How do thermal cameras work

Thermal cameras are a type of security camera that is frequently utilised in modern security systems. These CCTV cameras are effective over close and far distances, enabling them to have a variety of different applications, for both residential and commercial uses. 

At iCam Security, we stock a variety of thermal cameras from trusted brands like Hikvision. These products produce reliable footage all-year-round, regardless of changing weather and lighting conditions. Additionally, some of our thermal imaging cameras feature bi-spectrum image fusion technology and deep learning algorithms, producing enhanced images and extremely accurate analytics. 

Nearly everything in our world emits heat, also known as thermal energy, at different levels. For instance, the body temperature of a human is typically 37˚C, whilst the temperature of the ocean may be 12˚C on a cool day. Thermal imaging cameras contain advanced technology that recognises this difference in temperature that is invisible to the naked eye, allowing you to see the temperature of objects and animals. 

One of the major benefits of thermal cameras is that they can recognise tiny variations between temperatures, which can be as small as 0.01˚C! As thermal imaging cameras are so accurate, it is extremely difficult for a potential intruder to hide. 

For example, imagine an intruder has broken into private property in the middle of the night. With a normal security camera, the intruder would easily be able to remain hidden due to the low light level. 

However, with a thermal camera, this is not the case. Rather than relying on motion and sufficient lighting conditions, thermal imaging cameras detect thermal energy, meaning they can operate in complete darkness. As shown below, the intruder using an optical security camera is completely undetectable but can be easily detected using the thermal camera.

Optical vs thermal camera

Thermal cameras achieve this by recording the temperature of different objects in its field of view. Then, the camera assigns each temperature a specific colour. Typically, cooler temperatures have cool shades, such as blue, purple and green, whilst warmer temperatures are allocated warm shades, including red, orange and yellow.

As shown in the picture below, the car in the thermal image is a mixture of red and yellow. This indicates that the car is hot, whilst the background is blue and green, meaning it is cool. 

Visual camera vs thermal imaging camera

Although this is usual, some thermal cameras use greyscale, as shown in the private property example. In this instance, cooler temperatures are allocated a light shade of grey, while warm temperatures have a darker shade. Either way, in both coloured and greyscale thermal images, the thermal camera allows you to visually see the amount of heat an object is emitting in relation to the other objects around it.

Inside a thermal camera, there are electrical devices called microbolometers that measure thermal energy. The thermal energy that is emitted from the objects in the thermal cameras' field of view strikes each microbolometer element when the thermal camera is operating. This causes the temperature of the microbolometers to increase, which creates a change in its electrical resistance.  

This change in electrical resistance is measured, and through the thermal cameras, intelligent software is automatically processed into temperature values. Each temperature value is then assigned to each pixel, which are then allocated colours. Once this is completed, a final image is created that visually represents the colour of each object in the camera's field of view. 

Not only is this ability to differentiate between slight temperature variations useful for detection purposes, but it also improves the accuracy of analytics. The future is bright for thermal imaging cameras - they truly are shaping the future of surveillance.

If you have any questions about the products we sell, please do not hesitate to give us a call on 1300 004 226, or through our contact us page.
We are happy to answer any questions you have. 
CctvThermal cameras

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