Speckle illumination SFDI for projector-free optical property mapping

Chen, Mason T.; Papadakis, Melina; Durr, Nicholas J.

doi:10.1364/ol.411187

Cited by 8 publications

(10 citation statements)

References 25 publications

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“…Finally, we show for our tumour sample that it can be illuminated using a laser speckle pattern (Fig 7b), to simulate recent experimental work. 14 This technique, called speckle illumination spatial frequency domain imaging (si-SFDI) works by sampling the modulation transfer function of the imaged sample at a known spatial frequency. By calibrating with a phantom of known optical properties, changes in the MTF determine the optical…”

Section: Resultsmentioning

confidence: 99%

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Simulating medical applications of tissue optical property and shape imaging using open-source ray tracing software

Crowley

Gordon

2021

Biomedical Applications of Light Scattering XI

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Oesophageal cancer and colon cancer have five year survival rates of 15% 1 and 63% 2 respectively. These low survival rates are due in part to poor early detection during endoscopic screening, with conventional endoscopes providing insufficient information about tissue properties to spot a wide range of potential tumours. Improving early detection of gastrointestinal cancers would dramatically increase their five year survival rates. Spatial Frequency Domain Imaging (SFDI) is a low-cost imaging technique that can measure absorption, scattering and shape as potential indicators of cancer. Specific absorption and scattering properties are known to be linked to malignancy in the oesophagus, 3 and shape is an important indicator in colon cancer. 4 Though a range of research and commercial SFDI systems have been developed, 5 adapting these for in vivo clinical application is challenging due to constraints imposed by miniaturisation, sample geometry and illumination conditions. To facilitate design of novel SFDI systems under such constraints, we have developed a model of an SFDI imaging system built on the open-source 3D modelling software Blender. Using Blender's Cycles ray-tracing engine, we are able to simulate a range of different scattering and absorption coefficients for a number of different imaging configurations, sample geometries and illumination patterns. Using established processing algorithms, we show we can recover maps of absorption, scattering and shape in a range of simulated ex vivo and in vivo imaging geometries with relevance to clinical detection of tumours. Our system enables accessible exploration of different optical configurations and realistic illumination conditions that will inform future design of compact, low-cost instruments.

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Section: Resultsmentioning

confidence: 99%

“…(Captured image taken from 5 ) patterns can also be used. 14 In this way, SFDI can be viewed as a special case of more general structured illumination techniques. 15 These sinusoids are often projected onto the sample at small angle from the normal (e.g.…”

Section: Introduction 11 Spatial Frequency Domain Imagingmentioning

confidence: 99%

Simulating medical applications of tissue optical property and shape imaging using open-source ray tracing software

Crowley

Gordon

2021

Biomedical Applications of Light Scattering XI

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“…The spectral resolution can be increased in dual‐modality color/hyperspectral systems from sparse spectral signals with CNNs [150]. To enable quantitative spectroscopy measurements in endoscopic imaging, it may be necessary to combine hyperspectral techniques with structured illumination and 3D mapping [103,150,154,157].…”

Section: Applications In Biomedical Opticsmentioning

confidence: 99%

Deep Learning in Biomedical Optics

et al. 2021

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This article reviews deep learning applications in biomedical optics with a particular emphasis on image formation. The review is organized by imaging domains within biomedical optics and includes microscopy, fluorescence lifetime imaging, in vivo microscopy, widefield endoscopy, optical coherence tomography, photoacoustic imaging, diffuse tomography, and functional optical brain imaging. For each of these domains, we summarize how deep learning has been applied and highlight methods by which deep learning can enable new capabilities for optics in medicine. Challenges and opportunities to improve translation and adoption of deep learning in biomedical optics are also summarized. Lasers Surg. Med. © 2021 Wiley Periodicals LLC

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“…12 SSOP uses a Fourier demodulation method to perform spatial frequency demodulation, which typically results in poorer image quality, although a method to retain more spatial resolution has been proposed using a Hilbert transform instead, 13 and emerging convolutional neural network techniques can improve the resolution. 14,15 SSOP has been shown to successfully quantify bowel ischaemia. 16 SFDI has shown to return successful contrast between healthy and malignant resected esophageal and colon tissue.…”

Section: Introductionmentioning

confidence: 99%

Ultra-miniature dual-wavelength spatial frequency domain imaging for micro-endoscopy

Crowley,

Gordon

2024

J. Biomed. Opt.

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There is a need for a cost-effective, quantitative imaging tool that can be deployed endoscopically to better detect early stage gastrointestinal cancers. Spatial frequency domain imaging (SFDI) is a low-cost imaging technique that produces near-real time, quantitative maps of absorption and reduced scattering coefficients, but most implementations are bulky and suitable only for use outside the body.Aim: We aim to develop an ultra-miniature SFDI system comprising an optical fiber array (diameter 0.125 mm) and a micro camera (1 × 1 mm package) to displace conventionally bulky components, in particular, the projector.Approach: First, we fabricated a prototype with an outer diameter of 3 mm, although the individual component dimensions could permit future packaging to a <1.5 mm diameter. We developed a phase-tracking algorithm to rapidly extract images with fringe projections at three equispaced phase shifts to perform SFDI demodulation.Results: To validate the performance, we first demonstrate comparable recovery of quantitative optical properties between our ultra-miniature system and a conventional bench-top SFDI system with an agreement of 15% and 6% for absorption and reduced scattering, respectively. Next, we demonstrate imaging of absorption and reduced scattering of tissue-mimicking phantoms providing enhanced contrast between simulated tissue types (healthy and tumour), done simultaneously at wavelengths of 515 and 660 nm. Using a support vector machine classifier, we estimate that sensitivity and specificity values of >90% are feasible for detecting simulated squamous cell carcinoma.Conclusions: This device shows promise as a cost-effective, quantitative imaging tool to detect variations in optical absorption and scattering as indicators of cancer.

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Speckle illumination SFDI for projector-free optical property mapping

Cited by 8 publications

References 25 publications

Simulating medical applications of tissue optical property and shape imaging using open-source ray tracing software

Simulating medical applications of tissue optical property and shape imaging using open-source ray tracing software

Deep Learning in Biomedical Optics

Ultra-miniature dual-wavelength spatial frequency domain imaging for micro-endoscopy

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