Dr. Nikos Desypris, ndessipris@yahoo.com Oct. 2017 Lecture 2 Digital Television Dr. Nikos Desypris, ndessipris@yahoo.com Oct. 2017 Lecture 2

(sampling and quantisation - lossy) DTV Block Diagram Scene Receiver Decompression CAMERA Analogue sensor + A/D converter (sampling and quantisation - lossy) D/A converter Video adapter TRANSMISSION (Terrestrial, Sattelite, Cable, IPTV) Compression (lossy) Human Observer

Course Outline Image Processing Description of the human Visual System Limitations of the human Visual System The Electromagnetic Spectrum Imaging Sensors Sampling and Quantization

Indicative References Digital image Processing Third Edition R.C. Gonzalez, R.E. Woods, Pearson 2010. From Mars to Hollywood with a stop at the hospital (Guillermo Sapiro coursera.org) Click to edit certification nameFundamentals of Digital Image and Video Processing (by Aggelos Katsaggelos, coursera.org) Two dimensional Signal and Image Processing, J. S. Lim, Prentice Hall 1990

Digital Image Processing

Digital Image Processing

Digital Image Processing

The Human Eye

The Human Eye Cornea Κερατοειδής χιτών Vitreous humor Υαλοειδές υγρό Iris Ίριδα Retina Αμφιβληστροειδής χιτώνας Anterior chamber Πρόσθιος θάλαμος Blind spot Τυφλό σημείο Ciliary body Ακτινωτό Σώμα Fovea Βοθρίο Lens Φακός Sclera Σκληρός χιτώνας Ciliary muscle Ακτινωτός Μυς Choroid Χοριοειδής Ciliary fibres Ακτινωτές Ίνες Nerve and Sheath Νεύρο και Θήκη Visual axis Οπτικός άξονας Cones (6-7 Mil.) Rods (75-150 Mil.)

The Human Visual System

The Human Visual System For comparison purposes, the basic ability of the eye to resolve detail is comparable to current electronic imaging sensors

Image formation in the Eye

Reversing goggles

The Human Visual System

The Human Visual System

The Human Visual System

Why & how cinema works If a human is presented with a rapid sequence of images, he/she is confused that it is a smooth sequence, when the speed is > 16 frames /sec. (https://en.wikipedia.org/wiki/Motion_perception)

Grey Levels humans can see Eye discrimination range for image intensity differences 1010 (106 photopic, 104 scotopic)

Grey Levels humans can see

Grey Levels humans can see (32)

Grey Levels humans can see (64)

The Mach Band Effect

The Mach Band Effect

Simultanenous contrast

Simultaneous contrast

Filtering effect of human eye

Optical Illusions

Light and the EM Spectrum

Light and the EM Spectrum

Light and the EM Spectrum

Light and the EM Spectrum Advanced Light Source

Light and the EM Spectrum

Types of imaging sensors

Colour imaging sensor

3 Colour Digital Video Camera

3 CCD Digital Video Camera 3CCD Philips prism

Drum scanner

Image Formation Model

Sampling &Quantization

Result of Sampling & Quantization

Presentations of an image

Image Noise and Saturation

Bits per image NxN pels; k:bits/level

Spatial Resolution

Intensity Resolution

Point Image Transformations

Point Image Transformations

Point Image Transformations