Image recognition

• US 20040170301A1
• Filed: 02/28/2003
• Published: 09/02/2004
• Est. Priority Date: 02/28/2003
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Claramunt, David, Flotats, Carles, Rio Doval, Jose M., Ruiz, Rodrigo, Subirada, Francesc
• Granted Patent: US 7,146,049 B2
• Time in Patent Office: Days
• US Class Current: 382/107
• CPC Class Codes: G01P 3/68 using optical means, i.e. using infrared, visible, or ultraviolet light G01P3/80 takes precedence ; by reflection of waves G01S17/58
• CPC Class Codes: G06T 7/254 involving subtraction of images

Abstract

A method for image recognition. In the method, a section of an element is imaged while the element is at a first speed to obtain a first image pattern. The section of the element is also imaged while the element is at a second speed to obtain a second image pattern. The first speed differs from the second speed. In addition, the apparent speeds of the element in the first image pattern and the second image pattern are made to appear approximately the same.

Claims

1. A method for image recognition, said method comprising:

imaging a section of an element while the element is at a first speed to obtain a first image pattern;

imaging the section of the element while the element is at a second speed to obtain a second image pattern, wherein the first speed differs from the second speed; and

making the apparent speeds of the element in the first image pattern and the second image pattern appear approximately the same.

2. The method according to claim 1, wherein the step of making the apparent speeds appear approximately the same comprises increasing the distortion of at least one of the first image pattern and the second image pattern.

3. The method according to claim 2, wherein the step of increasing the distortion comprises increasing the exposure time for the image pattern imaged while the element is traveling at a slower velocity relative to the element velocity during imaging of the other image pattern.

4. The method according to claim 2, wherein said distortion increasing step comprises expanding the image pattern for the image pattern imaged while the element was traveling at a slower velocity relative to the element velocity during imaging of the other image pattern.

5. The method according to claim 1, wherein the step of making the apparent speeds appear approximately the same comprises decreasing the distortion of at least one of the first image pattern and the second image pattern.

6. The method according to claim 5, wherein said distortion decreasing step comprises imaging a wider section of the image pattern for the image pattern imaged while the element was traveling at a slower velocity relative to the element velocity during imaging of the other image pattern.

7. The method according to claim 5, wherein said distortion decreasing step comprises compressing the image pattern for the image pattern imaged while the element was traveling at a faster velocity relative to the element velocity during imaging of the other image pattern.

8. The method according to claim 1, wherein said step of making the apparent speeds appear approximately the same comprises decreasing the distortion of the image pattern imaged at the higher element advance speed and increasing the distortion of the image pattern photographed at the lower element advance speed.

9. The method according to claim 1, wherein the step of imaging a section of the element to obtain a first image pattern and imaging the section of the element to obtain a second image pattern comprises obtaining the first image pattern and the second image pattern with one or more photosensor arrays.

10. The method according to claim 1, wherein said step of imaging the section of the element to obtain the first image pattern and the step of imaging the section of the element to obtain the second image pattern includes imaging an indicia on the element.

11. The method according to claim 10, further comprising:

determining positional changes in the locations of indicia on the element between the first image pattern and the second image pattern; and

determining one or more of displacement, velocity, acceleration, and stress/strain of the element based upon the positional changes.

12. A system for image recognition, said system comprising:

at least one photosensor array configured to capture a first image pattern of an element and a second image pattern of the element, wherein the first image pattern and the second image pattern are configured to be captured while the element is traveling at different speeds;

a motor operable to vary the position of the element; and

a controller configured to control operation of the at least one photosensor array and the motor, said controller being configured to make the apparent speeds of the element in the first image pattern and the second image pattern appear approximately the same, and wherein said controller is configured to perform an image recognition operation on the first image pattern and the second image pattern.

13. The system according to claim 12, further comprising an encoder operable to detect information pertaining to advancement of the element, said encoder being configured to send the detected information to the controller, wherein said controller is configured to control operation of the at least one photosensor array in response to the detected information.

14. The system according to claim 12, wherein the controller is further operable to decrease the level of distortion of at least one of the first image pattern and the second image pattern to make the apparent speeds of the element in the first image pattern and the second image pattern appear approximately the same.

15. The system according to claim 14, wherein the controller is further operable to compress the image pattern for the image pattern captured while the element was traveling at a faster velocity relative to the element velocity during imaging of the other image pattern to decrease the level of distortion.

16. The system according to claim 12, wherein the controller is further operable to increase the level of distortion of at least one of the first image pattern and the second image pattern to make the apparent speeds of the element in the first image pattern and the second image pattern appear approximately the same.

17. The system according to claim 16, wherein the controller is operable to expand the image pattern captured while the element was traveling at a slower velocity relative to the element velocity during imaging of the other image pattern to decrease the level of distortion.

