Week 2 Flashcards
1
Q
How did we represent the world around us before ~1880?
A
Drawings, language, paintings, books
2
Q
How did we represent the world around us after 1900?
A
Drawings, language, paintings, books
AND
Photographs, movies, TV, record albums
3
Q
How do we represent our thought?
A
English words (maybe other language), pictures
4
Q
How do we represent our language?
A
Letters, words
5
Q
How did we SAVE representation of our thoughts before 1980ish?
A
Books, diaries, journals
6
Q
How do we SAVE representation of our thoughts now?
A
Blogs, Facebook, Twitter, Instagram, TikTok
7
Q
How do humans represent cost and quantities?
A
In North America: decimal numbers 0-9
8
Q
How did “the average person” calculate costs before home computers (Still used today)?
A
Calculators
9
Q
How did we calculate costs before 1950s?
A
Slide ruler
10
Q
How did we calculate costs before 1600s?
A
Abacus
11
Q
Why is our number system base 10? OR how did we calculate costs before 2700BC?
A
Count on fingers
12
Q
987 is a 3 digit number BUT how can it also be a 8 digit number?
A
000000987
If you had to represent the numbers with digit holders, you pad the front with zeros 0, zeroes don’t change meaning
13
Q
How does a computer represent
numbers and words and images and
sound?
A
With 0’s and 1’s: binary system
Only 2 digits
Use combinations to represent more numbers
Ex: 2=10 3=11
14
Q
What number system does DNA use?
A
Quaternary numeral system
Uses digits 0,1,2,3
Can represent world with more than just 0,1 (just used for digital)
15
Q
What “language” do computers only understand/speak?
A
Binary: 0,1
16
Q
Programmers have figured out how to convert our world to something a computer can understand, thus
what can they convert?
A
- Words to binary
- Images to binary
- Sound to binary
- Movies to binary
17
Q
How could we possibly represent anything with just 0’s and 1’s?
A
- Mapping program
18
Q
Example: Use only 1’s and 0’s to represent: over 6 feet tall.
A
Over 6 feet is: 1
If under 6 feet: 0
Represent with one 1 bit
19
Q
How do we use 1’s and 0’s to represent answers with more than 2 answers (yes or no)?
A
Ex: People who went to high school the longest in:
London 00
Ontario (but not London) 01
Canada (but not Ontario) 10
Outside of Canada 11
Represent with 2 bits
20
Q
How many bits do you need to represent more days of week, months, years?
A
Days of week: 3 bits = represent up to 8 peices of info so have 1 left over
Months: 4 bit= 16
Years 1913-2013: 7 bits= 128
21
Q
How many items can we represent with 1 bit?
A
2
Could represent:
-Black and White OR
-True and False
22
Q
How many items can we represent with 2 bit?
A
4
Could represent:
-Black, Light Gray, Dark
Gray, White OR
-DNA Bases OR
-Red, Blue, Yellow and Black
23
Q
How many items can we represent with 3 bit?
A
8
Could represent:
-days of the week but
not the months of the
year, WHY?
-8 shades of GRAY
24
Q
Every time we add extra bit we can represent ____ the amount that we were before.
A
Double
25
If I have an 8 bit number how many items can I represent?
256
26
Why is 8 bit significant in computer science?
Once we get to 8 bit we break into little chunks of bits
8 little bits together is called a BYTE
27
What is a byte?
8 bits together
28
How can we calculate how many items we can represent with the number of bits we have?
2^n
Where n is the number of bits
Ex: if we have 3 bits, 2^3=8 therefore we can represent 8 pieces of info
29
Up to what binary number can 8 bits represent?
255 even though it can represent 256 pieces of info because 0 is the first one
30
How are numbers formatted in binary?
Represent in 8 bits so pad front with 0's
Ex: 00010110
31
How is binary used to represent letters?
ASCII code
32
What is the ASCII code?
- Use binary to represent letters
- Use 1 byte for each letter
- Thus DOG would be encoded as:
01000100 01001111 01000111
33
What does the ASCII code for A represent in binary?
65
34
How many bytes do you need to represent characters of different languages in ASCII?
2 bytes=2^16 characters that we can represent
(technically called unicode)
35
How many characters can the ASCII code represent?
With 8 bits, (or 1 byte), we can encode 2^8=256 different characters
36
How many numbering systems are there?
