Owing to the inconsistent image quality existing in routine obstetric ultrasound (US) scans that leads to a large intraobserver and interobserver variability, the aim of this study is to develop a quality-assured, fully automated US fetal head measurement system. A texton-based fetal head segmentation is used as a prerequisite step to obtain the head region. Textons are calculated using a filter bank designed specific for US fetal head structure. Both shape- and anatomic-based features calculated from the segmented head region are then fed into a random forest classifier to determine the quality of the image (e.g., whether the image is acquired from a correct imaging plane), from which fetal head measurements [biparietal diameter (BPD), occipital–frontal diameter (OFD), and head circumference (HC)] are derived. The experimental results show a good performance of our method for US quality assessment and fetal head measurements. The overall precision for automatic image quality assessment is 95.24% with 87.5% sensitivity and 100% specificity, while segmentation performance shows 99.27% (±0.26) of accuracy, 97.07% (±2.3) of sensitivity, 2.23 mm (±0.74) of the maximum symmetric contour distance, and 0.84 mm (±0.28) of the average symmetric contour distance. The statistical analysis results using paired t-test and Bland–Altman plots analysis indicate that the 95% limits of agreement for inter observer variability between the automated measurements and the senior expert measurements are 2.7 mm of BPD, 5.8 mm of OFD, and 10.4 mm of HC, whereas the mean differences are −0.038±1.38 mm, −0.20±2.98 mm, and −0.72±5.36 mm, respectively. These narrow 95% limits of agreements indicate a good level of consistency between the automated and the senior expert’s measurements.
This paper presents the analysis and derivation of the geometric relation between vanishing points and camera
parameters of central catadioptric camera systems. These vanishing points correspond to the three mutually orthogonal
directions of 3D real world coordinate system (i.e. X, Y and Z axes). Compared to vanishing points (VPs) in the
perspective projection, the advantages of VPs under central catadioptric projection are that there are normally two
vanishing points for each set of parallel lines, since lines are projected to conics in the catadioptric image plane. Also,
their vanishing points are usually located inside the image frame. We show that knowledge of the VPs corresponding to
XYZ axes from a single image can lead to simple derivation of both intrinsic and extrinsic parameters of the central
catadioptric system. This derived novel theory is demonstrated and tested on both synthetic and real data with respect to
noise sensitivity.
Western blotting electrophoretic sequencing is an analytical technique widely used in Functional Proteomics
to detect, recognize and quantify specific labelled proteins in biological samples. A commonly used label
for western blotting is Enhanced ChemiLuminescence (ECL) reagents based on fluorescent light emission of
Luminol at 425nm. Film emulsion is the conventional detection medium, but is characterized by non-linear
response and limited dynamic range. Several western blotting digital imaging systems have being developed,
mainly based on the use of cooled Charge Coupled Devices (CCDs) and single avalanche diodes that address
these issues. Even so these systems present key drawbacks, such as a low frame rate and require operation at
low temperature. Direct optical detection using Complementary Metal Oxide Semiconductor (CMOS) Active
Pixel Sensors (APS)could represent a suitable digital alternative for this application. In this paper the authors
demonstrate the viability of direct chemiluminescent light detection in western blotting electrophoresis using a
CMOS APS at room temperature. Furthermore, in recent years, improvements in fabrication techniques have
made available reliable processes for very large imagers, which can be now scaled up to wafer size, allowing
direct contact imaging of full size western blotting samples. We propose using a novel wafer scale APS (12.8
cm×13.2 cm), with an array architecture using two different pixel geometries that can deliver an inherently low
noise and high dynamic range image at the same time representing a dramatic improvement with respect to
the current western blotting imaging systems.
X-ray diffraction studies are used to identify specific materials. Several laboratory-based x-ray diffraction studies were
made for breast cancer diagnosis. Ideally a large area, low noise, linear and wide dynamic range digital x-ray detector is
required to perform x-ray diffraction measurements. Recently, digital detectors based on Complementary Metal-Oxide-
Semiconductor (CMOS) Active Pixel Sensor (APS) technology have been used in x-ray diffraction studies. Two APS
detectors, namely Vanilla and Large Area Sensor (LAS), were developed by the Multidimensional Integrated Intelligent
Imaging (MI-3) consortium to cover a range of scientific applications including x-ray diffraction. The MI-3 Plus
consortium developed a novel large area APS, named as Dynamically Adjustable Medical Imaging Technology
(DynAMITe), to combine the key characteristics of Vanilla and LAS with a number of extra features. The active area
(12.8 × 13.1 cm2) of DynaMITe offers the ability of angle dispersive x-ray diffraction (ADXRD). The current study
demonstrates the feasibility of using DynaMITe for breast cancer diagnosis by identifying six breast-equivalent plastics.
Further work will be done to optimize the system in order to perform ADXRD for identification of suspicious areas of
breast tissue following a conventional mammogram taken with the same sensor.
