Retinal Oximetry with 510–600 nm Light Based on Partial Least-Squares Regression Technique

Abstract

A pronounced low-temperature resistance minimum has been found in dilute solutions of iron in copper-rich alloys of the E copperzinc phase, but m zincrich alloys of the same phase the mmimum is very much weaker; this quenching of the resistance minimum correlates well with the trend of the iron magnetic moment found by Waszink and Coles. The temperature-mdependent resistivity contributed by the iron is very large, and almost mdependent of solvent composition, These results suggest that the iron impurity forms a half-filled virtual bound state which is partly magnetized at the copper-rich end of the phase, but very nearly demagnetized at the zinc-rich end. The variation of resistance at low temperatures is not well described by current theories of magnetic impurities, and in particular no inhcation can be seen of a critical temperature or of condensation into a non-magnetic ground state.

Spectroscopic oximetry in the eye: a review

“…[9,38] The majority of multispectral and hyperspectral imaging studies have employed time-sequential filtering of broadband retinal images, utilising either multiple bandpass filters, a liquid-crystal tuneable filter (LCTF), [21,50,51,53,61,62] or an acousto-optic tuneable filter (AOTF) for spectral discrimination. [54,63,64] LCTFs and AOTFs offer the advantages electronicallycontrolled optical waveband switching in short timescales (~ 50 ms and 25 µs respectively), with a wide-variety of accessible wavelengths. [65] The Image Replicating Imaging Spectrometer (IRIS) has enabled video-rate oximetry which has been utilised observe oxygen release by ex vivo red blood cells upon exposure to sodium dithionite.…”

RGB Camera-Based Imaging of Oxygen Saturation and Hemoglobin Concentration in Ocular Fundus

“…Two commercial two-wavelength retinal oximetry systems, Vesselmap oxygen module (Imedos Systems GmbH, Jena, Germany) [21] and Oxymap T1 (Oxyma ehf., Reykjavik, Iceland) [22], have contributed to ophthalmological research. Recently, hyperspectral imaging (HSI) [24]- [26], [34], [35] and multispectral imaging (MSI) [25], [27]- [33], [36], [37], [34], [40]- [46] have also been used to estimate SO 2 in the fundus. HSI can be used to acquire spectral images with higher wavelength resolution than that of MSI but is limited to time-sequential measurements.…”

“…HSI-based oximetry with LCTF for the human retina was developed later [24], [34], [35]. Five-band MSI-based oximetry techniques with AOTFs were also proposed [25], [36], and HSI-based oximetry with AOTFs have also been developed [25], [26]. AOTFs can switch wavelengths faster and have narrower bandwidths than LCTFs.…”