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tCam-Mini: An ESP32-Based Radiometric Thermal Imaging Camera

A simple-to-build streaming radiometric thermal imaging camera with powerful desktop software.

tCam-Mini is a small wireless streaming thermal imaging camera I designed to make it easy to get and use radiometric data from a Flir Lepton 3.5 sensor. I am interested in the radiometric data because it includes the temperature of every pixel in the scene allowing all kinds of interesting thermographic analysis. Of course that data can also be turned into the beautiful false-color images everyone associates with thermal imaging.

I designed a PCB but tCam-Mini can also be built using commonly available development boards and a few extra components. I describe that build here.

The tCam-Mini camera exposes the full capabilities of the Lepton.

The camera can operate in either Radiometric/TLinear (each pixel contains temperature data) or AGC modes (no temperature data in each pixel but better images).
Simple json-based command set with communication of a TCP/IP Socket. Makes interfacing with the camera very simple from a custom application.
AP or STA Wifi modes (static or DHCP-served IPV4 address).
Single image or streaming data modes.
Control over camera emissivity, gain and spotmeter location.
The desktop application makes it easy to use the camera and analyze the data from it.

Display images or streams with multiple palettes.
Save and load images or streams in files preserving the radiometric data for use later or by other applications. Two file formats: image and video (described in the github repository).
Export images as jpg, png or tiff files.
Copy current image to computer’s clipboard.
Histogram display and analysis of pixel populations.
Spotmeter and up to four additional markers showing temperature at various points in an image.
Graphing function to plot spotmeter and marker data over time.
Graph baseline mode to allow comparing temperatures to a reference point in the scene (for example to compare a temperature to a blackbody constant).
Export graph data in a text file for analysis by other programs.
Print graph (or create a PDF on computers that can print to PDF).”

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