Showing papers on "Thermography published in 1979"
TL;DR: In this paper, the authors used video-thermography to investigate the initiation and progression of subsurface damage caused by fatigue and vibration in both homogeneous and composite materials.
Abstract: Video-thermography, the time-resolved observation of infrared radiation, is a nondestructive inspection technique which offers many potential applications in the study of material behavior. The present work emphasizes detection of damage in both homogeneous and composite materials. This work differs from most others because the materials are subjected to some steady-state mechanical energy, such as fatigue loads or low-amplitude vibrations, that activates heat sources near the damaged regions. Experimental observations are discussed for a variety of materials, including boron/aluminum, boron/epoxy, graphite/epoxy, aluminum, and plastics. Thermography has been used to investigate initiation and progression of subsurface damage caused by fatigue; vibrothermography has been used to locate delaminations and similar damaged regions. Discussed are several analytical studies of the relation between evolution of heat and the stress field in the region of the damaged zone, and the expected surface heat pattern from a subsurface heat source in an anisotropic material.
94 citations
TL;DR: Detailed results of a study of breast cancer detection at 1.3 and 3.3 GHz are presented, including the dependence of detection rates on microwave frequency, time, tumor depth, and tumor size.
Abstract: We review the physical principles, method of operation, measurement limitations, and potential medical applications of microwave thermography. We present detailed results of a study of breast cancer detection at 1.3 and 3.3 GHz, including the dependence of detection rates on microwave frequency, time, tumor depth, and tumor size. At 1.3 GHz, microwave thermography detects breast cancer as well as infrared thermography (true-positive rate = 0.76 when true-negative rate = 0.63). When the two methods are combined, the true-positive rate increases by about 0.1 over that of either method alone.
71 citations
TL;DR: Thermography has the advantages of being noninvasive and can be used to measure blood perfusion in parts of the body not easily monitored with occlusive techniques and indicates thermography to be a useful means of measuring blood flow.
Abstract: The scanning infrared camera has been used to verify an analytical model relating blood perfusion rate to skin temperature. The blood perfusion rates were measured with both the mercury strain gage and the volume plethysmograph on the human forearm. Thermograms were taken of the forearm and temperature measured using an optical densitometer. Comparison of the volume plethysmograph with the strain gage, and the thermograms with the strain gage indicate thermography to be a useful means of measuring blood flow. Thermography has the advantages of being noninvasive and can be used to measure blood perfusion in parts of the body not easily monitored with occlusive techniques.
46 citations
TL;DR: Thermography at centimeter and millimeter wavelengths can measure subsurface temperatures of the human body and recent clinical results in treatment monitoring of arthritis, detection of tumors in the neck and brain area, and breast cancer are reviewed.
Abstract: Thermography at centimeter and millimeter wavelengths can measure subsurface temperatures of the human body. Radiative and bio-heat transfer influence the wavelength dependent subcutaneous temperature and spatial resolution. Recent clinical results in treatment monitoring of arthritis, detection of tumors in the neck and brain area, and breast cancer are reviewed.
44 citations
TL;DR: Thermography appears to be an effective research tool for determining thermal changes during ultra-speed cavity preparation, with an increase in intrapulpal temperature during cutting procedures.
Abstract: Thermography was employed to determine the pattern of heat generation, distribution and dissipation during ultra-high speed cavity preparation. Results indicate an increase in intrapulpal temperature during cutting procedures. No significant differences in the cooling effectiveness between air-water spray and air alone were found. Thermography appears to be an effective research tool for determining thermal changes.
30 citations
Journal Article•
TL;DR: Thermographic recorded Ts changes during dynamic one-legged exercise were higher in the exercising leg than the resting leg, supported by comparative Ts data taken from thermograms and thermistors.
Abstract: The present study explores the dynamic changes of surface temperatures associated with peripheral vascular shifts during and following hand gripping, one-legged ergometric, and running exercise. An AGA 680 thermovision system, incorporating a Bolex 16-mm camera and displaying 10-colored isotherms on a slave monitor, generated synchronous infrared (IR) movies at 16 frame/s. Incremental increases in surface skin temperatures (Ts) were observed while gripping at 20, 50, and 80% of maximum with a peak rise of 1.7 degrees C. Thermographic recorded Ts changes during dynamic one-legged exercise were higher in the exercising leg than the resting leg. Surface temperatures dropped in both limbs following exercise. The advantages of the use of thermography during transient thermal states, as produced by dynamic exercise, is supported by comparative Ts data taken from thermograms and thermistors.
