digital images Flashcards
what are the two forms of images
vector and bitmap
what is colour depth
how many possible colours in a pixel
what is resolution
how many pixels in an inch of an image
what is a moving image file
an image that includes a moving/animated graphic
what are bitmap images commonly used for
photographs
what are vector images commonly used for
logos
what is lossy compression
It reconstructs all the original data but this means data is lost during the compression process
Once data is removed, it’s permanent and cannot be restored. It’s irreversible
This can impact the overall quality of the graphic
It does significantly reduce the overall size of the file
JPG is a common file format that uses lossy compression
what is lossless compression
Data is reconstructed and doesn’t remove any data.
Because data is retained, it’s reversible so changes can continue to be made.
The overall quality of the graphic is retained.
The size of these files tend to be large.
PNG/PSD are common file formats that use lossless compression.
what is the most popular form of audio file
MP3
what is the most popular form of image file
JPG
what is the most popular form of video file
MP4
what is the most popular form of moving image file
GIF
what is sampling
When sound is recorded, samples are taken at regular intervals as you can see in the diagram on the right. The sample rate is measured in Hz (Hertz)
what is bit depth
Bit depth is the number of bits available for each sample . If the bit depth increases it can increase the dynamic range of volume (this affects how loud the sound will be). This will also contribute to the quality of the sound file improving.
how many pixels in a nibble
4
how many pixels in a byte
8
how many bytes in a kilobyte
1000
how do you find out sound file size
sound file size = sample rate x duration (s) x bit depth
how do you find out image file size
image file size = colour depth x image height (px) x image width (px)
how do you find out text file size
text file size = bits per character x number of characters
what is secondary storage
Secondary storage has the ability to store files even when the computer is switched off. it’s a non-volatile form of storage.
what is a SSD
A solid-state drive (SSD) is a solid-state storage device that uses integrated circuit to store data persistently, typically using flash memory. Examples include Solid-State Drive, USB Flash Drive and SD Card.
what is optical storage
Optical storage is any storage type in which data is written and read with a laser. Common examples of optical storage include: CD, DVD, and Blu-ray.
what is cloud storage
Cloud storage allows you to save data and files in an off-site location that you access either through the public internet or a dedicated private network connection.
what is magnetic storage
The most common example of magnetic storage is a Hard Drive. The hard drive contains a number of moving mechanical parts such as a spinning platter with a thin magnetic coating. A “head” moves over the platter, writing 0’s and 1’s on the platter.
What are the tiny squares on an image referred to as?
a Squares
b Lines
c Curves
d Pixels
d
Images that contain pixels are known as what type of image
a Bitmap
b Vector
a
The number of bits that can be stored per pixel will determine what about the image?
a Resolution
b Metadata
c Colour depth
d Pixilatio
a
A decrease in colour depth will lead to….
a More bits stored per pixel
b Less bits stored per pixel
b
What term is used to refer to the number of pixels that can be stored per inch?
a Resolution
b Metadata
c Colour depth
d Sampling
a
How many bits in a nibble?
a 1
b 2
c 3
d 4
d
How many nibbles in a byte?
a 1
b 2
c 3
d 4
b
How do you convert GB to TB?
a Add 1000
b Divide by 1000
c Multiply by 1000
d Subtract 1000
b
How do you convert GB to MB?
a Add 1000
b Divide by 1000
c Multiply by 1000
d Subtract 1000
c
- Which of these is not a type of a compression method?
a Lossy
b Defragmentation
c Lossless
b
