Gamma Correction for Low Illuminance Image Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Images captured under low illuminance conditions in monitoring cameras require increased gain, leading to high noise and larger data sizes, which complicates compression and storage, as existing techniques fail to prevent data size increase while maintaining image quality.
Innovation Solution
An image processing device with an illuminance detection unit and gamma correction unit that adjusts the minimum and maximum output luminance values of the gamma characteristic based on detected illuminance, reducing noise and entropy to prevent data size growth while maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If gain is increased to capture images under low illuminance condition, then image brightness is improved, but image quality deteriorates with large amount of noise
Solution Approach 1:
The patent changes the gamma characteristic parameters (minimum output luminance value and maximum output luminance value) based on illuminance conditions. By adjusting these parameters dynamically, the system optimizes the luminance range for low illuminance images, reducing noise while maintaining brightness improvement.
2Illumination intensity
If gain is increased to capture images under low illuminance condition, then image brightness is improved, but data size increases
Solution Approach 1:
The patent dynamically adjusts gamma characteristic parameters according to illuminance levels. This parameter change approach reduces entropy in low illuminance images, which directly decreases the data size required for storage while maintaining adequate brightness.
3Illumination intensity
If luminance range is expanded in output image, then luminance range is improved, but data size increases
Solution Approach 1:
The patent changes the minimum and maximum output luminance values of the gamma characteristic based on detected illuminance. This targeted parameter adjustment expands the luminance range only when necessary (in low illuminance conditions) while controlling the associated increase in data size through entropy reduction.
4Reliability
If noise is reduced in low illuminance image, then image quality is improved, but compression performance deteriorates
Solution Approach 1:
The patent adjusts gamma characteristic parameters to reduce noise in low illuminance images. By optimizing the luminance range through parameter changes, the patent achieves noise reduction while maintaining compression performance, as the gamma correction optimizes the distribution of luminance values for better compression efficiency.
Data Source
AI summary
An illuminance calculation unit detects an illuminance of an image when the image is captured. Based on the detected illuminance, a gamma correction amount calculation unit corrects at least one of a minimum output luminance value and a maximum output luminance value in a gamma characteristic for correcting a gradation characteristic of a luminance of the image. A gamma setting unit corrects the gradation characteristic of the luminance of the image with the gamma characteristic corrected based on the illuminance.