Wavelength Scanning Digital Interference Holography for Tilted Plane Reconstruction
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Solution Overview
Problem
Conventional digital holography methods face limitations in adjusting pixel resolution, especially when the object-to-hologram distance is small, and in reconstructing images at arbitrarily tilted planes, leading to degraded image quality due to mismatched lateral and axial resolutions.
Innovation Solution
Wavelength scanning digital interference holography (WSDIH) involves scanning the laser wavelength in a range and numerically superposing holograms to achieve flexible tomographic scanning and improved resolution control, allowing reconstruction of images on arbitrarily tilted planes without the need for physical reorientation of the reference mirror or object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional digital holography methods are used with fixed scanning planes, then the reconstruction process is simple, but the image quality degrades when lateral and axial resolutions do not match
Solution Approach 1:
The patent changes the scanning parameters by introducing tilted scanning planes with adjustable angles and positions. Instead of using fixed axial scanning planes, the system allows dynamic adjustment of plane orientation and location to match the object geometry, thereby optimizing both lateral and axial resolution simultaneously without increasing physical device complexity
Solution Approach 2:
The patent implements dynamic scanning plane adjustment where the reference mirror can be tilted and repositioned during the scanning process. This allows the scanning planes to adapt to different object orientations and resolutions requirements, enabling optimal image quality for various specimen geometries while maintaining a single physical scanning system
2Manufacturing precision
If the reference mirror is physically tilted or the object is rotated to achieve better resolution matching, then the resolution matching improves, but the scanning process becomes repetitive and time-consuming
Solution Approach 1:
The patent performs preliminary calculation and determination of optimal tilted scanning plane parameters before the actual scanning process. By pre-calculating the required plane angles and positions based on object characteristics, the system avoids repetitive physical adjustments during scanning, thereby improving resolution matching while maintaining high scanning efficiency
Solution Approach 2:
The patent uses numerical simulation and calculation to create a virtual model of the optimal scanning configuration before physical scanning. This digital copy allows optimization of scanning parameters without physical trial-and-error, enabling better resolution matching while reducing the need for repetitive physical scanning processes
3Measurement precision
If zero padding method is used to control resolution, then the total pixel number increases, but the method cannot adjust pixel resolution for distances smaller than zmin
Solution Approach 1:
The patent changes the fundamental parameter of scanning plane orientation from axial (perpendicular to hologram plane) to tilted (at arbitrary angles). This parameter change allows the system to achieve variable pixel resolution control through angular adjustment rather than relying solely on zero padding, thereby extending adaptability to distances smaller than zmin while maintaining precise resolution control
4Length of moving object
If the object-to-hologram distance is small, then the imaging capability improves for close objects, but the pixel resolution cannot be adjusted using conventional methods
Solution Approach 1:
The patent introduces tilted scanning planes as a new parameter that decouples pixel resolution control from object-to-hologram distance constraints. By adjusting the tilt angle of scanning planes, the system can achieve appropriate pixel resolution even when imaging objects at very small distances from the hologram plane, where conventional axial scanning methods fail
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 enables high-resolution, flexible tomographic imaging with improved axial and lateral resolution matching, enhancing image quality and reducing the need for repetitive scanning processes, while maintaining consistent pixel resolution across various reconstruction distances.
Implementation Method 1
the image is numerically reconstructed by applying the results from the diffraction theory
Implementation Method 2
holographic interference pattern is digitally sampled by a CCD camera
Data Source
AI summary
A series of holograms is recorded by synchronizing a camera with laser pulses under the control of a digital delay generator. Amplitude and phase images are calculated while image distances are adjusted for the best focus on the object under observation. The amplitude and phase images are reconstructed while adjusting the image distances over a predetermined range to maintain the object in focus. Numerical superposition of a plurality of holographic fields taken with varying wavelengths provides high resolution microscopic three-dimensional imaging. Numerical reconstruction is based on an angular spectrum method that enables calculation of the image at any distance from the hologram plane. Wavelength scanning digital interference holography also enables image reconstruction along an arbitrarily tilted plane.