Depth-Based Exposure Control for Wide Dynamic Range Imaging

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Solution Overview

Problem

Existing methods for obtaining wide dynamic range images often result in deteriorated image quality due to fixed exposure times for underexposed and overexposed images, which fail to accurately capture scene details.

Innovation Solution

An exposure control method based on depth information, where a cached master image is processed to determine a foreground part, and reference exposure is used to set exposures for dark and bright images, ensuring appropriate dynamic range and image clarity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If fixed exposure times are used for underexposed and overexposed images, then the wide dynamic range image can be obtained, but the image quality deteriorates

Engineering Contradiction:
Improvedynamic rangeVSAvoidimage quality
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the exposure time variable rather than fixed. The exposure times for underexposed, reference, and overexposed images are dynamically adjusted based on the luminance of the foreground part. This allows the system to adapt exposure parameters to the specific scene requirements while maintaining wide dynamic range capability and image quality.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies local quality by focusing exposure control on the foreground part of the scene. The exposure times are determined based on the luminance characteristics of the foreground part specifically, allowing different parts of the scene to be captured with appropriate exposure levels. This ensures that the main subject (foreground) is properly exposed while still capturing the full dynamic range of the scene.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If exposure time is adjusted to capture scene details, then image quality improves, but the exposure control complexity increases

Engineering Contradiction:
Improveimage qualityVSAvoidexposure control
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the scene into foreground part and background parts based on depth information. The exposure control is specifically applied to the foreground part, which is segmented from the rest of the scene. This segmentation simplifies the exposure control process by focusing computational efforts on the most important part of the scene while maintaining overall image quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent uses depth information as an intermediary to guide exposure control. The depth map is used to identify the foreground part, which then serves as the basis for determining exposure times. This intermediary approach simplifies the exposure control complexity by providing a clear criterion (depth-based foreground identification) for making exposure decisions.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3579546B1Exposure control method, exposure control device and electronic device
Publication Date: 2021.04.07 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • EP3579546B1 patent drawingFigure 1
  • EP3579546B1 patent drawingFigure 2~3
  • EP3579546B1 patent drawingFigure 4~6

AI summary

Disclosed in the present invention is a depth-based exposure control method. The exposure control method comprises: (S11) processing scene data so as to obtain a foreground part of a cached main image; (S12) determining reference exposure according to brightness information of the foreground part; (S13) determining dark frame exposure and bright frame exposure according to the reference exposure; and (S14) controlling an imaging device (20) to expose according to the reference exposure, the dark frame exposure and the bright frame exposure. Also disclosed in the present invention are an exposure control device (10) and an electronic device (100).