Orthogonal Dual-View Imaging for 3D Precipitation Particle Reconstruction
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Solution Overview
Problem
Current instruments are inadequate for measuring the three-dimensional shape and characteristics of precipitation particles, such as raindrops and snowflakes, as they can only provide two-dimensional measurements or suffer from distortion due to horizontal winds, failing to meet the needs of fields like precipitation physics and remote sensing.
Innovation Solution
A method utilizing orthogonal dual-view imaging with two planar CCD/CMOS cameras, pulse light sources, a high-speed line image sensor, and a continuous light source to generate 3D images of precipitation particles, allowing for real-time measurement and reconstruction of their 3D sizes, axis ratio, orientation, and fall velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If orthogonal dual-view imaging with two planar cameras is used, then 3D measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent transitions from 2D planar imaging to 3D measurement by introducing orthogonal dual-view imaging. Two planar cameras are positioned perpendicular to each other, capturing images from orthogonal directions. This dimensional transition enables accurate 3D shape reconstruction of precipitation particles by combining information from both views, resolving the limitation of single-view 2D measurement.
Solution Approach 2:
The measurement system is segmented into two independent but coordinated planar cameras, each capturing 2D images from orthogonal directions. The 3D reconstruction process further segments the particle into volumetric elements that can be independently analyzed from each view, then integrated to form the complete 3D shape.
2Productivity
If high-speed line image sensor is used for real-time detection, then productivity is improved, but device complexity increases
Solution Approach 1:
The high-speed line image sensor continuously scans the measurement volume before actual particle detection occurs, establishing a ready state for immediate capture. This preliminary scanning prepares the system to trigger the dual cameras at the precise moment a particle enters the measurement zone, enabling real-time detection without missing events.
Solution Approach 2:
The line image sensor serves itself by automatically triggering the dual-camera system when particles are detected. The sensor monitors the measurement volume continuously and autonomously initiates the imaging sequence upon particle detection, eliminating the need for external control signals and simplifying the overall control architecture.
3Measurement precision
If pulse light sources with precise timing synchronization are used, then measurement precision is improved, but use of energy increases
Solution Approach 1:
The pulse light sources operate periodically rather than continuously, emitting light only during the brief moments when particles are expected to pass through the measurement volume. The pulse timing is synchronized with the particle detection system, providing illumination precisely when needed for capturing particle images while remaining dark otherwise, thus reducing overall energy consumption.
Solution Approach 2:
The timing synchronization system performs preliminary action by predicting when particles will enter the measurement zone and pre-positioning the light pulses accordingly. This ensures that illumination is activated just before particle arrival, maximizing measurement precision while minimizing the duration and total energy of light emission.
4Measurement precision
If telecentric lens is used to extend depth of field, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The telecentric lens serves multiple functions simultaneously: it provides extended depth of field for clear imaging of particles at various distances from the camera, maintains consistent magnification across the depth range, and reduces perspective distortion. This multi-functionality justifies the added optical complexity by eliminating the need for multiple lenses or complex focusing mechanisms.
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 accurate and real-time 3D characterization of precipitation particles, overcoming the limitations of existing instruments by providing precise measurements of 3D sizes, axis ratio, orientation, and fall velocity, enhancing the capability to analyze and identify different types of precipitation.
Implementation Method 1
Two pulse light sources generate two parallel light beams that are projected onto two planar cameras separately
Implementation Method 2
The continuous light source generates a parallel light sheet that is projected onto the line image sensor
Implementation Method 3
The line image sensor scans the sampling area with a high-speed in real-time, when the precipitation particles passing through and are detected
Implementation Method 4
two planar cameras record two orthogonal 2D images of precipitation particles in different time-sequences separately
Implementation Method 5
two planar cameras record two orthogonal 2D images of precipitation particles
Data Source
AI summary
This invention discloses a method for measurement and 3D reconstruction of precipitation particles based on orthogonal dual-view imaging. An orthogonal 3D sampling space are formed by a pair of line camera and continuum light source, two pairs of planar cameras and pulse light sources placed orthogonally. The line camera scans with a speed no less than 20,000 lines per second, two cameras and pulse light sources are triggered when the line camera detects the particles in sampling area, two orthogonal images are recorded by two planar cameras using the double-exposure or multiple-exposure in one frame. The 3D images of particles are obtained by pixel matching and grid reconstruction method, based on which the 3D sizes, axis ratio, orientation, fall velocity, and other characteristics of particles are calculated. This method can measure the 3D micro-physical characteristics of precipitation particles automatically and precisely.