Modular Imaging Research Articles

Acoustic Evolution Brings Full Characterization, Near-Deep Profiling

The evolution of sonic capabilities has now taken the form of a modular platform from which advanced geomechanical, petrophysical, geophysical, and reservoir measurements can be obtained, leading to actionable data about the drilling environment and the reservoir. Both short and long transmitter-to-receiver spacing and crossed dipole measurements, along with enhanced acoustic data for cement evaluation, are being obtained with the new Schlumberger sonic service. Currently in field-test, the new modular sonic imaging service, fully combinable with other wireline services, was developed to provide comprehensive, robust measurements in rock for incorporation with other formation measurements for use in reducing drilling risk, improving recovery, and maximizing productivity. Properties of elastic materials are well defined, but rock properties in formations vary with pressure and exhibit variations that are not easily predictable because of plastic and nonlinear deformation. Measurements at sonic frequencies continue to dominate evaluation efforts, with significant improvements being made since the introduction of wireline sonic tools in the 1950s. These improvements have culminated in a new sonic platform that can obtain stress information critical to wellbore placement and maximum reservoir drainage. The service provides a comprehensive, mechanical characterization of the wellbore, including 3D characterization of the compressional- and shear-wave slowness in terms of their axial, azimuthal, and radial variations that arise from nonuniform stress distributions, mechanical or near-wellbore-region alteration caused by the drilling process, and from formation intrinsic anisotropy related to the in-situ properties of the formation. The platform can be leveraged in a geomechanical application to deliver mechanical-property measurements that are derived from radial profiling using a dipole source that not only provides a large amount of energy over a wide frequency band, but also is capable of compensating for the effect of the sonic tool in the borehole (full characterization for acoustic predictability). Dipole radial profiling inverts the slowness response vs. frequency into a slowness response vs. depth into the formation. Radial profiling has not been previously available from either monopole or dipole tools. From a petrophysical perspective, monopole, dipole, and Stoneley acoustic measurements are applicable for gas detection, input to volumetrics, and permeability calculations. The new telemetry and optimized hardware and software can provide slowness measurements with enhanced reliability over an increased envelope of hole size and slowness, offering measurements from total depth to the mudline and at higher logging speeds. Benefits in Geomechanics Because shear-wave velocity responds to the solid framework of the rock and is not sensitive to fluid effects, it is important from a rock-mechanics perspective to evaluate shear velocity in both the far field and the near-wellbore region. Able to remain steady even in low-anisotropy conditions, new tool functions can discern the maximum-stress direction to as little as 2%. The importance of being able to profile shear slowness for the near-wellbore region and deep into the formation is seen when determining changes caused by drilling-induced stresses or stresses caused by intrinsic anisotropy (such as shales and fractures). It is also apparent when evaluating minimum/maximum stress direction for wellbore placement, during optimized drilling, and in oriented perforating. This is accomplished by rotating the measured waveforms into the fast (maximum stress) and slow (minimum stress) shear directions. The shear- and compression-al-wave velocity is also used as an input for calculating rock properties such as Poisson’s ratio, Young’s modulus, bulk modulus, and shear modulus. These properties, which control the physical behavior of the formation, are then used to calculate a safe mud-weight window or to reduce the uncertainty of well-bore instability ahead of the drill bit. They are also used in hydraulic-fracture design.

A system for imaging variable chlorophyll fluorescence of aquatic phototrophs

Abstract We describe a modular imaging system for mapping the variable chlorophyll fluorescence of photosynthetic organisms and tissues in the aquatic environment. The system is based on an array of blue LED's (470 nm) for excitation of chlorophyll and a modulated CCD camera equipped with a long-pass filter for detection of chlorophyll fluorescence >665 nm. The exposure of the sample with blue actinic light, non-actinic measuring light, and a flash of saturating light is based on a software-controlled sequence of variable pulse-widths of the LED's. The LED and the camera modulation are controlled via a custom designed timer-unit connected to a PC. We present examples of application for mapping the distribution of photosynthetic activity in coral tissue, communities of endolithic algae within coral skeleton as well as in tissue of didemnid ascidians harboring symbiotic cyanobacteria. It is possible to study spatio-temporal patterns of variable fluorescence (and the derived quantum yield of photosystem II-r...

