Infrared Sensor Dynamic Range Control for Sunlight Saturation
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Solution Overview
Problem
Infrared imaging systems face issues with sunlight exposure, leading to microbolometer saturation and reduced object detection functionality due to inadequate shutter control, necessitating a method to appropriately detect sunlight and protect the infrared sensor.
Innovation Solution
An image processing apparatus comprising a saturated region detection unit, dynamic range control unit, and shutter control unit that acquires imaging data, detects saturated pixels, adjusts the dynamic range, and controls the shutter to protect the microbolometer from sunlight, allowing for appropriate sunlight detection and prevention of sensor damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shutter is closed frequently to protect the microbolometer from sunlight, then the sensor is protected from saturation and damage, but the object detection function cannot be used during the shutter closed period
Solution Approach 1:
The patent replaces frequent mechanical shutter operations with a software-based dynamic range adjustment mechanism. The control unit detects saturated pixels and responds by changing the dynamic range setting of the microbolometer, thereby avoiding the need to close the shutter and maintaining continuous object detection capability while still preventing sensor saturation.
Solution Approach 2:
The patent changes the dynamic range parameter of the microbolometer based on detected sunlight conditions. When saturated pixels are detected, the control unit adjusts the dynamic range to a narrower range that prevents saturation, allowing the sensor to operate safely in sunlight conditions without requiring shutter closure.
2Measurement precision
If a microbolometer with reduced dynamic range is used to improve object detection resolution, then detection precision is improved, but the sensor saturates more easily under sunlight exposure
Solution Approach 1:
The patent makes the dynamic range setting dynamic rather than fixed. The control unit continuously monitors for saturated pixels and adjusts the dynamic range in real-time based on lighting conditions. This allows the system to maintain the benefits of a reduced dynamic range for high-resolution detection while adapting to prevent saturation when sunlight is detected.
Solution Approach 2:
The patent implements a feedback mechanism where the detection of saturated pixels triggers a response to adjust the dynamic range. The control unit uses the saturation detection as feedback to automatically modify the dynamic range setting, creating a closed-loop system that prevents saturation while maintaining optimal detection resolution.
3Loss of time
If the shutter control is made more sensitive to detect sunlight earlier, then protection timing is improved, but false detection may occur reducing object detection functionality
Solution Approach 1:
The patent replaces sensitive shutter control with a more reliable pixel saturation detection mechanism. Instead of attempting to predict sunlight conditions and trigger shutter closure, the system directly detects actual pixel saturation and responds by adjusting the dynamic range, eliminating false detections while maintaining rapid protection response.
Data Source
AI summary
An image processing apparatus includes a saturated region detection unit, a dynamic range control unit, and a shutter control unit. The saturated region detection unit acquires imaging data from an infrared imaging device that captures a thermal image of an outside of a mobile body, and detects that a saturated pixel is present in the imaging data. The dynamic range control unit sets, in accordance with a result of the detection of the saturated region, a dynamic range of the infrared imaging device to a first temperature range, or a second temperature range where a temperature at least on an upper limit side is higher than that in the first temperature range. The shutter control unit controls opening and closing of a shutter for protecting the infrared imaging device based on the result of the detection of the saturated region and the setting of the dynamic range.