Image capture using a fiducial reference pattern
Systems and methods are provided related to a system for imaging an object and a fiducial reference pattern that is projected onto or beside the object. The captured image of the fiducial reference pattern is used to detect a distortion in the captured image of the object.
1 . A system for imaging an object, the system comprising:
a fiducial projector configured to project a fiducial reference pattern of light upon one of a) the object and b) a location beside the object;
an image capture system configured to capture an image of the object and an image of the projected fiducial reference pattern; and
an image processor configured to use the captured image of the projected fiducial reference pattern to detect a distortion in the captured image of the object.
2 . The imaging system of claim 1 , wherein the distortion comprises at least one of a linear distortion and a non-linear distortion.
3 . The imaging system of claim 2 , wherein the fiducial reference pattern comprises a square; and the distortion is detected by measuring the length of at least one side of the captured image of the square.
4 . The imaging system of claim 2 , wherein the fiducial reference pattern comprises a square; and the distortion is detected by measuring a non-linearity of at least one side of the captured image of the square.
5 . The imaging system of claim 1 , wherein the fiducial projector comprises one of a laser and an LED.
6 . The imaging system of claim 5 , wherein the fiducial projector further comprises one of a diffractive optical element, an aperture element, and a lens.
7 . The imaging system of claim 1 , wherein the fiducial reference pattern comprises one of a square, a star, a circle, a cross-hair and an L-shape.
8 . The imaging system of claim 1 , housed in a hand-held device.
9 . The imaging system of claim 1 , wherein the fiducial projector projects visible light.
10 . The imaging system of claim 1 , wherein the fiducial projector projects near-infrared (near-IR) light.
11 . The imaging system of claim 10 , wherein the image capture system further comprises:
a filter array having a first filter element configured to pass visible light for capturing the image of the object, and a second filter element configured to pass the near-IR light for capturing the image of the projected fiducial reference pattern.
12 . The imaging system of claim 11 , wherein:
the first filter element is further configured to block the near-IR light.
13 . The imaging system of claim 12 , wherein:
the first filter element is located adjacent the second filter element in the filter array.
14 . The imaging system of claim 10 , further comprising:
a bulk filter configured to pass visible light for capturing the image of the object and near-IR light for capturing the image of the projected fiducial reference pattern, the bulk filter further configured to block light of other wavelengths.
15 . The imaging system of claim 1 , wherein the fiducial projector projects infrared (IR) light.
16 . The imaging system of claim 15 , wherein the image capture system further comprises:
a filter array having a first filter element configured to pass visible light for capturing the image of the object, and a second filter element configured to pass the IR light for capturing the image of the projected fiducial reference pattern.
17 . The imaging system as in claim 15 , further comprising:
a bulk filter configured to pass visible light for capturing the image of the object and IR light for capturing the image of the projected fiducial reference pattern, the bulk filter further configured to block light of other wavelengths.
18 . A method of capturing an image of an object, the method comprising:
projecting a fiducial reference pattern upon one of a) the object and b) a location beside the object;
capturing an image of the object and an image of the projected fiducial reference pattern; and
using the captured image of the projected fiducial reference patter to determine a distortion in the captured image of the object.
19 . The method of claim 18 , further comprising:
rectifying the determined distortion in the captured image of the object.
20 . The method of claim 19 , wherein the rectifying comprises:
measuring a first linear dimension in the fiducial reference pattern;
measuring a corresponding linear dimension in the captured image of the object; and
using the first linear dimension to modify the corresponding linear dimension in the captured image of the object.
21 . The method of claim 18 , wherein projecting the fiducial reference pattern comprises projecting a fiducial reference pattern that is visible to a human eye.
22 . The method of claim 18 , wherein projecting the fiducial reference pattern comprises projecting a fiducial reference pattern that is barely visible to a human eye.
23 . The method of claim 18 , wherein projecting the fiducial reference pattern comprises projecting a fiducial reference pattern that is invisible to a human eye.
24 . The method of claim 18 , wherein capturing the image of the object comprises capturing a 2-D image.
25 . The method of claim 18 , wherein capturing the image of the object comprises performing a non-contact scan of the object.