18. The system according to claim 16, wherein the controller is operable to increase the exposure time during capture of the image pattern while the element was traveling at a faster velocity relative to the element velocity during imaging of the other image pattern to decrease the level of distortion.

19. The system according to claim 12, wherein the controller is operable to decrease the distortion of the image pattern captured at the higher element advance speed and increase the distortion of the image pattern captured at the lower element advance speed to make the apparent speeds of the element appear approximately the same.

20. The system according to claim 12, wherein the controller is operable to detect indicia on the element in the first image pattern and the second image pattern.

21. The system according to claim 20, wherein the controller is operable to determine positional changes in the locations of indicia on the element between the first image pattern and the second image pattern and determine one or more of displacement, velocity, acceleration, and stress/strain of the element based upon the positional changes.

22. An apparatus for image recognition, said apparatus comprising:

means for capturing a first image pattern and a second image pattern of an element, wherein the first image pattern and the second image pattern are configured to be captured while the element is traveling at different speeds; and

means for making the apparent speeds of the element in the first image pattern and the second image pattern appear approximately the same.

23. The apparatus according to claim 22, wherein the means for making the apparent speeds of the element in the first image pattern and the second image pattern appear approximately the same comprises means for decreasing the level of distortion of at least one of the first image pattern and the second image pattern.

24. The apparatus according to claim 23, wherein means for decreasing the level of distortion of at least one of the first image pattern and the second image pattern comprises means for compressing the image pattern for the image pattern captured while the element was traveling at a faster velocity relative to the element velocity during capture of the other image pattern.

25. The apparatus according to claim 24, wherein means for making the apparent speeds of the element in the first image pattern and the second image pattern appear approximately the same comprises means for increasing the level of distortion of at least one of the first image pattern and the second image pattern.

26. The apparatus according to claim 25, wherein the means for increasing the level of distortion of at least one of the first image pattern and the second image pattern comprises means for expanding the image pattern for the image pattern captured while the element was traveling at a slower velocity relative to the element velocity during imaging of the other image pattern.

27. The apparatus according to claim 25, wherein the means for increasing the level of distortion of at least one of the first image pattern and the second image pattern comprises means for increasing the exposure time for the image pattern captured while the element is traveling at a slower velocity relative to the element velocity during imaging of the other image pattern.

28. The apparatus according to claim 22, wherein the means for making the apparent speeds of the element in the first image pattern and the second image pattern appear approximately the same comprises means for reducing the distortion of the image pattern captured at the higher element advance speed and means for increasing the distortion of the image pattern photographed at the lower element advance speed.

29. The apparatus according to claim 22, further comprising:

means for determining positional changes in the locations of indicia on the element between the first image pattern and the second image pattern; and

means for determining one or more of displacement, velocity, acceleration, and stress/strain of the element based upon the positional changes.

30. A computer readable storage medium on which is embedded one or more computer programs, said one or more computer programs implementing a method for image recognition, said one or more computer programs comprising a set of instructions for:

imaging a section of an element while the element is at a first speed to obtain a first image pattern;

imaging the section of the element while the element is at a second speed to obtain a second image pattern, wherein the first speed differs from the second speed; and

making the apparent speeds of the element in the first image pattern and the second image pattern appear approximately the same.

31. The computer readable storage medium according to claim 30, said one or more computer programs further comprising a set of instructions for:

increasing the distortion of at least one of the first image pattern and the second image pattern.

32. The computer readable storage medium according to claim 31, said one or more computer programs further comprising a set of instructions for:

increasing the exposure time for the image pattern imaged while the element is traveling at a slower velocity relative to the element velocity during imaging of the other image pattern.

33. The computer readable storage medium according to claim 31, said one or more computer programs further comprising a set of instructions for:

expanding the image pattern for the image pattern imaged while the element was traveling at a slower velocity relative to the element velocity during imaging of the other image pattern.

34. The computer readable storage medium according to claim 30, said one or more computer programs further comprising a set of instructions for:

compressing the image pattern for the image pattern imaged while the element was traveling at a faster velocity relative to the element velocity during imaging of the other image pattern.

35. The computer readable storage medium according to claim 30, said one or more computer programs further comprising a set of instructions for:

decreasing the distortion of the image pattern imaged at the higher element advance speed and increasing the distortion of the image pattern photographed at the lower element advance speed.

36. The computer readable storage medium according to claim 30, said one or more computer programs further comprising a set of instructions for:

determining positional changes in the locations of indicia on the element between the first image pattern and the second image pattern; and

determining one or more of displacement, velocity, acceleration, and stress/strain of the element based upon the positional changes.

37. A method of image recognition comprising the steps of:

generating first and second images of an object at first and second times, said object traveling at different speeds at said first and second times, wherein said first and second images are generated such that the apparent speed of the object in the first and second images are substantially the same.