Infinite
37
What are some of the common numbering systems?
- Binary (2 Binary Digits/ BITS) 0,1,10,11,100,101, 110, 111,1000, 1001, …
- Octal (8 Digits) 0,1,2,3,4,5,6,7,10,11, 12,13,14,15,16,17,20
- Decimal (10 Digits) 0,1,2,3,4,5,6,7,8,9,10,11,12,13,
14,15,16,17,18,19,20
- Hexadecimal (16 Digits) 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,10,11,12,
13,14,15,16,17,18,19,1A,1B,1C,1D,1E,1F,20… FA, FB, FC, FD, FE, FF, 100, 101, 102,…. FFE, FFF
38
What do you need as soon as you run out of patterns in numbering system?
You need an extra place holder (just like you learned in grade 2, that in decimal, when you have the numbers from 000 to 999, you only need 3 place holders but after 999, you will need another (4) place holder = 1000)
39
255 in decimal is what in binary and hex?
Hex: FF
Bin: 11111111
40
0 in decimal is what in binary and hex?
Hex: 0
Bin: 0
41
How do you convert from binary to decimal?
- Each digit must be converted individually and then the digits are added together
- How is a digit converted?
◦ If the digit is a 0, ignore it!
◦ If the digit is a 1, get the place value of the digit and calculate 2 to the power of that place value (2^place value)
◦ Note that the place values always begin with the right-most digit at place 0
42
How do you convert 1001 into decimal?
1001
1: place 3. 2^3 x 1=8
0: place 2. 2^2 x 0=0
0: place 1. 2^1 x 0=0
1: place 0. 2^0 x 0=1
8+0+0+1=9
43
What is 0111 in decimal?
7
44
What is 1011 in decimal?
11
45
What is 1100 in decimal?
12
46
If you're right most number in binary is 1 then you should end up with what kind of number in decimal?
Odd
47
If you're right most number in binary is 0 then you should end up with what kind of number in decimal?
Even
48
Why do computers like binary?
Think of lights in your home. If a light is on, it has a value of 1, if it’s off then it’s 0
A computer uses electricity and can
distinguish between getting a high volt or a low volt. High volt=1, low volt= 0
0000=off off off off
1111= on on on on
49
In theory the course is about taking the world around us and converting it into......?
A format a computer can use
50
The way our world is represented in is _____ form.
Analog
When using a pencil you don't make single little dots to make line
51
Computers are represented in _____.
Digital
It can't make things in a smooth line
It needs to break things into little chunks and needs to know how to represent each chunk
52
How can analog be represented in digital?
Take the continuous thing (analog) and break it into chunks and then give each chunk a value
53
A lot of our world that was once measured in an analog manner can now be represented in a digital manner. Give examples
Time: analog--> hand used to run around clock. digital-->represent numbers exact
Temperature: a--> thermometer move up in smooth continuous manner. d-->digital thermometer, half a degree
Sound: a--> record albums send sound waves. d--> stored in computer
Weight: a--> scale with needle. d--> digital read out
54
What is the 2 step conversion process to go from analog to digital?
1. Sampling
2. Quantizing
55
What is the sampling step in the analog to digital conversion process?
How often do I take a sample (measurement) to represent parts of the “thing” (how many parts will I break the thing up into)
where “thing” means image, sound, video, animation, text
56
What is the quantizing step in the analog to digital conversion process?
How many discrete values will I use to represent the parts the “thing”
where “thing” means image, sound, video, animation, text
57
What's an example of converting an image with 4 samples?
- Break down the photo into four equal samples and assign an average colour in each sample
- Don't get good representation of image
58
The more chunks you can break something into, the better _____ you will get.
Quality
The more samples you get the closer you can get to an analog representation (getting closer to smooth and continour)
59
What happens once you've decided how many chunks you have to have to get an accurate/representation for what you're doing?
Decide what value to give each chunk
60
Assume I have this image and I have
broken it into samples but I can only use ONE 0 or ONE 1 to represent each sample, what will it look like?
With 1 bit per sample you actually get a decently good image (with around 7000 samples)
61
When converting from analog to digital, what determines file size?
How many chunks and number of bits used per chunk
62
What happens if you had 4 bits to represent colour for each chunk?
