Journal: iScience

Article Title: Rapid diffused optical imaging for accurate 3D estimation of subcutaneous tissue features

doi: 10.1016/j.isci.2025.111818

Figure Lengend Snippet: Subcutaneous imaging with 3D-mDOI: approach overview (A–C) The imaging setup consists of a digital micromirror device (DMD) projector that generates patterns of light-beams and a CMOS camera capturing the reflectance of the re-emitted light from the sample. Specular reflection is mitigated by a pair of polarizers (Blue cover), thus improving the camera’s dynamic range for diffuse light. Each captured image is split into (B, bottom) small patches, each centered on a light source, with every pixel functioning as a detector. Reflectance values are selected from a neighboring cross-section (target detector) and associated with a distance from the light source. These values serve as the input for a (B, top) 2D nonlinear fitting of the RTE model, which computes the cross-section’s optical coefficients ( μ a , μ s ) (Magenta Dot). The (C, top) 2D optical coefficient map for each patch is assembled by integrating the optical coefficients from all target detectors. The corresponding (C, middle) 3D photon distribution expands the 2D optical coefficient map into a 3D optical coefficient matrix. We integrate multiple 3D optical coefficient matrices to form a (C, bottom) reconstructed 3D volume by a linear, single-step reconstruction. Each voxel is sampled multiple times, improving the quality of the 3D reconstruction. (D) The projector pattern is systematically scanned over the sample surface, repeating the steps A, B, and C to iteratively update the reconstructed 3D volume. (E) Measurements on a uniform phantom provide a calibration for the reconstructed 3D volume and improving the results. The result is a depth estimation of the ground truth features, evidenced by the visibility of objects or lesions at various depths within the relative 3D coefficient volume.

Article Snippet: The platform integrates a CMOS camera (acA2000-340km, Basler ace, Germany) and a programmable digital light projector (DLP4500-C350REF, Texas Instruments, America), positioned approximately 30 cm from the sample and roughly 15cm apart from each other.

Techniques: Imaging

Journal: iScience

Article Title: Rapid diffused optical imaging for accurate 3D estimation of subcutaneous tissue features

doi: 10.1016/j.isci.2025.111818

Figure Lengend Snippet: 3D-mDOI reconstructs distinguishable sub-surface features in the physical phantom Comprehensive analysis evaluating the physical phantom reconstruction for the methods of 3D-mDOI and FEM. (A) A physical phantom, crafted with different proportions of titanium dioxide (TiO2) and India ink in a polydimethylsiloxane (PDMS) medium, contains six unique features with varying absorption ( μ a ) and scattering ( μ s ) coefficients. The multisite image acquisition platform facilitates systematic scans of the phantom, employing a digital micromirror device (DMD) to create specific illumination patterns and a CMOS camera to capture the re-emitted light. (B) In the experimental reference intensity image, regions in red bounding boxes are selected features, which are subsequently normalized by the regions of background in neighboring yellow bounding boxes. Boxplots show the relative optical coefficients ( μ a , μ s ) ratio for phantom features, with the distributions of approximately 10 5 voxel samples for each feature. (C) These plots provide a clear statistical representation where the central box spans from the first quartile to the third quartile, bisected by a line representing the median. The whiskers extend to a maximum of 1.5 times the inter-quartile range, while any data points beyond these whiskers are denoted as flier points. μ s results from 3D-mDOI largely coincide with the expected optical coefficient ratios of the features. However, certain deviations can be observed in the ratio of μ a , especially for feature 4 and 5. Comparably, the FEM results have limited dynamic range, obscuring distinct differences between feature values. (D) 3D renderings of the phantom showcasing the reconstructed features and highlighting 3D-mDOI’s robustness against experimental noise compared to the FEM’s more ambiguous renderings with respect to the ground truth.

Article Snippet: The platform integrates a CMOS camera (acA2000-340km, Basler ace, Germany) and a programmable digital light projector (DLP4500-C350REF, Texas Instruments, America), positioned approximately 30 cm from the sample and roughly 15cm apart from each other.

Techniques: Titanium Dioxide