Search results for "computer vision"

Mobile platform for online processing of multimodal skin optical images: Using online Matlab server for processing remission, fluorescence and laser …

2015

Mobile platform for multimodal skin assessment has been developed. Different illumination sources allow switching between modalities. Diffuse reflectance spectral imaging is provided by five LEDs, fluorescence is excited by 405 nm LEDs, and laser speckle by 650 nm laser diode. Handheld, battery powered device includes all light sources and color camera with USB. The core of the system is Linux OS embedded microcontroller. USB, FTP and HTML with JavaScript combination is used to create standard image transfer and control interface. In combination with built in WiFi access point it allows online skin images storage and processing. It means that data processing algorithms are located and updat…

3×3 Technique for RGB Snapshot Mapping of Skin Chromophores

2015

Three monochromatic spectral images have been extracted from a single RGB image data set at simultaneous illumination of skin by 473nm, 532nm and 609nm spectral lines. They were further transformed into distribution maps of three skin chromophores - melanin, oxy-hemoglobin and deoxy-hemoglobin, related to pigmented and vascular skin malformations. Performance and clinical potential of the proposed 3×3 technique is discussed.

Skin chromphore mapping by means of a modified video-microscope for skin malformation diagnosis

2013

Many spectral imaging devices are commercially available and used to detect certain skin pathology; however an alternative cost-efficient device can provide an advanced spectral analisys of skin. Multispectral device for diagnosis of pigmented skin lesions was developed and tested. Possibilities to map skin chromophores using a modified low-cost digital video-microscope is discussed. It was adapted for an advanced skin microscopy and used for detailed spectral analysis of skin. The device comprises CMOS digital imaging sensor, four-colour LED illumination system and image acquisition optics. The main goal is to obtain a set of spectral images of the skin area of interest for further convers…

2017

Objective Computer-aided-surgery in ENT surgery is mainly used for sinus surgery but navigation accuracy still reaches its limits for skull base procedures. Knowledge of navigation accuracy in distinct anatomical regions is therefore mandatory. This study examined whether navigation accuracy can be improved in specific anatomical localizations by using hybrid registration technique. Study design Experimental phantom study. Setting Operating room. Subjects and methods The gold standard of screw registration was compared with automatic LED-mask-registration alone, and in combination with additional surface matching. 3D-printer-based skull models with individual fabricated silicone skin were u…

Computer-aided navigation in neurosurgery

2003

The article comprises three main parts: a historical review on navigation, the mathematical basics for calculation and the clinical applications of navigation devices. Main historical steps are described from the first idea till the realisation of the frame-based and frameless navigation devices including robots. In particular the idea of robots can be traced back to the Iliad of Homer, the first testimony of European literature over 2500 years ago. In the second part the mathematical calculation of the mapping between the navigation and the image space is demonstrated, including different registration modalities and error estimations. The error of the navigation has to be divided into the …

NeXt for neuro-radiosurgery: A fully automatic approach for necrosis extraction in brain tumor MRI using an unsupervised machine learning technique

2017

Stereotactic neuro-radiosurgery is a well-established therapy for intracranial diseases, especially brain metastases and highly invasive cancers that are difficult to treat with conventional surgery or radiotherapy. Nowadays, magnetic resonance imaging (MRI) is the most used modality in radiation therapy for soft-tissue anatomical districts, allowing for an accurate gross tumor volume (GTV) segmentation. Investigating also necrotic material within the whole tumor has significant clinical value in treatment planning and cancer progression assessment. These pathological necrotic regions are generally characterized by hypoxia, which is implicated in several aspects of tumor development and gro…

Development of a Protocol for CCD Calibration: Application to a Multispectral Imaging System

2005

In this paper we describe in detail a method for calibrating a CCD-based camera. The calibration aims to remove both temporal and systematic noises introduced by the sensor, electronics, and optics after which we can correct the non-linearity of its response. For the non-linearity correction we use a simple and powerful approach consisting on a complementary approach between a polynomial fitting and an LUT based algorithm. The proposed methodology is accurate in the sense that it takes into account individual characteristics of each pixel. In each pixel, systematic noises are measured through acquiring offset images, thermal images, and FlatField images. A rigorous protocol for acquiring th…

Multi-spectral skin imaging by a consumer photo-camera

2010

The possibilities to perform multi-band spectral imaging by means of a consumer color camera without external filters have been studied. Images at up to 6 spectral bands may be extracted from a single color image after appropriate signal processing. The proposed technique was tested in pilot measurements of in-vivo skin hemoglobin maps and laser-excited autofluorescence images.

High Dynamic Range Spectral Imaging Pipeline For Multispectral Filter Array Cameras

2017

Spectral filter arrays imaging exhibits a strong similarity with color filter arrays. This permits us to embed this technology in practical vision systems with little adaptation of the existing solutions. In this communication, we define an imaging pipeline that permits high dynamic range (HDR)-spectral imaging, which is extended from color filter arrays. We propose an implementation of this pipeline on a prototype sensor and evaluate the quality of our implementation results on real data with objective metrics and visual examples. We demonstrate that we reduce noise, and, in particular we solve the problem of noise generated by the lack of energy balance. Data are provided to the community…

Causal analysis of short-term cardiovascular variability: state-dependent contribution of feedback and feedforward mechanisms.

2016

Baroreflex function is usually assessed from spontaneous oscillations of blood pressure (BP) and cardiac RR interval assuming a unidirectional influence from BP to RR. However, the interaction of BP and RR is bidirectional—RR also influences BP. Novel methods based on the concept of Granger causality were recently developed for separate analysis of feedback (baroreflex) and feedforward (mechanical) interactions between RR and BP. We aimed at assessing the proportion of the two causal directions of the interactions between RR and systolic BP (SBP) oscillations during various conditions, and at comparing causality measures from SBP to RR with baroreflex gain indexes. Arterial BP and ECG sig…