Showing papers on "Thermography published in 1975"

Analytical calculation of the skin temperature distribution due to subcutaneous heat production in a spherical heat source (relevant to thermography)

Abstract: An analytical solution of the thermal conductivity equation describing the surface temperature distribution over a buried heat source is given in tabular form. The solution is applicable to experimental models for studies of the surface temperature over an implanted artificial heat source. The results can also be used for the analysis of the skin temperature over biological heat sources such as breast tumours.

Skin temperature over an artificial heat source implanted in man (applied to IR thermography)

Abstract: The medical application of infrared thermography makes use of the skin temperature as an indication of an underlying pathological process. In order to study the relation between the heat production from a source in living tissue and the overlying skin temperature, artificial heat sources were implanted subcutaneously in human volunteers. The experimental results show that a detectable surface temperature increase over the heat sources presupposes high power output or superficial implantation. The effect of forced convective heat loss from the skin surface and lowered ambient temperature was studied. Forced convection markedly decreased the temperature contrast. An implicit conclusion from experimental and theoretical work is that a localized 'hot spot' can only exceptionally be attributed to metabolic heat production conducted to the skin surface from a buried pathological process.

Microwave thermography: a method of detecting subsurface thermal patterns.

Abstract: A discussion has been given of the principles and techniques of microwave thermography. The method is analogous to infrared thermography in that it detects thermal radiation emitted by the body. It differs in that it is sensitive to temperatures several centimeters beneath the skin surface and has coarser spatial resolution. Results are shown of successful attempts to detect subsurface thermal gradients in feline and human tissue. Planned clinical evaluation is described.

Breast thermography as a screening technique: An evalutation of performance data

Abstract: The concepts of relative operating characteristics (ROC-curves) and detectability index (d') are introduced for the purpose of evaluating performance in breast thermography. In assessing published information on the subject we have found that much of it is anecdotal and lacks sufficient data to determine performance. We have also found that for those published findings which had sufficient data it was possible to reconcile conflicting conclusions as to the efficacy of thermography, and that performance could be quantitated with the use of the detectability index. Conclusions for optimizing available clinical thermographic techniques are given together with ways for future improvement.

Techniques of infrared thermography.

Abstract: Considering the main objectives of thermographic techniques and the particular characteristics of passive infrared detection, the essential arguments in favor of single detector scanners have been pointed out after a brief discussion of the detection and image pickup methods when quantitative and precise (0.1 degrees C) information on the temperature distribution near ambient temperature must be obtained. Single detector scanners can have sufficiently good performance to reach the objectives of precise thermography, but their real technical limits must be well-known in practice; consequently, the thermograph performance must be clearly defined by means of the modulation transfer function, the intrinsic thermal resolution and the response uniformity, as we indicate in the second part of this paper.

Thermography and plant physiology.

Abstract: The temperature of a plant in a climatised room depends on the irradiation level. The use of a thermocamera is valuable for the characterisation of the complicated temperature distributions as can be found, for example, on a leaf in an assimilation chamber. Point measurements of temperature are useful only when the temperature distribution over an object is sufficiently known. The measurement of the radiation temperature of an object behind an infra-red transmitting filter is possible. The temperature distribution over a leaf depends on the gradients in irradiation and air humidity to which it is exposed, on local difference in stomatal opening and on air velocity.

Airborne thermography or infrared remote sensing.

Abstract: Airborne thermography is part of the more general remote sensing activity. The instruments suitable for image display are infrared line scanners. A great deal of interest has developed during the past 10 years in airborne thermal remote sensing and many applications are in progress. Infrared scanners on board a satellite are used for observation of cloud cover; airborne infrared scanners are used for forest fire detection, heat budget of soils, detecting insect attack, diseases, air pollution damage, water stress, salinity stress on vegetation, only to cite some main applications relevant to agronomy. Using this system it has become possible to get a 'picture' of our thermal environment.

Detecting structural heat losses with mobile infrared thermography. Part 3: Survey of USA CRREL

Abstract: : During the winter of 1973-74 a mobile infrared thermography system was used to survey the USACRREL building at Hanover, New Hampshire. This report provides a description of excessive heat losses at several locations around the building. This report also discusses the need to carefully monitor meteorological conditions before starting a survey of a building exterior to determine if solar radiation decay from the building surface might interfere with thermographic analysis by masking the heat emanating from within the building.

Infrared Imaging For Thermal Analysis Of Quality Control And Reliability Problems

Abstract: Infrared imaging devices can be used to view thermal characteristics in real time and to solve a wide variety of problems. An infrared microscanner originally introduced at SPIE in 1972 is shown applied to produce infrared signatures of beam lead devices . A number of other applications using other scanning techniques are also presented, including the examination of heat pipes, coatings, hybrid circuits and coils. Methods of using these thermal images in solving quality control and reliability problems are discussed.

Airborne thermography of temperature patterns in sugar beet piles

Abstract: An investigation was conducted to evaluate the use of thermography for locating spoilage areas (chimneys) within storage piles and to subsequently use the information for the scheduling of their processing. Thermal-infrared quantitative scanner data were acquired initially on January 16, 1975, over the storage piles at Moorhead, Minnesota, both during the day and predawn. Photographic data were acquired during the day mission to evaluate the effect of uneven snow cover on the thermal emittance, and the predawn thermography was used to locate potential chimneys. The piles were examined the day prior for indications of spoilage areas, and the ground crew indicated that no spoilage areas were located using their existing methods. Nine spoilage areas were interpreted from the thermography. The piles were rechecked by ground methods three days following the flights. Six of the nine areas delineated by thermography were actual spoilage areas.