Mapping coal fires based on OMIS1 thermal infrared band image

OMIS1 (Operative Modular Imaging Spectrometer) is a new imaging spectrometer designed by Shanghai Institute of Technical Physics, and has eight thermal infrared bands (nos. 105–112). This paper presents the use of images obtained from these thermal infrared bands to detect and map coal fires in north-western China. According to experiments in the Rujigou area of Ningxia municipality, each thermal infrared band has high correlation (>0.939). Regression analysis of land surface temperature (LST) with the pixel value in each thermal infrared band indicates: (1) for images acquired at daytime (from 11:00 to 13:00 local time), the first four thermal infrared bands have a linear relationship, and the final four bands have an exponential relationship; (2) for images acquired in the early morning (from 06:00 to 07:30), each band has a linear relationship. In conclusion, the ground temperature map is based on the 107th band of morning time. The mapping error is greatly determined by the quantity and precision of ground data measured synchronously.

Polycyclic groups with modular finite homomorphic images

A group G is said to be a modular group if it has modular subgroup lattice. We will prove in this paper that a polycyclic group G is modular if and only if all its finite homomorphic images are modular groups. Similar results will also be obtained for other conditions of modular type.

High speed and high resolution cardiac MRI (parallel acquisition techniques & modular imaging)

High speed and high resolution cardiac MRI (parallel acquisition techniques & modular imaging)

High speed and high resolution cardiac MRI (parallel acquisition techniques & modular imaging)

In conclusion, further development is required before cardiac, and specifically coronary MRI, becomes a standard clinical tool, but new flexible concepts are being developed to achieve this goal.

Imaging spectrometry data correlated to hydrocarbon microseepage

Modular Airborne Imaging Spectrometer (MAIS) data were used to map hydrocarbon microseepages in the Weibei Depression, People's Republic of China, as an aid to petroleum exploration. To convert the radiance data to reflectance, the Empirical Line Method was used and the resulting data were similar to the field spectra. After first delineating the wheat fields, three bands (at 719.75nm, 739nm and 758.25nm) were used to map the pixels that had a red shift. A neighbourhood summation function was applied to evaluate which pixels were more likely to be anomalies. The non-systematic geometric distortions were corrected with the aid of linear features in the image and subsequently the systematic geometric distortions were corrected using ground control points. Ethane concentrations of 217 soil samples were used to assess the mapping result. It appears that high ethane concentrations in the map area are positively correlated to red-edge shift, which suggests that a high ethane concentration in soil may cause red-edge shift in wheat spectra. However, sub-surface structure and stratigraphy must be considered as well when analysing MAIS data.

Observations on temporal red shift of wheat from multi-date spaceborne MOS-B spectrometer data

High spectral resolution spectroscopy enables to have detailed information on chemical and morphological status of crop. An attempt of using space platform for detecting red edge shift during different growth stages of wheat crop is reported. Study was conducted during rabi 1996–97 season using Modular Opto-Electronic Scanner MOS-B Imaging data onboard IRS-P3 satellite. Inverted Gaussian model was fitted for satellite derived reflectances between 650 and 870 nm to derive inflection wavelength and its subsequent change with crop stages i.e. red shift. Red shift of 10 nm observed from crown root initiation stage (703.8 nm) to peak vegetative stage (714.2 nm). A comparative study on temporal behaviour of vegetative indices like NDVI and ARVI with Red edge showed that latter is more atmospherically stable parameter. It is concluded that red edge shift which hitherto has been observed from ground and airborne sensors, can also be detected from space.

MAIS imaging spectrometer data analysis for Ni-Cu prospecting in ultramafic rocks of the Jinchuan group, China

The Jinchuan intrusion, situated in the Gansu province of China some 30 km NE of Yongcang city is an ultramafic dyke-like body emplaced in the Longshoushan uplifted terrain on the southwest margin of the Sino-Korea platform. The intrusion is 6 km long, 35 m wide and hosts a major Ni-Cu sulfide deposit. The main stratigraphic units include the highly metamorphosed Lower Proterozoic Longshoushan group and the less extensively metamorphosed Dongzigou and Hanmushan groups of Middle and Upper Proterozoic age. The Longshoushan group consists of serpentine marble, schist, gneiss and plagioclase amphibolite. The Dongzigou group comprises schists and granitic rocks. The Hanmushan group basically is represented by a large variety of volcanics. Small mafic-ultramafic intrusions are located along faults in the Jinchuan terrain. These ultramafic rock bodies show a concentric zoning with a core of dunites and olivine pyroxenites forming the margins of the bodies. Hydrothermal alteration (mainly serpentinization) has affected the rocks of the ultramafic bodies to a variable extent; the dunites are extensively altered whereas the pyroxene rich units are relatively fresh. Field spectroscopy is used to spectrally characterize the major rock units. Imaging spectrometer data was flown during the end of July until beginning of August of 1993 with a Chinese imaging spectrometer instrument called MAIS: the Modular Airborne Imaging Spectrometer. Feature characterization permits lithologic mapping from MAIS data. This aids in mineral potential mapping in the Jinchuan region and permits the identification of areas of possible Ni-Cu deposits.

