Camera Module Pixel Group Exposure Control for Real-Time HDR
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Solution Overview
Problem
Electronic devices with cameras face challenges in capturing and synthesizing multiple images with different exposures in real-time, making it difficult to preview or shoot moving images with high dynamic range (HDR) effectively.
Innovation Solution
The implementation of an image processing method that alternately uses long exposure and short exposure pixels in the camera module's image sensor, allowing for real-time capture and processing of HDR images by adjusting exposure times based on image regions, enabling improved dynamic range and reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple images with different exposures are captured sequentially and synthesized to generate HDR image, then the dynamic range of the image is improved, but the time required for capturing and synthesizing multiple images increases, making it difficult to preview or shoot moving images in real time
Solution Approach 1:
The image sensor is divided into two distinct pixel groups: first pixel groups that capture long exposure images and second pixel groups that capture short exposure images. This segmentation allows simultaneous capture of multiple exposure levels without sequential processing, resolving the time delay issue while maintaining improved dynamic range through HDR synthesis.
Solution Approach 2:
The patent implements periodic switching between long exposure and short exposure pixel groups in a time-division multiplexing manner. During a first period, first pixel groups capture long exposure images while second pixel groups capture short exposure images; during a second period, the roles are reversed. This periodic action enables real-time HDR image generation by alternating capture responsibilities between pixel groups.
2Illumination intensity
If pixels are divided into groups to capture images with different capture times, then HDR image with broad dynamic range can be generated, but the device complexity increases due to need for multiple pixel groups and synchronization control
Solution Approach 1:
Each pixel group serves multiple functions: first pixel groups can capture both long exposure images (when activated as first pixel group) and short exposure images (when activated as second pixel group), and vice versa for second pixel groups. This multi-functionality reduces the need for dedicated hardware for each exposure type, simplifying the overall device structure while maintaining HDR capability.
Solution Approach 2:
The patent implements dynamic control where pixel groups can switch roles between capturing long exposure and short exposure images based on timing periods. This dynamic switching capability allows the system to adapt exposure capture responsibilities in real-time, reducing the need for fixed, complex hardware configurations while achieving broad dynamic range.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the production of HDR images with improved dynamic range and low noise, facilitating real-time preview and moving image shooting functions.
Implementation Method 1
an image sensor including a plurality of pixels, each pixel having differently controllable exposure times
Data Source
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AI summary
Provided is an image processing method for an electronic device having a camera module. The image processing method may include: acquiring a first image with a first exposure time by using a first pixel group; acquiring a second image with a second exposure time shorter than the first exposure time by using a second pixel group; determining whether the difference between the first exposure time and the second exposure time is greater than or equal to a preset threshold; acquiring, if the difference between the first exposure time and the second exposure time is greater than or equal to the preset threshold, a third image with a third exposure time by using the second pixel group; and generating a high dynamic range (HDR) image by combining the first to third images.