Probability Distributions.- Linear Models for Regression.- Linear Models for Classification.- Neural Networks.- Kernel Methods.- Sparse Kernel Machines.- Graphical Models.- Mixture Models and EM.- Approximate Inference.- Sampling Methods.- Continuous Latent Variables.- Sequential Data.- Combining Models.

Pattern Recognition and Machine Learning

Optical coherence tomography provides sections of tissues in a noncontact and noninvasive manner. The device measures the time delay and intensity of the light scattered or reflected from biological tissues, which results in tomographic imaging of their internal structure. This is achieved by scanning tissues at a resolution ranging from 1 to 15 μm. OCT enables real-time in situ imaging of tissues without the need for biopsy, histological procedures, or the use of X-rays, so it can be used in many fields of medicine. Its properties are not only particularly used in ophthalmology, in the diagnosis of all layers of the retina, but also increasingly in cardiology, gastroenterology, pulmonology, oncology, and dermatology. The basic properties of OCT, that is, noninvasiveness and low wattage of the used light, have also been appreciated in analytical technology by conservators, who use it to identify the quality and age of paintings, ceramics, or glass. Recently, the OCT technique of visualization is being tested in different fields of dentistry, which is depicted in the article.

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The Use of Optical Coherence Tomography in Dental Diagnostics: A State-of-the-Art Review

Near-infrared luminescent materials have attracted considerable interest because of their excellent performance in the field of optical imaging. Here, a series of Cr3+/Ni2+ co-doped near-infrared phosphors Zn1+ySnyGa2−2yO4 (ZSGO) were synthesized via a solid-state reaction. The phosphors show broad emissions in the range of 1100–1700 nm in the second NIR window. The emission intensity of Ni2+ could be greatly enhanced owing to the energy transfer from Cr3+ to Ni2+. The energy transfer mechanism was inferred from the excitation and emission spectra and the decay lifetime curve, which confirm that the primary process is the electric dipole–dipole interaction. In order to evaluate the potential optical imaging application, NIR-LED light source packages were fabricated with Cr3+/Ni2+ co-doped Zn1+ySnyGa2−2yO4 (ZSGO) phosphors and blue LED chips, which revealed high stability and a strong transilluminated biological tissue effect. These results indicate a great prospect in advanced optical imaging for NIR pc-LED applications.

Energy transfer enhanced broadband near-infrared phosphors: Cr3+/Ni2+ activated ZnGa2O4–Zn2SnO4 solid solutions for the second NIR window imaging

The aim of the present study was to determine the reliability of optical coherence tomography (OCT) in detecting cracked teeth and its relative clinical effectiveness by comparing it with other diagnostic methods including conventional visual inspection, trans-illumination, and micro-computed tomography (micro-CT). The reliability of swept source OCT (SS-OCT) was verified by comparing the number of detected crack lines on 109 surfaces of 61 teeth with those detected with other conventional methods. One to one comparison revealed that crack lines that were invisible with naked eyes could be found in SS-OCT images. The detection ability of SS-OCT was superior or similar to those of micro-CT (100.0 %) and trans-illumination. Crack lines shown in the SS-OCT images had distinct characteristics, and structural crack lines and craze lines could be distinguished in SS-OCT images. Thus, the detection ability of SS-OCT renders it an acceptable diagnostic device for cracked-tooth syndrome.

Dental optical coherence tomography: new potential diagnostic system for cracked-tooth syndrome

eCTG: an automatic procedure to extract digital cardiotocographic signals from digital images.

