Showing papers on "Thermography published in 1984"

Method of and apparatus for detecting corrosion utilizing infrared analysis

Abstract: A method and apparatus for the non-destructive identification and location of subcoating corrosion on a coated metal surface employing infrared thermography. The apparatus comprises a heat source for directing pulsed infrared radiation onto a test surface; a scanner for scanning the test surface for infrared radiation being emitted therefrom; a detector for capturing said emitted radiation and converting it into a signal representative of the thermal characteristics of the surface; and video display apparatus for visually displaying the signal as a thermal map of the surface. The method comprises the steps irradiating a test surface and detecting temperature differentials that occur on the irradiated surface.

Recent Advances in Medical Thermology

Abstract: Thermal Physiology.- Thermal Physiology - Introduction.- Human Skin Temperature and its Relevance in Physiology and Clinical Assessment.- The Special Thermal Physiology of Newborn Infants.- Skin Temperature Changes and Their Significance in the Human Newborn.- Changes in Thermal Physiology with Advancing Age.- Body Cooling and the Treatment of Heat Stroke.- The Physiology of Heat Production.- Thermoreception and Temperature Regulation in Man.- Cold Fiber Discharge Pattern under In Vitro Conditions: Ouabain and K+ Effects.- Physical Principles Governing Body Heat Exchange.- Environmental Heat Loss.- Thermographie Estimation of the Effective Heat Exchange Area between a Subject and Substrate.- Heat Loss from Patients During Anesthesia.- Environmental Influence on the Vascular Response of the Hands to Cold Challenge: Ambient Temperature and Time.- Temperature Changes Caused by Drugs.- Monitoring the Facial Flush: A Methodological Study.- Temperature Changes in Skin Disease.- Influence of Tissue Injury on Skin Temperature.- Development and Application of an Improved Thermal Dolorimeter.- Technical Developments and Instrumentation.- Technical Developments in Thermology - Introduction.- The Development of Thermal Imaging Systems.- Physical Aspects of Infrared Thermography.- Physical and Physiological Influence of Medical Ointments on Infrared Thermography.- Quality Control in Infrared Thermography.- Computer Processing of Thermographie Images.- Information Theory and Thermographie Quantification.- Microcomputer Standardization of the AGA 680M System.- Microprocessor-Assisted Breast Thermography.- Digital Thermography System.- Development of a Thermographie Skin Blood Flowmetry System.- A New Device for Thermography.- Pyroelectric Infrared Sensors.- Microwave Thermal Imaging: Technical Advances and Clinical Findings.- Progress in Microwave Thermography.- Temperature Distributions by Microwave Radiometric Measurements.- The Measurement of Permittivity and Temperature of Tissues.- Thermographie Techniques with Liquid Crystals in Medicine.- Non Sterol Liquid Crystal Thermographie Screen.- New Thermochromic Liquid Crystals.- BTD: Progress in Plate Thermography.- A Cheap and Simple Temperature Transducer: Its Application in Monitoring Breast Disease.- A Device for Thermal Clearance of the Skin.- An Assessment of the Thermal Clearance Method for Measuring Perfusion.- Vascular and Endocrine Diseases.- Vascular Diseases - Introduction.- The Concept of a Vascular Service.- An Assessment of Thermography in Arterial Disease.- The Role of Thermography in the Assessment of the Ischemic Limb.- The Correlation between After-Exercise Thermography (AET) and Deep Venous Insufficiency.- Thermography and Raynaud's Syndrome.- Comparison between Acute and Chronic Administration of a Combined Alpha- and Beta-Adrenoceptor Blocker (Labetolol) and a Beta-Adrenoceptor Blocker (Propranolol) in Hypertensive Subjects.- A Pilot Study in the Evaluation of B-Blockers in Hypertensive Patients with Thermography.- Thermography of Face and Neck of Patients after Cerebral Apoplexy.- Cardiac Muscle Thermography.- Telethermography in the Diagnosis of the Reflex Sympathetic Dystrophy.- Information from Scrotal Thermography.- Thermographie Examination of the Scrotum: Physical Factors.- Thermographie Characteristics of the Scrotum in the Infertile Male.- The Role of Liquid Crystal Thermography in the Diagnosis of Testicular and Thyroid Disorders.- Locomotor Diseases.- Locomotor Diseases - Introduction.- Thermography in Rheumatology.- Thermography and Muscular Injuries in Sports Medicine.- Thermology in the Assessment of Physical Therapy.- Heat Distribution over Joints:- the Normal and Abnormal Pattern.- Thermal Patterns of Osteoarthritic Knees and Hands.- Thermal Imaging in Assessment of Drugs in Rheumatology.- Thermography in Ankylosing Spondylitis.- Thermography and Radio-Isotopes in the Assessment of Sacroiliac Inflammation.- Lumbar, Thoracic and Cervical Thermography.- Liquid Crystal Thermography of the Spine and Extremities - Its Value in the Diagnosis of Spinal Root Syndrome.- Differential Diagnosis of Pain using Thermography.- Thermographie Diagnosis of Low Back Pain:-Relationship of Low Back Pain to Thermographie Changes in the Leg.- Thermography of Tennis Elbow.- A Finger Osteoid Osteoma: A Thermographie Investigation.- Infrared Thermography in the Assessment of Intradermal Skin Tests in Man.- Comparative Thermographie Assessment of Lower Leg Baths in Medicinal Mineral Waters (Nauheim Springs).- Thermography of Headaches.- Malignant Diseases.- Malignant Diseases - Introduction.- A Thermographie Prognostic Index.- Breast Cancer Detection by Absolute Temperature Thermography and Computer Techniques.- Breast Thermography as an Adjunct to Clinical Evaluation of the Breasts.- Detection of Subclinical Breast Cancers by Infrared Thermography.- Glucose Tests with Thermography in the Diagnosis of Breast Cancers.- Combined Diagnosis: Thermography, Mammography and Aspiration Cytology in Breast Disease.- Thermography in a Breast Screening Unit.- Correlation of Breast Images.- Bayesian Analysis of Thermographie Diagnosis of Breast Cancer.- Study of Breast Tumors by Thermography, 67Gallium Citrate and ECAT using 13N-Ammonia.- The Prognostic Value of Infrared Thermography for Operable Breast Cancer.- Results of Contact Thermography using the BTD System in 1500 Patients with 100 Mammary Carcinomas.- Breast Cancer Screening Indicator (BSCI): A Home-Use Device for the Detection of Breast Pathology.- Value of Infrared Thermography in the Assessment of Malignant Melanomas of the Skin.- Value of Thermography in the Diagnosis of Malignant Melanomas of the Skin.- Hyperthermia.- Hyperthermia - Introduction.- Infrared Thermography and Hyperthermia.- Progress in Microwave and Radiofrequency Hyperthermia Controlled by Microwave Thermography.- Experimental and Clinical Studies of Hyperthermia in Oncology using Different Electromagnetic Systems.- Kaliomimetic Ion Transport by Injured Membrane During In Vitro Hyperthermia of Tumor Cells.- Effect of Localised Hyperthermia on Tumor Blood Flow and Oxygenation.- Immunological Response to Whole Body Microwave Hyperthermia in Normal and Tumor - Bearing Animals.- Treatment of Malignant Neoplasms with Radiofrequency Hyperthermia - Clinical Experience.- Radiofrequency Hyperthermia (13.56 MHz) Associated with Radiotherapy or Chemotherapy in the Treatment of Cancer, with Atraumatic Control by Microwave Thermometry (2.4 GHz).- Hyperthermia Combined with Immune-Modulation in Cancer Therapy.- Author Index.

