Signal Processing Device Dynamic Gain Adjustment Color Accuracy
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Solution Overview
Problem
Conventional imaging systems face issues where a difference in dynamic range between color components leads to clipping of signals, especially when imaging subjects with high light amounts, resulting in ineffective use of information from other color components.
Innovation Solution
A signal processing device with a color space conversion part, gain setting part, gain adjustment part, and color space inverse conversion part is used to set gains for color difference signals based on a luminance signal, ensuring that the influence of dynamic range differences is minimized, even in high-light scenarios, by adjusting gains to prevent clipping and maintain color accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a signal of another color component is clipped in accordance with a signal of a color component having the lowest dynamic range, then the color accuracy is improved, but the information from other color components is lost
Solution Approach 1:
The patent applies dynamics by making the clipping reference dynamic rather than fixed. Instead of always using the color component with the lowest dynamic range as the clipping reference, the system dynamically determines which color component's signal level to use as the reference based on current imaging conditions. This allows the system to adaptively select the most appropriate reference signal to minimize color accuracy issues while preserving information from other color components.
Solution Approach 2:
The patent changes the parameter used for clipping determination from a fixed criterion (lowest dynamic range) to a variable parameter (signal level of predetermined color component). By changing the reference criterion based on actual signal levels rather than inherent sensor properties, the system can maintain color accuracy when needed while avoiding unnecessary clipping that would lose information.
2Reliability
If gain adjustment is performed on color difference signals, then the influence of dynamic range differences is reduced, but the device complexity increases
Solution Approach 1:
The patent applies preliminary action by performing gain adjustment on color difference signals before they are used in image processing. The gain setting part determines appropriate gain values in advance based on the luminance signal levels, and the gain adjustment part applies these gains before potential clipping operations. This preliminary adjustment ensures that color difference signals are properly scaled to match the dynamic range characteristics, reducing the need for aggressive clipping later while maintaining simple overall system architecture.
Data Source
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AI summary
An input signal for each of three primary color components is converted into a luminance signal and a color signal by a color space conversion part 11. A gain setting part 12 sets a gain for the color signal obtained by color space conversion according to a signal level of a setting reference signal generated on the basis of the input signal, for example, the luminance signal. A gain adjustment part 14 performs gain adjustment of the color signal with the gain set by the gain setting part 12, and in a case where the luminance signal is larger than a threshold set according to a dynamic range for each color component, the gain adjustment part 14 makes the subject achromatic so that, even in a case where a light amount of the subject is high, influence of a difference in the dynamic range is little.