IL165038A - Energy management of a video capsule - Google Patents

Description

ENERGY MANAGEMENT OF A VIDEO CAPSULE Eitan, Pearl, Latzer & Cohen-Zedek P-1367-IL1 ENERGY MANAGEMENT OF A VIDEO CAPSULE FIELD OF THE INVENTION The present invention concerns a management system for controlling the energy expenditure of autonomous video capsules. More specifically, the invention is in the field of internal medical inspection of the gastro-intestinal tract.

BACKGROUND OF THE INVENTION Endoscopic inspection is a common practice in the medical diagnosis of gastro-intestinal (G.I.) diseases. The video camera used for. identifying observable irregularities of the internal lining of the G.I. tract is installed within an endoscope and progressive scenes are observed by pushing the endoscope inside the tract. The endoscope is a tubular device typically containing either a camera with the associated electric circuits or a fiber-optic image guide. It also includes a light source or a light guide, and an electrical conductor for accepting signals and\or supplying energy. US Patent Number 5,551 ,947 describes a laparoscopic trocar and sleeve assembly in which the trocar is provided with a transparent tip that can include a blade edge and accommodates a light telescope for supplying a video console so that while the trocar is being surgically inserted through the abdominal wall and into the abdominal cavity, visualization on the video console will be possible.

EP Patent No. 0667115 describes an in vivo video camera system and an autonomous video endoscope, each system includes a swallowable capsule, a transmitter and a reception system. The swallowable capsule includes a camera system and an optical system for imaging an area of interest onto the camera system. The transmitter transmits the video output of the camera system and the reception system receives the transmitted video output.

German Patent No. 3440177 describes a television camera, designed for purposes of endoscopies in the shape of an ellipse, swalloable and transported by the natural peristalsis as advance feed, sends picture point signals to a storage provided outside the body, picture reproduction by means of a visual display unit or picture printing appliances, which retrieve the picture point signals from the storage.

Because the movement of the endoscope head along the G.I. tract is brought about by a pushing action, the mechanical impact associated with such application of force become especially adverse as soon as the head of the endoscope enters a bend. In such bends, the movement of the endoscope is greatly impeded, risking the G.I. tract walls which are susceptible to perforation and limiting the method of endoscopic inspection to non-convoluted regions of the G.I. tract.

An in-vivo autonomous video capsule, described in US Patent 5,604,531 whose disclosure is incorporated herein by reference, moves along the G.I. tract by virtue of the natural squeezing action of the tract's walls, thus overcoming the risk of the pushing action, and, in addition, offering a more convenient method of administering the camera. An additional benefit of the capsule is avoiding the cumbersome aspects of connecting the intestines of the patient to external appliances. Via the autonomous capsule, images of the gastro-intestinal tract are obtained without physical connections being made to an energy source or an information drain. An internal power supply energizes the capsule and supports the illumination, image acquisition and radio transmission of the information to an external receiver. Because of the considerable length of the G.I. tract, many images have to be acquired in order to cover the entire length of the tract, this amount of data may be augmented by redundant images of the same site which are acquired when the capsule stops moving or is only barely doing so. Such a task consumes a substantial amount of energy, thus potentially becoming a limiting factor in respect of quality and quantity of the set of images collected in a single inspection. An additional drawback connected with redundancy of images of a G.I. tract is the effectiveness of analysis stage. Once the entire sequence of images is presented to the analyzing physician, a lengthy process of finding the potential sites of interest ensues. Any redundancy existing in such a sequence of images poses a disturbance to analysis procedure.

SUMMARY OF THE PRESENT INVENTION It is an object of the present invention to provide a device to be incorporated in an autonomous capsule, used for the inspection of the G.I. tract, which minimizes energy expenditure of the imaging unit of the capsule.

In accordance with a preferred embodiment of the invention, the capsule which obtains in vivo images of the G.I. tract internally, includes a switching unit, an imaging unit, a radio transmission unit and a power supply. The switching unit prevents the acquisition of redundant images while enabling acquisition of useful images.

In accordance with a preferred embodiment of the invention, the switching unit includes an axial motion detector, which detects insufficient progress in the axial direction of the capsule, and when such insufficient progress is detected, the switching unit deactivates the imaging unit.

Finally, in accordance with a preferred embodiment of the invention, the axial motion detector is an accelerometer.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the appended drawings in which: Fig. 1 is a schematic block diagram illustration of the structure of a motile video camera residing inside an autonomous capsule.

Fig. 2 is a schematic block diagram illustration showing with details the imaging and the control unit which regulates its power consumption.

Fig. 3 is a block diagram illustration showing in detail the components of the motion detector which initiates the sequence of events leading the changes in the switching status of the energy supply.

Fig. 4 is an illustration showing the positioning of the autonomous capsule within the G.I. tract.

