Microwave Imaging Scan Unit for Gain Stability
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Solution Overview
Problem
Current microwave image systems face issues with gain drift in radiometers during extended integration periods and inaccurate scanning due to step motors, leading to increased design complexity and the need for calibration units.
Innovation Solution
An imaging system with a detection unit and a scan unit that scans a target area multiple times at a constant speed, using a rotatable reflection plate to focus radiation, generating sub-detection values which are summed to produce stable detection values, thereby eliminating the need for calibration and improving scanning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the integration period of scan is extended to accumulate enough energy, then the detection sensitivity is improved, but the gain drift increases
Solution Approach 1:
The patent divides the scanning process into multiple passes (N passes) over the same target area. Each pass generates a separate detection value, and these values are combined through averaging to produce the final result. This segmentation allows the system to accumulate sufficient energy for accurate detection while keeping each individual integration period short enough to avoid gain drift, thereby resolving the contradiction between detection sensitivity and gain stability.
2Duration of action of stationary object
If step motors are used to scan images at constant positions, then the integration period can be maintained, but the scanning accuracy deteriorates due to motor stop and motion errors
Solution Approach 1:
The patent replaces the mechanical step motor system with a continuous scanning mechanism that moves at constant velocity without stopping. This eliminates the start-stop errors inherent in step motors while maintaining the required integration period through multiple passes over the same area. The continuous motion system achieves both the duration needed for energy accumulation and the precision required for accurate positioning.
3Reliability
If a calibration unit is added to calibrate radiometer gains, then the gain drift is compensated, but the system complexity increases
Solution Approach 1:
The patent implements self-calibration through the scanning process itself. By scanning the same target area multiple times and averaging the detection values, the system inherently compensates for gain variations without requiring external calibration units or additional calibration procedures. This self-service approach maintains gain reliability while avoiding the complexity of separate calibration systems.
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
This approach reduces gain differences and eliminates the need for calibration units, providing accurate and stable microwave radiation detection without the use of stepping motors, simplifying system design and improving scanning precision.
Implementation Method 1
a detection unit (110) for sensing radiation of a target area (150)
Implementation Method 2
a scan unit (120) for directing the radiation of the target area (150) to the detection unit (110)
Data Source
AI summary
An imaging system is provided, including a detection unit and a scan unit. The detection unit senses radiation of a target area. The scan unit directs the radiation to the detection unit, in which the scanning unit scans the target area N times at a constant speed within a scan period, such that each of the pixels of the target area is scanned N times by the scan unit, thereby the detection unit generates N sub-detection values for each of the pixels and adds the N sub-detection values up to generate a detection value for each of the pixels.