Adaptive White Balance System for Endoscopic Camera Color Accuracy
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Solution Overview
Problem
Endoscopic camera systems face challenges in maintaining color accuracy when drive current variations occur, leading to inaccurate image visualization due to shifts in illumination source color, especially with white LEDs and temperature-dependent changes in excitation light sources.
Innovation Solution
An adaptive white balance system that determines relationships between light source drive current levels and color gain values, generating a light source control table to adjust red, blue, and green gains, ensuring accurate color rendition across different drive current levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If drive current to light source is reduced to minimum possible, then power consumption and heat generation are reduced, but color accuracy of emitted light deteriorates due to color shift
Solution Approach 1:
The system dynamically adjusts color gain parameters (red, green, blue) based on the drive current level to compensate for color shifts. By changing these parameters according to the operating conditions, the system maintains color accuracy across different power consumption levels.
Solution Approach 2:
The system incorporates a feedback mechanism where the camera control unit continuously monitors the drive current level and automatically adjusts the color gains accordingly. This closed-loop control ensures that color accuracy is maintained without requiring manual intervention or sacrificing power efficiency.
2Illumination intensity
If drive current to light source is increased, then illumination intensity is improved, but color accuracy deteriorates due to blue shift in white LED emission
Solution Approach 1:
The system adjusts color gain parameters dynamically based on drive current level. When drive current increases causing blue shift, the system compensates by adjusting the red and green gains relative to blue, thereby maintaining color accuracy across the full range of illumination intensities.
Solution Approach 2:
The system preemptively applies color correction gains before the color shift becomes visually apparent. By anticipating the color change based on drive current level and applying compensatory gains in advance, the system prevents color accuracy deterioration rather than attempting to correct it after the fact.
3Reliability
If temperature based variation in excitation light occurs, then light emission efficiency from phosphors changes, but color accuracy deteriorates due to changing chromaticity
Solution Approach 1:
The system adjusts color gain parameters in response to temperature-induced variations in phosphor emission efficiency. By monitoring changes in light output characteristics and dynamically adjusting the color gains, the system compensates for chromaticity shifts while maintaining reliable light emission across varying temperatures.
4Adaptability or versatility
If variation in drive current occurs among different light sources, then system adaptability is improved, but color accuracy deteriorates due to color shift among light sources
Solution Approach 1:
The system implements a universal color correction mechanism that works across multiple light sources with different drive current characteristics. The camera control unit applies the same color gain adjustment logic regardless of which light source is active, enabling the system to handle drive current variations among different light sources while maintaining consistent color accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively maintains color accuracy by compensating for drive current variations, reducing heat and power consumption, and enhancing portability of endoscopic devices while providing reliable image visualization.
Implementation Method 1
a white light emitting diode is used as light source
Implementation Method 2
an excitation light source, such as a blue laser emitting diode, is used to excite light from phosphors
Data Source
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AI summary
A method for color correction in a camera system having a camera, a light source and a controller, comprising: setting a first light source drive current level; performing a first white balance operation and obtaining at least one of red gain, blue gain and green gain values corresponding to the first light source drive current level; setting a second light source drive current level different than the first light source drive current level; performing a second white balance operation and obtaining at least one of red gain, blue gain and green gain values corresponding to the second light source drive current level; and determining a relationship between light source current levels and at least one of red gain, blue gain and green gain values using the obtained at least one of red gain, blue gain and green gain values corresponding to the first and second light source drive current levels.