Apparatus, System and Method for Correcting Nonuniform Rotational Distortion in an Image

Patent metadata

Field	Value
Publication number	US-2020149929-A1
Application number	US-201816184646-A
Country	US
Kind code	A1
Filing date	Nov 8, 2018
Priority date	Nov 8, 2018
Publication date	May 14, 2020
Grant date	—

Abstract

An image processing apparatus and method for detecting a position of a rotating optical fiber is provided. The apparatus includes at least one rotating optical fiber that rotates about an axis of rotation and that emits light towards a surface and at least two stationary fibers for transmitting light reflected from a surface, each of the at least two stationary fibers having a known predetermined position relative to each other and to the axis of rotation of the at least one rotating optical fiber. At least one detector is configured to detect an intensity of light transmitted through each of the at least two stationary fibers within a given time interval and at least one calculator is configured to use the detected intensities and the known predetermined positions of each of the at least two stationary fibers to determine a relative angular position of the rotating optical fiber with respect to the at least two stationary fibers.

First claim

We claim:

1 . An apparatus comprising:
at least one rotating optical fiber rotating about an axis of rotation that emits light towards a surface; at least two stationary fibers for transmitting light reflected from a surface, each of the at least two stationary fibers having a known predetermined position relative to each other and to the axis of rotation of the at least one rotating optical fiber; at least one detector configured to detect an intensity of light transmitted through each of the at least two stationary fibers within a given time interval; at least one calculator configured to
use the detected intensities and the known predetermined positions of each of the at least two stationary fibers to determine a relative angular position of the rotating optical fiber with respect to the at least two stationary fibers.

2 . The apparatus of claim 1 , further comprising
an image processor that uses the determined angular position within a given time interval to correct one or more defects caused by non-uniform rotation in an image generated from light transmitted through each of the at least two stationary fibers.

3 . The apparatus of claim 1 , wherein
the at least one calculator is configured to determine a relative angular position of the rotating optical fiber with respect to the at least two stationary fibers by selecting which of the at least two stationary fibers transmitting light has the greatest intensity.

4 . The apparatus of claim 1 , wherein
the at least one calculator is configured to interpolate the detected intensity values within a predefined angular range, and use the interpolated intensity values to determine a relative angular position of the rotating optical fiber with respect to the at least two stationary fibers by analyzing where the interpolated intensity has the greatest value.

5 . The apparatus of claim 1 , wherein
the at least one calculator is configured to generate a two dimensional array of transmitted light intensity values with a first dimension representing respective ones of the at least two stationary fibers and a second dimension representing the wavelength of light transmitted through the at least two stationary fibers; use detected intensity values from a predetermined set of respective wavelengths in the second dimension to determine a relative angular position of the rotating optical fiber with respect to the at least two stationary fibers.

6 . The apparatus of claim 1 , wherein the at least two stationary fibers are equally spaced and arranged in a substantially circular arrangement around the rotating optical fiber, and the at least one calculator is configured to
identify one of the at least two stationary fibers as transmitting light having the greatest intensity; determine the position of the identified one of the at least two stationary fibers relative to all other of the at least two stationary fibers; obtain the angular information by multiplying the determined position by a predetermined value and dividing the result by a total number of stationary fibers.

7 . The apparatus of claim 1 , wherein the surface from which light is reflected when measuring light intensity is a surface from which the image is generated.

8 . The apparatus of claim 1 , wherein the surface from which light is reflected when measuring light intensity is an optical window positioned at a distal end of the at least one rotating optical fiber.

9 . The apparatus claim 1 , wherein the at least two stationary fibers include at least sixteen stationary fibers substantially equally spaced from one another and arranged in a substantially circular arrangement around the at least one rotating fiber.

10 . The apparatus of claim 1 , wherein the determined position with respect to each of the two stationary fibers is one of (a) a respective one of each of the two stationary fibers or (b) a point between adjacent stationary fibers.

11 . A method of detecting a position of a rotating optical fiber that rotates about an axis of rotation and that emits light toward a surface comprising the steps of:
detecting an intensity of light reflected from the surface and which is transmitted through at least two stationary fibers within a given time interval, wherein each of the at least two stationary fibers have a known predetermined position relative to each other and to the axis of rotation of the at least one rotating optical fiber; and using the detected intensities and the known predetermined positions of each of the at least two stationary fibers to determine a relative angular position of the rotating optical fiber with respect to the at least two stationary fibers.

12 . The method of claim 11 , further comprising
correcting one or more defects caused by non-uniform rotation in an image generated from light transmitted through each of the at least two stationary fibers using the determined angular position within the given time interval.

13 . The method of claim 11 , further comprising
determining a relative angular position of the rotating optical fiber with respect to the at least two stationary fibers by selecting which of the at least two stationary fibers transmitting light has the greatest intensity.

14 . The method of claim 11 , further comprising
interpolating the detected intensity values within a predefined angular range, and using the interpolated intensity values to determine a relative angular position of the rotating optical fiber with respect to the at least two stationary fibers by analyzing where the interpolated intensity has the greatest value.

15 . The method of claim 11 , further comprising
generating a two dimensional array of transmitted light intensity values with a first dimension representing respective ones of the at least two stationary fibers and a second dimension representing wavelengths of light transmitted through the at least two stationary fibers;
using detected intensity values from a predetermined set of respective wavelengths in the second dimension to determine a relative angular position of the rotating optical fiber with respect to the at least two stationary fibers.

16 . The method of claim 11 , wherein the at least two stationary fibers are equally spaced and arranged in a substantially circular arrangement around the rotating optical fiber, and further comprising
identifying one of the at least two stationary fibers as transmitting light having the greatest intensity; determining the position of the identified one of the at least two stationary fibers relative to all other of the at least two stationary fibers; obtaining the angular information by multiplying the determined position by a predetermined value and dividing the result by a total number of stationary fibers.

17 . The method of claim 11 , wherein the surface from which light is reflected when measuring light intensity a surface from which the image is generated.

18 . The method of claim 11 , wherein the surface from which light is reflected when measuring light intensity is an optical window positioned at a distal end of the at least one rotating optical fiber.

19 . The method claim 11 , wherein the at least two stationary fibers include at least sixteen stationary fibers substantially equally spaced from one another and arranged in a substantially circular arrangement around the at least one rotating fiber.

20 . The method of claim 11 , wherein the determined position with respect to each of the two stationary fibers is one of (a) a r

Assignees

• Canon Usa Inc

Inventors

• Altshuler Alexander
• Brauer Jacob Schieffelin
• Mach Anderson Thi

Classifications

• G06T7/70

  Determining position or orientation of objects or cameras (camera calibration G06T7/80) · CPC title

• G01D5/30 Primary

  the beams of light being detected by photocells · CPC title

• G06T5/006

  Physics · mapped topic

• H04N25/61

  the noise originating only from the lens unit, e.g. flare, shading, vignetting or "cos4" · CPC title

• G01D5/268

  using optical fibres (G01D5/28 - G01D5/38 take precedence) · CPC title