We propose a color-image reconstruction method for two-wavelength digital holography using generalized phase-shifting digital holography (GPSDH). In this method, color interference fringes are captured by a digital camera with a Bayer array color filter, and phase shifting is simultaneously performed for all wavelengths. Color interference fringes are separated into three monochromatic interference fringes using a color-separation method that suppresses the color-filter crosstalk. The object wave is extracted from each monochromatic interference fringe using GPSDH, which prevents problems due to the phase shift wavelength dependence. Image reconstruction is performed using a shifted Fresnel transform-based method, in which the color reconstructed image is obtained by directly superposing the reconstructed images for all wavelengths. We verify the proposed method through optical experiments with a two-wavelength digital holography system. The results show that the dual-color image can be successfully reconstructed without chromatic aberration.
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http://dx.doi.org/10.1364/AO.56.006554 | DOI Listing |
Invest Radiol
January 2025
From the Department of Radiology, Stanford University, Stanford, CA (K.W., M.J.M., A.M.L., A.B.S., A.J.H., D.B.E., R.L.B.); Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA (K.W.); GE HealthCare, Houston, TX (X.W.); GE HealthCare, Boston, MA (A.G.); and GE HealthCare, Menlo Park, CA (P.L.).
Objectives: Pancreatic diffusion-weighted imaging (DWI) has numerous clinical applications, but conventional single-shot methods suffer from off resonance-induced artifacts like distortion and blurring while cardiovascular motion-induced phase inconsistency leads to quantitative errors and signal loss, limiting its utility. Multishot DWI (msDWI) offers reduced image distortion and blurring relative to single-shot methods but increases sensitivity to motion artifacts. Motion-compensated diffusion-encoding gradients (MCGs) reduce motion artifacts and could improve motion robustness of msDWI but come with the cost of extended echo time, further reducing signal.
View Article and Find Full Text PDFBiomed Opt Express
January 2025
Department of Electronic Engineering, Maynooth University, Maynooth, Co. Kildare, Ireland.
Optical diffraction tomography enables label-free, 3D refractive index (RI) imaging of biological samples. We present a novel, cost-effective approach to ODT that employs a modular design incorporating a self-reference holographic capture module. This two-part system consists of an illumination module and a capture module that can be seamlessly integrated with any life-science microscope using an automated alignment protocol.
View Article and Find Full Text PDFWe present the first, to our knowledge, metasurface holographic display method with exceptional fidelity and minimal edge noise, based on highly uniform flat-top light generated by a digital micromirror device (DMD). Based on the error-diffusion algorithm and iterative refinement process, the amplitude distribution of the initial Gaussian light was dynamically closed-loop modulated, and the standard difference of the intensity of the 3 mm diameter center flat-top beam was reduced to less than 3.4%.
View Article and Find Full Text PDFSingle-shot ptychography is a quantitative phase imaging method wherein overlapping beams of light arranged in a grid pattern simultaneously illuminate a sample, allowing a full ptychographic dataset to be collected in a single shot. It is primarily used at optical wavelengths, but there is interest in using it for x-ray imaging. However, constraints imposed by x-ray optics have limited the resolution achievable to date.
View Article and Find Full Text PDFLinear digital filters are at the core of image reconstruction and processing for many coherent optical imaging techniques, such as digital holography (DH) or optical coherence tomography (OCT). They can also be efficiently implemented using fast Fourier transform (FFT) with appropriate transfer/filter functions that operate in the frequency domain. However, even with optimal filter design, they suffer from side effects such as sidelobe generation or resolution limitations, e.
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