Aperture Synthesis Thermography -- A New Approach to Passive Microwave Temperature Measurements in the Body

Abstract: The radio astronomical technique of aperture synthesis is proposed for use in medical applications to give, noninvasively, a thermal image of a large fraction of the human body to a depth of several centimeters with no microwave irradiation. The principles of operation are illustrated by a practical design which could give a sensitivity of a few milli-Kelvin over a 50-cm field in a 10-s exposure. Applications of the proposed system include detection of cancers and other infections, and also rest-time monitoring of the effects of hyperthermia on the surrounding tissue.

Infrared Thermography As A Control For The Welding Process

Abstract: A feasibility study was performed to determine if infrared thermography could be used to detect perturbations in the arc welding process which result in defects. Data were gathered using an infrared camera with a resolution of .2°C which was trained on the molten metal pool during welding. Several defects were then intentionally induced and the resulting thermal images were preserved on film. These images revealed that different types of weld defects induce different characteristic changes in the thermal image by detectably altering the temperature field around the weld. These perturbations in the temperature field can be used to identify and locate defects such as arc misalignment, plate gap, puddle impurities etc. Macrostructural examinations permitted investigations into the relationships between weld puddle penetration depth and the temperature field. Using computer aided processing of these thermal images, it is expected that the welding process can be controlled to a higher degree than is presently possible.© (1984) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Liquid crystal thermography in water tunnels

Abstract: On decrit une methode utilisant des cristaux liquides thermographiques pour obtenir des mesures de temperature de surface quantitatives sur des maquettes en tunnel hydrodynamique

