Thermal imaging apparatus and method of thermal imaging

A thermal imaging apparatus comprising:

• a thermal detector device comprising an array of thermal sensing pixels;
• signal processing circuitry operably coupled to the thermal detector device and comprising a background identifier and a pixel classifier, the background identifier comprising a common intensity identifier and an expected background intensity calculator;
• the background identifier is configured to receive pixel measurement data of an image captured, when in use, by the thermal detector device in respect of pixels of the array of thermal sensing pixels and the common intensity identifier is configured to identify a largest number of substantially the same pixel intensity values from the pixel measurement data received;
• the expected background intensity calculator is configured to use the largest number of substantially the same pixel intensity values to generate a model of expected background intensity levels referable by pixel;
• and
• the pixel classifier is configured to use the model to determine whether an intensity measurement by a pixel of the array of thermal sensing pixels corresponds to a background of the image or an object in the image.