0000
0001
0010.....
1111
Therefore can choose from 16 different colours for each chunk
63
How many bits do I need per chunk to represent 16 million+ different colours?
24 bits= 8 bits for red, 8 bits for green, 8 bits for blue
64
What happens as you increase the number of bits used to represent colour per chunk?
Get a more accurate representation
65
What are images great for?
- Information (to tell you what's happening)
- Explanation (to give explanation on how something works)
- Entertainment (just to make you smile)
66
Where do we get our images to use on our computer/
- By scanning existing images (a drawing or an old photograph or a painting) (converting from analog to digital)
- By taking a picture with our digital camera (automatically takes analog representation and digitalizes it)
- By creating something original using MS Paint or Photoshop or some graphics program (creating something right in computer)
67
When scanning or getting an image from our digital camera, the scanner or the camera can determine how many ________ to take.
Samples to take (how finely to break down the images)
68
The more samples that are taken, what will happen to the resolution?
The higher the resolution will be (better quality)
69
How are samples on scanners/printers measured?
As dots per inch (DPI) which basically means number of chunks per inch
70
How are samples on a monitor measured?
As pixels per inch (PPI) which basically means number of chunks per inch
71
What will an image that's 1 inch by 1 inch look like if its scanned at 4dpi?
It will 16 pixels total (4 pixels by 4 pixels)
Low resolution
72
What happens when we set resolution when scanning something?
Takes image and breaks it down into how every many chunks you set it as, sample it, then quantize it (assign each chunk a value or colour or number of bits per chunk)
73
How many samples will we get if we scan an 8-inch by 10-inch image at
100dpi?
(8*100) * (10*100) = 800*1000 = 800,000 samples (almost 1 million samples)
74
What determines file size and quality?
Number of pixels we break an image down into that determines file size as well as quantize how many bits we give per sample
75
What do we call a sample in an image?
Each chunk/sample is called a PIXEL
An 8 inch by 10 inch image at 100dpi, the image will have 800,000 pixels
76
What is the smallest possible unit (in digital images)?
A pixel is the smallest image component and thus shows the smallest detail
77
What is a pixel and how is it used?
An image is represented by a grid (array, matrix) of squared Picture elements called pixels
78
How are pixels arranged?
Arranged in column and rows
79
How is a pixel assigned a colour?
Each pixel is given a numerical value that represents the corresponding
colour:
◦ Green might be 1000
◦ Gray might be 1010
◦ Blue might be 1110
Using 4 bits to represent colour in this example=16 colours
80
How does sampling work (in terms of pixels)?
An image is broken into samples (called pixels --> sampling the image)
81
How does quantizing work (in terms of pixels)?
Each pixel (after image is sampled) is assigned a colour (represented by 0s and 1s --> quantizing the image)
82
If we scan that same 8 inch by 10 inch picture in and we set the resolution to 300dpi, after scanning how many pixels will we get?
(8 * 300) * (10 * 300) = 7,200,000 pixels (about 7 million pixels)
83
When printing an image, you should print with at least what dpi?
Dpi of at least 300 because human eye can detect pixelization if you print at lower than 300 dpi
84
What is a megapixel?
How many millions of pixels you can
capture in a photograph on your digital camera (how many “samples” it will break the image into)
85
Kodak DCS 460/660 captures 3072 by 2048 pixels for one photograph which is how many pixels and mega pixels?
About 6 million pixels or about 6
megapixels
86
If you have camera/phone that only captures 1 mega pixel, then if you print at 300 dpi, what's the largest size image you can print?
4.2" by 3.2" (without noticing pixelization)
87
A camera with more megapixels can print a larger image without what hapenning?
The human eye detecting a loss of quality
88
If you just want to print 4” by 6” images, you don’t need much more than how many mega pixels?
3 megapixels
89
IMPORTANT: When printing an image, the image must be printed at a size that has a minimum of how many pixels per inch?
300 pixels per inch
90
IMPORTANT: If you had an image that was 3000 pixels by 1500 pixels, for the print quality to be good enough to the human eye, what size should you print it at?
3000/300 --> 10 inches by 1500/300
--> 5 inches. DON’T PRINT IT ANY LARGER THAN 10” by 5”
91
How do we take pixels/samples and put them onto a monitor or paper?
