Teledyne FLIR’s New Radiometric Thermal Camera Offers Widest FOV Yet

August 15, 2023 by Aaron Carman

With a wider FOV and radiometric abilities, the newest thermal camera module allows designers to see more in the same package size as previous Lepton cameras.

Building on its Lepton series of thermal imagers, Teledyne FLIR has released the Lepton 3.1R radiometric thermal camera. The Lepton series allows designers to integrate thermal imaging and radiometric capabilities into all new devices thanks to its small size, and the Lepton 3.1R continues this trend by offering improved specs in the same package.


The Lepton 3.1R

The Lepton 3.1R gives designers a wider FOV and radiometric abilities for safety-critical applications such as fire or people monitoring in a familiar ultra-small package. Image used courtesy of Teledyne FLIR

At its core, the Lepton 3.1R improves past generations by supporting a wider field of view and radiometric capabilities, something that distinguishes it from others in the Lepton family and opens new applications for the cameras. This article breaks down radiometric thermal imaging to give readers a sense of why the Lepton 3.1R is an important step toward new solutions when space is at a premium.


Absolute Temperature Measurements

One of the major benefits of the Lepton 3.1R is the radiometric output of the sensor. In broad terms, radiometric thermal cameras can output the absolute temperature at every pixel in the thermal image, while nonradiometric thermal cameras only output the temperature differences in relation to the rest of the image.


Radiometric thermal cameras

To measure absolute temperature, radiometric thermal cameras must detect the intensity of IR signals at each point in the sensor array. Image used courtesy of Gamma Scientific

Designers can accomplish radiometry for thermal imaging by precisely measuring the intensity of the infrared radiation reaching the sensor. By performing this operation at every point in the image using a combination of IR lenses and an IR detector array, designers can determine the absolute temperature values at every point.

This makes the camera useful for applications that require accurate absolute measurements, such as safety-critical designs. Compared to nonradiometric thermal cameras, radiometric thermal imagers give designers access to the true temperature at each point, enabling better performance.


An Expanded Field of View

In addition to its radiometric capabilities, the Lepton 3.1R stands out due to its extremely wide field of view (FOV) of 95°. While other members of the Lepton family offer a maximum of 57° FOV (and not always with radiometry abilities), the Lepton 3.1R gives designers considerably more measurement ability in the same form factor.


A comparison of the FOV of two members of the Lepton family

A comparison of the FOV of two members of the Lepton family shows the increased FOV of the Lepton 3.1R and how it could benefit designs needing to monitor a wide area. Screenshot used courtesy of Teledyne FLIR

The Lepton 3.1R uses the same communications protocols and form factors as previous generations, making upgrading to the camera module a simple task. The device is available for order now alongside the FLIR Lepton breakout board to allow designers to rapidly evaluate the camera’s performance using familiar equipment such as the Raspberry Pi


Variety Within the Lepton Family

Although the Lepton 3.1R sounds like an all-around upgrade over previous generations, engineers can choose different members of the Lepton family according to specific design parameters. If, for example, a designer needs more angular resolution, the Lepton 3.5 may be the right solution due to its similar resolution with a smaller FOV. In instances that require absolute measurements over a wide FOV, such as fire monitoring or industrial efficiency measurements, the Lepton 3.1R can still deliver.