Dynamic Exposure Adjustment for HDR Imaging in Backlight Scenes
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Solution Overview
Problem
Conventional high dynamic range (HDR) techniques in electronic devices, such as digital cameras and smartphones, use fixed exposure times, which are ineffective in extreme scenes like severe backlight environments, failing to produce clear shadow details without overexposure.
Innovation Solution
A dynamic exposure adjusting method that captures preview and additional images to analyze luminance distribution, adjusts long and short exposure times based on the scene, and combines images to produce a processed image with clear shadow details and no overexposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed exposure times are used for HDR, then the device can maintain consistent processing workflow, but the HDR function becomes ineffective in extreme scenes like severe backlight environments
Solution Approach 1:
The patent implements dynamic exposure time adjustment by analyzing luminance distribution in the image and automatically selecting appropriate long and short exposure times. The system transitions from fixed exposure values to adaptive exposure times based on scene characteristics, particularly effective in extreme lighting conditions like severe backlight environments where conventional fixed HDR fails
Solution Approach 2:
The patent changes the exposure time parameter dynamically based on luminance distribution analysis. By calculating the ratio of bright to dark pixel areas and applying predefined adjustment rules, the system selects optimal exposure times from a set of predetermined values, enabling effective HDR processing across diverse shooting scenarios
2Illumination intensity
If long exposure is used to improve shadow details, then darker regions become brighter, but bright regions may become overexposed
Solution Approach 1:
The patent applies different exposure characteristics to different regions of the image by combining multiple images captured at different exposure times. The tone mapping process selectively adjusts brightness levels in different luminance regions, enhancing shadow details while preserving highlight information, thereby achieving local quality optimization across the entire image
3Object-affected harmful factors
If short exposure is used to prevent overexposure in bright regions, then bright areas are protected, but shadow details become unclear
Solution Approach 1:
The patent merges multiple images captured at different exposure times (short, normal, and long exposure) into a single HDR image. By combining these images with different exposure characteristics, the system simultaneously captures both shadow details from long exposure images and highlight information from short exposure images, achieving comprehensive scene representation
Data Source
AI summary
A dynamic exposure adjusting method and an electronic apparatus using the same are provided. The method includes the following steps: capturing a plurality of preview images, a plurality of additional images and a first image, wherein the additional images are not displayed in a display unit of the electronic apparatus;analyzing a luminance distribution condition of the first image; obtaining a long exposure time and a short exposure time according to the luminance distribution condition; retrieving at least one specific image corresponding to the long exposure time and the short exposure time from the additional images; combining the first image with the at least one specific image as a processed image.