SIMS-IS146 – 17.03.2005 1

History and Technology of Digital Imaging

Visual material used from the film Minority Report, TM and © 2002 Twentieth Century Fox and Dreamworks

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Image reading

•Visual communication is always coded–“It seems transparent only because we know the code already, at least passively — but without knowing what it is we know, without having the means for talking about what it is we do when we read an image.”

•Our culture is moving from textual to visual–“Until now, language, especially written language, was the most highly valued, the most frequently analyzed, the most prescriptively taught and the most meticulously policed code in our society.”

•Visual “literacy” is not taught and needs to be–“If schools are to equip students adequately for the new semiotic order, if they are not to produce people unable to use the 'new writing' actively and effectively, then the old boundaries between 'writing' on the one hand, traditionally the form of literacy without which people cannot adequately function as citizens, and, on the other hand, the 'visual arts', a marginal subject for the specially gifted, and 'technical drawing', a technical subject with limited and specialized application, should be redrawn.”

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Image technology

PaintingVERMEER VAN DELFT, c. 1665,Oil on canvas, 46,5 x 40 cm, Mauritshuis, The Hague

Photo (1830)

development of technology (e.g. colour, brushes, canvas, etc.) development of presentation techniques (e.g. central perspective)

Digital image (1950)

development of technology (e.g. camera, film stock, etc.) development of presentation techniques (e.g. illumination)

development of technology (e.g. camera, compression, manipulation) development of presentation techniques (e.g. automatic collage)

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The eye

Capture

Transcoding

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Vision – A matter of light

Newton’s experimentum crucis

„no colour"

780

520

380

Wavelength550 nm

500

480

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The camera

Analog camera produces a continuous image, simulating the capture of the eye.

Negative (reverse reality)

Actual image (various manipulation processes)

Analog technology is expensive and complicated to handle.

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The digital image

The image is a matrix of values, representing the colour, texture, dimension, etc.

0000001

000001

00001

0001

001

01

1

0

0

0

0

0

0

0

1

1

1

1

1

1

1

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The digital image - colour

RGB: Red, Green and Blue light get mixedUse in screens or cameras

CMY(K): Fraction of white light is removedCyan R B und G Magenta G R und B Yellow B R und G

Used in printing

HSB: Hue (Wavelength value)Saturation (Amount of hue in a colour)Brightness Used in image editing software

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The digital image - Texture

The distinctive physical composition or structure of something, especially with respect to the size, shape, and arrangement of its parts • structural analysis : small units and rules for composition • statistical analysis : local grey values, regularity, contrast

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The digital image - size

1 Bit -> black and white 8 Bit -> greyscale16 Bit -> 64.000 colours (High Colour)24 Bit -> 16 Mil. colours (True Colour)

File size for True Colour

640 x 480 x 3 = 0,87 MB 800 x 600 x 3 = 1,37 MB1024 x 768 x 3 = 2,25 MB1280 x 1024 x 3 = 3,75 MB

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The digital image - manipulation

Pixel or vector

Image format• Resolution• Mode• File type

Image enhancement• resize• colour enhancement• artistic filters• establishing planes• any other sort of manipulation

ALWAYS ask: what do I intend to do with the image now AND in the future?

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The digital image - Questions

Are there ways a digital image can keep its integrity? If so, why should it?

What does the Cartesian grid representation of an image tell us semantically/semiotically?