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M. Rondanelli-Reyes

Publications and source records attributed to M. Rondanelli-Reyes.

2 recordsLinked to original sources

Automated Palynological Analysis System: Integrating Deep Metric Learning and $U^{2}$-Net Detection in $H\infty$ bright field microscopy

Traditional melissopalynology is a time-consuming and subjective process, often taking 4-6 hours per sample. We present an automated, high-throughput microscopy system that integrates $H\infty$ robust mechanical control with advanced deep learning pipelines for the precise counting, classification, and morphological analysis of pollen grains from Bio Bio region in south central territory in Chile. Our system employs $U^{2}$-Net for salient object detection and a DINOv2 Vision Transformer backbone trained via Deep Metric Learning for classification. By integrating Gradient-Weighted Attention, the model provides human-interpretable texture and diagnostic feature annotations. The system achieves a 95.8$\%$ classification recall and a 6x processing speedup compared to manual expert analysis.

cs.CV

Three-Dimensional Volumetric Reconstruction of Native Chilean Pollen via Lens-Free Digital In-line Holographic Microscopy

This study presents a methodology for the three-dimensional volumetric reconstruction and morphological characterization of native Chilean pollen grains using lens-free Digital In-line Holographic Microscopy (DLHM). A 532 nm point source, a 3.45 $\mu$m pixel pitch CMOS sensor and a source--sample distance of $0.46$ mm with a $25$ mm stand-off give a magnification of $\simeq 55\times$ and an effective pixel of 62.9 nm. Wavefronts of \textit{Anthemis cotula}, \textit{Gevuina avellana} and \textit{Conium maculatum} were reconstructed by the Kirchhoff-Helmholtz transform, yielding volumes from $3780.2 \pm 18$ to $4320.5 \pm 15$ $\mu$m$^3$ and sphericities from $0.76 \pm 0.03$ for the echinate \textit{A. cotula} to $0.89 \pm 0.02$ for \textit{G. avellana}. Three independent targets make these reconstructions traceable. Certified polystyrene microspheres ($\varnothing = 20.0$ $\mu$m) make the source--sample distance an optically retrieved quantity, the 2.5D height map returning $2068$ $\mu$m$^3$ against an analytical $2094.4$ $\mu$m$^3$. A human erythrocyte, reconstructed with a haemoglobin refractive-index increment taken from the literature rather than fitted, returns $88.9$ fL with a $2.36$ $\mu$m rim and a $1.03$ $\mu$m dimple, within physiological range. Finally, transport-of-intensity retrieval on bright-field micrographs from a separate, independently calibrated instrument reproduces the projected morphology of \textit{G. avellana}, though no volume follows from it. These results support label-free "digital fingerprints" for automated melissopalynology in a South American biodiversity hotspot.

physics.optics