Gauge monitoring methods, devices and systems

• US 20090190795A1
• Filed: 01/30/2009
• Published: 07/30/2009
• Est. Priority Date: 01/30/2008
• Status: Active Grant

• Current Assignee: Cypress Envirosystems, Inc (Infineon Technologies AG)
• Original Assignee: Cypress Envirosystems, Inc (Infineon Technologies AG)
• Inventors: Nagaraj, Sundaram, Derkalousdian, Moses, Kramer, Marcus, Sim, Harry
• Granted Patent: US 8,594,365 B2
• Time in Patent Office: Days
• US Class Current: 382/100
• CPC Class Codes: G06F 18/00 Pattern recognition
• CPC Class Codes: G06V 2201/02 Recognising information on displays, dials, clocks

Abstract

A method of reading a gauge may include capturing a digital image of the gauge with a gauge reading device attached to the gauge, the digital image comprising a plurality of pixels; determining an angle of a gauge feature based on positions of predetermined pixels of the digital image; and converting the angle into a gauge reading. Gauge reader devices and network based systems are also disclosed.

Claims

1. A method of reading a gauge, comprising:

capturing a digital image of the gauge with a gauge reading device attached to the gauge, the digital image comprising a plurality of pixels;

determining an angle of a gauge feature based on positions of predetermined pixels of the digital image; and

converting the angle into a gauge reading.

2. The method of claim 1, wherein:

the gauge feature comprises a needle; and

determining the angle includes

determining an initial angle of the needle from the image pixel locations,

if the initial angle is outside predetermined limits, rotating all the pixel locations in a first direction about an anchor point by a displacement angle, determining a rotated angle of the needle from the rotated image pixel locations, and modifying the rotated angle by the displacement angle to generate the angle of the gauge feature.

3. The method of claim 1, wherein:

the gauge feature comprises a needle; and

determining the angle includes

generating line pixel locations corresponding to a plurality of lines at different angles,

determining differences between line pixel locations and image pixel locations,

determining the angle of the gauge feature based on the differences between the line pixel locations and image pixel locations.

4. The method of claim 3, wherein:

determining the angle of the gauge feature based on the differences between the line pixel locations and image pixel locations includes

selecting one of the plurality of lines as a best fit line when the line has the smallest difference between predetermined line pixel locations and predetermined image pixel locations, and

assigning an angle of the best fit line as the angle of the gauge feature.

5. The method of claim 3, wherein:

determining the angle of the gauge feature based on the differences between the line pixel locations and image pixel locations includes

selecting one of the plurality of lines as a best fit line when the line has a largest number of predetermined image pixel locations within a location difference range to predetermined image pixel locations, and

assigning an angle of the best fit line as the angle of the gauge feature.

6. The method of claim 1, wherein:

the gauge feature comprises a needle; and

determining the angle of the gauge feature includes

establishing a region of interest (ROI) that is a portion of the digital image including a travel path of the needle,

storing at least position and intensity values for each pixel in the ROI,

assigning a pixel location as a pixel needle position based on variance in intensity within the ROI, and

calculating the angle of the gauge feature from the location of the pixel needle position.

7. The method of claim 6, wherein:

the ROI comprises pixel positions having X and Y coordinate locations within the digital image, and

storing at least position and intensity values for each pixel in the ROI includes

forming an array, and

storing Y locations and intensity values at each location of the array, each array location corresponding to, but not storing, a different X location.

8. The method of claim 6, wherein:

starting at one end of the ROI, determining an intensity difference between adjacent pixels of the ROI,

averaging intensity differences for groups of adjacent pixels in the ROI, and

assigning a pixel location as a pixel needle position based on a greatest increase in intensity difference and a greatest decrease in intensity difference with respect to one of the average intensity differences.

9. The method of claim 6, wherein:

establishing the ROI includes defining a plurality of line segments, each comprising a plurality of pixels, the plurality of segments forming the ROI.

10. The device of claim 9, wherein:

capturing the digital image of the gauge includes capturing an image that includes a reading needle and a set point needle, the reading needle being the gauge feature; and

determining the angle of the gauge feature includes distinguishing pixels corresponding to the set point needle from pixels corresponding to the reading needle.

11. A gauge reader system, comprising:

at least one gauge reader device that includes

an adapter section that couples to a gauge,

at least one image sensor that acquires image data of the gauge, the image data comprising a plurality of pixels,

an angle determination section that determines an angle corresponding to a gauge feature, and

a conversion section that transforms the angle into a gauge reading.

12. The system of claim 11, wherein:

the at least one gauge reader further includes a processor, and

the angle determination section comprises an angle determination routine embodied on a machine readable media executable by the processor, including instructions for

determining an initial angle of a gauge needle from the image data, if the initial angle is outside of a predetermined range, rotating all the pixel locations in a first direction about a predetermined position by a displacement angle, determining a modified angle for the gauge needle, and determining a gauge needle angle from the modified angle and the displacement angle.

13. The system of claim 11, wherein:

the at least one gauge reader further includes a processor, and

the angle determination section comprises an angle determination routine embodied on a machine readable media executable by the processor, including instructions for

generating pixel positions for a plurality of lines at different angles, and comparing predetermined pixel positions of each line to predetermined pixel positions of the gauge image.

14. The system of claim 13, wherein:

the angle determination routine further includes instructions for

matching one of the plurality of lines with a gauge needle orientation based on a minimum distance between the predetermined pixel positions of the gauge image and the matching line, and

setting the angle of the matching line as the angle for translation into the gauge reading.

15. The system of claim 13, wherein:

the angle determination routine further includes instructions for

matching one of the plurality of lines with a gauge needle orientation based on a distance range between predetermined pixel positions of the gauge image and the matching line, and

setting the angle of the matching line as the angle for translation into the gauge reading.

16. The system of claim 11, further including:

a central web server system that monitors gauge readers at locations remote from the web server system, the web servers system comprising

a data base, and

a web service that accesses site data from the gauge readers through a firewall in response to poll requests from remote locations and stores such data in a database, the site data including at least gauge identifying data and a gauge reading, and provides web pages for providing the site data.

17. The system of claim 16, further including:

a text message sending system coupled to receive predetermined notifications from a site, and forwarding corresponding text messages to network endpoints in response to such notifications.

18. A gauge reading system, comprising:

at least one gauge reader in communication with a site server, the gauge reader being a self-contained device comprising

an image sensor that acquires an image of a corresponding gauge,

an image processor that generates pixel locations corresponding to a plurality of lines, and determines an angle of a gauge needle by comparing predetermined pixel positions of each line to predetermined image pixel positions to arrive at a matching line, and

a reading generator that generates a gauge reading based on the angle of the matching line; and

a central web server coupled to the site server by a communication firewall to receive at least gauge readings from the gauge reader device in response to predetermined requests from the site server.

19. The system of claim 18, wherein:

the central web server includes a monitoring service that periodically stores readings from a plurality of gauges for access via a network.

20. The system of claim 18, further including:

a text message service that forwards text messages to predetermined network end points in response to at least a gauge reading, and forwards text messages from network endpoints to the central web server; and

the central web server forwards received text message data in response to a poll request from the site server.