Image Processing Apparatus Target Color Brightness Control
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Solution Overview
Problem
Current image processing methods struggle to independently control the brightness of a desired color in an image without affecting its saturation and hue, particularly when using high-sensitivity image sensors, leading to issues like increased brightness and saturation in red-based subjects, which can result in decreased contrast and texture.
Innovation Solution
An image processing apparatus that generates a third brightness signal by adjusting the mixing ratio of first and second brightness signals, where the second brightness signal has a decreased weight corresponding to the target color, allowing precise control of the brightness of the target color while maintaining its saturation and hue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensitivity of the R element is increased to improve high sensitivity imaging, then the brightness and saturation of red-based subjects are increased, but contrast and texture deteriorate
Solution Approach 1:
The patent segments the brightness signal into two separate brightness signals: a first brightness signal generated from RGB signals subjected to color correction (which preserves color reproducibility) and a second brightness signal generated from RGB signals not subjected to color correction (which reduces noise). By combining these two signals, the invention achieves both high sensitivity and preserved contrast/texture without the harmful effects of excessive brightness and saturation in red-based subjects.
2Manufacturing precision
If a linear matrix process is used to adjust brightness, saturation, and hue by multiplying RGB signal values by a 3×3 coefficient matrix, then color reproduction is improved, but it is difficult to independently establish all three parameters (brightness, saturation, and hue) because they change in connection with each other
Solution Approach 1:
The patent segments the brightness control function by creating two separate brightness signals with different characteristics. The first brightness signal (Y1) is generated using color-corrected RGB signals with a first coefficient matrix optimized for color reproduction. The second brightness signal (Y2) is generated using non-color-corrected RGB signals with a second coefficient matrix that reduces the weight of the red component, thereby controlling brightness independently from saturation and hue changes.
Solution Approach 2:
The patent changes the parameters of the coefficient matrices used in different stages. The first coefficient matrix (for color correction) has different values than the second coefficient matrix (for brightness control). Specifically, the second matrix reduces the weight of the red component to prevent excessive brightness and saturation in red-based subjects while maintaining accurate color reproduction through the first matrix.
3Manufacturing precision
If color correction is applied to generate a brightness signal, then color reproducibility is improved, but noise is increased
Solution Approach 1:
The patent segments the brightness signal generation into two parallel paths: one path applies color correction to generate a first brightness signal (Y1) that ensures accurate color reproduction, while the other path processes RGB signals without color correction to generate a second brightness signal (Y2) that has reduced noise. The final brightness signal is a combination of these two signals, achieving both accurate color reproduction and reduced noise.
Data Source
AI summary
An image processing apparatus, an imaging apparatus, an image processing method, and a non-transitory computer readable medium for storing an image processing program capable of controlling the brightness of a desired color in a captured image are provided. A brightness and color difference conversion processing unit generates a reference first brightness signal “Y1” and color difference signals “Cb and Cr” from color signals “R1, G1, and B1” of three primary colors after gamma conversion. A second brightness signal generation unit generates a second brightness signal “Y2” in which a value of a brightness signal corresponding to a target color is decreased with respect to the first brightness signal “Y1” from the color signals “R1, G1, and B1”. The brightness of the desired target color can be controlled according to the reference first brightness signal “Y1” and the second brightness signal “Y2”.