HDR Image Compositing With Exposure-Based Noise Correction
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Solution Overview
Problem
Existing high dynamic range (HDR) compositing techniques using Dual Gain Output (DGO) devices fail to effectively reduce noise when compositing images with significant exposure differences, leading to degraded image quality.
Innovation Solution
An image processing apparatus and method that adjusts exposure and applies noise reduction techniques to images captured with different gains, using exposure difference-based correction amounts to generate a composite image with reduced noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If images with different exposure amounts are composited to achieve high dynamic range, then the dynamic range is expanded, but noise increases in the composite image
Solution Approach 1:
The patent applies noise correction processing to image data before compositing. By calculating the appropriate correction amount based on exposure differences and applying it in advance to high-gain image data, the noise is reduced before the images are combined, preventing noise from appearing in the final composite image while maintaining the expanded dynamic range benefit
Solution Approach 2:
The patent changes the gain parameter of image data through correction processing. By adjusting the correction amount based on exposure differences between images, the system modifies the amplitude characteristics of signal components, effectively reducing noise in high-gain images before compositing while preserving the dynamic range expansion achieved through multi-exposure capture
2Measurement precision
If high gain image data is used to capture dark portions, then sensitivity is improved, but noise increases due to amplification
Solution Approach 1:
The patent applies noise correction processing to high-gain image data before compositing. By calculating the appropriate correction amount based on exposure differences and applying it in advance, the noise introduced by amplification is reduced before the images are combined, allowing the system to benefit from high sensitivity in dark portions without the detrimental noise effects
Solution Approach 2:
The patent converts the harmful noise effect of high-gain amplification into a manageable parameter through correction processing. By calculating correction amounts based on exposure differences and applying them to high-gain image data, the system transforms the noise problem into a controlled adjustment process, allowing high sensitivity to be utilized while minimizing noise impact in the final composite image
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
The solution effectively reduces noise in composite images with exposure differences, resulting in improved image quality by aligning brightness and applying noise correction where necessary.
Implementation Method 1
a signal obtained by photoelectric conversion
Data Source
AI summary
The present invention provides an image processing apparatus operable to process first and second image data from an image capturing unit capable of amplifying, with different gains, a signal obtained by photoelectric conversion and outputting the first and second image data, wherein the apparatus comprises an acquiring unit configured to acquire an exposure difference between the first and second image data; a correcting unit configured to determine a correction amount for reducing a noise difference between the first and second image data based on the exposure difference acquired by the acquiring unit and correct at least one of the first and second image data based on the determined correction amount; and a generating unit configured to generate a composite image by compositing the first and second image data, at least one of which has been corrected by the correcting unit.