23 citations
TL;DR: The presented type of thermography has obvious qualifications as a screening method in the early diagnosis of acute venous thromboses, being far less expensive but never the less more suited for objective numerical analyses and evaluation than conventional thermography with scanning cameras.
Abstract: A simplified thermographic technique has been developed to provide continuous leg temperature profiles by manual scanning with a noncontactile infrared radiation transducer connected to a linear potentiometer for determination of the transducer position. The clinical value of the technique in the diagnosis of acute venous thromboses has been estimated in seventy patients and thirty controls, using plethysmography and phlebography as methods of reference. The thermographic diagnosis was based on side differences in temperature levels within different segments of the limbs, as calculated from the temperature profiles by means of planimetric technique. Standardized temperature profiles from the medial side of the limbs were found to demonstrate a side difference above the reference level in fifty-seven of fifty-nine patients with acute venous thromboses, which means a diagnostic sensitivity corresponding to that of conventional thermography. Skin temperature profiles were superior to plethysmography, particu...
18 citations
TL;DR: There is a need for a statistically more significant number of cases, extension towards lower sensing frequencies and experiments on postoperative specimens and phantom models, indicating the depth sensing capabilities of millimeter waves.
Abstract: Thermographic studies of 14 patients with breast carcinoma were performed using two millimeter wave scanners for 30 and 68 GHz. Small correlation with infrared thermograms was observed indicating the depth sensing capabilities of millimeter waves. Correlation with mammographic and other clinical findings was good for tumors with medium subcutaneous depth. These preliminary results indicate a need for a statistically more significant number of cases, extension towards lower sensing frequencies and experiments on postoperative specimens and phantom models.
15 citations
TL;DR: Dynamic thermoangiography, a new physiological method of performing thermography with liquid crystal sheaths which may be vacuum contoured to any breast, is presented and preliminary results appear to show good correlation with conventional telethermography.
12 citations
TL;DR: Millimeter wave thermographic studies of neck and head diseases are reported; they yield more diagnostic information about subcutaneous and even intracranial thermal abnormalities than conventional infrared thermography which is limited to cutaneous temperature measurements.
Abstract: Millimeter wave thermographic studies of neck and head diseases are reported; they yield more diagnostic information about subcutaneous and even intracranial thermal abnormalities than conventional infrared thermography which is limited to cutaneous temperature measurements.
10 citations
Patent•
13 Mar 1979
TL;DR: In this article, a slit of an adjustable gap in front of the opening part of a black body furnace was provided to enable temperature calibration with one piece with good accuracy by providing a slit.
Abstract: PURPOSE:To enable temperature calibration to be performed with one piece with good accuracy by providing a slit of an adjustable gap in front of the opening part of a black body furnace in the black body furnace for temperature calibration of thermography apparatus.
01 Jan 1979
TL;DR: In this article, the utility of aerial thermography for determining rooftop heat losses was investigated, and it was found that the roof heat losses calculated using the remotely determined roof temperature agreed to within 17% of those calculated from ground measurements.
Abstract: The utility of aerial thermography for determining rooftop heat losses is investigated. Actual rooftop heat losses were obtained both from in-situ instrumentation of test roofs with known thermal resistances and aerial thermography obtained from overflights at an altitude of 305 m. It is found that the roof heat losses calculated using the remotely determined roof temperature agreed to within 17% of those calculated from ground measurements. However it is noted that an acceptable quantitative determination of roof heat losses using aerial thermography is only feasible when the convective term is accurately known or minimized. In addition, the sensitivity of the heat loss determination to environmental conditions is also evaluated. Finally, the analysis shows that the most reliable determinations can probably be obtained under conditions of total cloud cover with low wind speeds and at low ambient temperatures.
TL;DR: The results suggest that a thermography combined with auditory stimuli is useful to detect not only the distribution of skin temperature but also the activity level of the autonomic nerve.
Abstract: Vibration disease results from the usage of vibrating tools such as chain saws or pneumatic hammers for a long period. One of the principal manifestations of this disease is Raynaud's phenomenon in the fingers. In order to examine peripheral circulatory functions, a thermography was applied to the patients with vibration disease. The distribution of skin temperature in digits was clearly demonstrated by a thermography. By combination with auditory stimuli, a thermography showed dynamic changes of skin temperature in time. The recovery time course of skin temperature once reduced by auditory stimuli was related to the activity level of the autonomic nerve. However, this relation was not observed in cold water immersion test which was used as one of the peripheral circulatory function tests. These results suggest that a thermography combined with auditory stimuli is useful to detect not only the distribution of skin temperature but also the activity level of the autonomic nerve.
