A University of Houston professor of electrical and computer engineering is improving thermal imaging and infrared thermography with a new method to measure the continuous spectrum of light.

Jiming Bao's innovative method involves techniques that will be used to measure and visualize temperature distributions without direct contact with the subject being photographed, according to a news release from the university. The challenges generally faced by conventional thermal imaging is addressed, as the new study hopes to eliminate temperature dependence, and wavelength.

Thermal cameras and infrared thermometers measure temperature accurately from a distance because they are highly sensitive to light, which makes them valuable tools. Fields from the military, building, and mechanical inspections, and medical diagnostics, these industries depend on thermal cameras and infrared since they detect infrared radiation that is invisible to the human eye, and convert it into visible images. The issue is the level of accuracy, which Bao hopes to address with his solution.

“We designed a technique using a near-infrared spectrometer to measure the continuous spectrum and fit it using the ideal blackbody radiation formula,” Bao tells the journal Device. “This technique includes a simple calibration step to eliminate temperature- and wavelength-dependent emissivity.”

By using the near-infrared spectrometer, thermal radiation from a hot target can be collected with an optical fiber and recorded digitally. The collected spectrum is then normalized by using a system calibration response and finally fitted to determine the temperature.

“This technique overcomes challenges faced by conventional thermal cameras and infrared thermometers due to the unknown emissivity of targets and reveals much higher surface temperatures of photothermal catalysts than those measured by a buried thermocouple under strong light illumination,” Bao says in a news release.

Jiming Bao is a University of Houston professor of electrical and computer engineering. Photo via UH.edu