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 processing
- Processing digital images by means of a digital computer
Humans are
limited to the visual band of the electromagnetic spectrum, imaging machine
cover almost the entire electromagnetic spectrum, ranging from gamma to radio
waves.
Image processing - Discipline in
which both input and output of process are images.
Computer vision – To use computers
to imitate human vision, including learning and being able to make inferences
and take actions based on visual inputs.
Image analysis / Image
understanding - The area in between image processing and computer vision.
Levels of Image processing-
1.
Low level processes - Image preprocessing to
reduce noise, contrast enhancement, and image sharpening.
Both its inputs and outputs are
images.
2.
Mid level processes - Segmentation and
classification.
Its information sources for the most part are images, however its yields are characteristics (e.g., contours, edges etc.) extricated from those images.
Its information sources for the most part are images, however its yields are characteristics (e.g., contours, edges etc.) extricated from those images.
3.
High level processes- “making sense” of an ensemble of recognized objects and
performing cognitive functions normally associated with vision.
Benefits of
digital image processing-
- Pictorial information gets improved for human interpretation
- Improvement in processing of Image data for storage ,transmission and representation
- Autonomous machine perception becomes easier
Informative....
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