FEATURE DETECTION APPARATUS AND METHOD FOR MEASURING OBJECT DISTANCES

• US 20100165101A1
• Filed: 12/28/2009
• Published: 07/01/2010
• Est. Priority Date: 07/02/2007
• Status: Active Grant

• Current Assignee: Trimble Jena GmbH (Trimble Inc.)
• Original Assignee: Trimble Jena GmbH (Trimble Inc.)
• Inventors: Swann, Brendon, Kludas, Torsten, Mein, Nick
• Granted Patent: US 8,633,983 B2
• Time in Patent Office: Days
• US Class Current: 348/135
• CPC Class Codes: G01C 3/04 Adaptation of rangefinders for combination with telescopes or binoculars
• CPC Class Codes: G06V 10/987 with the intervention of an operator

Abstract

A feature detection apparatus and method for obtaining in a defined area of interest a parametric shape based on a selected combination of parameter values, constituting an approximation to an object feature. The feature detection apparatus includes an input unit for receiving at least two area indicator lines for defining in a digital image an area of interest, a parameter range defining unit for defining ranges of at least two parameters of a parametric shape, for which the parametric shape intersects at least one of the area indicator lines; a parameter selection unit for selecting a combination of parameter values from the parameter ranges, for which the parametric shape constitutes an approximation to an object feature of the object in the area of interest; and an output unit for providing the parametric shape based on said combination of parameter values for a display in the digital image.

Claims

1. A feature detection apparatus comprising:

an input unit for receiving at least two area indicator lines for defining in a digital image an area of interest comprising parts of an object;

a parameter range defining unit for defining ranges of at least two parameters of a parametric shape to be introduced into the digital image, for which the parametric shape intersects at least one of the area indicator lines;

a parameter selection unit for selecting a combination of parameter values from the parameter ranges, for which the parametric shape constitutes an approximation to an object feature of the object in the area of interest; and

an output unit for providing the parametric shape based on said combination of parameter values for display in the digital image.

2. The feature detection apparatus of claim 1 wherein the input unit is adapted to receive information identifying the parametric shape, the parametric shape constituting one of a plurality of pre-selectable candidate parametric shapes.

3. The feature detection apparatus of claim 1 wherein the parameter range defining unit is adapted to define ranges of parameters of a plurality of different parametric shapes, for which each of the parametric shapes intersects at least one of the area indicator lines.

4. The feature detection apparatus of claim 1 wherein the parameter selection unit is adapted to select the combination of parameter values such that the parametric shape constitutes a best fit approximation to the object feature of the object in the area of interest.

5. The feature detection apparatus of claim 1 wherein the parameter range defining unit is adapted to define sub ranges of the at least two parameters of at least one parametric shape, for which the at least one parametric shape intersects at least two area indicator lines.

6. The feature detection apparatus of claim 1 wherein the input unit is adapted to receive at least two indicator points to define the end points of an area indicator line.

7. The feature detection apparatus of claim 1 wherein the at least two area indicator lines are based on two indicator points, the area indicator lines extending through the indicator points so that the area indicator lines define an essentially rectangular area of interest.

8. The feature detection apparatus of claim 1 further comprising a detection unit for obtaining object feature pixels of the object feature in the area of interest by processing the area of interest using a detection algorithm or by an operator for selecting the object feature pixels in the area of interest.

9. The feature detection apparatus of claim 8 further comprising a calculation unit, for calculating the approximation to said object feature based on the obtained object feature pixels of the object feature.

10. The feature detection apparatus of claim 8 further comprising:

a filter unit for filtering out from said obtained object feature pixels object feature pixels exceeding a specific distance to said parametric shape; and

a recalculation unit for recalculating the approximation to said object feature based on the obtained object feature pixels not including the object feature pixels exceeding the specific distance.

11. The feature detection apparatus of claim 1 wherein the parametric shape based on said selected parameter values is superimposed on the object feature in the digital image on a display unit.

12. The feature detection apparatus of claim 1 wherein the parameter selection unit is adapted to select another combination of parameter values from the parameter ranges, for which a second parametric shape constitutes an approximation to a second object feature in the area of interest, and wherein a central line between the two parametric shapes is calculated.

