.

12. A biological optical measuring instrument comprising a light generating unit which irradiates light having a predetermined wavelength to a subject, a light detecting unit which detects light which is irradiated from the light generating unit and is transmitted through the subject, a signal processing unit which analyzes signals detected by the light detecting unit and prepares biological information including blood stream information in the subject, a first memory means which store a first part of the biological information obtained when the subject is executing a task, a second memory means which store a second part of the biological information obtained when the subject is not executing the task, evaluation means which evaluates a hemoglobin variation when the subject is executing the task based on difference information of the biological information stored respectively in the first and second memory means, and control means which controls the light generating unit, the light detecting unit, the signal processing unit, the first memory means, the second memory means and the evaluation means, wherein the signal processing means includes means for detecting spike shaped noise components contained in the detected signals in a form of steep peaks which are due to body movement of the subject, and means for removing a signal portion containing the detected spike shaped components from the signals.

13. A biological optical measuring instrument according to claim 12, wherein the noise components detecting means determines differential values of the signals obtained time-sequentially and judges, when the differential values exceed a predetermined value, that the spike shaped noise components are contained in the concerned portion of the signals.

14. A biological optical measuring instrument according to claim 13, wherein the noise components detecting means includes means for determining an average value of a plurality of signals prior to signals in which whether the spiked shaped noise components are contained is to be judged, means for further determining a difference value between the determined average value and the signals in which whether the spiked shaped noise components are contained is to be judged, and means for judging, when the difference value is larger than a predetermined value, that the spiked shaped noise components are contained in the signals.

15. A biological optical measuring instrument according to claim 12, wherein the first part of the biological information is prepared time-sequentially during task executing period when the subject is executing a task and the second part of the biological information is prepared time-sequentially during non-task executing period when the subject is not executing a task.

16. A biological optical measuring instrument according to claim 15, wherein the control means, while causing to repeat light detection during the task executing period and during the non-task executing period, prepares biological information in combination of a plurality of task executing periods and non-task executing periods.

17. A biological optical measuring instrument according to claim 12, wherein each interval of the plurality of task executing periods and non-task executing periods is the same and the respective biological information in the plurality of task executing periods and non-task executing periods are averaged for evaluating the hemoglobin variation.

18. A biological optical measuring instrument according to claim 17, wherein when the noise components detecting means judges that the spiked shaped noise components are contained in the concerned signals, the concerned signals are removed for the averaging process.

19. A biological optical measuring instrument according to claim 17, wherein when the noise components detecting means judges that the spiked shaped noise components are contained in the concerned signals, the concerned signals are removed for the averaging process and the removed signals portion is interpolated by hemoglobin values at immediate both sides of the removed signals portion for the averaging process.

20. A biological optical measuring instrument according to claim 12, wherein the task executed by the subject is motion and language.