Imaging system and method for providing extended depth of focus, range extraction and super resolved imaging

• US 7,646,549 B2
• Filed: 12/18/2007
• Issued: 01/12/2010
• Est. Priority Date: 12/18/2006
• Status: Active Grant

• Current Assignee: Brien Holden Vision Institute
• Original Assignee: Xceed Imaging Ltd.
• Inventors: Zalevsky, Zeev, Zlotnik, Alex
• Primary Examiner(s): Lester; Evelyn A.
• Application Number:
  US11/959,256
• Publication Number:
  US 20080151391A1
• Time in Patent Office: 756 Days
• Field of Search: 359/558, 359/559, 359/739, 359/721, 359/740, 438/468, 438/535, 438/508
• US Class Current: 359/738
• CPC Class Codes: G02B 2207/129 Coded aperture imaging
• CPC Class Codes: G02B 27/0075 with means for altering, e.g. increasing, the depth of field or depth of focus
• CPC Class Codes: G02B 27/58 Optics for apodization or superresolution; Optical synthetic aperture systems

Abstract

An imaging system is presented for imaging objects within a field of view of the system. The imaging system comprises an imaging lens arrangement, a light detector unit at a certain distance from the imaging lens arrangement, and a control unit connectable to the output of the detection unit. The imaging lens arrangement comprises an imaging lens and an optical element located in the vicinity of the lens aperture, said optical element introducing aperture coding by an array of regions differently affecting a phase of light incident thereon which are randomly distributed within the lens aperture, thereby generating an axially-dependent randomized phase distribution in the Optical Transfer Function (OTF) of the imaging system resulting in an extended depth of focus of the imaging system. The control unit is configured to decode the sampled output of the detection unit by using the random aperture coding to thereby extract 3D information of the objects in the field of view of the light detector unit.

Claims

1. An imaging system for imaging objects, the imaging system comprising an imaging lens arrangement, a light detector unit at a certain distance from the imaging lens arrangement, and a control unit connectable to the output of the detection unit;

the imaging lens arrangement comprising an imaging lens and an optical element located in the vicinity of the lens aperture, said optical element introducing aperture coding by an array of regions differently affecting a phase of light incident thereon which are randomly distributed within the lens aperture, thereby generating an axially-dependent randomized phase distribution in the Optical Transfer Function (OTF) of the imaging system resulting in an extended depth of focus of the imaging system;

said control unit being configured to decode the sampled output of the detection unit by using the random aperture coding to thereby extract 3D information of the objects in the field of view of the light detector unit.

2. The imaging system of claim 1, wherein the control unit is configured to provide a range estimation of the distance of different objects in the field of view of the detector.

3. The imaging system of claim 2, wherein the range estimation is provided by decoding the sampled output of the detection unit indicative of the data information of a single image.

4. The imaging system of claim 1, wherein said control unit is configured to provide an image resolution for at least a part of the field of view exceeding by a predetermined factor a geometrical resolution defined by the light detector unit.

5. The imaging system of claim 1, wherein the enhanced geometrical resolution is provided by decoding the sampled output of the detection unit indicative of the data information of a single image.

6. The imaging system of claim 1, wherein said optical element is configured to reduce a quadratic factor phase resulting from light getting out of focus of the imaging lens and maximize a defocused OTF of the imaging system by providing the out of focus OTF as much as possible away from zero.

7. The imaging system of claim 1, wherein said optical element is configured to configured to generate an orthogonal coding of the various spectral bands in the OTF plane prior to being aliased, enabling the recovering of the aliased information resulting in the re-separation and the reconstruction of the spectral bands, and the enhancement of the image resolution for at least a part of the object exceeding by a predetermined factor a geometrical resolution defined by the light detector unit.

8. The imaging system of claim 1, wherein said random phase aperture coding is positioned in the exit pupil plane of the imaging lens.

9. The imaging system of claim 1, wherein said random phase aperture coding is positioned in the entrance pupil plane of the imaging lens.

10. The imaging system of claim 1, wherein the imaging lens arrangement and the light detector unit are optically aligned and stationary mounted.

11. The imaging system of claim 1, wherein the optical element has a different random phase distribution for each wavelength corresponding to the red, green and blue spectra.

12. An imaging method comprising applying an aperture coding to an imaging lens, said aperture coding comprising affecting phase of light by randomly distributed different phase affecting regions within the lens aperture thereby generating an axially-dependent randomized phase in the Optical Transfer Function (OTF) distribution, resulting in an extended depth of focusing;

and processing data indicative of an image of a region of interest to provide a linear correlation between the random phase distribution and each axial distance, and to extract 3D information on imaged objects in the region of interest from the linear correlation.

13. The method of claim 12, wherein extracting 3D information is obtained by multiplying the OTF with different random phase corresponding to different axial distance.

14. The method of claim 12, comprising optical processing of the light signal with a function coding, so as to provide orthogonality of spectral data indicative of a sampled output of a detector.

15. The method of claim 14, wherein the orthogonality of spectral data increases the geometrical resolution of the detector.

16. The method of claim 12, comprising applying a filtering to reduce the amount of noise.