33
1

6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

  • Upload
    others

  • View
    1

  • Download
    0

Embed Size (px)

Citation preview

Page 1: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

������������������ ���������������������������������������� ���������� ������������������������������������������������������������������� ����� ���

1

Page 2: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

5

Page 3: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

6

White (TFT Off) Black (TFT On)

Pixel Electrode

Common Electrode

Color Filter

Polarizer

Liquid Crystal

300 μm

One Pixel

Phosphor dots

Screen

Shadow mask

Electron beams

Color signals

Electron beams

Electron guns

Cathode Ray Tube

Picture tube

������������ �������������

Page 4: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

7

Page 5: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

how CRTs can make pixels larger or smaller by changing frequency of scan (analog resampling), but LCD pixels are fixed

display�s natural resolution always looks sharpest

square vs. nonsquare pixels

8

QVGA320x240

VGA640x480

PAL768x876

SVGA800x600

XGA1024x768

SXGA1400x1059

SXGA+1400x1050

UXGA1600x1200

QXGA2048x1536

QSXGA2560x2048

WQXGA2560x1600

WUXGA1920x1200

2K2048x1080

HD 10801920x1080

WSXGA+1680x1050

WXGA1280x800

WXGA1280x768

HD 7201280x720

1152x768

WSVGA1024x600

WVGA850x480

WVGA800x400

NTSC720x480CGA

320x200

1280x9541280x960

1440x900

1366x768

1440x960

17:9

16:95:3

8:53:2

4:35:4

������������ �������������

Page 6: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

������������������������������������!�

Note that DPI and PPI are sometimes used confusingly���sometimes the quoted��dpi�for an LCD panel is actually three times its true ppi, because they�re counting the three subpixels

Smartphone PPI: http://pocketnow.com/index.php?a=portal_detail&t=news&id=4341

Lines per inch refers to number of halftone grid lines per inch. Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray, you�d need 10x10 pixel grid squares, so a 600 ppi printer would only be able to get 60 lpi halftoning.

So a bad rule of thumb is to multiply the lpi by 10 to find the equivalent ppi. Magazine printing using digital halftoning can be up to 2500 ppi!

9

Page 7: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

������������������������������������!�

������������������������������������!�

Subpixel rendering takes this a step further. Every pixel on an LCD screen consists of three discrete pixels side-by-side: red, green, and blue. So we can get a horizontal pixel density which is three times the nominal pixel density of the screen, simply by choosing the colors of the pixels along the edge so that the appropriate subpixels are light or dark. It only works on LCD screens, not CRTs, because CRT pixels are often arranged in triangles, and because CRTs are analog, so the blue in a single �pixel� usually consists of a bunch of blue phosphor dots interspersed with green and red phosphor dots. You also have to be careful to smooth out the edge to avoid color fringing effects on perfectly vertical edges. And it works best for high-contrast edges, like this edge between black and white. Subpixel rendering is ideal for text rendering, since text is usually small, high-contrast, and benefits the most from a boost in horizontal resolution. Windows XP includes ClearType, an implementation of subpixel rendering for Windows fonts. (For more about subpixel rendering, see Steve Gibson, �Sub-Pixel Font Rendering Technology�, http://grc.com/cleartype.htm)

10

Page 8: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

������������������������������������!�

+

+

+

_

_

_

-- -

- -- -

- -- -- -

- ---

- -- -

-- -- -

-- -

- -- -

- - -- -

-

++ + + + +

+

++

++

++ +

+++ ++

+

++

+++

++++

+

++

+++++

+ +

������������ �������������

white particles are titanium dioxide (about a micron in size)

11

Page 9: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

12

Page 10: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

Mirror -10 deg.

Mirror +10 deg.

Hinge

Yoke

Landing Tip

CMOS Substrate

������������ �������������

������������ �������������

13

Page 11: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

14

Page 12: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

���������������"�#������$�����������%������ ���������������"�%����$������%������

���������������"�������!����������%������ ���������������"����������������%������

Mouse Touchpad Trackpoint Trackball

Focusing on indirect pointing devices today � Friday�s lecture will say more about direct touch on the screen

15

Page 13: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

more about direct touch on Friday

mouse vs. trackball: Mackenzie et al. �A Comparison of Input Devices in Elemental Pointing and Dragging Tasks.� CHI 1990.

mouse vs. trackball vs. touchpad vs. joystick: MacKenzie et al, �Accuracy Measures for Evaluating Computer Pointing Devices�, CHI 2001. http://www.yorku.ca/mack/CHI01.htm

16

Page 14: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

6

0

1

2

3

4

5

0

2

4

6

8

10

12

14

Mouse Trackball Joystick Touchpad

Trou

ghpu

t (b

ps)

Erro

r ra

te (

%)

Troughput Error rate

������������ �������������

17

Page 15: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

����'������������������������!�

18

Page 16: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

����'������������������������!�

Blanch et al. �Semantic pointing: improving target acquisition with control-display ratio adaptation.� CHI 2004.

19

Page 17: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

20

Page 18: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

21

Page 19: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

27

������������ �������������

Page 20: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

31

������������ �������������

Page 21: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

34

������������ �������������

Page 22: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

Fast accurate finger or stylus

Not Multi-touch75

%

������������ �������������

40

Page 23: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

19 C 15 C

17 C

17 C

������������ �������������

49

Page 24: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

Not multi-touch

Bare finger orconducting stylus

90%

������������ �������������

53

Page 25: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

How the iphone works Mutual capacitance screen*

Sensing lines

Insulating material

Protective Driving linesanti-reflective

coating

Protective cover

Bonding layer

Driving lines

Sensing linesGlass substrate

LCD display layers

������������ �������������

54

Page 26: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

61

������������ �������������

Page 27: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

68

������������ �������������

Page 28: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

70

������������ �������������

Page 29: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

71

Page 30: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

�������������������������������������!�

designed for multiple users around a tabletop rotation becomes an important issue multiple users (and multiple touches per user) are identified by an array of transmitting antennas in the surface and sensors connected to their chairs front-projected (because the antenna array is presently opaque), so occlusion of the display is worse

72

Page 31: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

73

Page 32: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

74

Page 33: 6.831/6.813 Lecture 25 Notes, Input/output technology · 2020. 12. 30. · Digital halftoning uses a subgrid of pixels instead of different sizes of dots. So for 100 shades of gray,

��������� ���� ��������������������

����������������� ���� ����!���"�������#���������$� �"�%&���

'� �� � �������(��������"����������� ��#��� ��� ��� ���� ����)�*��������������������������� ����