Infrared thermography system with sensitivity improved by progressive accumulation of image lines

Abstract: A thermography system comprising an infrared camera with line and raster scanners and at least one photosensitive detector, an electronic digital signal processor, and means for the visualization of the signal processed on the screen of a television monitor, a control unit can slow down raster scan in the camera by radio l/n, and can, simultaneously, cause special signal processing. "n" signals are added with respect to each element in a field by an adder and stored in a storage. The signals are provided at the line scanning rate, and cause the sum for each element in a line to be entered in an image storage, the image of the field of view with the sensitivity improved by line accumulation is reconstructed on the screen of the television monitor by repetitive reading of the image storage.

Accurate localisation of thermal gradients in lossy materials by correlation microwave thermography

Abstract: Correlation microwave thermography is able to bring new information about the geometry of thermal structures located in lossy materials. As an example, an experiment carried out in water points to the possibility of the location of a lateral thermal gradient with an accuracy of nearly one millimetre.

A thermal plume in the Tay estuary detected by aerial thermography

Abstract: The appearance of a small thermal plume detected on two successive overflights by an airborne infrared scanner operating in the 8-12 μm band is described. The spatial and temporal resolution achieved is discussed with reference to applying this technique to plumes from sewage outfalls and power stations.

Quality Control in Infrared Thermography

Abstract: The image produced by infrared (IR) thermography is used in a number of different forms. Direct viewing of the monochrome video screen is sometimes sufficient, and is described as thermoscopy. More often the image is processed in some way, with single isotherms, multiple color isotherms or digitization through a computer. Photographic or magnetic storage are frequently used.

Detection of Subclinical Breast Cancers by Infrared Thermography

Abstract: In our series of 4,000 verified breast cancers we have observed 130 sub-clinical, non-palpable carcinomas of 3 to 5 mm in diameter.

A Television Compatible Portable IR-CCD Camera System

Abstract: The design and performance of a standard television compatible, portable infrared charge-coupled device camera system is described. The sensor utilized is a 64 x 128 element Schottky barrier IR-CCD focal plane array cooled to cryogenic temperatures (77°K). The camera electronics generates the CCD clock waveforms necessary to drive the imager and contains all the video processing circuitry required to produce high quality IR imagery. The main feature of the video processing circuitry is a single-field subtraction circuit, using a field store with 8-bits of resolution, which suppresses fixed pattern noise (FPN), improves signal to noise (S/N), and decreases the minimum resolvable temperature. The RS-170 video signal output format enables direct interface to any standard video recording, processing or analysis equipment. A liquid nitrogen (dewar) cooling system and 12 volt D.C. power requirement permit portable applications of the system. Unlike scanning thermal imaging systems currently available, this prototype design is the first to incorporate a staring infrared focal plane array suitable for commercial applications. This camera demonstrates the high performance, design efficiency, and cost-effectiveness of a monolithic silicon Schottky barrier area sensor approach in an industrial infrared imaging system.

Progress in Microwave and Radiofrequency Hyperthermia Controlled by Microwave Thermography

Abstract: Previous feasibility experiments have indicated the possibility of achieving microwave local heating and microwave thermography with the same system.1,2 This combined process is now available for measurement and control of the local increase of temperature in hyperthermia therapy. Several systems have been built according to this principle3,4,5 which are intended for biomedical applications.

Objective documentation of myofascial triggerpoints by thermography

Abstract: ROOT COMPRESSION AND IRRITATION IN PAINFUL STATES. 6. E. Edwards, M.D. The Pain Rehabilitation Center., South Bend, Indiana 46617 Recent advances in Thermography technic and equipment have enabled many clinics to more fully evaluate pain problems, vascular compromise, and various neuropathies, which are many times difficult to diagnose and classify. Thermography demonstrates the subtle change in surface infra-red heat emanation reflecting underlying pathology of the body. Typical changes related to radicular pain, nerve root irritation, injury or 'compression are demonstrated. Circulatory changes observed in reflex sympathetic dystrophy with response to treatment are presented. These findings aid in the differential diagnosis of pain problems and are especially valuable in managing the patient who has been told repeatedly that "it is all in your head-go see a Psychiatrist".

