Blur filter for eliminating aliasing in electrically sampled images

• US 5,682,266 A
• Filed: 04/05/1995
• Issued: 10/28/1997
• Est. Priority Date: 04/05/1995
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Eastman Kodak Company
• Inventors: Meyers, Mark M.
• Primary Examiner(s): Henry, Jon W.
• Application Number:
  US08/417,422
• Time in Patent Office: 937 Days
• Field of Search: 359/566, 359/569, 359/571, 359/575, 359/565, 359/20, 250/208.1
• US Class Current: 359/571
• CPC Class Codes: G02B 27/46 Systems using spatial filters
• CPC Class Codes: G02B 5/1871 Transmissive phase gratings

Abstract

A blur filter for use with a multi-element electro-optical sensor is formed with a plurality of diffractive elements positioned adjacent each other with each of the elements being comprised of uniformly spaced concentric diffractive features. The plurality of diffractive elements are secured in a plane near the sensing surfaces of a multi-element electro-optical sensor. Each element of the multi-element sensor has a plurality of sensing surfaces for receiving incident light from a plurality of diffractive features.

Claims

1. A blur filter for use with a multi-element electro-optical sensor comprising:

a plurality of diffractive elements positioned adjacent each other, each of said elements comprised of concentric diffractive features with uniform spacing between features;

a multi-element electro-optical sensor wherein each element has a plurality of sensing surfaces each receiving incident light from a plurality of diffractive features; and

means for spacing the plurality of diffractive elements in a plane near the sensing surfaces of the multi-element electro-optical sensor.

2. The blur filter according to claim 1 wherein the means for spacing spaces the diffractive elements in a plane that is 500 microns or less from the sensing surface of the multi-element electro-optical sensor.

3. The blur filter according to claim 1 wherein the means for spacing spaces the diffractive elements in a plane that is a distance X from the sensing surface of the multi-element electro-optical sensor wherein X=S*Tan θ

_x and wherein θ

_x equals the angle of diffraction of incident light; and

S=the center-to-center spacing between electro-optical sensor elements.

8. The blur filter according to claim 1 wherein each of said plurality of diffractive elements is a series of concentric circles.

9. The blur filter according to claim 1 wherein each of said plurality of diffractive elements is a series of concentric rectangles.

10. The blur filter according to claim 1 wherein each of said plurality of diffractive elements is a series of spaced apart concentric circles.

11. The blur filter according to claim 1 wherein each of said plurality of diffractive elements is a series of spaced apart concentric rectangles.

4. A blur filter for use with a multi-element electro-optical sensor comprising:

a plurality of diffractive elements positioned adjacent each other, each of said diffractive elements comprised of concentric diffractive features with uniform spacing between features, each of said diffractive features having a maximum diffractive surface height of h_max =λ

₀ /(n(λ

₀)-1) where λ

₀ is the design wavelength which is at the center of the wavelength region of interest;

a multi-element electro-optical sensor wherein each element has a plurality of sensing surfaces each receiving incident light from a plurality of diffractive features and arranged such that the sensing surfaces are in a plane; and

means for spacing the plurality of diffractive elements in a plane near the sensing surfaces of the multi-element electro-optical sensor.

5. A blur filter for use with a multi-element electro-optical sensor comprising:

a plurality of diffractive elements positioned adjacent each other, each of said diffractive elements comprised of concentric diffractive features with uniform spacing between features, each of said diffractive features having a diffractive surface height in the range of (1/4)h_max <

h<

(2)h_max wherein h_max =λ

₀ /(n(λ

₀)-1) where λ

₀ is the design wavelength which is at the center of the wavelength region of interest;

a multi-element electro-optical sensor wherein each element has a plurality of sensing surfaces each receiving incident light and arranged such that the sensing surfaces are in a plane; and

means for spacing the plurality of diffractive elements in a plane near the sensing surfaces of the multi-element electro-optical sensor.

6. A blur filter for use with a multi-element electro-optical sensor comprising:

a plurality of diffractive elements positioned adjacent each other, each of said elements comprised of concentric diffractive features with uniform spacing between features, each of said diffractive elements having a size that is at least 2 times the size of each electro-optical sensor;

a multi-element electro-optical sensor wherein each element has a plurality of sensing surfaces each receiving incident light from a plurality of diffractive features and arranged such that the sensing surfaces are in a plane; and

means for spacing the plurality of diffractive elements in a plane near the sensing surfaces of the multi-element electro-optical sensor.

7. The blur filter according to claim 6 wherein said plurality of diffractive elements are arranged in a matrix.