Operating a device to capture high dynamic range images

Patent metadata

Field	Value
Publication number	US-9420198-B2
Application number	US-201414537746-A
Country	US
Kind code	B2
Filing date	Nov 10, 2014
Priority date	Jul 5, 2010
Publication date	Aug 16, 2016
Grant date	Aug 16, 2016

Abstract

Some embodiments provide a method of operating a device to capture an image of a high dynamic range (HDR) scene. Upon the device entering an HDR mode, the method captures and stores multiple images at a first image exposure level. Upon receiving a command to capture the HDR scene, the method captures a first image at a second image exposure level. The method selects a second image from the captured plurality of images. The method composites the first and second images to produce a composite image that captures the HDR scene. In some embodiments, the method captures multiple images at multiple different exposure levels.

First claim

What is claimed is:

1. A non-transitory machine readable medium of a device that captures images, the medium storing a program that when executed by at least one processing unit captures an image of a high dynamic range (HDR) scene, the program comprising sets of instructions for:
capturing a plurality of images of the HDR scene at different exposure levels, wherein the different exposure levels are selected based at least in part upon detected lighting conditions within the HDR scene, including:
capturing and storing, prior to receiving a command to capture the HDR scene, at least one image at a first exposure level;
detecting the lighting conditions within the HDR scene based on an analysis of at least one of the at least one image captured and stored; and
capturing, upon receiving a command to capture the HDR scene, at least a first image at a second exposure level selected based at least in part upon the detected lighting conditions within the HDR scene; and

compositing the plurality of images to produce a composite image of the HDR scene.

2. The machine readable medium of claim 1 , wherein the sets of instructions for capturing a plurality of images of the HDR scene at different exposure levels comprises sets of instructions for:
capturing and storing, upon the device entering an HDR mode, a first plurality of images at the first exposure level; and
capturing, upon receiving the command to capture the HDR scene, at least one image at one or more different exposure levels, wherein the one or more different exposure levels are selected based at least in part upon the detected lighting conditions within the HDR scene.

3. The machine readable medium of claim 2 , wherein the program further comprises sets of instructions for:
computing the first exposure level based on the detected lighting conditions within the HDR scene; and
computing the one or more different exposure levels based on the first exposure level.

4. The machine readable medium of claim 2 , wherein the set of instructions for capturing and storing, upon the device entering the HDR mode, the first plurality of images at the first exposure level comprises a set of instructions for analyzing at least one of the first plurality of images to detect the lighting conditions within the HDR scene.

5. The machine readable medium of claim 2 , wherein:
capturing at least one image at one or more different exposure levels comprises:
capturing at least the first image at the second exposure level when the device is determined to be operating in a first set of lighting conditions, where the determination is based at least in part upon analyzing at least one image of the captured first plurality of images; and
capturing at least a second image at the same first exposure level when the device is determined to be operating in low light conditions, where the determination is based at least in part upon analyzing at least one image of the captured first plurality of images; and

compositing the plurality of images to produce a composite image of the HDR scene comprises:
compositing at least the first image and a third image from the captured first plurality of images, when the device is determined to be operating in the first set of lighting conditions, in order to produce a first composite HDR image; and
compositing at least the second image and the third image when the device is determined to be operating in low light conditions in order to produce a second composite HDR image with reduced noise.

6. The machine readable medium of claim 1 , wherein the sets of instructions for compositing the plurality of images to produce a composite image of the HDR scene comprises sets of instructions for:
compositing at least one particular image selected from a plurality of images captured at a particular exposure level of the different exposure levels.

7. The machine readable medium of claim 6 , wherein the set of instructions for selecting the particular image from the plurality of images comprises a set of instructions for selecting a sharpest image of the plurality of images.

8. A method of operating a device to capture an image of a high dynamic range (HDR) scene, the method comprising:
capturing a plurality of images of the HDR scene at a plurality of selected exposure levels, wherein the exposure levels are selected based at least in part upon detected lighting conditions within the HDR scene, including:
capturing and storing, prior to receiving a command to capture the HDR scene, at least one image at a first exposure level;
detecting the lighting conditions within the HDR scene based on an analysis of at least one of the at least one image captured and stored; and
capturing, upon receiving a command to capture the HDR scene, at least a first image at a second exposure level selected based at least in part upon the detected lighting conditions within the HDR scene; and

compositing the plurality of images to produce a composite image of the HDR scene.

9. The method of claim 8 , wherein capturing a plurality of images of the HDR scene at different exposure levels comprises:
capturing and storing, upon the device entering an HDR mode, a first plurality of images at the first exposure level; and
capturing, upon receiving a command to capture the HDR scene, at least one image at one or more different exposure levels, wherein the one or more different exposure levels are selected based at least in part upon the detected lighting conditions within the HDR scene.

10. The method of claim 9 , comprising:
computing the first exposure level based on the detected lighting conditions within the HDR scene; and
computing the one or more different exposure levels based on the first exposure level.

11. The method of claim 9 , wherein capturing and storing, upon the device entering an HDR mode, the first plurality of images at the first exposure level comprises analyzing at least one of the first plurality of images to detect the lighting conditions within the HDR scene.

12. The method of claim 9 , wherein:
capturing at least one image at one or more different exposure levels comprises:
capturing at least the first image at the second exposure level when the device is determined to be operating in a first set of lighting conditions, where the determination is based at least in part upon analyzing at least one image of the captured first plurality of images; and
capturing at least a second image at the same first exposure level when the device is determined to be operating in low light conditions, where the determination is based at least in part upon analyzing at least one image of the captured first plurality of images; and

compositing the plurality of images to produce a composite image of the HDR scene comprises:
compositing at least the first image and a third image from the captured first plurality of images, when the device is determined to be operating in the first set of lighting conditions, in order to produce a first composite HDR image; and
compositing at least the second image and the third image when the device is determined to be operating in low light conditions in order to produce a second composite HDR image with reduced noise.

13. The method of claim 8 , wherein the sets of instructions for compositing the plurality of images to produce a composite image of the HDR scene comprises sets of instructions for:
compositing at least one particular image selected from a particular plurality of images captured at a particular exposure level of the different exposure levels.

14. The method of claim 13 , wherein selecting the particular image from the particu

Assignees

• Apple Inc

Inventors

• Cote Guy
• Johnson Garrett M
• Orr Iv James Edmund

Classifications

• H04N23/741 Primary

  by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors · CPC title

• H04N23/6812

  based on additional sensors, e.g. acceleration sensors · CPC title

• H04N23/667

  Camera operation mode switching, e.g. between still and video, sport and normal or high- and low-resolution modes · CPC title

• H04N23/743

  Bracketing, i.e. taking a series of images with varying exposure conditions · CPC title

• H04N23/6811

  based on the image signal · CPC title