DETECTION OF WHEN A CAPSULE CAMERA ENTERS INTO OR GOES OUT OF A HUMAN BODY AND ASSOCIATED OPERATIONS

• US 20150208908A1
• Filed: 04/07/2015
• Published: 07/30/2015
• Est. Priority Date: 01/22/2007
• Status: Abandoned Application

• Current Assignee: CapsoVision, Inc.
• Original Assignee: CapsoVision, Inc.
• Inventors: Wang, Kang-Huai
• Application Number:
  US14/680,925
• Publication Number:
  US 20150208908A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 1/041 Capsule endoscopes for imaging
• CPC Class Codes: A61B 5/06 Devices, other than using radiation, for detecting or locating foreign bodies for removing same A61B17/50 ; determining position of probes within or on the body of the patient
• CPC Class Codes: A61B 5/42 Detecting, measuring or recording for evaluating the gastrointestinal, the endocrine or the exocrine systems A61B1/00, A61B5/4857, A61B5/486, A61B5/4866, A61B5/4869 take precedence
• CPC Class Codes: H04N 17/002 for television cameras

Abstract

A method for detecting a capsule camera entering into or exiting the GI tract, includes (a) taking a first test image under the condition that an illumination system of the capsule camera is disabled; (b) taking a second test image under the same condition as the first test image; (c) comparing selected corresponding pixel values of the first test image and the second test image to determine if a significant change in pixel values has occurred; and (d) upon detecting the significant change in pixel values, determining if the capsule camera has entered or exited the GI tract, and performing operations appropriate to follow such determination.

Claims

1. A method for detecting a capsule camera entering into or exiting the GI tract, comprising:

operating the capsule camera to take a plurality of images along the GI tract;

using a sensing circuit in the capsule camera that is sensitive to an environmental difference between the GI tract and an environment outside of a human body, determining whether or not the capsule camera has exited the GI tract; and

upon determining that the capsule camera has exited the GI tract, deleting a predetermined number of the images taken immediately preceding the determination.

2. The method of claim 1, wherein the sensing circuit comprises an image sensor array for capturing the images, wherein the image sensor array (i) takes a test image under a condition that an illumination system of the capsule camera is disabled, (ii) determining whether or not a function computed based on selected pixel values of the test image exceeds a predetermine threshold.

3. The method of claim 2 wherein the predetermined threshold is determined using a previously obtained test image.

4. The method of claim 2, wherein the selected pixel values correspond to data in a subset of the image sensor array.

5. The method of claim 2, wherein the function computed is based on selected pixel values relates to a red component in the test image.

6. The method of claim 1, wherein the sensing circuit comprises a semiconductor thermometer.

7. The method of claim 1, wherein the environmental difference is detected by comparing a temperature measured by the semiconductor thermometer against a predetermined range.

8. The method of claim 7 further comprising calibrating the capsule camera under test conditions to determine the predetermined range.

9. The method of claim 8, wherein results of the calibrating step are recorded in a storage device in the capsule camera for subsequent retrieval.

10. The method of claim 8, wherein a separate predetermined range is determined for each test condition.

11. The method of claim 7, where the predetermined range is stored in a storage device in the capsule camera.

12. The method of claim 6, wherein the environmental difference is detected by comparing temperature measurements taken at different times.

13. The method of claim 6, wherein the semiconductor thermometer detects a temperature change based on a leakage current in a PN junction.

14. The method of claim 13, further comprising pre-charging the PN junction by applying a reverse bias voltage across the PN junction, and measuring a voltage of the PN junction after a predetermined time period.

15. The method of claim 14, further comprising providing an analog-to-digital converter to provide a read-out of the voltage.

16. The method of claim 15, wherein the predetermined period is set by the sampling time of the voltage at the analog-to-digital converter.

17. The method of claim 6, wherein the semiconductor thermometer detects a change in temperature based on a temperature-dependence in a channel current of an MOS transistor.

18. The method of claim 6, wherein the semiconductor thermometer detects a change in temperature based on a difference in temperature-dependence among a plurality of MOS transistors.

19. The method of claim 18, wherein the difference in temperature-dependence arises from a difference in channel length among the MOS transistors.