13. An optical instrument comprising the feature detection apparatus according to claim 1.

14. The optical instrument according to claim 13 further comprising a first control element for defining on the parametric shape a measurement pixel and converting the measurement pixel into an approximation of coordinates of a position of the object to be measured assuming a default distance between the position and the optical instrument.

15. The optical instrument according to claim 14 further comprising:

a lens arrangement for sighting the object;

a positioning unit for adjusting the optical axis of the lens arrangement relative to at least one reference axis; and

a second control element adapted to instruct the positioning unit to adjust the optical axis of the lens arrangement onto the position to be measured.

16. The optical instrument according to claim 15 further comprising:

a distance measuring unit for measuring a distance to the object along a measurement axis of the distance measuring unit parallel to the optical axis of the lens arrangement, wherein

the second control element is adapted to instruct the distance measuring unit to measure the distance to the position to be measured, and

the first control element is further adapted to recalculate the coordinates of the position based on the measured distance.

17. The optical instrument according to claim 15 further comprising a camera aligned with the optical axis of the lens arrangement for acquiring the image of the area of interest comprising parts of the object.

18. A method of feature detection, the method comprising:

receiving at least two area indicator lines for defining in a digital image an area of interest comprising parts of an object;

defining ranges of at least two parameters of a parametric shape to be introduced into the digital image, for which the parametric shape intersects at least one of the area indicator lines;

selecting a combination of parameter values from the parameter ranges, for which the parametric shape constitutes an approximation to an object feature of the object in the area of interest; and

providing the parametric shape based on said combination of parameter values for display in the digital image.

19. The method of claim 18 further comprising receiving information identifying the parametric shape, the parametric shape constituting one of a plurality of pre-selectable candidate parametric shapes.

20. The method of claim 18 further comprising defining ranges of parameters of a plurality of different parametric shapes, for which each of the parametric shapes intersects at least one of the area indicator lines.

21. The method of claim 18 further comprising selecting the combination of parameter values such that the parametric shape constitutes a best fit approximation to the object feature of the object in the area of interest.

22. The method of claim 18 further comprising defining sub ranges of the at least two parameters of at least one parametric shape, for which the at least one parametric shape intersects at least two area indicator lines.

23. The method of claim 18 further comprising receiving at least two indicator points to define the end points of an area indicator line.

24. The method of claim 18 wherein the at least two area indicator lines are based on two indicator points, the area indicator lines extending through the indicator points so that the area indicator lines define an essentially rectangular area of interest.

25. The method of claim 18 further comprising obtaining object feature pixels of the object feature in the area of interest by processing the area of interest using a detection algorithm or by an operator for selecting the object feature pixels in the area of interest.

26. The method of claim 25 further comprising calculating the approximation to said object feature based on the obtained object feature pixels of the object feature.

27. The method of claim 25 further comprising:

filtering out from said obtained object feature pixels object feature pixels exceeding a specific distance to said parametric shape; and

recalculating the approximation to said object feature based on the obtained object feature pixels not including the object feature pixels exceeding the specific distance.

28. The method of claim 18 wherein the parametric shape based on said selected parameter values is superimposed on the object feature in the digital image on a display unit.

29. The method of claim 18 further comprising:

selecting another combination of parameter values from the parameter ranges, for which a second parametric shape constitutes an approximation to a second object feature in the area of interest; and

calculating a central line between the two parametric shapes.

30. The method of claim 18 further comprising

defining on the parametric shape a measurement pixel;

and

converting the measurement pixel into an approximation of coordinates of a position of the object to be measured assuming a default distance to the position.

31. The method of claim 30, further comprising:

sighting the object with a lens arrangement; and

adjusting the optical axis of the lens arrangement onto the position to be measured.

32. The method of claim 31 further comprising:

measuring a distance to the position to be measured along a measurement axis; and

recalculating the coordinates of the position based on the measured distance.

33. The method of claim 30 further comprising acquiring the image of the area of interest comprising parts of the object.

34. A program including instructions adapted to cause data processing means to carry out the method of claim 18.

35. A computer readable medium, in which a program is embodied, where the program, when executed, makes a computer execute the method of claim 18.

36. A computer program product comprising the computer readable medium according to claim 35.