Imaging Device Pixel Group Exposure Control for HDR

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Solution Overview

Problem

Existing imaging devices face challenges in generating high-dynamic-range (HDR) images due to blurring caused by hand shaking or object movement when using varying exposure periods, and existing solutions for generating HDR images from single images with different exposure levels do not effectively address noise and luminance distribution issues.

Innovation Solution

An imaging device that acquires images with pixels having different exposure periods, generates corrected images by interpolating pixel values and executing exposure correction, and combines these images using an HDR combining unit that adjusts the combining ratio based on pixel value differences to extend the dynamic range and accurately reflect object luminance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If exposure period is increased to capture more light for HDR imaging, then dynamic range is improved, but blurring due to hand shaking or object movement occurs

Engineering Contradiction:

Improvedynamic rangeVSAvoidimage sharpness

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The imaging element is divided into multiple pixel groups, each with different exposure periods. This segmentation allows simultaneous capture of both short-exposure (sharp) and long-exposure (high dynamic range) data without requiring multiple separate shots, thereby resolving the contradiction between dynamic range and image sharpness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different pixel groups are exposed for different periods within the same imaging cycle. By periodically varying the exposure duration across pixel groups rather than using a single exposure time for all pixels, the system achieves both short-exposure sharpness and long-exposure dynamic range in a single capture.

Inventive Principle:

Principle #19Periodic action

2Illumination intensity

If multiple images with different exposure levels are combined to generate HDR image, then dynamic range is improved, but processing complexity increases

Engineering Contradiction:

Improvedynamic rangeVSAvoidprocessing complexity

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The pixel array is segmented into multiple groups with different exposure periods, allowing HDR data to be captured in a single imaging operation rather than requiring multiple separate exposures. This reduces processing complexity by eliminating the need to align and combine multiple sequentially captured images.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Multiple exposure levels are merged into a single image capture by having different pixel groups simultaneously expose for different durations. The resulting single image contains embedded HDR information that can be processed more simply than traditional multi-image HDR workflows.

Inventive Principle:

Principle #5Merging (Combining)

3Illumination intensity

If pixels with different exposure periods are used in the same imaging element, then HDR capability is improved, but noise and luminance distribution issues arise

Engineering Contradiction:

ImproveHDR capabilityVSAvoidnoise control

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

Different regions (pixel groups) of the imaging element are assigned different exposure periods appropriate to their local luminance requirements. This local quality approach allows optimal exposure for each region while maintaining overall noise control through targeted exposure strategies in different spatial zones.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system uses feedback mechanisms to determine optimal exposure periods for different pixel groups based on scene luminance characteristics. By analyzing luminance distribution and adjusting exposure periods accordingly, the system maintains noise control while achieving HDR capability.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS10104305B2Imaging device which generates a high-dynamic-range image using an imaging element in which pixel groups are controlled to have different exposure periods

Publication Date: 2018.10.16 OLYMPUS CORPORATION(JP)

AI summary

An imaging device includes an image acquisition unit that acquires an original image in which pixels with different exposure periods coexist; a corrected-image generating unit that generates corrected images individually for a plurality of pixel groups formed by classifying the pixels according to the exposure periods, the corrected images being generated by interpolating pixel values and executing exposure correction; and an HDR combining unit that combines the corrected images, wherein, in a case where the difference between the pixel value of a pixel belonging to one of the pixel groups, acquired by exposure, and the pixel value of a pixel belonging to another one of the pixel groups, generated by interpolation at the same position as the aforementioned pixel, is greater than a predetermined threshold, the HDR combining unit increases the combining ratio of the pixel in the corrected image belonging to the one of the pixel group.