On-Camera HDR Panorama Generation via Dynamic Exposure Sequencing
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Solution Overview
Problem
Conventional digital cameras capture Low Dynamic Range (LDR) images, which fail to represent the full gray scale range of a scene, especially in shadow and highlight regions, leading to loss of detail in panoramic images due to fixed exposure settings and limited dynamic range.
Innovation Solution
A digital camera system that captures a video stream with frames alternating between different exposure settings, aligns and mixes these frames to generate High Dynamic Range (HDR) images, and stitches them into panoramic images in real-time, using a processor and hardware to determine suitable frames for saving and processing, including motion estimation and image registration to handle scene motion and exposure variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fixed exposure settings are used for panoramic photography, then lighting consistency across stitched images is maintained, but shadow and highlight details are lost due to limited dynamic range
Solution Approach 1:
The patent applies dynamics by transitioning from fixed exposure settings to dynamic exposure adjustment. The camera automatically modifies exposure parameters for subsequent frames based on scene analysis, enabling adaptation to varying lighting conditions across the panoramic field of view while maintaining consistency through algorithmic control
Solution Approach 2:
The patent implements parameter changes by systematically adjusting exposure settings (shutter speed, aperture, ISO) for different frames in the sequence. This allows capture of both shadow and highlight details by varying exposure parameters across frames, which are then merged to create the final panorama with preserved detail in all regions
2Loss of information
If multiple LDR images are captured at different exposure levels, then full gray scale range can be represented, but processing complexity increases
Solution Approach 1:
The patent applies self-service by implementing automated HDR processing within the camera itself. The camera captures multiple exposure frames and automatically performs alignment, merging, and tone mapping to generate the final HDR panorama, eliminating the need for external computer processing and making the complex operation transparent to the user
Solution Approach 2:
The patent replaces manual mechanical panoramic photography (tripod mounting, physical film stitching) with electronic/digital processes. Digital frames are captured sequentially and merged through computational algorithms, substituting physical manipulation with electronic processing that is both faster and more flexible
3Loss of information
If real-time HDR panorama generation is implemented, then image quality with full dynamic range is achieved, but processing time and computational load increase
Solution Approach 1:
The patent applies preliminary action by pre-processing frames during capture. Motion estimation and alignment are performed on incoming frames before they are fully integrated into the panorama, preparing the data structure in advance to accelerate the final merging process and enable real-time output
Solution Approach 2:
The patent implements segmentation by dividing the panorama generation process into independent stages: motion estimation, frame alignment, exposure merging, and tone mapping. This modular approach allows parallel processing of different frames and operations, reducing overall processing time through concurrent computation
Data Source
AI summary
A digital camera captures a sequence of frames such that captured frames of the sequence alternate between sets of frames, in which each frame in the set has a different exposure setting. Each set of frames includes a nominal exposure frame. For each set of frames of the sequence that is captured after the reference set of frames has been captured, a determination is made as to whether or not the captured set of frames should be saved, based, at least in part, on overlap. For each of the saved sets of frames, the frames in the set are aligned with each other, and then image mixing of the frames in the set of frames is performed to generate a high dynamic range image. A panoramic, high dynamic range image is generated from each of the high dynamic range images.