Machine vision counting system apparatus and method

• US 7,599,516 B2
• Filed: 01/13/2006
• Issued: 10/06/2009
• Est. Priority Date: 08/23/2005
• Status: Active Grant

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Illinois Tool Works Inc.
• Inventors: Burt, Christopher S., Gouin, Philip R., Limer, Daniel J., Dischinger, Randall D., Tarr, Nelson D., Lang, David A.
• Primary Examiner(s): Werner; Brian P
• Assistant Examiner(s): PATEL, JAYESH A
• Application Number:
  US11/331,343
• Publication Number:
  US 20070047980A1
• Time in Patent Office: 1,362 Days
• Field of Search: None
• US Class Current: 382/100
• CPC Class Codes: A61J 7/02 Pill counting devices
• CPC Class Codes: G01N 15/1433 using image recognition
• CPC Class Codes: G01N 2015/1472 with colour
• CPC Class Codes: G01N 2015/1486 Counting the particles
• CPC Class Codes: G06M 1/101 by electro-optical means
• CPC Class Codes: G06M 11/00 Counting of objects distributed at random, e.g. on a surface
• CPC Class Codes: G06V 20/66 Trinkets, e.g. shirt buttons or jewellery items recognising microscopic objects G06V20/69

Abstract

A machine-vision-based counter includes an image acquisition component (imager), wherein light provides discrimination between a background field and imageable units located away from the imager. The imager outputs data representing the field and units; an image processor receiving imager data finds countable units therein. An operator interface accepts command inputs and presents count output. A controller manages image acquisition, processor, and operator interface functions. A counting method includes configuring an imager to detect light, directing light from a source to units positioned to be detected by the imager, and directing the light to the imager. The method includes discriminating between a background field and imageable units; providing, as an imager output, data representing the field and units; configuring an image-processor to receive imager data; configuring the processor to interpret the data as counted units on a background field; and configuring an operator interface to present a count result.

Claims

1. A machine-vision-based counter for counting discrete units, comprising:

an image acquisition component configured to detect light having at least one wavelength, wherein the light provides discrimination between a background field and a quantity of imageable units located at a distance from the image acquisition component, and to provide, as an output, data representing the background field and the units;

an image processor configured to receive data from the image acquisition component, and further configured to interpret the data as a field image whereon are superimposed a quantity of countable units;

an operator interface component configured to present a count result output from the counter and to accept at least one command input to the counter; and

a counter controller configured to manage at least the image acquisition, image processor, and operator interface functions of the counter;

a first light source, wherein the first light source illuminates at least an area associated with the background field, wherein the first light source has a first spectral component, wherein light, emitted from the first light source and directed to units positioned to be detected by the image acquisition component, is thereafter directed at least in part to the image acquisition component;

a tray having a generally planar tray floor, substantially nonobstructive to light of at least one wavelength emitted by the first light source, and having a perimeter sidewall, wherein the sidewall substantially adjoins the tray floor and establishes a physical boundary for the tray floor that is open at least in part, wherein the sidewall rises above the tray floor to a specifiable extent;

a bracket whereby the tray is removably attachable to the counter;

a first hinge mechanism that links the tray to the bracket, wherein the tray is configured to rotate over a range that includes a first tray floor orientation that is substantially horizontal when the counter is in its normal operating orientation, and that further includes a second tray floor orientation that is tilted sufficiently to direct units resting on the tray floor toward the sidewall open part;

a pivotable stop bar affixed to the bracket by a second hinge mechanism, wherein tray tilt coupled to the stop bar opens a gap between the stop bar and the tray sidewall open part; and

a collection chute positioned beneath the sidewall open part, whereby units directed toward the sidewall open part and spilled therefrom are gathered into a lower opening of the collection chute.

2. The machine-vision-based counter of claim 1, wherein the image acquisition component further comprises:

a machine vision transducer, whereby data correlated to the relative intensity of radiation impinging on an imaging plane of the machine vision transducer in at least one frequency range is converted to a form suitable for transmission and processing;

a mount configured to affix the transducer with respect to the background field; and

a transducer data management function, whereby machine vision output data corresponding to the background field and any units present thereupon is transmitted to the image processor.

