Method for image acquisition

Patent metadata

Field	Value
Publication number	US-9247218-B2
Application number	US-201213983619-A
Country	US
Kind code	B2
Filing date	Feb 10, 2012
Priority date	Feb 15, 2011
Publication date	Jan 26, 2016
Grant date	Jan 26, 2016

Abstract

A method for image acquisition of an object in transit on a movable supporting surface includes detecting a presence signal of the object in a preset position, and at least one dimension and/or position signals, the signals being generated by at least one sensor arranged upstream of a linear camera; detecting a “trigger event” signal, generated on the basis of the presence signal, the linear camera starting to acquire an image on the basis of the “trigger event” signal; starting to acquire an image of the object, when the object has travelled a preset distance from the preset position, the distance being calculated by an advance sensor suitable for generating a signal comprising an electric pulse at each preset movement of the movable supporting surface; and setting a mode for image acquisition of the linear camera on the basis of a resolution of the advance sensor.

First claim

What is claimed is:

1. A method for image acquisition of an object in transit on a movable supporting surface, comprising the following steps:
arranging at least one optical device for image acquisition comprising a respective linear camera associated with a lighting device;
detecting a presence signal of said object in a preset position on said movable supporting surface, and signals indicating at least one dimension and/or the position of said object on said movable supporting surface, said signals being generated by at least one sensor arranged upstream of said linear camera in the advancing direction of said movable supporting surface;
detecting a trigger event signal, generated on the basis of said presence signal, said linear camera starting to acquire an image of said object on the basis of said trigger event signal;
starting to acquire an image of said object by said linear camera, when said object has travelled a preset distance from said preset position, said distance depending on said at least one dimension of said object and/or on the position of said object on said movable supporting surface, said distance being calculated by an advance sensor associated with said movable supporting surface, said advance sensor being suitable for generating a signal comprising an electric pulse at each preset movement of said movable supporting surface, said advance sensor being operationally connected to said linear camera, or to a control device that controls said linear camera, wherein the method further comprises setting a mode for image acquisition of said linear camera on the basis of the resolution of said advance sensor, said resolution consisting of a distance travelled by said movable supporting surface in the time that elapses between two successive pulses generated by said advance sensor.

2. The method according to claim 1 , wherein said setting comprises selecting said acquisition mode from a plurality of different acquisition modes.

3. The method according to claim 1 , wherein said resolution is detected automatically by said linear camera, or by said control device.

4. The method according to claim 1 , wherein said resolution is set by an operator in said linear camera, or in said control device.

5. The method according to claim 1 , wherein said setting comprises:
adjusting an image acquisition frequency of said linear camera on the basis of the period of the signal generated by said advance sensor;
adjusting at least one further acquisition parameter of said linear camera in function of a position of said object on said movable supporting surface, said position being calculated by counting the number of pulses emitted by said advance sensor after said trigger event signal has been emitted.

6. The method according to claim 1 , wherein said adjusting comprises:
synchronising an image acquisition frequency of said linear camera with the pulses emitted by said advance sensor, in such a manner that an image line is acquired for every single pulse emitted by said advance sensor, or for every preset multiple of said single pulse;
adjusting at least one further parameter of said linear camera in function of a position of said object on said movable supporting surface, said position being calculated by counting the number of pulses emitted by said advance sensor after said trigger event signal has been emitted.

7. The method according to claim 5 , wherein said advance sensor has a resolution in the order of a few millimeters.

8. The method according to claim 6 , wherein said advance sensor has a resolution of approximately 0.1-0.2 mm.

9. The method according to claim 5 , wherein said further acquisition parameter comprises an acquisition sensitivity and/or a focus position of the linear camera.

10. The method according to claim 1 , further comprising providing said linear camera with an electronic shutter, said electronic shutter being driven in the interval of time that elapses between the acquisition of an image line and the subsequent acquisition, such as to prevent said linear camera continuing to acquire in said interval of time.

11. The method according to claim 1 , further comprising connecting said advance sensor to said linear camera, or to said control device, via a dedicated data transmission line.

12. The method according to claim 1 , wherein said at least one dimension comprises overall dimensions of said object in the advancing direction of said movable supporting plane and/or a height of said object.

Assignees

• Saporetti Claudio
• Datalogic IP Tech Srl

Inventors

• Saporetti Claudio

Classifications

• G06K7/10752 Primary

  Exposure time control · CPC title

• H04N7/183 Primary

  for receiving images from a single remote source · CPC title

• G06K7/10861

  sensing of data fields affixed to objects or articles, e.g. coded labels (postal sorting B07C3/14, conveying articles B65G47/48) · CPC title