Automated image analysis DNA cytometry to predict the pathological stage in clinical stage I nonseminomatous testicular germ cell tumors.

Automated image analysis DNA cytometry was used to predict the pathological stage in clinical stage I nonseminomatous testicular germ cell tumor patients. Orchiectomy specimens of 74 patients (41 pathological stage I, 33 pathological stage II) were analyzed by modular image analysis computer, and several mathematical indices from the DNA histogram were calculated. The 5c-exceeding rate (rate of hyperpentaploid nuclei) was found to be significantly higher in patients with pathological stage II disease as compared with patients without metastases (p = 0.0174). Tumor tissue from lymph node metastases showed even higher amounts of hyperpentaploid nuclei (p < 0.0005). In this study, all patients with a 5c-exceeding rate above 3.1% had metastatic disease. Single-cell cytophotometry was able to show significant differences in 5c-exceeding rates between patients with and without tumor metastases. Because of high standard deviations, however, it was not possible to use this parameter for correct staging in all patients.

A commercial image processing system considered for triggering in future LHC experiments

Experiments at the future Large Hadron Collider (LHC) at CERN will be faced with an extraordinary problem of event selection in real time. Algorithms at different levels of locality are needed, among them local feature extraction algorithms that are typical in many image processing tasks. We report here about implementations of several such local algorithms on a commercial modular image processing system, for a decision frequency of 100 kHz (“second-level”). Such devices can keep up with the required decision frequency for suitable algorithms, for some algorithms custom hardware additions would be necessary.

Automated image analysis DNA cytometry in testicular cancer.

The value of automated DNA cytometry for differentiation of testis cancer was evaluated in 54 seminomas, 13 HCG-positive seminomas, and 48 embryonal carcinomas. Slices of paraffin embedded tissue were enzymatically digested and stained with Feulgen SITS after fixation on glass slides. Automated DNA cytometry was performed with a Modular Image Analysis Computer (MIAC). DNA histogram phenotpye and computed DNA indices were correlated with the different tumor types. The ratio of hypertriploid to hypotriploid increased from HCG-positive seminoma over embryonal carcinoma to seminoma. The following mathematical DNA indices were found to correlate with tumor type: mean ploidy, 2c deviation index, 5c exceeding rate, variation coefficient of the GO/1 fraction and DNA nucleus diameter correlation.

Automated image cytometry for detection of rare, viral antigen-positive cells in peripheral blood.

A cell detection method based upon automated screening is described for recognition of low frequencies (1 in 100,000) of immuno-enzymatically labelled white blood cells in human peripheral blood. The used image cytometry instrumentation (LEYTAS) includes a wide-field, fully automated microscope (Autoplan) and a modular image analysis computer (MIAC), both from Leica, Wetzlar, Germany. The MIAC contains image boards for optimum use of mathematical morphology algorithms. Communication with the MIAC is via a personal computer. Programs for automated cell analysis have been written in C language. Main features of the system are fast analysis of large microscope fields including a count of all cells, selection of objects of interest (alarms), and display of digitally stored images of these alarms. We tested this system for the detection of white blood cells expressing antigen of cytomegalovirus (pp65) in 50 human blood smears from kidney transplant recipients. Immuno-enzymatic (peroxidase) staining was performed with DAB and counterstaining with hematoxylin. For determination of the sensitivity, a series of dilutions of a positive sample with a negative sample was performed. The lowest frequency detected was 1 antigen-positive cell/3 x 10(5) antigen-negative cells. Screening time was about 60 min for one million cells.

Symmorphic space groups of finite crystal lattices

The symmorphic space group of a finite n-dimensional crystal lattice is studied and its factorization is presented. This lattice is determined by a direct product of cyclic groups and then its translation, point and space groups are defined as modular images of corresponding ones for a lattice of infinite extent. A factorization of holohedries (of an infinite lattice) is used in order to present a symmorphic finite space group as a direct product. As an example, and as a very special case, a space group in the case of the hypercubic lattice is studied and its irreducible representations are investigated. The results obtained suggest that for vectors lying on a surface of the first Brillouin zone (i.e. for which at least one coordinate is equal to 0 or 1/2) an additional index describing their symmetry properties should be introduced. This enables the authors to make a more detailed classification of states (energy levels). On the other hand, finite symmorphic space groups can be used within, e.g., the so-called finite-lattice approach.