KEYWORDS: Sensors, Signal to noise ratio, High dynamic range imaging, Image sensors, CMOS sensors, Signal detection, Interference (communication), Transistors, Active sensors, Double positive medium
A new pixel structure for high dynamic range imaging is proposed. The internal pixel circuit resets the pixel each
time the well capacity nears saturation and a counter, implemented in the pixel itself (or in an external memory),
records the number of resets per integration time. The increase in the dynamic range is given by a factor of (m + 1)
where m is the number of internal resets per integration time. The peak signal-to-noise ratio will be increased due to
the effective increase in the well capacity. A multiple sampling technique can be used in the combination with this
proposed structure to achieve a further increase in dynamic range.
The paper describes a neural-based method for matching spatially distorted image sets. The matching of partially overlapping images is important in many applications-- integrating information from images formed from different spectral ranges, detecting changes in a scene and identifying objects of differing orientations and sizes. Our approach consists of extracting contour features from both images, describing the contour curves as sets of line segments, comparing these sets, determining the corresponding curves and their common reference points, calculating the image-to-image co-ordinate transformation parameters on the basis of the most successful variant of the derived curve relationships. The main steps are performed by custom neural networks. The algorithms describe in this paper have been successfully tested on a large set of images of the same terrain taken in different spectral ranges, at different seasons and rotated by various angles. In general, this experimental verification indicates that the proposed method for image fusion allows the robust detection of similar objects in noisy, distorted scenes where traditional approaches often fail.
M. Pokric, Nigel Allinson, Anthony Jorden, Matthew Cox, Andrew Marshall, P. Graham Long, Kevin Moon, Paul Jerram, Peter Pool, Colin Nave, Gareth Derbyshire, John Helliwell
The design and development of an area CCD-based X-ray detector system, using the first CCD imagers specially designed for macromolecular crystallography, is presented. The system is intended to produce the highest quality data for physically small crystals at synchrotron sources through the use of large CCDs--that is approaching wafer scale. This work is part of a large research and development program for advanced X-ray sensor technology, funded by industry and the Particle Physics and Astronomy Research Council in the UK. The detector has been optimized by increasing its efficiency at low X-ray energies for conventional laboratory sources, and offers fast readout and high dynamic range needed for efficient measurements at synchrotron sources. The detector consists of CCDs optically coupled to a X-ray sensitive phosphor via skewed fiber-optic studs. The individual three- sides buttable CCD consists of 2048 X 1536 27 micrometers square pixels (55.3 X 41.5 mm). The pixel size has been optimized to match diffraction spot profiling needs and the high dynamic range required for such applications. The multiple amplifier outputs possess switched responsivity to maximize the trade-off between signal handling capabilities and linearity. The readout noise is 5 electrons rms at a 1 MHz pixel rate at the high responsivity setting. A prototype detector system comprising two close-butted cooled CCDs is being developed. This system employs a high-efficiency scintillator with very low point spread function, skewed optical-fiber studs (instead of the more usual demagnifying tapers) to maximize the system's detective quantum efficiency and minimize optical distortions. Full system specifications and a novel crystallographic data processing are presented.
S. Bradbrook, Andrew Deacon, J. Habash, John Helliwell, M. Helliwell, Y. Nieh, E. Snell, S. Trapani, Andrew Thompson, J. Campbell, Nigel Allinson, Kevin Moon, T. Ursby, Michael Wulff
Time-resolved macromolecular x-ray crystallography is a new capability for structural analysis driven by continuing improvements in synchrotron x-ray sources, optics, and detectors (image plates and CCDs). Protein crystal Laue data (stationary crystal and polychromatic x-rays) were recorded at SRS Daresbury station 9.5 and ESRF Grenoble beamline 3, and processed with the Daresbury Laue software package. The Laue method allows exposure times set by the synchrotron electron bunch width, e.g. 50 picoseconds. The instruments and methods developments widen opportunities for perturbation chemical crystallography studies too. A temperature dependent phase transition of a liquid crystal nickel-octahexylphthalocyanine is studied with a rapid readout CCD detector. Structure solution by molecular replacement methods with Laue data is reported for orthorhombic lysozyme. By use of tetragonal lysozyme as a test case it is shown that with fine angular intervals, wide total angular coverage of Laue exposures and the deconvolution of multiples, good connectivity of electron density maps can be realized. The monochromatic rotating crystal method offers possibilites of extremely fast rotations which allow a complete data set to be recorded onto a single image--large-angle oscillation technique (LOT). the processed LOT data looks promising. LOT electron density maps are presented.
The paper presents the use of deep level transient spectroscopy to characterize trapping centers in CCD imagers. A discussion is presented regarding the effects of UV illumination and elevated temperature annealing in a hydrogen-rich environment. Two trapping centers are described, and the annealing experiments suggest techniques for extending CCD lifetimes.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.