Signal Processing Device Blending Ratio for HDR Image Quality
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Solution Overview
Problem
Conventional high dynamic range (HDR) rendering techniques fail to simultaneously suppress false color occurrence and prevent pixel value saturation, leading to deteriorated image quality.
Innovation Solution
A signal processing device and method that calculate a blending ratio for blending small-pixel RAW and large-pixel RAW signals, while determining saturation of the large-pixel RAW signal and adjusting the blending ratio accordingly to prevent saturation and false colors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional HDR rendering combines large-pixel and small-pixel RAW signals, then dynamic range is expanded, but false color occurrence and pixel saturation cannot be simultaneously suppressed
Solution Approach 1:
The patent dynamically adjusts the blending ratio parameter based on saturation determination values and reference signal levels. By changing the blending ratio from 0 to 1 depending on signal conditions, the system optimizes the combination of large-pixel and small-pixel RAW signals to expand dynamic range while preventing false colors and saturation artifacts
Solution Approach 2:
The patent implements a feedback mechanism where the saturation determination unit continuously monitors the large-pixel RAW signal and provides saturation determination values back to the blending ratio calculation. This closed-loop control allows the system to adaptively adjust blending ratios to maintain image quality across varying light conditions
2Reliability
If blending ratio is increased to prevent pixel saturation, then dynamic range is protected, but false color occurrence increases
Solution Approach 1:
The patent applies different blending ratios to different pixel regions based on local signal characteristics. The calculation unit determines saturation determination values and reference signals for each pixel independently, allowing localized optimization where high blending ratios are applied only where needed to prevent saturation, while maintaining lower ratios in other regions to avoid false colors
3Object-affected harmful factors
If blending ratio is decreased to suppress false colors, then color accuracy is improved, but pixel saturation cannot be prevented
Solution Approach 1:
The patent makes the blending ratio dynamic rather than static. The system continuously adjusts the blending ratio based on real-time saturation determination values and reference signal levels, transitioning between different blending states (0, 0.5, 1) to adapt to changing light conditions and prevent both false colors and saturation
Data Source
AI summary
The present disclosure relates to a signal processing device, a signal processing method, and a program that enable further improvement in image quality. A calculation unit compares a reference signal based on a large-pixel RAW signal of a pixel of interest with a threshold, and calculates a blending ratio for use in blending processing in which a pixel value of a small-pixel RAW signal of the pixel of interest with a pixel value of the large-pixel RAW signal of the pixel of interest. A saturation determination unit compares the pixel value of the large-pixel RAW signal of the pixel of interest with a saturation determination threshold, and outputs a saturation determination value indicating whether or not the large-pixel RAW signal of the pixel of interest is saturated. A selection unit selects, according to the saturation determination value, whether to output the blending ratio as it is or by replacing the blending ratio with 1. The present technology can be applied to, for example, a sensor module that outputs an image with a wide dynamic range.