Physical Aspects of Infrared Thermography

Abstract: Thermography in the widest sense of the term can be defined as the recording of temperature. In a similar way the well known rotating drum which records the air-temperature can be thought of as a thermograph. Indeed, such an instrument is often combined with a barograph and/or a hygrograph. However, nowadays the term thermography is mostly used in a narrower sense for a method of forming an image (the thermogram) of the temperature distribution over the surface of a body1 and this is achieved by using the radiation emitted from the surface of the body. Some authors call this tele-thermography to distinguish the method from contact thermography in which the thermal sensor is in direct contact with the body (eg liquid crystal thermography).2 In (tele-) thermography we may distinguish: 1. Infrared thermography using the infrared radiation emitted by the surface of the body at wavelengths between 0.8 μm and 1 mm. 2. Microwave Thermography using the microwave energy emitted by the body at wavelengths between 1 mm and 1 m.3

Microwave Thermal Imaging: Technical Advances and Clinical Findings

Abstract: In the last few years, prototype equipments of microwave thermography have been developed and used to evaluate subcutaneous temperature distributions in certain medical conditions. The clinical results obtained indicate the potential for microwave thermography for the thermal assessment of certain diseases. Applications include prognosis and follow-up, and the monitoring of tumour temperature during hyperthermia generated for therapeutic purposes.

Value of Infrared Thermography in the Assessment of Malignant Melanomas of the Skin

Abstract: Our material comprises 98 histologically confirmed cases of cutaneous malignant melanoma which we have been able to study since 1970 by means of infrared (IR) thermography. Attention to the application of this technique was previously drawn by Grosl and Maillard and Hessler.2 From ten years experience we have found infrared thermography to be of practical use in four ways: 1. For positive diagnosis. 2. To determine the spread of the disease. 3. For prognosis. 4. For monitoring the effects of treatment.

Computer Assisted Thermography And Its Application In Ovulation Detection

Abstract: Hardware and software of a computer-assisted image analyzing system used for infrared images in medical applications are discussed. The application of computer-assisted thermography (CAT) as a complementary diagnostic tool in centralized diagnostic management is proposed. The authors adopted 'Computer Assisted Thermography' to study physiological changes in the breasts related to the hormones characterizing the menstrual cycle of a woman. Based on clinical experi-ments followed by thermal image analysis, they suggest that 'differential skin temperature (DST)1 be measured to detect the fertility interval in the menstrual cycle of a woman.

A Comparison Of Infrared Flyover, Infrared Walkover, And Visual Inspection Techniques For Detecting Roof Moisture Anomalies

Abstract: This paper compares results of aerial infrared, infrared walkover, and Air Force visual inspection techniques for assessing the condition of built-up roofing systems. The two infrared techniques focus on locating thermal signatures indicating subsurface moisture damage. The visual inspection method rates visible surface defects, which may represent current or potential sources of moisture damage. The subject in this case was an 8.8-acre factory/warehouse roof in Danville, Illinois. Results of aerial and walkover infrared inspections corresponded strongly for large anomalies, but diverged on smaller ones. Roof Condition Index ratings from the visual inspection did not correlate significantly with the percentage of roof area judged suspect by either the aerial or walkover infrared inspection.© (1984) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Physical and Physiological Influence of Medical Ointments on Infrared Thermography

Abstract: Emission of electromagnetic energy at infrared wavelengths from the human body surface is the physical basis of infrared thermography (IRT). This implies that infrared emission of skin is well known and constant. If this is so then real surface temperatures can be calculated from detected radiance values. Local or temporary differences in emissivity of skin, however, can lead to misinterpretation of IRT measurements taken either for diagnosis or disease follow up.

Toward In-situ Building R-Value Measurement,

Abstract: : A technique for measuring the thermal resistance (r-value) of large areas of building envelope is under development. It employs infrared thermography to locate radiant temperature extremes on a building surface and to provide a map of normalized temperature values for interpolation between locations. Contact thermal sensors (thermocouples for temperature and thermopiles for heat flow) are used to calculated the r-value at specific locations by summing the output from each sensor until the ratio between temperature difference delta T from inside to outside surface and heat flow converges to a constant value. R-value measurements of a wood frame insulated wall were within 13% of the expected theoretical value. Similar measurements of masonry wall were 31 and 43% less than expected. Experimentation demonstrated that a large delta T was the single most important variable affecting accuracy and speed of convergence. Thermal guards around heat flow sensors were of little value, according to both experimentation and computer simulation. Attempts to match the absorptivity of sensors with their surroundings may have been insufficient to diminish about 10% of the remaining error in measurement. Lateral heat flow and convection may have been significant problems for accuracy in the masonry construction. Currently, an investigator cannot rely on the literature for guidance in assessing the limitations on accuracy for in-situ building r-value measurement.

