Atmospheric Wave Imaging Using Refractive Index Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Imaging an object in a measurement area using scattered waves is challenging, particularly when the measurement area is in the atmosphere, due to varying atmospheric density affecting wave propagation.
Innovation Solution
An imaging device that includes transmitters and receivers to capture scattered waves, utilizing an information processing circuit to derive a scattering field function and imaging function that accounts for changing refractive indices in the atmosphere, enabling accurate object imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional imaging methods using scattered waves are applied in the atmosphere, then imaging can be performed, but imaging accuracy deteriorates due to varying atmospheric density affecting wave propagation
Solution Approach 1:
The patent applies parameter changes by incorporating the atmospheric refractive index profile into the scattering field function. The refractive index varies with altitude, and this variation is reflected in the wavenumber calculations. By changing the parameter of the scattering field function to account for refractive index variations, the imaging accuracy is improved despite atmospheric refraction effects.
Solution Approach 2:
The patent performs preliminary action by pre-calculating and storing the scattering field function that already incorporates atmospheric refraction effects. Instead of correcting for refraction during image reconstruction, the refraction effects are built into the forward model beforehand. This allows the imaging algorithm to directly use the pre-computed scattering field function without additional correction steps.
2Measurement precision
If the scattering field function reflects varying refractive index with altitude, then imaging accuracy in the atmosphere is improved, but computational complexity increases
Solution Approach 1:
The scattering field function is computed in advance and stored, rather than calculating it in real-time during image reconstruction. By performing the complex integration involving the refractive index profile beforehand, the patent reduces the computational burden during the actual imaging process, making the system more practical despite the increased model complexity.
Solution Approach 2:
The patent transforms the complex partial differential wave equation into an integral equation form with a pre-computable scattering field function. By changing the mathematical representation and using parameterized forms of the refractive index profile, the complex physics problem becomes more tractable and suitable for practical implementation.
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
Enables high-accuracy imaging of objects in atmospheric conditions by reflecting the varying refractive index with altitude in the scattering field and imaging functions.
Implementation Method 1
the density of the atmosphere differs depending on altitude, so waves incident on the measurement area may not travel straight. In deriving the scattering field function, the information processing circuit reflects in the scattering field function that a wavenumber of the wave changes as a refractive index in the atmosphere changes with height in the atmosphere
Implementation Method 2
a plurality of transmitters that each transmit a wave to a measurement area in an atmosphere; a plurality of receivers that each receive a scattered wave of the wave from the measurement area
Implementation Method 3
derives, using the measurement data, a scattering field function that receives a transmission position of the wave and a reception position of the scattered wave as input and outputs an amount of the scattered wave at the reception position
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An imaging device (100) includes: a plurality of transmitters (101) that each transmit a wave to a measurement area in the atmosphere; a plurality of receivers (102) that each receive a scattered wave of the wave from the measurement area; and an information processing circuit (103) that images an object in the measurement area using measurement data of the scattered wave. The information processing circuit (103): derives a scattering field function using the measurement data; derives an imaging function that is defined using an amount output from the scattering field function in response to inputting an imaging target position into the scattering field function; and images the object in the measurement area using the imaging function. The information processing circuit (103) reflects in the scattering field function that the wavenumber of the wave changes as the refractive index in the atmosphere changes with height in the atmosphere.