Lecture 1 Overview And DIP Flashcards
What is the most commonly used numeral system?
Decimal numeral system
How many possible values of a digit do decimal numeral system have?
10
0,1,2,3,4,5,6,7,8,9
What numeral system do computers write and read numbers?
Binary numeral system
How many possible values of a digit do binary numeral system have ?
2
0,1
What do 1k means in binary numeral system?
1024
What is the basic unit of digital data?
Byte (B)
1 byte = ? Bit
8 bits (b)
What is the range and number of bytes of an unsigned 8 bot integer (uint8)?
Range = 0 to 255
Byte = 1
What is the range and number of bytes of an unsigned 16-bit integer (uint16)?
Range = 0 to 65535
Bytes = 2
What is the range and number of bytes of a signed 8-bit integer (int8) ?
Range = -128 to 127
Byte = 1
What is the range and number of bytes of a signed 16-bit integer (int16) ?
Range = -32768 to 32767
Bytes = 2
What do the class [double] means in classes of digital data?
The class double means floating point number with double precision. The number of byte is 8 bytes = 64 bits.
What is the importance of the most significant bit of signed-bit integer?
In signed integer, the most significant bit carries the negative sign
What is the definition of discretisation?
The projection of real world object in continuous-space continuous-value onto an image in discrete-space discrete-value.
Discretisation is a process changing analog data into digital data.
By what method can analog data changes to digital data (I.e. discretisation) ?
- Spatial sampling
- Amplitude quantisation
What is the problem of discretisation of data?
It creates discrepancy from the original signal.
What can be done to reduce discrepancy of the image from the original signal?
Increase bit depth
Improve density resolution
Increase bit per pixel
What do number of bits per pixel determines in a digital image?
The number of bits per pixel determines the number of intensity levels.
The origin of a grayscale image starts from which corner?
Left top corner
What is the wavelength of visible light?
400-700 nm
What is the responsibility of cones cells and rod cells respectively in visual perception?
Cone cells = sensitive to colour
Rod cells = sensitive to intensity
What are the three primary colours?
Red green blue
Name the two Color reproduction systems.
Additive and subtractive
Mixing two primary colours gives a ________________.
Secondary colour
Secondary colour is __________________ to a primary colour
Complementary
What are the three secondary colours?
Magenta cyan and yellow
When all primary adds together it shows ___________.
White
When all primary colour light is absorbed it shows ___________.
Black
What are the 4 colours in 4 colour printing?
CMYK
Cyan magenta yellow and black
What is HSV cone?
H = hue : ring
S = saturation : radius
V = Value of brightness : diagonal
What is the central axis of the HSV cone represents?
Grayscale
How many bit in a colour pixel?
24 bit
(I.e. 8 x 3) (RGB)
What are the descriptive parameters of image quality?
- Density resolution (Bit depth)
- Contrast
- Spatial resolution
- Signal-to-noise ratio (SNR)
- Artefacts
What is the difference between luminance and brightness?
Luminance is the measure of the actual density, independent to the surroundings. unit = cd/m2
Brightness is the perceived luminance by rod cells, it is affected by the surrounding and background
What is the definition of contrast?
It is the measure of differences in brightness in adjacent regions of the image
What is the definition of spatial resolution?
How fine the pixels in the image
I.e pixel size (mm)
2 Formula of signal-to-noise ratio
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