Gamma-Ray Imaging Gamma Ray - It is a parcel of electromagnetic energy emitted in the decay of certain subatomic particles and in the disintegration of radioactive atomic nuclei . Characteristics - Gamma rays are high-energy photons Gamma rays have high power of penetration Gamma rays travel at the speed of light Gamma photons have no mass Gamma photons have no electrical charge Imaging with Gamma Rays- 1. In Medical Field PET (Positron Emission Tomography) SPECT (Single-Photon Emission Computed Tomography) 2. In Astronomical Observations Gamma rays are emitted in universe by supernova explosions, regions around black holes, neutron stars etc. Source of Gamma Rays Gamma rays can be observed using telescopes such as Fermi Gamma-Ray Space Telescope. GLAST (Gamma-Ray Large Area Space Telescope)
Digital Image Processing Image – a two-dimensional function f(x,y). Where, x and y = Spatial (plane) coordinates Image is a 2-D array specifically arranged in rows and columns. Color image - It has 24 bit color depth = 8 x 8 x 8 bits = 256 x 256 x 256 colors = ~16 million colors Grayscale image - In a (8-bit) grayscale image each picture element has an assigned intensity that ranges from 0 to 255. A grey scale image is not a black and white image, but includes many shades of grey. Gray level of image - Amplitude of f at any pair of coordinates (x,y) . Digital image - When x, y and the amplitude values of f are all finite, discrete quantities. Digital image is composed of a finite number of elements, each of which has a particular location and value. Pixel - the element of a digital image. Field of digital image