Every image is broken down into the smallest possible unit=pixel. We have to make pixel display proper colour for image on monitor or display on paper using ink
92
We map the _____ pixels on to the _____ pixels IN A ______ and see our image.
Image
Screen
ONE TO ONE MAPPING
93
What happens in a one to one mapping?
Each single image pixel gets put onto a monitor pixel
94
What makes a big difference in one to one mapping between image and screen pixels?
Screen Resolution, image will look different depending on your monitor or screen resolution
95
What is screen resolution?
The number of pixels across by the number of pixels down that a screen is currently displaying
96
What are some common screen resolutions?
- 640 by 480
- 800 by 600
- 1024 by 768
- 1280 by 1024
97
If you had 14 inch monitors but one was 640 x 480 resolution and the other was 1280 x 1024, how would the size of the pixels differ?
640 x 480 = lower resolution, bigger and less pixels
1280 x 1024 = higher resolution, smaller and more pixels
98
How are screens like peg boards?
Holes are the monitor pixels (if you set resolution high=more holes, low res=less holes but bigger holding fatter pegs)
Image is like pegs (pegs are the image pixels)
One to One mapping
99
How do you change screen resolution on a Windows machine?
◦ Right click on the Desktop
◦ Select Properties
◦ Select Settings
◦ Change the Screen resolution
100
What do most people now have their resolution set as?
57% of internet users have their resolution higher than 1024x768
101
What does higher resolution and more pixels give you in terms of screen realestate?
Get more screen real estate, more places to use to put more and more images
102
How does a lower resolution (640 by 480) effect size of fonts, icons,
images and mount of data you can
fit on the screen at one time?
Size: Appear large, text larger, easier to read
Amount of data: Not as much
103
How does a higher resolution (1280 by 1024 ) effect size of fonts, icons,
images and mount of data you can
fit on the screen at one time?
Size: Appear smaller, text small, harder to read
Amount of data: A lot !
104
Images that are the same size in pixels will look different on different monitors not become of the image size but because of the....?
Screen resolution
105
What is the amount of space the image takes up on the screen is dependent on:
◦ Size of the image
◦ The current resolution of the screen
◦ NOT THE DPI
106
An image that is 400 pixels by 300 pixels will take up ¼ of the screen on a monitor with resolution 800 by 600 how much space will the same image take on a monitor that's set at 1600 by 1200?
400/1600=1/4
300/1200=1/4
1/4x1/4= 1/16 on a screen
Dependent on resolution
107
Does dpi affect file size?
No, also doesn't affect image resolution (number of pixels that makes them up)
108
Dpi doesn't make a difference when displaying an image, but how does it affect printing?
Look same on monitors but when printing and using software such as Word, higher dpi=smaller image (more dots, smaller) lower dpi=bigger image (less dots, bigger)
109
What does the average Pixels Per Inch for Monitors depend on?
◦ Size of the monitor in inches
◦ Current resolution
110
What is the average pixels per inch?
Around 72ppi or dpi (industry average for monitors, usually not different unless you have huge monitor with very high resolution)
111
Why does 72PPI matter?
If we always create an image at 72 ppi, we are guaranteed that what we see with the zoom level at 100% will be about the same size as on a
typical screen as it would if we decided to print it.
112
What dpi or ppi should you use when an image is for a webpage vs when it needs to be printed out?
Webpage=72 ppi
Printed=300dpi
113
What happens when we resize an image (resampling) that is 400 pixels
by 300 pixels and making it smaller
to (200 by 150)?
◦ Removes pixels
◦ Makes it crisper
◦ Gives it a smaller file size
No issues really, move pixels to keep basic look of image
114
What happens when we resize an image (resampling) that is 400 pixels
by 300 pixels and making it bigger
making it bigger to (1600 by 1200)?
- More pixels
- Makes it pixelated, jagged
- Adds pixels (guesses (G) where to put them, like a digital zoom on a
digital camera)
- Makes the file size bigger
Run into issues
115
How is the file size for an image determined by the number of pixels?
- More pixels = greater file size
- Less pixels = smaller file size
◦ DPI/PPI does not make a difference in the file size
116
What should you do to avoid an image taking a long time to download on a webpage?
You want the SMALLEST FILE
SIZE possible BUT you still want to display your image at a size appropriate for your page!
