Doppler Observation Device for Moving Objects
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Solution Overview
Problem
Existing observation devices using the phase shift method require stationary objects to obtain three-dimensional images, leading to decreased image quality and sensitivity due to the need for high-speed, expensive optical detectors with low spatial resolution, and the Hilbert transform method further deteriorates spatial resolution, resulting in low image quality when imaging moving objects.
Innovation Solution
An observation device that utilizes a light source emitting light from multiple directions, a detection section receiving scattered light with identical scattering angles, and an arithmetic operation section performing one-dimensional Fourier transforms to extract data based on the Doppler Effect, allowing for the extraction of data with identical incident angles without the need for multiple images during the object's stationary state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a phase shift method is used to obtain three-dimensional images of moving objects, then image quality and sensitivity can be improved, but high-speed optical detectors with low spatial resolution are required, increasing device cost and complexity
Solution Approach 1:
The invention changes the measurement parameter from spatial resolution to temporal frequency analysis. Instead of requiring high-speed detectors with high spatial resolution, the system uses standard detectors and analyzes the temporal frequency characteristics of the interference signal to extract velocity information and reconstruct three-dimensional images of moving objects.
Solution Approach 2:
The invention replaces the mechanical requirement for high-speed detectors with a signal processing approach. By substituting the need for fast detector response with temporal frequency analysis of the interference pattern, the system achieves three-dimensional imaging of moving objects using conventional detectors.
2Speed
If four two-dimensional images are taken at high speed to capture moving objects, then the object motion can be frozen, but the exposure time is limited reducing signal-to-noise ratio and image quality
Solution Approach 1:
The invention enables continuous measurement of the interference pattern over an extended period, allowing accumulation of signal information. By continuously recording the temporal evolution of the interference pattern and analyzing its frequency characteristics, the system achieves both motion capture and high signal-to-noise ratio.
3Productivity
If the Hilbert transform method is used to obtain complex amplitude from one captured image, then the processing speed is improved, but the spatial resolution is deteriorated by about 1/4
Solution Approach 1:
The invention replaces the Hilbert transform method with a temporal frequency analysis approach. Instead of using mathematical transforms that degrade spatial resolution, the system extracts complex amplitude information by analyzing the temporal frequency characteristics of the interference signal, preserving spatial resolution while achieving efficient processing.
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 the acquisition of images from moving objects using optical detectors with low reading speeds per pixel, improving image quality and reducing the need for high-speed, high-resolution detectors.
Implementation Method 1
scattered light having an identical scattering angle from among scattered light generated by the object upon irradiation with the light by the light source enters at an identical position
Implementation Method 2
outputting data temporally changing at a frequency corresponding to an amount of Doppler shift of light that reaches at each position on the predetermined plane
Implementation Method 3
causing a heterodyne interference between the first light and the second light on the predetermined plane
Implementation Method 4
causing a heterodyne interference between the first light and the second light on the predetermined plane
Data Source
AI summary
An observation device is provided with a light source section, a detection section and an arithmetic operation section. The light source section emits light to a moving object from multiple directions. a detection section is disposed on a predetermined plane such that scattered light having an identical scattering angle enters at an identical position, outputs data temporally changing at a frequency corresponding to an amount of Doppler shift of light that reaches at each position on the predetermined plane. An arithmetic operation section performs a one-dimensional Fourier transform with respect to time variables, for data having a position in the first direction on the predetermined plane, a position in the second direction on the predetermined plane, and a time as variables, and extracts data having an identical incident angle relative to the object from the Fourier-transformed data, on the basis of Doppler Effect.