WDR Image Processing Mode Switching Without Reset
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Solution Overview
Problem
Conventional wide dynamic range (WDR) image generation technologies cannot fully utilize maximum exposure time, leading to reduced image quality, especially in dark environments, due to the need for rapid switching between WDR modes and the resulting noise increase.
Innovation Solution
An image processing apparatus and method that dynamically adjusts WDR modes by changing the register values of the image sensor, allowing seamless mode changes without resetting the image signal processor, thereby maintaining image quality and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional WDR technology synthesizes multiple sub-images with different exposure times, then dynamic range coverage is improved, but the effective exposure time is reduced to about 1/4 of normal mode, causing light shortage and increased noise
Solution Approach 1:
The patent applies dynamics by making the WDR mode switchable and adaptable based on scene requirements. The system dynamically adjusts between normal mode and WDR mode (with different synthesis configurations like 2WDR or 4WDR) according to lighting conditions, allowing the exposure time and synthesis strategy to be optimized for each specific scenario rather than being fixed
Solution Approach 2:
The patent changes parameters by adjusting the number of sub-images synthesized (2 or 4), their respective exposure times (very long, long, short, very short), and the synthesis weights. This allows flexible control over the trade-off between dynamic range coverage and effective exposure time, enabling optimization for different lighting conditions
2Adaptability or versatility
If rapid switching between WDR modes is implemented, then adaptability to varying lighting conditions is improved, but image quality deteriorates due to noise increase from reduced light accumulation
Solution Approach 1:
The system dynamically selects appropriate WDR modes (normal, 2WDR, 4WDR) based on real-time lighting conditions and scene characteristics. By making the mode selection adaptive rather than fixed, the system can choose the configuration that maintains image quality for each specific scenario
Solution Approach 2:
The patent changes synthesis parameters (number of sub-images, exposure times, synthesis weights) to optimize image quality. For example, using 2WDR with longer exposure times for darker scenes or 4WDR with shorter exposure times for brighter scenes, thereby maintaining acceptable image quality across different lighting conditions
3Adaptability or versatility
If WDR mode changes are implemented, then versatility is improved, but processing time increases due to the need to reset the image signal processor
Solution Approach 1:
The patent implements dynamic mode switching between WDR configurations without requiring a complete reset of the image signal processor. The system can transition between normal mode, 2WDR mode, and 4WDR mode rapidly by adjusting synthesis parameters rather than reinitializing the entire processing pipeline
Solution Approach 2:
The system prepares multiple synthesis configurations in advance (2WDR and 4WDR modes with different exposure time combinations). When mode switching is needed, the pre-prepared configurations can be activated immediately without extensive reprocessing, reducing the time penalty for mode changes
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 solution enables adaptive mode switching, minimizing image quality deterioration and noise, while allowing for rapid changes between WDR modes without frame loss, resulting in improved image quality across varying lighting conditions.
Implementation Method 1
A solid-state pickup device such as a charge-coupled device (CCD) image sensor or a complementary metal oxide semiconductor (CMOS) image sensor used in a video camera or a digital camera performs photoelectric conversion. That is, such a device accumulates electric charge according to the amount of incident light and outputs an electrical signal corresponding to the accumulated charge.
Data Source
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AI summary
Provided is an image processing apparatus which generates a wide dynamic range (WDR) image using an image sensor. The image processing apparatus includes: an image sensor which outputs image data having a plurality of image channels (A,B,C,D); a mode setting unit which changes a photographing mode from a first mode (4WDR) in which a first number of sub-images are synthesized to a second mode (2WDR) in which a second number of sub-images are synthesized, based on luminance of the output image data; a register setting unit which changes a register value (shutter speed) of the image sensor according to the second mode; and an image signal processor (ISP) which generates a result image by synthesizing the second number of sub-images from the image data according to the changed register value, wherein the second number of sub-images have different exposure times.