Dual Camera HDR Ghosting Prevention
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Solution Overview
Problem
High dynamic range imaging (HDR) in mobile terminals faces challenges such as image shifting due to camera shake and ghosting caused by moving objects, which existing technologies fail to adequately address.
Innovation Solution
A mobile terminal system with dual cameras that switches to HDR mode when saturation areas are detected, analyzes image disparities, and adjusts exposure settings to prevent ghosting by shifting and aligning objects between images, ensuring accurate HDR image capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single camera captures two images with different exposure states for HDR, then HDR image quality is improved, but image shifting occurs due to camera shake between captures
Solution Approach 1:
The patent divides the imaging system into two separate cameras (first camera and second camera) that simultaneously capture images with different exposure states. This segmentation allows each camera to capture its image without the time interval constraint, eliminating camera shake-induced shifting while maintaining HDR quality through computational merging of the two independent captures.
Solution Approach 2:
The system performs preliminary actions by capturing images from both cameras simultaneously before any processing occurs. The controller identifies saturation areas in advance and determines which camera's image to use as reference, preparing the data structure for subsequent ghost object removal and HDR synthesis without time-based delays.
2Measurement precision
If a single camera captures images with different exposure states, then dynamic range is improved, but ghost images appear due to moving objects between captures
Solution Approach 1:
By segmenting the capture process into two simultaneous camera captures rather than sequential single-camera captures, the system eliminates the time interval that causes moving objects to generate ghost images. Both cameras capture their respective exposure states at the same moment, ensuring consistent object positions.
Solution Approach 2:
The controller continuously monitors the captured images to identify saturation areas and ghost objects. When ghost objects are detected in the merged image, the controller uses feedback to remove them by reference to the other camera's image data, maintaining HDR quality while eliminating harmful ghost artifacts.
3Reliability
If dual cameras are used for HDR imaging, then image shifting and ghosting are reduced, but device complexity increases
Solution Approach 1:
The patent implements multi-functionality by enabling the two cameras to serve multiple purposes: they simultaneously capture images with different exposure states for HDR synthesis, provide reference data for ghost object removal, and enable disparity-based depth information extraction. This universal use of dual cameras for multiple functions justifies the added complexity by delivering superior HDR reliability.
Solution Approach 2:
The system manages complexity through parameter changes in the controller's processing logic rather than hardware complexity. By dynamically adjusting exposure settings, identifying saturation areas, and selectively using data from either camera based on image content analysis, the system achieves reliable HDR imaging while keeping the overall system architecture manageable.
Data Source
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AI summary
A mobile terminal and a method of controlling the same are provided. The mobile terminal detects an object in which a ghost may appear through a preview image of an image acquired using a dual camera. The mobile terminal may display an indicator for identifying the detected object. Accordingly, a higher quality high dynamic range (HDR) image can be more efficiently acquired.