290 Journal of Engineering Technology (ISSN: 0747-9964 ) Volume 6, Issue 2, July, 2017, PP.290-303 Thermal imaging system and its real time applications: a survey Mritunjay Rai 1 , Tanmoy Maity 2 , R.K.Yadav 3 1 Research Scholar, Indian Institute of Technology (ISM) Dhanbad 2 Associate Professor, Department of Mining Machinery Engineering, IIT (ISM), Dhanbad. 3 Professor, Department of Electronics and Communication, JRE Group of Institutions, Greater Noida. Abstract: The IR radiations emitted by Thermal Imaging systems are captured by passive sensors for all the objects having temperature overhead the absolute zero. This method of detection was initially settled for surveillance and night vision device for military purposes, but are now economically more viable, hence there is a wider scope of application than ever. The illumination complications of normal Greyscale and RGB cameras are significantly reduced when this sensor is positioned in vision system. This paper produces real time application of thermal imaging system i.e. application in agriculture, medical diagnosis, detection, tracking and recognition of humans along with their facial expressions. Further, this paper explains the natural surroundings of thermal radiation and the imaging system technology. Present paper has the following further sections: section 2 contains the definition of thermal radiation. Section 3 is about the machinery of thermal camera. Section 4 describes the application area and the survey of the work done so far. Section 5 contains brief summary and discussions regarding deployment of thermal cameras. Keywords Thermal imaging system, IR radiation, Medical diagnosis, agriculture, Facial expression 1. Introduction The human vision is extended by the use of thermal imaging to far IR region as it utilizes the light emitted by warm objects. The human eye lacks response in the absence of light in the 0.4μm to 0.7μm range, hence the device that can create the image by generating the dominant energy in low light conditions is needed. The photons emitted by the human body must be captured by the night eye as these dominate energy when solar radiations are absent. Moreover, the night eye should have spectral reaction where significant, emissivity, temperature and reflective differences exist in the scene. This is mandatory to make sure that the radiation pattern is sufficiently similar to the corresponding visual reflectivity ethics in order to make the visual interpretation of the converted scene possible. This spectral sensitivity must align with an atmospheric transmission window which doesn’t overly absorb the desired radiation [1]. The complexity of generating the thermal image may be esteemed by taking into account the perfection of human eye because of which it generates the visible images. The human eye is a perfect sensor of visible light in three aspects. First, the spectral response of the human eye lies between 0.4 μm - 0.7 μm which coincides with the peak of solar spectral output. Around 38% of the solar radiant energy is concentrated in this band, and terrestrial objects tend to have a good reflectivity. Second, the retinal radiation detectors make the human eye an ideal quantum noise limited device as they have low noise at the quantum energy level in this band. Third, the retinal detector have negligible response to the photons emitted at the body temperature thus making this long wavelength unmask the response to desired wavelength. This optimization enables the human eye to do its