Temporally Aligned Exposure Bracketing for High Dynamic Range Imaging

Abstract

The invention provides an optical imaging system for temporally aligning bracketed exposures of a single image, the system comprising a light aperture, a prism and a image capturing device, where the prism is capable of splitting an incoming image from the light aperture into at least two temporally aligned images, and where the image capturing device captures the temporally aligned images at different levels of exposure.

Description

REFERENCE TO RELATED APPLICATION[0001]This application claims the benefit of U.S. Provisional Patent Application No. 61 / 157,494, filed Mar. 4, 2009, the complete disclosure of which is incorporated herein, in the entirety.COPYRIGHT NOTICE[0002]A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the United States Patent and Trademark Office patent files and records, but otherwise reserves all other copyright rights.BACKGROUND OF THE INVENTION[0003]1. Field of the Invention[0004]This invention relates generally to imaging systems, and more particularly, to imaging systems that provide varying exposures for production of high dynamic range images.[0005]2. Description of Related Art[0006]High dynamic range imaging (HDRI) is a term applied in image processing, computer graphics and photog...

AI Technical Summary

Benefits of technology

[0039]In a still different embodiment, the prism is capable of splitting the image into four or more levels of e...

Problems solved by technology

HDRI is most commonly employed in situations where the range between light and dark areas is great, and subsequently a normal exposure, or even a digitally enhanced exposure, are not adequate to resolve all of the image area.

The real challenge with HDRI is not the file formats or computer algorithms to tone map them to 8-bit displays.

The hardest part of capturing HDR images is the physical devices used to capture the imagery.

They are not point and shoot cameras and are not capable of motion photography.

Both of these techniques have substantial disadvantages.

The second technique can be done with conventional hardware, but it is time consuming and takes substantial expertise to pull off.

In addition, because the images are not temporally aligned, meaning they were taken one after another at different moments in time, there can be changes in the scene that produce artifacts when the HDRI software attempts to eliminate or synthesize the objects in motion across the frame.

As such this technique is totally useless for motion photography and can only be used with substantial success in still photography applications.

For this reason, exposure bracketed HDRI is typically restricted to still subjects, and any animals, cars, pedestrians, moving leaves or litter, clouds, etc., in fact anything that is shifting within the frame will preclude HDRI, or at the very least lead to unhappy results.

Further, producing HDRI from multiple images can be a time consuming and frustrating task.

HDRI requires multiple, huge files, multiple steps, and typically specialized and complicated software.

The first technique is very expensive and requires exotic hardware or sophisticated electronic and software systems.

While imaging chips are moving ever forward in sensitivity and dynamic range, they still do not produce the dramatic results that the first technique of changing exposures does.

In addition, these special cameras are not capable of shooting higher frame rates required to shoot motion pictures.

The system employs filters at the end of the chain, and lenses are placed in front of each of the sensors, creating additional sources of optical distortion.

The system is complicated, and employs light reducing filters to create exposures of varying intensity.

Much of the light is lost, reducing clarity and introducing sources of distortion and noise to the images.

Multiple lenses are required to implement this method, which is expensive and creates parallax and optic imagery distortions with each lens addition.

None of the prior approaches have been able to provide a simple means for capturing multiple images that overcome the difficulties of temporal misalignment, and that are simple and quickly resolved into a high definition range image.

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