Camera Dynamic Exposure Mode Switching for SNR
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Solution Overview
Problem
Existing imaging systems face challenges in maintaining high signal-to-noise ratios in both bright and dark regions of images, especially under varying ambient light intensities, which affects the accuracy of object distance calculations.
Innovation Solution
A camera with embedded digital-overlap (DOL) and dual-conversion-gain (DCG) modes, coupled with a control host, determines the exposure mode based on ambient light intensity. The camera operates in DOL mode for high light conditions and DCG mode for low light conditions, ensuring high signal-to-noise ratios in all regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single exposure mode is used in the imaging system, then the device complexity is reduced, but the signal-to-noise ratio in regions with varying ambient light intensity deteriorates
Solution Approach 1:
The imaging system dynamically switches between DOL mode and DCG mode based on the ambient light intensity detected by the light sensor. When ambient light is sufficient, the system uses DOL mode; when ambient light is insufficient, it switches to DCG mode. This dynamic adaptation ensures optimal signal-to-noise ratio across varying lighting conditions without requiring multiple fixed exposure modes simultaneously
Solution Approach 2:
The system changes the conversion gain parameter of the image sensor based on ambient light conditions. In DCG mode, the sensor operates with high conversion gain to amplify weak signals in low light, while in DOL mode, it uses standard conversion gain. This parameter change allows the same hardware to optimize performance across different lighting environments
2Illumination intensity
If the camera operates in DOL mode for high light conditions, then the brightness of bright regions is improved, but the signal-to-noise ratio in dark regions deteriorates
Solution Approach 1:
The system dynamically switches between DOL mode and DCG mode based on the ambient light intensity detected by the light sensor. When ambient light is sufficient, the system uses DOL mode; when ambient light is insufficient, it switches to DCG mode. This dynamic adaptation ensures optimal signal-to-noise ratio across varying lighting conditions without requiring multiple fixed exposure modes simultaneously
Solution Approach 2:
The system changes the conversion gain parameter of the image sensor based on ambient light conditions. In DCG mode, the sensor operates with high conversion gain to amplify weak signals in low light, while in DOL mode, it uses standard conversion gain. This parameter change allows the same hardware to optimize performance across different lighting environments
3Reliability
If the camera operates in DCG mode for low light conditions, then the signal-to-noise ratio in dark regions is improved, but the brightness of bright regions deteriorates
Solution Approach 1:
The system dynamically switches between DOL mode and DCG mode based on the ambient light intensity detected by the light sensor. When ambient light is sufficient, the system uses DOL mode; when ambient light is insufficient, it switches to DCG mode. This dynamic adaptation ensures optimal signal-to-noise ratio across varying lighting conditions without requiring multiple fixed exposure modes simultaneously
Solution Approach 2:
The system changes the conversion gain parameter of the image sensor based on ambient light conditions. In DCG mode, the sensor operates with high conversion gain to amplify weak signals in low light, while in DOL mode, it uses standard conversion gain. This parameter change allows the same hardware to optimize performance across different lighting environments
4Ease of operation
If the control host does not correctly match the exposure mode after waking up, then the ease of operation is improved, but the measurement precision of object distance deteriorates
Solution Approach 1:
The camera sends an exposure mode signal to the control host after waking up, indicating whether it is operating in DOL mode or DCG mode. The control host receives this feedback signal and automatically matches its processing mode accordingly. This feedback mechanism ensures that the control host correctly interprets the image data without requiring manual intervention, while maintaining accurate object distance measurements through proper mode correspondence
Data Source
AI summary
There is provided an imaging system including a camera and a control host. The camera identifies ambient light intensity and performs trigger event detection in a low power mode. When the camera detects a trigger event in the low power mode, the control host is woken up. The camera also determines an exposure mode according the ambient light intensity and informs the exposure mode to the control host such that an operating mode of the control host after being woken up matches the exposure mode of the camera.