Thermal imaging device is a benefit to the armed forces like navy, army and air force because of its 24 hours working capability to perform well in all climate conditions. Thermal detectors capture the IR(Infrared) radiation produced by all objects above complete zero temperature. The temperature differences of the captured section are denoted as a hectogram. With the beginning of IR detector technology, the large cooled thermal detectors having moving parts and difficult cryogenic temperatures have changed into small, and less expensive uncooled microbolometers having no moving parts. Thermal imaging system due to its numerous advantages has various applications in the military and also defines.
It is widely used by the armed forces for border surveillance and law implementation. It is also used in ship accident avoidance and control systems. In the aviation industry, it seriously mitigates the dangers of flying in the night conditions. They are widely used in military flight to recognize, find and aim the enemy forces. Recently, they are also being merged in civil aviation for health checking of aircraft.
What is a Thermal Imaging Sensor?
The thermal imaging sensor is a one kind of sensor used to determine an image based on the absolute temperature of the object. The image is formed based on the object’s heat signature. These devices record the present signatures of the devices based on their heat pattern and do not require a beam such as active infrared devices. The range of thermal imaging is ranges from -50oC to 2,000 oC.
Types of Thermal Imaging
The thermal imaging sensors are classified into two types, namely cooled thermal imaging and un-cooled thermal imaging.
Cooled thermal images are normally contained in a vacuum sealed case and cryogenically cooled. These devices require cooling for the operation of the semiconductor materials.used else they would be blinded by their own radiation. Cooled IR cameras gives superior image quality.These are bulky and expensive to run and produce. Cooling is time consuming and power hungry. Hence the camera requires time to cool down before it can start working again.
Uncooled thermal images use a sensor, that operates at ambient temperature or room temperature using control elements. The quality of the image and resolution tend to be less than cooled detectors. Uncooled thermal imagers are smaller in size and low cost to produce and run. The operation of these imagers is faster, and consumes less power.
Thermal Imaging Sensor Circuit Diagram
The Required Components of a Thermal flashlight include 1 MelexisMLX90614 non-contact IR measuring device (3v), common-anode RGB led-1, 4.7k Ohm resistors-2, 100 Ohm resistors-2, 180 Ohm resistor-1, 0.1 μF capacitor-1, Wire, A breadboard, 9v battery and holder
Alternative differences of the flashlight are frequently created with a 5.5V Melexis detector and Common Cathode LED for the 5.5 V sensors.
Connections of the MLX90614 as follows
- Pin-1 on MLX (SCL) connected to analog pin-5 on the Arduino UNO board, Pin-2 on MLX (SDA) connected to analog pin-4 on the Arduino, Pin-3 on MLX (VDD) connect to 3.3V on Arduino, Pin-4 on MLX (VSS) connect to GND on Arduino board.
- Now use “pull ups” on the SDA & SCL lines by connecting a 4.7K ohm resistor from the Pin-3 VDD line to the SCC line & a 4.7K ohm resistor from the Pin-3 VDD line to the SDA line.
- Connect the RBG LED. Simple wiring diagram for RGB LED.
- Leg-1 = RED pin of the LED to PWM pin-6, Leg-2 = Ground, Leg 3 = GREEN pin of the LED to PWM pin-5, Leg-4 = BLUE pin of the LED to PWM pin-3.
- Dump your code into the microcontroller.
How does Thermal Imaging Work?
- A special lens is used to focus the infrared (IR) emission produced by objects.
- The light which is focused is scanned by a phased collection of IR detector elements. These elements produce a much expanded temperature pattern denoted to as a thermogram. It only takes regarding one-thirtieth of a second for the array of detector to get the data of the temperature to form the thermogram. This temperature data are found from several thousand points in the field of view of the detector array.
- The thermogram formed by the detector elements is transformed into electrical impulses.
- The impulses are directed to a signal-processing unit, a circuit card with a chip that reads the information from the fundamentals into data for the display.
- The signal-processing unit sends the data to the display where, it seems as several colors depending on the strength of the infrared radiation. The combination of all the impulses from all of the elements makes the image. It is quite forthright to examine everything during the day, but at nighttime you will be able to see slight or no. This imaging allows you to see once more.
Thermal Imaging Applications
The applications of thermal image sensor include the following
- Condition monitoring
- Border security
- Security and law enforcement
- Energy losses in building and building envelope inspections
- Thermal mapping
- Digital infrared thermal imaging in healthcare
- Veterinary thermal imaging
- Night vision
- UAV surveillance
- Process control
- Nondestructive testing
- Surveillance in security, law enforcement,and defense
- Chemical imaging
Advantages of Thermal Imaging Sensor
The advantages of thermal image sensing include the following
- Produces accurate, immediate and fast temperature measurement and assists in fault detection
- Cameras are very simple to install and surveys can be achieved at a convenient time
- It is capable of catching moving targets in real time and also in low light conditions
- It can be used to observe or measure subjects in areas inaccessible or hazardous for other methods
- It can help in recognizing air leakage, documenting irregular heat dispersion and recognizing possible irregularities in insulation.
- Cameras can passively observe all objects, regardless of ambient light
From the above information, finally we can conclude that “Thermal imaging” is a method of improving the brightness of objects in a dark environment by sensing the objects’ IR radiation and making an image based on that information. The three night vision technologies like Thermal imaging technology, low-light imaging and near-infrared illumination. Unlike the remaining two methods, thermal imaging works in environments without any ambient light such as near infrared illumination, thermal imaging can enter obscurants like fog, smoke, and haze. Here is a question for you what is the function of a thermal imaging sensor?