T2 - Characters and Images

Question 1

Uppercase and lowercase in binary

Answer 1

different binary values

Question 2

When text is encoded and stored using ASCII,

Answer 2

each of the characters is assigned a denary character code,

represented + stored in the computer as binary.

Question 3

A 7-bit character code (like ASCII) has

Answer 3

128 different characters that can be encoded

Question 4

An 8-bit character code (like extended ASCII) has

Answer 4

256 different characters that can be encoded

Question 5

A character set

Answer 5

• a set of letters, symbols and digits that can be represented by a computer:

Question 6

types of character sets

Answer 6

ASCII
Unicode

Question 7

Unicode

Answer 7

• To represent other characters for different languages, 16 bits 65 536 possible combinations

Question 8

Types of image files:

Answer 8

Bitmap - uses pixels
JPG - uses pixels
GIF - moving one
PNG - low quality
TIFF - raw (high quality)
Vector - uses a formula to maintain qualities
SVG

Question 9

Bitmap images

Answer 9

• made from pixels which each have a colour + binary number for this

Question 10

Image resolution

Answer 10

= the concentration of pixels within a specific area

Question 11

Colours in pixel

Answer 11

• Each pixel has a proportion
  of red, green and blue = makes one colour

Question 12

Increasing the number of colours in bitmap:
More bits per pixel

Answer 12

= more colour combinations

Question 13

bit depth

Answer 13

• number of colours

Question 14

Higher bit depth

Answer 14

= more variety of colours

Question 15

Bit depth formula

Answer 15

= 2^n where n is bits

Gives number of colours used

Question 16

Size of bitmap images formula

Answer 16

= w*h in pixels

Question 17

In 32-bit colour what are the last 8 bits for?

Answer 17

Transparency channel:

32 bits per pixel 8 bits are given
-allow a background to show through

Question 18

Image size in bits formula

Answer 18

: width * height * colour depth

Question 19

Image size in bytes: formula

Answer 19

(width * height * colour depth) /8

Question 20

Metadata:

Answer 20

Colour depth in bits per pixel
Resolution (Height and width in pixels)
Date created
Author

Question 21

Pros of colour values being in hex:

Answer 21

easier to read/write = reduces errors

Question 22

RGB value range:

Answer 22

0 to 255
each colour must be 8 bits to store range

Question 23

bit number per RGB

Answer 23

3 * 8 = 24 bits