SU1728680A1 - Device for thermovision temperature measurement - Google Patents

Abstract

The invention relates to instrumentation and can be used in measuring devices in determining the floor temperature of various objects. The purpose of the invention is to improve the accuracy of temperature measurement. The goal is achieved due to the fact that the device additionally introduces blocks for the formation of a contrast-frequency characteristic, accumulation of signals, determination of emissivity, blocks for scaling and correction filters, eliminates the influence of high-frequency components. 1 il.

Description

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The invention relates to an infrared (IR) technique and can be used in measuring devices and thermal flaw detection in determining the floor temperature of various objects, in particular, products of microelectronic technology.

Thermal imaging devices for temperature measurement using IR receivers and systems for digital processing of thermal images of objects are well known and widely used.

Known thermal imaging devices for temperature measurement have a number of specific disadvantages that reduce the accuracy of the measurement. So, for example, thermal imaging devices-defectos measure the temperature only if there is a reference reference thermogram by comparing it with the thermogram of the object under study. In this case, active monitoring is carried out by heating the object depending on time.

A significant disadvantage of the prior art thermal imaging device is the need to introduce a weakening reducing element. In addition, this device requires the immutability of the emissivity value over the entire thermal field of the object.

The closest to the invention in technical essence and the achieved result is a thermal imaging device for measuring temperature, which contains an object in the field of view of an IR receiver, a reference emitter, a source of reference radiation, a reference heating unit, a memory unit, a dividing unit and a display unit.

The main disadvantage of the known device is the low accuracy of temperature measurement. Large errors in temperature measurement introduce the multiplicative noise of the radiation-absorbing properties of the object.

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ABOUT

The purpose of the invention is to improve the accuracy of temperature measurement.

The goal is achieved by the fact that an object, a reference emitter, a reference radiation source, a reference heating unit, a memory unit, a dividing unit and a display unit are additionally introduced into a thermal imaging device for measuring temperature, which contains the location in the IR receiver's field of view. -frequency response, signal accumulation unit, two subtraction units, emissivity determination unit, background filter unit, correction unit, logarithmic conversion unit, unit an injector filter, an exponential conversion unit, a scaling unit, and a background emitter located in the field of view of the IR receiver, the reference heating unit being two-piece, and the output of the IR receiver connected to the input of the contrast-frequency characteristic shaping unit, the first output of which is connected to the first the input of the memory block, the second input of which is connected to the first output of the optical receiver, and the output of the memory block is connected to the input of the signal accumulation unit, the first and second outputs of which are connected to respectively, through the first and second subtraction units with the first and second inputs of the division unit, the output of which is through the serially connected emissivity unit, the background filter unit, the correction block, the logarithmic conversion unit, the notch filter unit, the exponential conversion unit, the scaling unit connected to the input of the unit indication, while the second and third inputs of the correction unit are connected to the second outputs of the formation unit of the contrast-frequency characteristic and the optical receiver and respectively.

Accuracy improvement is achieved by introducing a number of new blocks into a known device. In particular, the introduction of a background emitter and a background filter unit into a known device makes it possible to eliminate the influence of these components on the measurement accuracy. Introduction to the prototype circuit of the signal accumulation unit allows to increase the signal-to-noise ratio, and therefore, to increase the measurement reliability when the object is in strong thermal noise or in the presence of IR receiver noise and a digital signal processing system. The use of an optical radiation receiver and a unit for forming a contrast-frequency characteristic makes it possible to exclude the influence of the diffraction, aberration and defocusing of the optical-mechanical path on the measurement accuracy of the field.

thermal imaging device. The introduction of blocks of homomorphic processing significantly reduces the influence of the multiplicative noise fluctuations of the radiation-absorbing properties of an object.

