Dual Camera Terminal Exposure Control for HDR Imaging

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Solution Overview

Problem

Existing HDR synthesis methods fail to accurately determine the required exposure for images based on the current scene, leading to potential overexposure or underexposure issues.

Innovation Solution

A terminal equipped with two cameras and a processor analyzes an image from one camera to determine the optimal exposure for the other camera, using various metering techniques such as center-weighted average, matrix, or bright/dark zone weighted metering to ensure accurate exposure adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If fixed exposure bracketing is used to acquire images with different exposure, then the acquisition process is simple and fast, but the exposure cannot be accurately determined according to the current scene

Engineering Contradiction:
Improveexposure determination accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary analysis on a first image to determine the appropriate metering manner before acquiring the second image with adjusted exposure. This preliminary action enables accurate exposure determination for the current scene while maintaining a relatively simple acquisition process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The image acquisition process is divided into multiple stages: acquiring a first image for analysis, determining metering manner based on analysis results, and then acquiring a second image with adjusted exposure. This segmentation allows complex exposure determination to be broken down into manageable steps.

Inventive Principle:
Principle #1Segmentation

2Reliability

If multiple images with different exposure are acquired for HDR synthesis, then the dynamic range of the synthesized image is improved, but the time required for image acquisition increases

Engineering Contradiction:
ImproveHDR synthesis qualityVSAvoidimage acquisition time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary analysis on the first image to determine the appropriate metering manner and exposure adjustment before acquiring the second image. This preliminary action ensures that the second image is acquired with optimal exposure settings, improving HDR synthesis quality while minimizing the number of images needed and reducing acquisition time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from analyzing the first image to adjust the exposure settings for acquiring the second image. This feedback mechanism ensures that the exposure is accurately determined according to the current scene, improving the reliability of HDR synthesis while reducing the need for multiple trial acquisitions.

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If fixed exposure values are used for image acquisition, then the operation is simple and fast, but the image details in bright and dark locations cannot be truly recorded

Engineering Contradiction:
Improveimage detail recording accuracyVSAvoidexposure adjustment complexity
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The system performs preliminary analysis on the first image to determine the appropriate metering manner before acquiring the second image with adjusted exposure. This preliminary action enables accurate determination of exposure values tailored to the current scene, ensuring that image details in both bright and dark locations are truly recorded while keeping the operation relatively simple.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the exposure settings for the second image based on the analysis results of the first image. Different metering manners (such as bright zone weighted or dark zone weighted) are selected dynamically according to the scene characteristics, enabling accurate recording of image details while adapting to different shooting conditions.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3062509B1Terminal and image processing method
Publication Date: 2020.06.03 HUAWEI DEVICE CO LTD
  • EP3062509B1 patent drawingFigure 1~2
  • EP3062509B1 patent drawingFigure 3
  • EP3062509B1 patent drawingFigure 4

AI summary

The present invention relates to the field of multimedia technologies and discloses a terminal, an image processing method, and an image acquisition method, so as to resolve a technical problem in the prior art that a required group of desired exposure cannot be determined according to a current scene. The terminal includes: a first camera, a second camera, and a processor, where the processor is connected to both the first camera and the second camera, and the first camera and the second camera are located on a same side of the terminal, where the first camera is configured to acquire an image in a first region; the processor is configured to: analyze the image acquired by the first camera, and determine, according to an analysis result, exposure used when the second camera acquires an image in a second region; the second camera acquires the image in the second region according to the exposure that is determined by the processor and is used when the second camera acquires the image in the second region; and the processor is configured to synthesize the image acquired by the first camera and the image acquired by the second camera into a high dynamic image.