digital image procesing. 1960 nasa lunar and planetary exploration
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DIGITAL IMAGE PROCESING
1960
NASA LUNAR AND PLANETARY EXPLORATION
ANALOG DIGITAL
ADC
APPLICATION OF DIGITAL IMAGING
• ULTRASOUND
• DIGITAL RADIOGRAPHY
• NUCLEAR MEDICINE
• CT
• MRI
RADIOGRAPHY - PAST
TODAY
FLUOROSCOPY IN THE PAST
CONVENTIONAL
DIGITAL FLUOROSCOPY
CASTELMAN (1996)
CLASSIFICATION OF THE IMAGES BASED ON THEIR
FORM OR METHOD OF FORMATION
IMAGES
• VISIBLE
• OPTICAL
• NONVISIBLE IMAGES
• MATHEMATICAL
ANALOG IMAGE
CONTINUOUS IMAGES.
ANALOG IMAGERADIOGRAPH- CONTINUOUS DISTRIBUTION OF LIGHT
INTENSITY AS A FUNCTION OF POSITION ON THE RADIOGRAPH
DIGITAL IMAGE
NUMERIC REPRESENTATION OR IMAGES OF OBJECTS
ANALOG TO DIGITAL
ADC
PROCESSING
ANALOG vs DIGITAL
DIGITAL TO ANALOG
DAC
ANALOG PROCESSING
INPUT AND OUTPUT IMAGES ARE BOTH ANALOG
DIGITAL PROCESSING
INPUT AND OUTPUT IMAGES ARE BOTH DISCRETE
IMAGE DIGITIZATION - ADC
• SCANNING
• SAMPLING
• QUANTIZATION
SAMPLING FREQUENCY
LOW SAMPLING ALIASING ARTIFACT
CT- SIGNAL FROM DETECTORS: ANALOG
ANALOG
MRI- SIGNAL FROM DETECTORS: ANALOG
ANALOG
PET- SIGNAL FROM DETECTORS: ANALOG
ANALOG
BASIC DATA AQUSITION SCHEME IN CT
ADC
DETECTORS
P.M. TUBE SOLID STATE
DETECTORS
MATRIX - EYE OF THE BEE?!
DIGITAL RADIOGRAPH
Y
MATRIX
MATRIXIMAGE RECEPTOR
PIXEL RESOLUTION IN MATRIX
4 x 4---16 PIXELS4 x 4 MATRIX
MATRIX
PIXEL
WHAT MATRIX?5 X 4 20 PIXELS
HIGH vs LOW RESOLUTION
SPATIAL RESOLUTION
SPATIAL RESOLUTION
SPATIAL RESOLUTION= FOV/ MATRIXSPATIAL RESOLUTION= FOV/ MATRIX
IMAGE MATRIX SIZES FOR DIFFERENT MODALITIES
• NUCLEAR MEDICINE
• CT
• MRI
• DR
• CR
• 64 X 64
• 256 X 256
• 512 X 512
• 1024 X 1024
• 2048 X 2048
DYNAMIC RANGE:
• THE RANGE OF VALUES OVER WHICH THE SYSTEM CAN RESPOND
HOW MANY DIFFERENT SHADES CAN BE DISPLAYED IN THE PIXEL?
DYNAMIC RANGE
• 1 BIT• 2 BIT• 3 BIT• 4 BIT• 5 BIT
• 2 COLORS• 4 COLORS• 8 COLORS• 16 COLORS• 32 COLORS
2 X BIT
1 BIT
2 BIT
5 BIT
IMAGE MANIPULATION
• WINDOWING
• INVERSION
• IMAGE SHARPENING
WINDOW CENTER (LEVEL) CONTROLS:
IMAGE DENSITY
WINDOW WIDTH CONTROLS:
IMAGE CONTRAST
WINDOWING
WINDOWING
IMAGE INVERSION
IMAGE SHARPENING
RECENT ADVANCEMENTS
VIRTUAL REALITY
CINE
CT ANGIOGRAPHY
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