IR SENSORS An infrared sensor is an electronic instrument which is used to sense certain characteristics of its surroundings by either emitting and/or detecting infrared radiation. Infrared sensors are also capable of measuring the heat being emitted by an object and detecting motion. Infrared waves are not visible to the human eye. In the electromagnetic spectrum, infrared radiation can be found between the visible and microwave regions. The infrared waves typically have wavelengths between 0.75 and 1000µm.
by using small doses of radioactive chemical particles which depends on the part of body is introduced for scanning. A Radionuclide is also known as a radioisotope which is a chemical and emits radioactivity known as gamma rays. A very little amount of radionuclide is inserted into the body by various ways like it is injected into the vein,
Remote sensing refers to the acquisition of information about an object or phenomena without making physical contact with the object (Reddy, 2001). In modern usage remote sensing can be refer to the use of area sensor technology to detect and classify object on earth (Both on the surface, in the atmosphere and Oceans). It is the acquisition of data through which a sensor is mounted on platforms located at a distance from the target in other to derive information about an object or material (target). This is still by far the most accurate and detailed way of
INFRARED SPECTROSCOPY: Definition: It is defined as the spectroscopy that is concerned with the infrared region of electromagnetic energy spectrum. As the name suggests, this type of spectroscopy is used to study the interaction of light of low wavelength with matter. IR spectroscopy deals with the vibrational energy of atoms, and thus determines the functional groups. Theory: An infrared spectrum is obtained when infrared light passes through the given sample, and finds out the amount of incident radiation absorbed by the sample. Infrared light directly does not cause electrons to shift to higher energy states , but it has enough energy to undergo interaction with a molecule and alter its vibration and rotation.
1.1. UV-SPECTROPHOTOMETRY Spectroscopy is the measurement and interpretation of electromagnetic radiation absorbed or emitted when the molecules or atoms or ions of a sample move from one energy state to another energy state. Spectroscopy is a general methodology that can be adapted in many ways to extract the information you need (energies of electronic, vibrational, rotational states, structure and symmetry of molecules, dynamic information). Ultraviolet-Visible Spectrophotometry is one of the most frequently employed techniques in Pharmaceutical analysis. It involves the measurement of the amount of Ultraviolet (190-380nm) radiation by a substance in a solution.
Intra beam viewing of a point source of light produces a very small spot on the retina resulting in a greatly increased power density and an increase chance of damage. A large source of light such as a diffuse reflection of a laser beam produces light that enters the eye at a large angle is called an extended source. An extended source produces a relatively large image on the retina and energy is not concentrated on a small area the retina as in a point source. Absorption of Radiation by the Eye Certain areas of the eye absorb more light in one spectral region than in other regions. Absorption of laser radiation above a certain level leads to tissue injury.
IR or near-IR wavelengths are better for measurement of deep-tissue blood flow. Recently, Green-wavelength PPG devices are becoming increasingly popular due to the large intensity variations in modulation observed during the pulse rate for these wavelengths iii. Reflected and Transmitted Signal of PPG sensor Wearable PPG system has two operating mode – transmission and reflectance mode as shown in figure 3, 4. In transmission mode, the light transmitted through the medium was detected by a Photodector (PD) opposite to light-emitting diode (LED) source; while in reflectance mode, PD detects light which back-scattered or reflected from tissue, bone or blood vessels. Figure 3: Reflection type PPG Figure 4: Transmission type
Reflected light microscopes are most commonly used for metallography studies, while transmitted light microscopes are used to examine transparent or semi-transparent materials mainly in biological studies. The main components of light microscope are illumination system, objective lens, eyepiece and movable specimen stage. The differences in properties of the light waves which are reflected from microscopic objects enable one to observe these objects by light microscopy. The light wave changes either in amplitude or phase when it interacts with an object.
Sensors are the input devices of the robots which provide information about the external environment that what is happening and act accordingly. This information might be any color, quantity of light, distance of an object or it can be temperature etc. There are also different types of sensors like light sensor, IR sensor and Temperature sensor etc. which are used depending on the type of information. Motors are the output devices in the robots which let the robot move according to the program encoded.