The drawing shows a structural

thermal imaging device for measuring temperature,

The thermal imaging device for temperature measurement contains a two-piece

reference heating unit 1, emissivity sensor 2, object 3, reference emitter 4, background emitter 5, IR receiver 6, optical receiver 7, frequency-frequency forming unit

characteristics 8, memory unit 9, signal accumulation unit 10, thermogram subtraction unit of the emissivity sensor 11, object thermogram subtraction unit 12, thermogram division unit

13, the emissivity determination unit 14, the background influence influence unit 15. the correction unit 16, the logarithmic conversion unit 17, the notch unit

filters 18, exponential conversion unit 19, scaling unit 20 and display unit 21,

In the static state, the device has the following connections between individual

in blocks. The device contains a two-section reference heating unit 1, which is used to sequentially uniformly heat the emissivity sensor 2 and the object 3 to two known temperatures Ti and T2 located planarly in the field of view of the IR receiver 6. Planar with the emissivity sensor 2 and the object 3 in the field of view of the IR receiver 6 are also located

a reference emitter 4 intended for thermal calibration of the thermal imager, and a background emitter 5 providing information about the effect of the background. The radiation flux of the sensor, emissivity 2 enters the IR receiver 6, and the radiation flux of the object 3 enters both the IR receiver 6. and the optical receiver 7.

From the output of the IR receiver 6, the thermograms of the emissivity sensor 2 and the object 3 through the block for forming the contrast night characteristics 8 are fed to the first input of the memory block 9, the second input of which is fed to the optical image of the object 5 received in the optical receiver 7 and taken from his first exit. Corresponding signals with

the memory unit 9 through the accumulation unit of signals 10 is fed to the inputs of the unit for reading the thermograms of the emissivity sensor 11 and the unit for reading the thermograms of the object 12, from the outputs of which the full difference signals are fed to the first and second inputs of the unit of the thermograms 13. Signals from the output of the unit thermograms 13 through the emissivity determination unit 14 and the background influence influence unit 15 are fed to the first input of the correction unit 16, the second and third inputs of which receive signals from the second output of the optical receiver 7 and from the second output of the contrast-frequency shaping unit 8.

The corrected signals from the correction unit 16 through the logarithmic conversion units 17, notch filters 18, the exponential conversion 19 and the scaling 20 are fed to the display unit 21.

A thermal imaging device for temperature measurement has a number of significant advantages over basic samples and, in particular, over the selected prototype. Thus, for example, the device makes it possible to increase the reliability of measurements at low signal-to-noise ratios, when the useful signal is close to the noise level. This is achieved by accumulating signals. The efficiency and accuracy of temperature measurements are increased by eliminating the influence of the emissivity and high-frequency components of the multiplicative noise, as well as by taking into account the effect of the imperfection of the optical-mechanical path of the thermal imaging device.

Since all of the above reasons lead to temperature measurement errors reaching 30 ... 80%, the exclusion of even a part of them contributes to an increase in the accuracy of temperature measurement.

Claims (1)

The invention includes a thermal imaging device for measuring the temperature, which contains a reference emitter located in the field of view of an IR receiver, a reference radiation source, a reference heating unit, a memory unit, a dividing unit and an indication unit, characterized in that, in order to improve the measurement accuracy, 6nog formation of the contrast-frequency characteristic, signal accumulation unit, two subtraction units, emissivity determination unit, background filter unit, correction unit, logarithmic conversion unit, block notch filters, an exponential conversion unit, a scaling unit, a reference heating unit made of two sections, and a background emitter located in the field of view of the IR receiver, the output of the IR receiver connected to the input of the frequency-response characteristic unit, the first output of which is connected to the first the input of the memory block, the second input of which is connected to the first output of the optical receiver, and the output of the memory block is connected to the input of the signal accumulation unit, the first and second outputs of which are connected to respectively, through the first and second subtraction units with the first and second inputs of the dividing unit, the output of which is through the series-connected emissivity determination unit, background filter unit, correction unit, logarithmic conversion unit, notch filter unit, exponential conversion unit, scaling unit connected to the input of the unit indication, while the second and third inputs of the correction unit are connected to the second outputs of the block forming the contrast-frequency characteristic and optical receiver ka, respectively. Compiled by V. Bityukov Editor S. BotuzTehred M.MorgentalKorrektor M. Kucher va Order 1400 Circulation: Subscription VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, 4/5 Raushsk nab.