Two Wavelength Measurement : 2파장 측정
이를 많은 응용에 적용할 수 있도록, 스펙트럼 범위가 서로 가깝거나 부분적으로 겹치는 두 개의 검출기를 사용하는 것이 일반적입니다. 그러나 그 경우에도 두 방사율(emissivity)은 대개 서로 비슷한 수준에 불과한 경우가 많습니다. 따라서 두 방사율의 비율, 즉 이른바 기울기(slope)를 조정하는 것이 관행이 되었습니다. 개별 방사율 수준이 일정하지 않더라도 이 기울기는 대체로 거의 일정한 경우가 많습니다.
이중 파장 측정은 고온 및 까다로운 측정 조건이 특징인 산업 응용에서 특히 유리합니다. 주요 장점으로는 재료의 방사율이 알려져 있지 않거나 변동하더라도 정확한 측정을 보장하는 방사율 독립성이 있습니다. 이 기법은 또한 오염이나 측정 대상의 부분적 가림에 대한 강인성을 보여주며, 산업 공정에 필수적인 빠르고 정밀한 측정을 제공하는 높은 정확도와 속도를 제공합니다.
Two-wavelength measurement, also known as ratio pyrometry or two-color measurement, is an advanced non-contact temperature measurement technique that quantifies the ratio of radiation intensities at two distinct wavelengths instead of directly evaluating radiation intensities. This method facilitates precise temperature measurements, even under conditions of varying emissivity or partial obscuration of the measuring object. The technology leverages the fact that a material’s emissivity varies at different wavelengths. By calculating the ratio of the measured intensities, a temperature-independent quantity is derived, enabling accurate temperature determination. This applies strictly if the influence of the process under consideration or the environment on the emissivities of both wavelength signals is the same.
To make this possible for many applications, two detectors with spectral ranges that are close together or even partially overlapping are usually used. However, even then, both emissivities are often only similar to one another. It has therefore become common practice to adjust the ratio of both emissivities, the so-called slope. This is often approximately constant, even if the individual emissivity levels are not.
Two-wavelength measurement is particularly advantageous in industrial applications characterized by high temperatures and challenging measurement conditions. Key benefits include emissivity independence, which ensures precise measurements even with unknown or variable emissivity of the material. The technique also exhibits robustness, demonstrating resilience to contamination or partial obscuration of the measuring object, and provides high accuracy and speed, offering rapid and precise measurements crucial for industrial processes.