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Title:
DEVICE FOR DETECTING ELONGATED BODIES
Document Type and Number:
WIPO Patent Application WO/2008/062485
Kind Code:
A1
Abstract:
A device for detecting elongated bodies is disclosed, comprising a videocamera (2; 9,10) . Preferably, the position is determined through comparison with a series of calibration curves.

Inventors:
RAINER WERNER (IT)
GIRIBONA PAOLO (IT)
BALDASSARI DANIELE (IT)
GABBARRINI ALFERINO (IT)
Application Number:
PCT/IT2006/000816
Publication Date:
May 29, 2008
Filing Date:
November 22, 2006
Export Citation:
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Assignee:
HEALTH ROBOTICS SRL (IT)
RAINER WERNER (IT)
GIRIBONA PAOLO (IT)
BALDASSARI DANIELE (IT)
GABBARRINI ALFERINO (IT)
International Classes:
A61B17/34
Domestic Patent References:
WO2004023783A22004-03-18
WO1999027839A21999-06-10
Foreign References:
US20030060706A12003-03-27
US20060149147A12006-07-06
EP0676178A11995-10-11
US6314311B12001-11-06
US5279309A1994-01-18
Attorney, Agent or Firm:
FAGGIONI, Carlo, Maria et al. (Via S. Agnese 12, Milano, IT)
Download PDF:
Claims:

CLAIMS

1) A device for detecting elongated bodies, characterised in that it comprises a videocamera (2; 9,10) .

2) A device as claimed in claim 1, characterised in that the videocamera (2) is carried by a cartesian robot (1) , possessing six degrees of freedom.

3) A device as claimed in claim 1, characterised in that it comprises a cartesian robot (6) possessing three degrees of freedom. 4) A device as claimed in claim 3, characterised in that the robot (6) comprises a case (7) , displaceable along a rod (8) .

5) A device as claimed in claim 4, characterised in that two videocameras (9, 10) are positioned at one end of the case (7).

6) A device as in claim 5, characterised in that the videocameras (9, 10) exhibit an angle.

7) A device as claimed in claim 6, characterised in that the angle ranges from 20 to 60°. 8) A device as claimed in claim 7, characterised in that the angle it ranges from 30 to 50°.

9) A device as claimed in claim 8, characterised in that the angle is 40° .

10) A device as claimed in any previous claim, characterised in that the true position of the elongated body is calculated by correlating the image acquired by the videocamera (s) (2; 9, 10) with one or more calibration curves.

11) A device as claimed in any previous claim, characterised in that the data acquisition is performed through the technique of opticle triangles.

12) Use of a device as in any previous claim in a device for the preparation of toxic substances .

13) Use as claimed in claim 12, characterised in that such toxic substances are cytotoxic drugs . 14) Use of a device as claimed in any claim 1 to 11, in a device for automatically injecting a drug into a patient.

Description:

DEVICE FOR DETECTING ELONGATED BODIES oooδooo FIELD OF THE INVENTION

This invention relates to a device for detecting elongated bodies, particularly for detecting needles of syringes. BACKGROUND OF THE INVENTION

The exact position of the tip of a syringe needle is a main problem in apparatus employing syringes for dosing substances. This .is particularly true for automatic apparatus. Indeed, the needle uses to curve, displacing its tip from its original, vertical position. This can be due to errors in the production, but also to modifications in the shape, taking place subsequently for mechanical and/or thermal shocks.

Most existing devices use a sensor. Unfortunately, such sensors are not precise enough and cannot provide the user with the coordinates of the needle tip. A wrong feeling in the position of the tip can lead to drawbacks, in particular it can even prevent either the loading or the injection of the liquid. SUMMARY OF THE INVENTION The above drawbacks are brilliantly solved by this invention, relating to a device for detecting elongated bodies, characterised in that it comprises a videocamera. BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 is a side view, illustrating an embodiment of this invention,-

Fig. 2 is a plan view, diagrammaticalIy illustrating a particular of the first embodiment of this invention;

Fig. 3 is a schematic view, showing an alternative embodiment of this invention; ' Fig. 4 is a flow sheet showing a calibration process according to this invention; and

Fig. 5 is a flow sheet showing an algorhythm on which the detection is possible.

BEST WAY OF CARRYING OUT THE INVENTION In the following, this invention will be disclosed for the case of the detection of a syringe needle, which is the

favourite case. Anyway, the description applies to the case of any elongated body, mutatis mutandis.

According to its first embodiment, this invention is comprised of a cartesian robot 1, possessing six degrees of ' freedom. On one end, the robot 1 bears, in articulated manner, a videocamera 2, having its lens 3, to be positioned in front of the needle 4 to be detected.

The calibration pattern 5 is shown in Fig. 2.

According to an alternative embodiment, shown in Fig. 2, a cartesian robot 6 is provided, possessing three degrees of freedom. The robot 6 comprises a case 7, displaceable along a rod 8. Two videocameras 9, 10 are positioned at one end of the case 7. The videocameras 9, 10 preferably exhibit an angle. Preferably, the angle ranges from 20 to 60°, more preferably it ranges from 30 to 50°, most preferably it is 40°.

Before starting in using the inventive device, a calibration is carried out. The calibration takes place according to what shown in Fig. 2. The calibration is performed in two steps: a three-D calibration and a two-D calibration. In the three-D calibration, a pattern 5 is scanned with the videocamera at different, known distances. The pattern 5 is a table comprising a number of circles having size and position known. The videocamera takes the picture and inputs the datum into a computer which, correlating it to the corresponding distance and to the exact position of the robot 1 or 6, draws the calibration curve (usually a straight line) . A two-D calibration is performed each three-D calibration. First of all

the small circles are found out, then their centre is sought for and finally the position is interpolated through triangles. When a curve for each pixel is complete, it is acquired by the computer and stored in its memory and the resulting beam of curves can be used for the whole life of the device.

The device is now ready for detecting the position of the needle 4. The robot 1 brings the videocamera 2 in front of the needle 4 and acquires the image. The true position of the needle is calculated by correlating the image with the calibration

curve. Preferably, the videocamera is firstly displaced on a position relative to the needle 4, then to the opposite position and both images are correlated, after a gaussian filtering. The filtering can take place on either a edge detection or an edge strength basis.

According to the alternative embodiment, the robot 6 displaces both videocameras 9, 10, so as to take pictures from different positions. The correlation step is similar than in the previous case, but the position of the needle 4 can be detected with only an acquisition step instead of two. A flow sheet of the process is reported in Figs. 4 and 5.

In any case, the data acquisition can be performed through the technique of opticle triangles.

It is apparent that the device according to this invention allows to detect the position of any kind of needle or any other elongated body. It is very useful in a number of applications. For instance it can be used in automatic devices for preparing toxic substances, like cytotoxic drugs, or in a device for automatically injecting a drug into a patient.