Thin multi-aperture imaging system with auto-focus and methods for using same

Patent metadata

Field	Value
Publication number	US-2016182821-A1
Application number	US-201414906116-A
Country	US
Kind code	A1
Filing date	Jul 24, 2014
Priority date	Aug 1, 2013
Publication date	Jun 23, 2016
Grant date	—

Abstract

Dual-aperture digital cameras with auto-focus (AF) and related methods for obtaining a focused and, optionally optically stabilized color image of an object or scene. A dual-aperture camera includes a first sub-camera having a first optics bloc and a color image sensor for providing a color image, a second sub-camera having a second optics bloc and a clear image sensor for providing a luminance image, the first and second sub-cameras having substantially the same field of view, an AF mechanism coupled mechanically at least to the first optics bloc, and a camera controller coupled to the AF mechanism and to the two image sensors and configured to control the AF mechanism, to calculate a scaling difference and a sharpness difference between the color and luminance images, the scaling and sharpness differences being due to the AF mechanism, and to process the color and luminance images into a fused color image using the calculated differences.

First claim

What is claimed is:

1 . A dual-aperture digital camera with auto-focus (AF) for imaging an object or scene, comprising:
a) a first sub-camera that includes a first optics bloc and a color image sensor with a first number of pixels, the first camera operative to provide a color image of the object or scene; b) a second sub-camera that includes a second optics bloc and a clear image sensor having a second number of pixels, the second sub-camera operative to provide a luminance image of the object or scene, wherein the first and second sub-cameras have substantially the same field of view; c) an AF mechanism coupled mechanically at least to the first optics bloc; and d) a camera controller coupled to the AF mechanism and to the two image sensors and configured to control the AF mechanism, to calculate a scaling difference and a sharpness difference between the color and luminance images, the scaling and sharpness differences being due to the AF mechanism, and to process the color and luminance images into a fused color image using the calculated differences.

2 . The camera of claim 1 , wherein the AF mechanism is coupled mechanically to the first optics bloc and wherein the second optics bloc has a fixed focus position.

3 . The camera of claim 2 , wherein the fixed focus position is such that a depth of field range of the second sub-camera is between infinity and less than about 100 cm.

4 . The camera of claim 1 , wherein the AF mechanism is coupled mechanically to the first and second optics blocs and operative to move them together in a direction common to respective optics bloc optical axes.

5 . The camera of claim 4 , further comprising an optical image stabilization mechanism coupled mechanically to the first and second optics blocs and operative to move them together in a direction perpendicular to respective optics bloc optical axes to optically stabilize the AF fused color image.

6 . The camera of claim 1 , wherein the first number of pixels and second number of pixels are equal.

7 . The camera of claim 1 , wherein the first number of pixels and the second numbers of pixels are different.

8 . The camera of claim 1 , wherein the first and second images sensors are formed on a single substrate.

9 . The camera of claim 1 , wherein the first sub-camera includes an infra-red (IR) filter that blocks IR wavelengths from entering the color image sensor and wherein the second sub-camera is configured to allow at least some IR wavelengths to enter the clear image sensor.

10 . The camera of claim 1 , wherein the color image sensor include a non-Bayer color filter array (CFA).

11 . The camera of claim 10 , wherein the non-Bayer CFA includes a repetition of a 3×3 micro-cell in which the color filter order is GBRRGBBRG.

12 . A method for obtaining a focused color image of an object or scene using a dual-aperture camera, comprising the steps of:
a) obtaining simultaneously an auto-focused (AF) color image and an auto-focused or fixed focus (FF) luminance image of the object or scene, wherein the color image has a first resolution, a first effective resolution and a first signal-to-noise ratio (SNR), and wherein the luminance image has a second resolution, a second effective resolution and a second SNR; b) preprocessing the two images to obtain respective rectified, normalized and scale-adjusted color and luminance images considering scaling and sharpness differences caused by the AF action; c) performing local registration between the rectified, normalized and scale-adjusted color and luminance images to obtain registered images; and d) fusing the registered images into a focused fused color image.

13 . The method of claim 12 , wherein the step of preprocessing to obtain scale-adjusted color and luminance images includes calculating a set of corresponding points in the color and luminance images, extracting a single coordinate from each corresponding point and using the single coordinate to estimate a scaling factor S between the color and luminance images.

14 . The method of claim 13 , wherein the extracted coordinate is Y and wherein the scaling factor S is given by S=(Y2′*W*Y2)\Y2′*W*Y1, wherein Y1 is a vector of Y coordinates of points taken from one image, Y2 is a vector of Y coordinates of points taken from the other image, and W is a diagonal matrix which holds the absolute values of Y2.

15 . The method of claim 14 , further comprising the step of using scaling factor S to scale one of the images to match the other image, thereby obtaining the registered images.

16 . The method of claim 12 , further comprising the step of optically stabilizing the obtained color and luminance images.

Assignees

• Corephotonics Ltd

Inventors

• Shabtay Gal
• Cohen Noy
• Geva Nadav
• Gigushinski Oded
• Goldenberg Ephraim

Classifications

• H04N23/67 Primary

  Focus control based on electronic image sensor signals · CPC title

• H04N25/134

  based on three different wavelength filter elements · CPC title

• H04N23/951

  by using two or more images to influence resolution, frame rate or aspect ratio · CPC title

• H04N23/843

  Demosaicing, e.g. interpolating colour pixel values · CPC title

• H04N25/133

  including elements passing panchromatic light, e.g. filters passing white light · CPC title