Cardiovascular disease (CVD) is the one of the biggest health problem in Indian and around the world as well. Electrocardiogram is a traditional method used for the diagnosis of heart diseases for about a century. Maintaining and retrieving patient history during a course of treatment is a essential but a laborious process. More particularly, over a decade ago thermal ECG records were stored physically, off late, due to advancement in technology; it has been stored as scanned ECG images. Storing the scanned ECG trace images requires considerable storage space. This necessitated the development of an automated solution capable of storing the ECG digitally, retrieving it quickly and detecting cardiac arrhythmia automatically. Majority of the ECG’s clinical information is said to be found in the intervals and amplitudes defined by its features (characteristic wave peaks and time durations).According to author’s knowledge, very few researchers [Lawson et al., 1995, Silva et al., Wang et al., 2009, Chebil et.al., 2008, Kao et al.,2001] have approached the extraction of ECG digital time series signal from scanned ECG trace images. Lawson et al., chose a scanning resolution of 200 dpi and used global thresholds to separate the ECG trace from the background grid lines. The low resolution results in loss of data accuracy and global thresholds results in missing pixels which are replenished by linear interpolation. Fabio Badilini et al., 2005 developed an application for extraction of the ECG trace from the image. But the method requires the user to fix anchor points for missing peaks and thus the accuracy comes down. Shen et al., separated the ECG trace from the background grids using the histogram. The missing pixels are replenished by checking the value of the pixel in the original image. This is a tedious process. Kao et al., employed a color filter to remove the background gridlines in the color image. There was a problem of missing pixels in the process which was replenished by linear interpolation. Jalel Chebil et al., performed a comparative study of the extracted trace accuracy by scanning the image at various resolutions. Global thresholds and median filtering were employed to remove background grids. The threshold to separate the trace from the background should be selected based on the nature of the image to avoid any

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A Novel Technique for ECG Morphology Interpretation and Arrhythmia Detection Based on Time Series Signal Extracted from Scanned ECG Record

Optical coherence tomography based imaging of dental demineralisation and cavity restoration in 840 nm and 1310 nm wavelength regions

A conventional optical coherence tomography (OCT) system was set up in-house to image early dental caries, identify gap formation in the bonding interface for restoration and secondary caries. Two-dimensional images of tooth samples was obtained and dental defect were identified. A novel electro-optic tuning system is proposed in order to improve scanning speed and to perform noiseless imaging. Preliminary studies were conducted with two crystals namely, LiNbO3 (Lithium Niobate) and KTP (Potassium Titanyl Phosphate) using a SLED source for OCT system and the simulated and experimental results were found to be qualitatively similar. The tuning range for LiNbO3 and KTP was found to be in the order of few micrometers whereas KTN (Potassium Tantalate Niobate) using the quadratic electro-optic effect is expected to show scanning range of tens of micrometers. KTN based hybrid scanning for dental caries imaging is also planned.

Development of an electro-optically tuned optical coherence tomography system for imaging dental lesions.

ECG is a valuable source of information regarding the patient's clinical data repository. Archiving the paper Electrocardiogram (ECG) trace as an image requires immense storage space and manpower for storage and retrieval of the patient records. Objective of this paper is to extract the ECG Morphological features from the paper ECG. In this paper, we have proposed a novel technique to extract the ECG Morphological features. The proposed algorithm has been evaluated with 25 patient's ECG sheets printed from 12-lead ECG equipments. Further, the proposed technique enhances the accuracy of heart rate and morphological feature extraction from the obtained time series signal. The evaluation of the digital time series data conversion algorithm has been performed by comparing obtained heart rate with value printed on the paper. The accuracy of the heart rate was found to be 99.12%. Evaluation of the proposed slope method for ECG morphological feature extraction was done by comparing the obtained values with manual data and this method offered an accuracy of 97.09%.

A novel method to extract ECG morphology from scanned ECG records

The Optical coherence tomography (OCT) based technique is proposed and demonstrated for determining the progress of dental caries. A conventional OCT system was setup in-house and was used to image natural caries, artificial caries and secondary caries with a resolution of 6.26 pm and 12.30 pm corresponding to 840 nm and 1310 nm, respectively. Dental caries were simulated artificially by mimicking the acidity of the oral cavity and imaged at different time intervals for upto 60 hours of demineralisation. The caries progression was estimated from the OCT images by measuring the thickness of the scattering and was found to be 45 to 50 micrometer deep in the 840 nm imaging and 40 to 48 micrometer deep for 1310 nm imaging for 60 hours of demineralisation. The same study was performed in an accelerated demineralisation environment in order to study the progression of caries and was found to be 200 to 210 micrometer deep for 68 hours of demineralisation.

Vani Damodaran

Papers

A Novel Technique for ECG Morphology Interpretation and Arrhythmia Detection Based on Time Series Signal Extracted from Scanned ECG Record

Optical coherence tomography based imaging of dental demineralisation and cavity restoration in 840 nm and 1310 nm wavelength regions

Development of an electro-optically tuned optical coherence tomography system for imaging dental lesions.

A novel method to extract ECG morphology from scanned ECG records

Imaging artificially induced dental caries using optical coherence tomography near 800 and 1300 nm region