20. The method of claim 18, wherein the MOS transistors comprise a first set of one or more devices connected in series with a second set of one or more devices, wherein each set of devices has a common temperature-dependence, but the temperature-dependence of the first of devices is different than the temperature-dependence of the second set of devices.

21. The method of claim 20, wherein the first set of devices comprises one or more short channel transistors, and wherein the second set of devices comprises one or more long channel devices.

22. The method of claim 20, wherein the first set of devices are each biased to operate within a linear region, and wherein the second set of devices are biased to operate in a saturation region.

23. The method of claim 22, further comprising a digital-to-analog converter sensing a voltage at an electrical node between the first set of devices and the second set of devices.

24. The method as in claim 20, wherein the first and second sets of devices operate with a strong inversion layer.

25. The method of claim 1 further comprising activating an audio signal to indicate the capsule camera has exited the GI tract.

26. The method of claim 1, wherein the capsule camera stores the images in an on-board archival memory.

27. The method of claim 1, wherein the capsule camera transmits the images by wireless as the images are taken, and as the capsule camera travels along the GI tract.

28. The method of claim 1, further comprising recording each time the function exceeds the predetermined threshold in a history record of an on-board storage device, and examining the history record in a power-on self-test.

29. The method of claim 28, wherein the power-on self-test comprises a self-diagnosing function.

30. The method of claim 1, further comprising enabling a lighting pattern using an illumination system in the capsule camera upon the determination that the capsule camera has exited the GI tract.

31. An integrated circuit, comprising:

a semiconductor thermometer; and

a control circuit which detects an environmental difference during operation of the integrated circuit using the semiconductor thermometer.

32. The integrated circuit of claim 31, wherein the control circuit detects the environmental difference by comparing a temperature measured by the semiconductor thermometer against a predetermined range.

33. The integrated circuit of claim 31, wherein the control circuit calibrates the semiconductor thermometer under test conditions.

34. The integrated circuit of claim 33, further comprising a storage device in which calibration results under the test conditions are recorded.

35. The integrated circuit of claim 34, wherein a separate predetermined range is recorded for each test condition.

36. The integrated circuit of claim 31, wherein the control circuit detects the environmental difference by comparing temperature measurements taken at different times.

37. The integrated circuit of claim 31, wherein the semiconductor thermometer detects a temperature change based on a leakage current in a PN junction.

38. The integrated circuit of claim 37, further comprising a pre-charging circuit that applies a reverse bias voltage across the PN junction, wherein the control circuit measures a voltage of the PN junction after a predetermined time period of the reverse bias voltage being applied.

39. The integrated circuit of claim 38, further comprising an analog-to-digital converter which provides the control circuit a read-out of the voltage being measured.

40. The integrated circuit of claim 39, wherein the predetermined period is set by the sampling time of the voltage at the analog-to-digital converter.

41. The integrated circuit of claim 31, wherein the semiconductor thermometer detects a change in temperature based on a temperature-dependence in a channel current of an MOS transistor.

42. The integrated circuit of claim 31, wherein the semiconductor thermometer detects a change in temperature based on a difference in temperature-dependence among a plurality of MOS transistors.

43. The integrated circuit of claim 42, wherein the difference in temperature-dependence arise from a difference in channel length among the MOS transistors.

44. The integrated circuit of claim 42, wherein the MOS transistors comprise a first set of one or more devices connected in series with a second set of one or more devices, wherein each set of devices has a common temperature-dependence, but the temperature-dependence of the first of devices is different than the temperature-dependence of the second set of devices.

45. The integrated circuit of claim 44, wherein the first set of devices comprise one or more short channel transistors, and wherein the second set of devices comprise one or more long channel devices.

46. The integrated circuit of claim 44, wherein the first set of devices are each biased to operate within a linear region, and wherein the second set of devices are biased to operate in a saturation region.

47. The integrated circuit of claim 46, further comprising a digital-to-analog converter which receives a voltage at an electrical node between the first set of devices and the second set of devices.

48. The integrated circuit of claim 44, wherein the first and second sets of devices operate with a strong inversion layer.

49. The integrated circuit of claim 31, further comprising an array of non-volatile memory cells.

50. The integrated circuit of claim 31, wherein the control circuit performs a power-on self-test.

51. The integrated circuit of claim 50, wherein the power-on self-test comprises a self-diagnosing function.