3. The machine-vision-based counter of claim 2, wherein the image acquisition component further comprises:

a filter interposed between the machine vision transducer and substantially all light impinging thereupon, whereby light having a spectral component of interest is passed relatively free of impediment to the transducer, and light lacking a spectral component of interest is substantially blocked from the transducer;

a focusing element, whereby a pattern of light from the background field, directed in part toward the image acquisition component, is formed into an image at least at the imaging plane of the machine vision transducer; and

an image converter for transforming an image at the imaging plane of the machine vision transducer into an array of pixels, wherein each pixel has a value representing an intensity of light falling thereupon.

4. The machine-vision-based counter of claim 1, further comprising:

a communication interface component, wherein the communication interface component provides information interchange in at least one direction between the counter and a device external to the counter.

5. The machine-vision-based counter of claim 1, wherein the first light source further comprises:

a first emitter configured to emit light in the form of a sequence of intervals of relatively high brightness light emission interspersed with intervals of relatively low brightness light emission; and

a synchronizing control signal generator whereby the first light source emission sequence is coordinated with operation of the image acquisition component.

6. The machine-vision-based counter of claim 1, wherein the first light source further comprises a first emitter configured to apply light sequentially over an array of discrete locations cumulatively comprising the background field, wherein light directed to the image acquisition component from the locations in succession permits acquisition of an image of the background field and any imageable units located thereon.

7. The machine-vision-based counter of claim 1, wherein the first light source further comprises:

a substantially uniformly emissive panel positioned distal to the image acquisition component, whereby subject units positioned between the background field and the machine vision transducer are illuminated in silhouette;

a substantially diffusely emissive panel, positioned distal to the background field and any subject units, so illuminating the background field and any subject units that light reflected therefrom is applied to the image acquisition component;

or

at least one source of light substantially comprising a discrete point source, positioned distal to the background field and any subject units, so illuminating the background field and any subject units that light reflected therefrom is applied to the image acquisition component.

8. The machine-vision-based counter of claim 1, further comprising a second light source, wherein the second light source is configured to emit light that includes at least an emitted color spectrum component not used in image processing associated with the first light source, wherein the second light source is so located that at least one attribute of the units is differently detected by the image acquisition component using light from the first light source and light from the second light source.

9. The machine-vision-based counter of claim 1, wherein the image processor is configured with:

a data interface function, wherein a data stream from the image acquisition component is interpreted as an image in the form of an array of pixels representing the brightness of a plurality of locations on the background field, including any countable units located thereon;

a localization function, wherein at least one region within image limits of the background field is identified as a region to analyze for countable units;

a pattern recognition function, wherein successive subregions within a region to analyze are compared to a unit model in search of a match;

a pattern match criterion, wherein a sufficiently small difference between the unit model and a subregion is interpreted as a match;

a unit count function, wherein identification of a match increments the count;

an erasure function, wherein incrementation of the unit count function marks as blank such pixels in the region to analyze as are associated with the match;

a completion function, wherein an identified region to analyze, lacking subregions satisfying the pattern match criterion, is reidentified as empty; and

a count control function, wherein the count control function determines a unit count function sequential repetition rate.

10. The machine-vision-based counter of claim 1, further comprising

a unit geometric pattern database, wherein the database includes recordation for a specified type of unit, wherein the unit recordation comprises a combination of size, shape, and at least one spatial orientation for the type of unit, whereby an image of a unit acquired by the image acquisition component is identifiably associable with the corresponding unit recordation.

11. The machine-vision-based counter of claim 1, further comprising:

an actively-transmitting scanner, further comprising;

a moving light beam, narrowly illuminating at least a single linear segment of area within a specified radius of the counter;

a detector for reflected light originating in the moving light beam, wherein the detector converts the reflected light to a data bit sequence containing at least one recognizable code, wherein the code comprises a counter-related datum; and

an electronic output signal to transfer the code to the counter controller;

a data correlation function, wherein the transferred code and a reference code are compared; and

a control function positively enabling at least one counter operation only if the correlation function result meets a specified criterion.