DETAILED DESCRIPTION OF THE INVENTION Reference is now made to Fig. 1. which shows the schematic structure of an autonomous capsule 10 containing a control unit 14 for controlling energy flow from a power supply 24 to the major power consumer in the capsule which is an imaging unit 12. Minor power consumers 13 are not subjected to the intervention of unit 14. The power supply 24 of the autonomous capsule, is therefore connected to the imaging unit 12 indirectly, thus subjecting the flow of energy to the control exerted by the control unit 14. The autonomous capsule, containing its own limited supply of energy, travels the entire length of the G.I. tract acquiring a potentially large amount of images on the entire length of the tract. Therefore the present invention minimizes the amount of energy consumed should be kept in order to provide for the acquisition of as much as possible valuable information as possible.

Fig. 2, to which reference is now made, shows among other units, the details of the control unit 14 and imaging unit 12. Other embodiments, providing the same energy economizing effect, are included in the present invention.

Unit 14 comprises an axial motion detector 22, a switch driver 20, and an on/of switch 18. The axial motion detector 22 detects the movement changes of the capsule and extracts the axial movement component of the capsule. It then sends an actuation command to switch driver 20 if the conditions of a prescribed decision rule have been met. In such case, the switching unit 18 either connects or disconnects the power supply 24 to and from the imaging unit 12 respectively. The imaging unit comprises three major power consumers, namely radio transmitter 27, illuminator 26, and camera assembly 25. Power distributor 16 controls the supply to these consumers.

Fig. 3, to which reference is now being made, is a schematic elaboration of detector 22, showing the items comprising detector 22 and their relative connections. Accordingly, the axial accelerometer 30 is connected to amplifier 32 which conveys the enhanced signal to an axial acceleration analyzer 34. The value provided by this analyzer is sent to a threshold acceleration comparator 36 which passes information to the switch driver 20.

The linear accelerometer 30 is selectively sensitive to accelerations in the axial direction of the body of the accelerometer. It therefore has to be physically aligned with the motion axis of the capsule. Such alignment is illustrated in Fig. 4, showing some of the structures of the capsule 10. The movement of capsule 10 is passively achieved along the contracted void 52 of the G.I. tract by a squeezing action of the walls of the G.I. tract, also causing the longitudinal axis of the capsule marked 54 to align longitudinally with the local axis of the G.I. tract 56. In order for the axial accelerometer 30 to detect the progressive motion within the G.I. tract, its longitudinal axis 56 must be aligned in parallel with the longitudinally overlapping axes of the capsule and the G.I. tract.

Returning to Fig. 3, the procedure for extracting the decision as to the command to be given to the switch driver 20 from the signal of the accelerometer 30, is explained with reference to the figure. The output signal from the accelerometer 30 is first amplified by unit 32, to be subsequently provided to analyzer 34 which determines the actual axial acceleration. Unit 36 compares the acceleration value to a predetermined threshold value and performs a positive or negative decision on whether to change the existing switching indication provided by switch driver 20. Thus, upon deceleration of the capsule relative to the G.I. tract, the axial accelerometer would indicate a negative acceleration, and depending on the magnitude of the signal as analyzed by unit 34, a threshold comparison performed subsequently by unit 36 would, for a given input and above, decide on disconnecting the power supply by the switch 18 through a command from driver 20. An opposite situation would take place if a dormant capsule would suddenly start moving. The signal provided by the accelerometer 30 is analyzed and compared to a threshold figure to command the switch driver 20 to connect the power supply by switch 18. The imaging unit 12 is thus actuated.

False alarms arising from body movements having a component in the axial direction of the capsule would actuate an otherwise dormant capsule, if a signal amplitude above a predefined threshold occurs. In order to detect such body movements, an external detector can be employed in addition to the internal accelerometer of the capsule.

It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described herein above. Rather the scope of the invention is defined by the claims which follow:

Claims (16)

1. An in vivo device for acquiring in vivo images, said device comprising: at least one imaging unit; a control unit connected to said at least one imaging unit, said control unit comprising: a switching unit; and a motion detector connected to said switching unit; wherein said control unit is to, in response to a signal from the motion detector, disconnect a power supply from the device.

2. A device according to claim 1 wherein said motion detector comprises: an accelerometer.

3. A device according to claim 6 wherein said analyzer comprises a comparator to compare an analyzed signal with a pre-determined threshold.

4. The device of claim 1 , comprising: an amplifier; and an analyzer connected to said amplifier.

5. The device of claim 1 , wherein the device is a swallowable capsule.

6. The device of claim 1 , comprising a transmitter.

7. The device of claim 2, comprising an axial accelerometer.

8. The device of claim 1 , wherein the device is capable of imaging the gastrointestinal tract.

9. A system comprising: the device of claim 1 ; and a second motion detector disposed external to a body being examined.

10. The device of claim 1 , comprising a power supply.

11. 1 1. A device according to any one of claims 1-8 substantially as described hereinabove.

12. A device according to any one of claims 1-8 substantially as illustrated in any of the drawings.

13. A system according to claim 9 substantially as described hereinabove.

14. A system according to claim 9 substantially as illustrated in any of the drawings.

15. A device according to claim 10 substantially as described hereinabove.

16. A device according to claim 10 substantially as illustrated in any of the drawings Eitan, Pearl, Latzer & Cohen-Zedek Lawyers, Patent Attorneys & Notaries P-1367-IL1