Prevention of cranial reossification after surgical craniectomy.

An experimental study in rats was designed to see whether the pericranium, used as a graft over the dura, can prevent or delay osseous reunion after craniectomy. A 10 x 3-mm section of the frontal and parietal bones, including the coronal suture line, was resected in 15 rats. Pericranium was then used as a free graft on one-half of the defect to cover the dura and separate it from the cut edges of the craniectomy. The other side acted as a control. All animals were killed 2 months after operation, the skull was removed, and any remaining bony defect on either side of the midline was revealed. The area of residual defect in 13 specimens was determined by statistical image analysis using the Oxford Modular Cataract Image Analysis System (Oxford, England) and Wilcoxon's rank sum test and showed a highly significant difference between the treated and the untreated sides (p = 0.002).

A proposed modular imaging system for photoelectron and electron probe microscopy with aberration correction, and for mirror microscopy and low-energy electron microscopy

The design of an electron microscope is proposed which introduces a hyperbolic electron mirror to provide simultaneous correction of spherical and chromatic aberration. The beam-separating system is of novel design. The instrument is modular, and can be configured to be a photoelectron microscope (PEM, also called a photoelectron emission microscope, PEEM), an electron probe, or a transmission electron microscope (TEM), all with aberration correction. By substituting a high-voltage PEM-type specimen stage for the hyperbolic mirror, the instrument becomes a mirror electron microscope (MEM) or a low-energy electron microscope (LEEM).

Automated Cell Analysis for DNA Studies of Large Cell Populations Using the LEYTAS Image Cytometry System

Image cytometry by means of LEYTAS features analysis of both fresh and archival cellular material. Although not as accurate in ploidy determination as flow cytometry, LEYTAS cytometry incorporates extensive artefact rejection algorithms, thereby allowing detection of low frequency cells. This feature is very useful for the search of rare cells, as e.g. in cervical screening, or for the quantitation of the number of high DNA content cells in the total cell sample. LEYTAS main components are an automated microscope (Autoplan) and a Modular Image Analysis Computer (MIAC), both from Wild Leitz (W-Germany). This paper discusses LEYTAS instrumentation and cell analysis by means of programs especially written for LEYTAS.

The computation of polynomial greatest common divisors over an algebraic number field

We present a modular algorithm for computing the greatest common divisor of two polynomials over an algebraic number field. Our algorithm is an application of ideas of Brown and Collins. We use the Weinberger-Rothschild homomorphic scheme with the important change that we avoid factoring the modular image of the minimal polynomial. We perform a computing time analysis and report some empirical computing times.

86 - MIAC: A Modular Image Analysis Computer for Automated Cytology

86 - MIAC: A Modular Image Analysis Computer for Automated Cytology

Surface-based radar imaging of sea ice

The paper examines the use of a surface-based marine radar for imaging the surface features of sea ice in full ice cover. Two aspects of the problem are considered: 1) selection of radar parameters which maximize the effectiveness of the radar for ice imaging, and 2) evaluation of image processing (display) techniques that effectively convey to an operator the information contained in the radar returns. Both aspects of the study are supported by data collected at a radar site on Baffin Island, Canada. The paper also briefly describes the characteristics of first-year ice, multiyear ice, and icebergs, which are pertinent to the understanding of the radar ice-imaging problem. Based on the results presented on radar parameter evaluation, it is recommended that: 1) the radar resolution should be as high as possible; 2) the antenna should be installed as high as possible; 3) the radar should receive both like- and cross-polarized returns; 4) two radars, operating at widely separate frequencies, should be used. Based on the results of the display work, it is recommended that: 1) the display should use a scan technology that affords the required number of intensity levels; 2) median filtering should be used to reduce the effects of spike noise, if present; 3) normalization should be used to remove the range-dependence of radar returns; 4) selective edge enhancement be employed to maximize significant image detail; 5) to fully utilize the intensity levels available in the display, the histogram of the image should be modified, taking into account the visual response of the operator; 6) color can be used to accommodate the display of multi-parameter images, such as those arising from the use of like. and cross-polarization; 7) Features 3), 4), and 5) may be integrated into a modular image processing system.