Method and device for detecting an object with background suppression

Patent metadata

Field	Value
Publication number	US-9459372-B2
Application number	US-201113984394-A
Country	US
Kind code	B2
Filing date	Feb 15, 2011
Priority date	Feb 15, 2011
Publication date	Oct 4, 2016
Grant date	Oct 4, 2016

Abstract

A background suppression device includes emitting means emitting a light beam emitted in a set direction and optoelectronic receiving means of a light beam reflected by an object providing a first and a second signal, and processing means which, in the detecting condition of the device, receives the first and second signal and provides an output information signal, in function of the first and second signal, indicating the presence or the absence of the object within an interval of set distances. The processing means stores, in a calibrating condition, the first and second signal and provides the output information signal in function of the first and/or of the second signal in the detecting condition and of the first and/or second signal in the calibrating condition. In the calibrating condition the object is absent and accordingly the first and second signal in the calibrating condition store the background.

First claim

What is claimed is:

1. A background suppression device comprising emitting means emitting a light beam emitted in a set direction; optoelectronic receiving means which is suitable for receiving a light beam reflected by an object and for providing a first and a second signal; processing means that is suitable for receiving, in a detecting condition of said device, said first and said second signal and for providing an output information signal, as a function of said first and said second signal, indicating the presence or absence of said object within an interval of set distances; wherein said processing means is suitable for storing, in a calibrating condition of said device during which a calibrating procedure for said device is performed, said first and said second signal and for providing said output information signal as a function of said first and/or said second signal obtained in said detecting condition and of said first and/or said second signal stored in said calibrating condition,
wherein a set limit distance of said interval of set distances is selectable in an interval of operational work distances, said emitted light beam not being focused or being substantially collimated in said interval of operational work distances,
wherein said emitted light beam has a diameter when impinging at a background that is greater than a desired minimum diameter value, said device comprising a focussing lens or collimating lens between said emitting means and said background, and
wherein the device further comprises adjusting and calibrating means allowing manual control of an adjustable receiving lens to direct the reflected light beam to different positions of the optoelectronic receiving means.

2. The device according to claim 1 , wherein said first signal is associable with a light beam reflected by an object within said interval of set distances and said second signal is associable with a light beam reflected by the background.

3. The device according to claim 1 , wherein said information signal is obtainable by comparing said first signal in said detecting condition with said first signal in the calibrating condition and/or said second signal in said detecting condition with said second signal in the calibrating condition.

4. The device according to claim 1 , wherein said information signal is obtainable by creating a differential signal in said detecting condition of said first and said second signal and making a comparison between said first signal in said detecting condition and said first signal in the calibrating condition and/or between said second signal in said detecting condition and said second signal in the calibrating condition, if said differential signal indicates the absence of said object.

5. The device according to claim 4 , wherein said processing means is suitable for making said comparison if said second signal has a greater amplitude than said first signal.

6. The device according to claim 1 , wherein said processing means is suitable for providing said information signal comparing respective amplitudes of said first and/or second signal in said detecting condition and in said calibrating condition.

7. The device according to claim 6 , wherein said information signal is suitable for indicating the presence of said object if the difference between the maximum amplitude of said first signal in the detecting condition and of said first signal in the calibrating condition, regardless of the sign of said difference, is greater than a first threshold value.

8. The device according to claim 6 , wherein said information signal is suitable for indicating the presence of said object if the difference between the maximum amplitude of said second signal in the detecting condition and of said second signal in the calibrating condition, regardless of the sign of said difference, is greater than a second threshold value.

9. The device according to claim 1 , wherein said object is absent within said interval of set distances in said calibrating condition, said optoelectronic receiving means being suitable in said calibrating condition for receiving said light beam reflected by a background.

10. The device according to claim 1 , wherein said calibrating condition being activatable by an operator via said adjusting and calibrating means.

11. The device according to claim 10 , wherein said adjusting and calibrating means comprises a calibrating trimmer, a first arrangement of said trimmer being associable with a command activating the calibrating procedure, a second arrangement of said trimmer being associable with a further command activating said calibrating condition and terminating said calibrating procedure.

12. The device according to claim 10 , wherein said adjusting and calibrating means comprises an optical adjustment trimmer to perform an optical adjustment procedure to adjust a set limit distance of said interval of set distances.

13. The device according to claim 1 , wherein said calibrating condition is activatable at intervals of time predefined by said processing means during and simultaneously with said detecting condition, when said object is absent within said interval of set distances.

14. The device according to claim 1 , wherein said emitted light has a diameter in the interval of operational work distances between 3 mm and 5 mm.

15. A method for detecting an object with background suppression, comprising the following steps: emitting a light beam in a set direction; receiving a light beam reflected by an object to provide a first and a second signal; processing said first and said second signal in a detecting condition and, as a function of said first and said second signal, providing an output information signal indicating the presence or absence of said object inside an interval of set distances; wherein said processing comprises the step of storing said first and said second signal in a calibrating condition during which a calibrating procedure for said device is performed, to provide said output information signal as a function of said first and/or said second signal obtained in said detecting condition and of said first and/or said second signal stored in said calibrating condition, the method further comprising:
selecting in an interval of operational work distances a set limit distance of said interval of set distances and acting in such a way that in said interval of operational work distances said emitted light beam is not focused or substantially collimated,
wherein said emitted light beam has a diameter when impinging at a background that is greater than a desired minimum diameter value, and
wherein the calibrating procedure includes an optical adjustment procedure during which a receiving lens is manually adjusted to direct the reflected light beam to different positions of an optoelectronic receiving means.

16. The method according to claim 15 , and comprising associating said first signal with a light beam reflected by an object within said interval of set distances and said second signal with a light beam reflected by the background.

17. The method according to claim 15 , wherein said providing said output information signal comprises comparing said first signal in said detecting condition with said first signal in the calibrating condition and/or said second signal in said detecting condition with said second signal in the calibrating condition.

18. The method according to claim 15 , wherein said providing said output information signal comprises creating a differential signal in said detecting condition of said first and said sec

Assignees

• Fabbri Alberto
• Faetani Sara
• Lazzarin Davide
• Naldi Danilo
• Datalogic IP Tech Srl

Inventors

• Fabbri Alberto
• Faetani Sara
• Lazzarin Davide
• Naldi Danilo

Classifications

• G01S17/48

  Active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves · CPC title

• G01S7/493 Primary

  Extracting wanted echo signals · CPC title

• G01S7/497

  Means for monitoring or calibrating · CPC title

• G01S17/04

  Systems determining the presence of a target · CPC title

• G01V8/10 Primary

  Detecting, e.g. by using light barriers (by reflection from the object G01S17/00) · CPC title