how did photography go digital? - gail...

COMP 1001: Introduction to Computers for Arts and Social Sciences

How Did Photography Go Digital?

Binary Numbers and Data Representation


Admin Stuff

Assignment 1 Posted (how to submit, etc…)


Learning Objectives

• Learn how information is stored on a computer.


Part 1

How photography

works

Pixels

Black and white images

Colour images

Part 2

Binary numbers

Converting binary and

decimal

Using Python to convert numbers

Part 3

Bits and bytes

Numbers and text in

memory

Images in memory

Vector versus raster images


http://www.flickr.com/photos/grange85/12501119/


Part 1

How photography

works

Pixels


Colour images

Part 2

Binary numbers


decimal


Part 3

Bits and bytes

Numbers and text in

memory

Images in memory



Which of the following is not an accurate fact about one-number-per-

pixel encoding?

It is always less efficient than run-length encoding. Losing a number from a row could greatly affect the picture. Getting one number wrong will not greatly affect the picture.


Which type of image would be most suitable to send over a slow,

unreliable cell network?

One-number-per-pixel Simple run-length encoding

Both are equally fine Neither are appropriate


Part 1

How photography

works

Pixels


Colour images

Part 2

Binary numbers


decimal


Part 3

Bits and bytes

Numbers and text in

memory

Images in memory



Find the bags we need to break for the following numbers of stones:

19 3

29 15 8

31


Is it always possible to get the exact number of stones we want from the

bags?

Yes No

It depends


Is there more than one way to choose the bags to break in order to get the

exact number of stones we want?

Yes No

It depends


Part 1

How photography

works

Pixels


Colour images

Part 2

Binary numbers


decimal


Part 3

Bits and bytes

Numbers and text in

memory

Images in memory



Number of stones Binary

19 10011

3 11

29 11101

8 1000

20 10100


Number of stones Binary

19 10011

3 00011

29 11101

8 01000

20 10100


Binary

Decimal


Binary

Decimal

Digits 0-1. Each column is double its neighbour.

Digits 0-9. Each column is ten times its neighbour.


What is 01011011 in decimal?


What is 10101010 in decimal?


Figure out this joke:

There are 10 types of people in this world: those who know binary, and those who

don’t.


How can you count to 31 on one hand?


Part 1

How photography

works

Pixels


Colour images

Part 2

Binary numbers


decimal


Part 3

Bits and bytes

Numbers and text in

memory

Images in memory



Type the following into the shell, pressing enter after each one:

0b11

0b101

0b10000

0b11111



0b123

0bhello



bin(1234)

bin(0b111)


Part 1

How photography

works

Pixels


Colour images

Part 2

Binary numbers


decimal


Part 3

Bits and bytes

Numbers and text in

memory

Images in memory



Binary digit

Bit (A single 1 or 0)


What is the largest number (in decimal) that you can store in a single

byte?

127 128 255 256

11111111 99999999


What about larger numbers?


183

109


0b1011011101101101 = 46,957


Data Types

Name Type

int plain integer – no decimal point

float floating point number – has a decimal point

complex real + imaginary parts


Storing Text in Memory

0b01000001 (65) A 0b01100001 (97) a

0b01000010 (66) B 0b01100010 (98) b

0b01000011 (67) C 0b01100011 (99) c

Like a code: binary to character


Storing Grayscale Images in Bytes

0%

50%

100%

0b00000000

0b00110010

0b01100100



0%

50%

100%

0b00000000

0b00110010

0b01100100

We can store a bigger number than 100 in 8 bits! We are wasting space.



0% = 0

50% = 127

100% = 255

0b00000000

0b01111111

0b11111111


8-bit Color

R R R G G G B B

one byte


8-bit Color

R R R G G G B B

one byte

Although this byte could be interpreted as a single number, we can also set up a standard that says the first three bits will be one number

(for red), the second three bits will be another number (for green), and finally the last two bits will be a third number (for blue).


8-bit Color

R R R G G G B B

8 * 8 * 4 = 256 colors

Red can be between 0 and 7 (8 choices), green is the same, and blue can be between 0 and 3 (4 choices). To get all the combinations of

these colors we multiply 8*8*4 and get 256. Thus, 8-bit color allows for 256 colors.


8-bit Color

http://www.deviantart.com/morelikethis/211513504


24-bit Color

R R R R R R R R

G G G G G G G G

B B B B B B B B

256*256*256 = 16,777,216 colors


Pixel/Raster/Bitmap Graphics


Vector Graphics


The Difference

Two versions of the same image. One is a raster image, the other vector.

VectorVsRasterExample.svg


Intro to 3D Graphics


What type of graphics do 3D games and animations use?

Vector Raster Both

Neither


Mathematical 3D Objects


Translation


Rotation


Scaling


Issues Encountered in 3D

How much can the camera see?

http://www.chadvernon.com/blog/wp-content/uploads/2007/07/frustum.jpg






Should objects further away look smaller?




http://o.aolcdn.com/gd-media/games/super-mario-galaxy/wii/93.jpg

YES











http://www.codeguru.com/dbfiles/get_image.php?id=10123&lbl=3DPROJ04_GIF&ds=20061023

NO

http://www.codeguru.com/dbfiles/get_image.php?id=10123&lbl=3DPROJ04_GIF&ds=20061023


A Cool, Fairly Recent Example

3-Sweep: Extracting Editable Objects from a Single Photo

http://www.youtube.com/watch?v=Oie1ZXWceqM





Part 1

How photography

works

Pixels


Colour images

Part 2

Binary numbers


decimal


Part 3

Bits and bytes

Numbers and text in

memory

Images in memory


how did photography go digital? - gail...

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