HDR Image Composition Using Geometric Correction for Position Shift
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Solution Overview
Problem
In high-dynamic-range (HDR) image composition, highlight-detail loss and shadow-detail loss occur in bright and low-brightness images respectively, leading to inaccurate position shift correction between images, which hampers the application of geometric correction and results in lower image quality.
Innovation Solution
A capturing control apparatus that uses two cameras with different exposure settings to capture images synchronously, derives correction parameters for geometric correction based on a frame image captured under specific conditions, and performs geometric correction before HDR composition to improve the accuracy of corresponding point search and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If HDR composition is performed using images captured under different exposures, then the dynamic range of the combined image is improved, but position shift correction accuracy deteriorates due to highlight-detail loss and shadow-detail loss
Solution Approach 1:
The patent applies preliminary action by performing geometric correction before HDR composition. Specifically, it derives correction parameters from images captured under conditions optimized for position accuracy (standard dynamic range mode) and applies this correction to align images before combining them in HDR processing. This preliminary geometric correction ensures accurate position alignment is established before the HDR composition step, resolving the contradiction between achieving high dynamic range and maintaining position shift correction accuracy.
2Stability of the object's composition
If geometric correction is applied to correct position shifts between images, then image alignment is improved, but image quality deteriorates due to degradation from inaccurate correction parameters
Solution Approach 1:
The patent applies local quality by using different capturing conditions for different purposes: standard dynamic range capturing conditions are used specifically for deriving geometric correction parameters to ensure high position accuracy, while HDR capturing conditions are used for the actual composition to achieve high dynamic range. This localized optimization of capturing conditions for specific functions ensures that geometric correction is performed with high precision without compromising the quality of the final HDR image.
3Measurement precision
If images are captured under standard dynamic range conditions for accurate position correction, then position shift correction accuracy is improved, but highlight-detail loss and shadow-detail loss occur reducing overall image quality
Solution Approach 1:
The patent applies segmentation by dividing the image processing workflow into distinct functional stages: (1) capturing images under standard dynamic range conditions specifically for geometric correction parameter derivation, and (2) capturing images under HDR conditions for the actual composition. This segmentation allows each stage to use optimized conditions for its specific purpose, ensuring both accurate position correction and high image quality in the final HDR composite without the trade-off present in a single-stage approach.
Data Source
AI summary
A capturing control apparatus, method of controlling the capturing control apparatus, and a recording medium storing a program for controlling capturing control apparatus are disclosed. The capturing control apparatus generates a high-dynamic-range moving image by combining a first moving image captured by a first capturing unit and a second moving image captured by a second capturing unit using a first capturing condition and a second capturing condition. A correction parameter is derived for correcting a position shift between a frame image included in a first moving image and a frame image included in a second moving image based on the frame image captured under the second capturing condition. The capturing control apparatus performs geometric correction processing for at least one of the first moving image and the second moving image using the correction parameter, and combines the corrected first moving image and the corrected second moving image.