In vivo measurement of skin microrelief using photometric stereo in the presence of interreflections

Sohaib, Ali; Farooq, Abdul; Atkinson, Gary A.; Smith, Lyndon; Smith, Melvyn L.; Warr, Robert

doi:10.1364/josaa.30.000278

“…Photometric stereoimaging 19 is a widely used technique in computer graphics for surface analysis and reconstruction, 20 and it has also been successfully applied in small-scale surface topography measurement, e.g., in paper products 21 and dermatology. 22 In the photometric stereosetup, the translucent CNF sample was fixed on top of a flat black sheet of cardboard while it was imaged with a camera placed atop. Four images were acquired from the sample with different, but precisely known, illumination directions, using blue LEDs whose dominant wavelength was 460 nm.…”

Section: Cnf Film Characterizationmentioning

confidence: 99%

Cellulose Nanofibril Film as a Piezoelectric Sensor Material

Rajala

¹

,

Siponkoski

²

,

Sarlin

³

et al. 2016

ACS Appl. Mater. Interfaces

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Self-standing films (45-μm thick) of native cellulose nanofibrils (CNF) were synthesized and characterized for their piezoelectric response. The surface and the microstructure of the films were evaluated with image-based analysis and scanning electron microscopy (SEM). The measured dielectric properties of the films at 1 kHz and 9.97 GHz indicated a relative permittivity of 3.47 and 3.38 and loss tangent tan  of 0.011 and 0.071, respectively. The films were used as functional sensing layers in piezoelectric sensors with corresponding sensitivities of 4.7 to 6.4 pC/N in ambient conditions. This piezoelectric response is expected to increase remarkably upon film polarization resulting from the alignment of the cellulose crystalline regions in the film. The CNF sensor characteristics were compared with those of polyvinylidene fluoride (PVDF) as reference piezoelectric polymer. Overall, the results suggest that CNF is a suitable precursor material for disposable piezoelectric sensors, actuator or energy generators with potential applications in the fields of electronics, sensors and biomedical diagnostics.

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“…While active triangulation techniques would provide the required measurement precision on human skin [21], the hardware necessary to perform the respective measurement is still rarely found in consumer devices. Another active method able to measure small surface details is Photometric Stereo (PS) [22]. Here, multiple light sources are placed around the diffuse object, capturing images with each light source switched on and the remaining lights off.…”

Section: D Imaging Of Human Skinmentioning

confidence: 99%

Skinscan: Low-Cost 3D-Scanning for Dermatologic Diagnosis and Documentation

Nau

¹

,

Schiffers

²

,

Li

³

et al. 2021

2021 IEEE International Conference on Image Processing (ICIP)

1

0

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The utilization of computational photography becomes increasingly essential in the medical field. Today, imaging techniques for dermatology range from two-dimensional (2D) color imagery with a mobile device to professional clinical imaging systems measuring additional detailed threedimensional (3D) data. The latter are commonly expensive and not accessible to a broad audience. In this work, we propose a novel system and software framework that relies only on low-cost (and even mobile) commodity devices present in every household to measure detailed 3D information of the human skin with a 3D-gradient-illumination-based method. We believe that our system has great potential for early-stage diagnosis and monitoring of skin diseases, especially in vastly populated or underdeveloped areas.

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“…While active triangulation techniques would provide the required measurement precision on human skin [19], the hardware necessary to perform the respective measurement is still rarely found in consumer devices. Another active method able to measure small surface details is Photometric Stereo (PS) [20].…”

Section: D Imaging Of Human Skinmentioning

confidence: 99%

SkinScan: Low-Cost 3D-Scanning for Dermatologic Diagnosis and Documentation

Nau,

Schiffers,

Li

et al. 2021

Preprint

0

View full text Add to dashboard Cite

The utilization of computational photography becomes increasingly essential in the medical field. Today, imaging techniques for dermatology range from two-dimensional (2D) color imagery with a mobile device to professional clinical imaging systems measuring additional detailed threedimensional (3D) data. The latter are commonly expensive and not accessible to a broad audience. In this work, we propose a novel system and software framework that relies only on low-cost (and even mobile) commodity devices present in every household to measure detailed 3D information of the human skin with a 3D-gradient-illumination-based method. We believe that our system has great potential for early-stage diagnosis and monitoring of skin diseases, especially in vastly populated or underdeveloped areas.

show abstract

In vivo measurement of skin microrelief using photometric stereo in the presence of interreflections

Cited by 14 publications

References 37 publications

Cellulose Nanofibril Film as a Piezoelectric Sensor Material

Cellulose Nanofibril Film as a Piezoelectric Sensor Material

Skinscan: Low-Cost 3D-Scanning for Dermatologic Diagnosis and Documentation

SkinScan: Low-Cost 3D-Scanning for Dermatologic Diagnosis and Documentation

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