Visible light imaging | EPFL Graph Search

Visible light imaging is an imaging modality that uses visible light. In Medicine Standardization and Adoption Even prior to specific support in DICOM for visible light imaging, the standard could already encapsulate color images, e.g., in JPEG format as Secondary Capture images . The need for standardized communication of digital visible light images from various specialties, and the need for specialty-specific acquisition context metadata and an appropriate controlled terminology was recognized not long after the DICOM standard was introduced and the terminology of visible light imaging was introduced to the standard . The United States Department of Veterans Affairs was an early adopter of a standardized approach to incorporating visible light images into the electronic medical record . Increasingly, visible light imaging is being deployed beyond individual departments, as part of a trend referred to as Enterprise Imaging . Applicability Endo

Combining visible and near-infrared images for realistic skin smoothing

Nathalie Barbuscia, Sabine Süsstrunk

Skin tone images, portraits in particular, are of tremendous importance in digital photography, but a number of factors, such as pigmentation irregularities (e.g., moles, freckles), irritation, roughness, or wrinkles can reduce their appeal. Moreover, such “defects” are oftentimes enhanced by lighting conditions, e.g., when a flash is used. Starting with the observations that melanin and hemoglobin, the key components of skin colour, have little absorption in the near-infrared part of the spectrum, and that the depth of light penetration in the epidermis is proportional to the incident light’s wavelength, we propose that near-infrared images provide information that can be used to automatically smooth skin tones in a physically realistic manner. Specifically, we develop a framework that consists of capturing a pair of visible/near-infrared images and separating both of them into base and detail layers (akin to a low/high frequency decomposition) with the fast bilateral filter. We show that a smooth, realistic, output image can be obtained by fusing the base layer of the visible image with the near-infrared detail layer. This method not only outperforms equivalent decomposition in the wavelet domain, but the results also look more realistic than with a simple luminance transfer. Moreover, the proposed method delivers consistently good results across various skin types.

2009

Interaction of Oil and Lipids in Freestanding Lipid Bilayer Membranes Studied with Label-Free High-Throughput Wide-Field Second-Harmonic Microscopy

Maksim Eremchev, Sylvie Roke, Orly Bagunu Tarun

The interaction of oils and lipids is relevant for membrane biochemistry since the cell uses bilayer membranes, lipid droplets, and oily substances in its metabolic cycle. In addition, a variety of model lipid membrane systems, such as freestanding horizontal membranes and droplet interface bilayers, are made using oil to facilitate membrane monolayer apposition. We characterize the behavior of excess oil inside horizontal freestanding lipid bilayers using different oils, focusing on hexadecane and squalene. Using a combination of second-harmonic (SH) and white-light imaging, we measure how oil redistributes within the membrane bilayer after formation. SH imaging shows that squalene forms a wider annulus compared with hexadecane, suggesting that there is a higher quantity of squalene remaining in the bilayer compared with hexadecane. Excess oil droplets that appear right after membrane formation are tracked with white-light microscopy. Hexadecane droplets move directionally to the edge of the membrane with diffusion constants similar to those of single lipids, whereas squalene oil droplets move randomly with lower diffusion speeds similar to lipid condensed domains and remain trapped in the center of the bilayer for ∼1–3 h. We discuss the observed differences in terms of different coupling mechanisms between the oil and lipid molecules induced by the different chemical structures of the oils.

2018

Automatic Skin Enhancement with Visible and Near-Infrared Image Fusion

Sabine Süsstrunk, Daniel Tamburrino

Skin tones, portraits in particular, are of critical importance in photography and video, but a number of factors, such as pigmentation irregularities (e.g., moles, freckles), irritation, roughness, or wrinkles can reduce their appeal. Moreover, such “defects” are oftentimes enhanced by scene lighting conditions. Starting with the observations that melanin and hemoglobin, the key components of skin color, have little absorption in the near-infrared (NIR) part of the spectrum, and that the depth of light penetration in the epidermis is proportional to the incident light’s wavelength, we show that near-infrared images provide information that can be used to automatically smooth skin tones in a physically realistic manner. Specifically, we developed a prototype camera system that consists of capturing a pair of visible/near-infrared images and separating both of them into base and detail layers (akin to a low/high frequency decomposition) with the fast bilateral filter. Smooth and realistic output images are obtained by fusing the base layer of the visible image with the near-infrared detail layer. The proposed method delivers consistently good results across various skin types. The prototype system is currently in use at the Swiss Camera Museum in Vevey, Switzerland, where the visitors can take their pictures and e-mail themselves the results. In the process, we are collecting the users’ preference for either the “original” (visible) image or the “enhanced” (visible and NIR fused) image. The system has been deployed for three months. Preliminary statistics indicate that a large majority (79%) prefers the enhanced image.

2010