1.2 InfoRepr&Multimedia.multimedia

Question 1

What is a bit-map image?

Answer 1

A system that uses pixels to make up an image, stored as a two-dimensional matrix of pixels.

Question 2

What is a pixel?

Answer 2

The smallest picture element that makes up an image.

Question 3

What is colour depth?

Answer 3

The number of bits used to represent colours in a pixel; for example, 8-bit colour depth can represent 256 colours.

Question 4

What is bit depth in images?

Answer 4

The number of bits used to represent the smallest unit in an image; a higher bit depth improves colour quality.

Question 5

What is image resolution?

Answer 5

The number of pixels that make up an image; for example, 4096 × 3192 pixels (12,738,656 pixels in total).

Question 6

What is screen resolution?

Answer 6

The number of horizontal and vertical pixels making up a screen display; lower screen resolution than image resolution reduces quality.

Question 7

What is pixel density?

Answer 7

The number of pixels per square centimetre

Question 8

What are vector graphics?

Answer 8

Images that use 2D points to describe lines, curves, and shapes rather than pixels.

Question 9

What is sampling resolution in sound?

Answer 9

The number of bits used to represent sound amplitude (also known as bit depth).

Question 10

What is the sampling rate?

Answer 10

The number of sound samples taken per second.

Question 11

What is frame rate in video?

Answer 11

The number of video frames per second.

Question 12

How does bit depth affect colour representation in bit-map images?

Answer 12

A higher bit depth allows for more colours; for example, 8-bit depth enables 256 colours, while 32-bit depth enables over 4 billion colours.

Question 13

What happens when a pixel-generated image is scaled up?

Answer 13

The number of pixels remains the same, but they cover a larger area, which can reduce sharpness.

Question 14

What is pixel density?

Answer 14

The number of pixels per unit area; key when scaling up images to maintain quality.

Question 15

What is the main drawback of using high-resolution images?

Answer 15

Increased file size, which affects storage capacity, download time, and transfer speed.

Question 16

How do bit-map images take advantage of human vision?

Answer 16

The human eye can tolerate some resolution reduction before the quality loss becomes significant.

Question 17

How is the file size of a bit-map image calculated?

Answer 17

File size = Image resolution × Bit depth (in bits), then divided by 8 to convert to bytes.

Question 18

Calculate the file size of a 1920 × 1080 image with a 24-bit depth.

Answer 18

1920 × 1080 × 24 = 49,766,400 bits (≈6.222 MB in SI units or 5.933 MiB in IEC units).

Question 19

What additional data is stored in a bit-map image file header?

Answer 19

File type, file size, image resolution, bit depth, and compression type (if any).

Question 20

What are vector graphics?

Answer 20

Images that use 2D points to describe lines, curves, and their properties, forming geometric shapes.

Question 21

How are vector graphics created?

Answer 21

Using CAD software or drawing applications with a digital canvas.

Question 22

What is a drawing list in a vector graphic file?

Answer 22

A list containing commands, attributes, object positions, and relationships between objects.

Question 23

Why do vector graphics not lose quality when scaled up?

Answer 23

They store relative positions and properties mathematically rather than using pixels.

Question 24

Why do vector graphics need to be converted to bit-map images for printing?

Answer 24

Most printers work with bit-map formats rather than vector-based formats.

Question 25

How do vector graphics compare to bit-map images in terms of file size?

Answer 25

Vector graphics have smaller file sizes since they store geometric shapes instead of individual pixels.

Question 26

Why are vector graphics less realistic than bit-map images?

Answer 26

They use geometric shapes with limited detail rather than tiny pixels for precise colour and shading.

Question 27

What file formats are commonly used for vector and bit-map images?

Answer 27

Vector: .svg, .cgm, .odg | Bit-map: .jpeg, .bmp, .png

Question 28

When should vector graphics be used instead of bit-map images?

Answer 28

- When the image needs resizing or scaling - When the image must be drawn to scale - When file size must be minimised

Question 29

When are bit-map images better than vector graphics?

Answer 29

- When the image must look realistic - When modifying photographs - When pixel-level editing is required

Question 30

What are some applications of vector graphics?

Answer 30

Logo design, CAD drawings, and technical diagrams like exploded views of machines.

Question 31

Why do bit-map images require larger file sizes?

Answer 31

They store information pixel by pixel, capturing more detail and colour variations.

Question 32

How does sound travel?

Answer 32

Sound requires a medium (such as air or water) to travel through as it moves by causing oscillations of particles.

Question 33

Why can't sound travel in a vacuum?

Answer 33

Sound relies on particle oscillations to propagate, and a vacuum lacks particles to transmit the waves.

Question 34

What characteristics define a sound wave?

Answer 34

Frequency, wavelength, and amplitude (which determines loudness).

Question 35

How is sound stored in a computer?

Answer 35

It is converted from analogue to digital using an analogue-to-digital converter (ADC).

Question 36

Why is sound filtered before digitisation?

Answer 36

To remove frequencies outside the range of human hearing, making storage more efficient.

Question 37

What is sound sampling?

Answer 37

Measuring the amplitude of a sound wave at set time intervals and encoding it in binary.

Question 38

What is sampling resolution (bit depth)?

Answer 38

The number of possible values used to represent sound amplitude, affecting accuracy.

Question 39

What is sampling rate?

Answer 39

The number of sound samples taken per second.

Question 40

How does increasing sampling rate and bit depth affect sound quality?

Answer 40

It improves accuracy and sound quality but increases file size.

Question 41

What is the standard bit depth used for CDs?

Answer 41

16-bit sampling resolution

Question 42

What are the advantages of higher sampling rate and resolution?

Answer 42

- Larger dynamic range - Better sound quality - Less sound distortion

Question 43

What are the disadvantages of higher sampling rate and resolution?

Answer 43

- Larger file sizes - Longer transmission/download times - Requires greater processing power

Question 44

What are some common sound editing features?

Answer 44

- Edit start/stop times and duration - Extract, save, or delete parts of a sample - Alter frequency and amplitude - Fade in/fade out - Mix and merge multiple tracks - Remove noise and enhance specific sounds - Convert between different audio formats

Question 45

How do digital cameras, smartphones, and tablets capture moving images?

Answer 45

By ‘stitching’ a series of still frames together to create motion.

Question 46

What does DV stand for in video recording?

Answer 46

Digital Video

Question 47

What is motion JPEG?

Answer 47

A video format where compressed photo frames are stored at a speed of 25 MB per second.

Question 48

How do cameras capture light from an image?

Answer 48

Using light-sensitive sensors that convert light into an electronic signal.

Question 49

How is video data stored in DV cameras?

Answer 49

The electronic signals are automatically converted into a compressed digital file format.

Question 50

What is frame rate in video recording?

Answer 50

The number of frames recorded per second.