Assessment Of Thermography As A Means For Determining Steam Trap Performance

Abstract: Several instrumented steam traps of all common types were tested to evaluate the thermal measurement technique as a way of determining steam trap performance. The results indicate that the thermal technique is not consistent in pinpointing faulty traps.

A Stabilized Broadband Correlator for Medical Microwave Thermography

Abstract: A stabilized broadband summing microwave correlator is presented that has particular application to medical microwave thermography. A dual IF is employed to minimize long-term drifts resulting from antenna-source mismatch, RF amplifier gain drifts, and changes in uncorrelated background radiation. The correlation of the source is generated by means of a digital line stretcher, rather than antenna-source movement. Preliminary measurements using a low-temperature thermal source in air are presented.

Comparison of microwave and infrared thermography in detecting malignant breast tumors

Abstract: Microwave thermography is a new method in the diagnosis of breast cancer. The paper reports on the use of a microwave thermographic unit in the examination of 190 patients. Evaluation criteria are defined and the results are compared with those obtained by infrared thermography.

Comparison Of Aerial To On-The-Roof Infrared Moisture Surveys

Abstract: Prior research by the Corps of Engineers has shown aerial thermography to he useful as a reconnaissance tool for finding wet roof insulation. This conclusion was based on findings from thermal line scanners flown at about 1000 feet in military fixed-wing aircraft and from hand-held thermal imagers flown at about 500 feet in military helicopters. During the spring of 1983 a comprehensive aerial to on-the-roof infrared comparison study was conducted on several roofs at Fort Devens, Massachusetts. These recent studies confirm our earlier opinion that oblique thermography is generally of reconnaissance value only. However, "straight-down" thermography from either fixed-wing aircraft or from helicopters can be used to produce reasonably accurate maps of wet roof areas. The most accurate maps were produced by thermal imaging systems in a helicopter hovering as close as 200 feet above a roof. This study suggests that some forms of airborne thermography can be of more value than just a reconnaissance tool in finding wet roof insulation. Of course, a visual examination of each roof along with a few core samples are still needed before recommendations for maintenance and repair can be made.

The Role Of Thermography In The Assessment Of The Thermal Integrity Of Federal Office Buildings

Abstract: Results were presented from ground-based infrared thermographic studies performed by the National Bureau of Standards (NBS) on eight federal office buildings. Infrared thermography was utilized to observe the thermal anomalies in those buildings, as part of a diagnostic program to evaluate the thermal integrity of building envelopes. Thermographic data were collected via complete exterior scannings and selected interior scannings at regions where thermal defects were identified or suspected during the outside inspections. Analysis from thermographic inspections with examples of defects found in some of these buildings are also included. The potential applications of the diagnostic procedures to both new and existing buildings are discussed.© (1984) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Thermal-Imaging System Performance Measures For Nondestructive Testing

Abstract: Thermal images result from temperature differences and/or emissivity differences (apparent temperature differences) in a scene or target. It is the function of a thermal-imaging system to reproduce an acceptable visible image of the scene or target from its thermal content. Thus, a thermal-imaging system is required to resolve spatial differences of temperature and emissivity. The performance of a thermal-imaging system may be specified by means of the fundamental performance measures, noise-equivalent temperature difference (NEAT), minimum-resolvable temperature difference (MRTD), and/or minimum detectable temperature difference (MDTD). Noise-equivalent temperature difference is a convenient measure of an imaging system's thermal sensitivity to a broad-area target (extended source); however, by itself it is no indicator of imaging capability. On the other hand, both minimum-resolvable temperature difference and minimum-detectable temperature difference address the imagery, which includes the human factor; i.e., the image observer. Thus, MRTD is a measure of the compound system-observer capability to spatially resolve temperature differences in a standard periodic-bar target by observing its display on a video monitor. The minimum-detectable temperature difference is similar to the MRTD, except the target geometry differs in being an aperiodic square. The measurement and the significance of each of these performance measures is discussed.

Microwave and Infrared Thermograms of Hot Spots in Tissue

Abstract: The steady-state temperature distribution in the vicinity of hot spots in tissue is investigated using the finite-difference method in a 3-dimensional model. Starting from these results the thermograms from microwave radiometers are computed and compared with those attainable with infrared (IR) thermography.

On Possibilities of Thermal Pattern Recognition by Correlation Microwave Thermography

Abstract: New results concern Correlation Microwave Thermography, a radiometric process, able to complement Microwave Thermography in biomedical applications. Experimental data point out a spatial resolution which, for steep thermal gradients, can reach about 1 mm for a difference of temperature ?T ? 1°C. Consequently, Thermal Pattern Recognition can be improved with this method, mainly in the monitoring of Hyperthermia.