Brightness Control Unit Combining Feedback and Feedforward Gain
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Solution Overview
Problem
Conventional image processing systems experience feedback control delay, leading to brightness fluctuations and increased power consumption during rapid brightness changes, which affects image quality and power supply stability.
Innovation Solution
An image processing apparatus that combines feedback and feedforward brightness control, where a first gain is calculated from corrected image data and multiplied by pre-correction image data, and a second gain is calculated to correct for differences caused by feedback control delay, especially during scene changes, ensuring appropriate brightness control and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback control is used to calculate gain from corrected image data, then brightness control accuracy is improved, but feedback control delay occurs causing brightness fluctuations during scene changes
Solution Approach 1:
The patent applies preliminary action by calculating the feedforward gain from the current frame's corrected image data in advance, before the feedback control delay would affect the display. This feedforward gain is then combined with the delayed feedback gain to compensate for the timing mismatch, ensuring accurate brightness control during scene changes without waiting for the feedback loop to complete.
2Productivity
If gain is multiplied by pre-correction image data, then brightness control can be performed before correction processing, but the gain calculated from post-correction image data does not match the pre-correction image data causing control inaccuracy
Solution Approach 1:
The patent introduces an intermediary compensation mechanism by calculating a correction factor that bridges the gap between pre-correction and post-correction image data. This compensation gain acts as a mediator that adjusts the feedforward gain to account for the differences introduced by the correction processing, ensuring that the brightness control remains accurate even though it operates on pre-correction data.
3Reliability
If feedback control delay causes gain to be multiplied by wrong image data, then brightness control becomes inaccurate, but increasing power supply output capacity is needed to handle brightness fluctuations
Solution Approach 1:
The patent employs feedback by continuously monitoring the corrected image data and using it to calculate an updated feedforward gain that compensates for the feedback control delay. This closed-loop approach ensures that brightness control remains accurate without requiring excessive power supply capacity to handle fluctuations, as the system adaptively adjusts the gain based on actual image content.
Data Source
AI summary
A brightness control unit includes: a “feedback brightness control unit” that calculates a first gain from a corrected image data and multiplies the first gain by image data prior to correct; and a “feedforward brightness control unit” which, when a scene change is detected, calculates a second gain on the basis of a difference between the first gain which is calculated from the corrected image data and the first gain which has been multiplied by the pre-correction image data of the corrected image data in order to correct the difference, and multiplies the second gain by the corrected image data.