Patent•
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05 Jul 1979
TL;DR: In this article, an annular pleat 6 is provided in the position close to the region Z where heat equalizing characteristic within the cavity 3 and the face G facing the outside is made lower in emissivity by metal gloss.
Abstract: PURPOSE:To enable only the infrared radiation from the region Z of good heat equalizing characteristic to be detected by providing a portion of lower emissivity within the black body furnace in the black body furnace for temperature calibration of a thermography apparatus. CONSTITUTION:Heating wires 2 are wound on the circumference of a furnace core part 1 and a cavity 3 is provided therein to increase the emissivity of the inside surface. Further, a heat insulating material 4 and shield plate 5 are provided on the front face. An annular pleat 6 is provided in the position close to the region Z where heat equalizing characteristic within the cavity 3 and the face G thereof facing the outside is made lower in emissivity by metal gloss. When the focal length of the optical system is so controlled that the rise or fall of the portion of the detection signal when the luminous flux LB of the thermography apparauts scans the black body furnace becomes sharpest, then the optical system may be focused at the edge part F' of the pleat 6 and if scanning is made by the luminous flux LB of the same opening angle theta, the period T while scanning the region Z becomes longer and temperature calibration is accurately accomplished.
01 Jan 1979
TL;DR: Thermography is an alternative to X-Ray mammography for tumor detection by application of low level microwave energy and computer aided analysis techniques of the data is discussed.
Abstract: Thermography is an alternative to X-Ray mammography for tumor detection. Sensitivity of thermography is increased by application of low level microwave energy. Data obtained using guinea pig and rat implantable tumors is presented. Computer aided analysis techniques of the data is discussed.
TL;DR: In this paper, infrared thermography has been used to observe the beam-target interaction in a prototype injector vessel, which allowed the evaluation of the signal to noise ratio in the injection experiment.
Abstract: In conjunction with an experiment on high‐power neutral beam injection for a fusion device, infrared thermography has been used to observe the beam‐target interaction in a prototype injector vessel. The infrared radiation from the beam itself was studied, which allowed the evaluation of the signal to noise ratio in the injection experiment.
Journal Article•
06 Nov 1979
TL;DR: The prime consideration in the development of interactive software for the present phase (Phase II) was to minimize the chances of having undetected errors in this large data base of 20,000 breast images.
Abstract: Absolute Temperature Thermography (ATT) is the measurement and quantitative representation of ther mal radiation emitted at the skin surface. Accurate thermal data are obtained by calibrating a precise radiometric infrared scanner against a set of constant-temperature sources and subsequent digitization. The absolute temperature data are represented by an array of numbers. From these arrays of picture element (pel) values, diagnostic features (variables) are computed. The variables (features) are utilized in developing classification algorithms which will assign subjects into a normal or cancer class. The ATT approach is new and is the basis of a three-phased research program aimed at developing a safe and effective system for mass screening for breast cancer. A population sample of 10,000 women was obtained. The prime consideration in thedevel opment of interactive software for the presentphase (Phase II) was to minimize the chances of having undetected errors in this large data base of 20,000 breast images. A number of features of this "protective" software package are discussed.
06 Jul 1979
TL;DR: In this paper, a new method of infra-red thermography is developed using one and two dimensional arrays of Schottky barrier imaging detectors utilizing charge coupled device (CCD) readouts.
Abstract: A totally new method of infra-red thermography is being developed using one and two dimensional arrays of Schottky barrier imaging detectors utilizing charge coupled device (CCD) readouts. This system, operating in the region of high contrast infra-red output from the human body (3.4-4.2 microns,)offers the promise of providing higher spactial resolution than existing thermographic systems. The signal output from mirror scanned 256 element linear, and 25 X 50 element square arrays can be presented as a dynamic video display in a topological view, as well as in grey scale and colorized format, greatly enhancing the capacity for detailed diagnosis from the visible thermographic image. In addition, the detector signal can be computer analyzed for the acquisition of additional diagnostic information, as well as for enhancement of the visible display.© (1979) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.