Graphics image 1 Learning Outcomes Pada akhir pertemuan

Graphics (image) 1

Learning Outcomes Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu : • Menunjukkan Penggunaan Gambar pada Aplikasi Multimedia 2

Outline Materi • • • What is an Image Media Types Bitmap Image Vector Image 3 -Dimensional Graphic Models Working With Graphics 3

What is an Image? • An image is the graphical and visual representation of some information that can be displayed on a computer screen or printed out • Images come in a variety of forms: – Photographs – Drawings – Paintings – Television and motion pictures – Semantics – Maps, etc. • Images play an important part in multimedia – Navigation – User interface components – Help systems – Clip art 4

Image Media Types • Images can be generally divided into two formats: – Bitmapped or Raster images – Draw-type or Vector graphics or Metafile images • Bitmapped images are stored as an array of pixels. It represents the image as an array of dots, called pixels • Vector graphics are stored as geometric shape to represent the image 5

Bitmaps Image • A pixel is the smallest element of resolution on a computer screen (Screen Resolution) • A pixel is the basic unit of a digital images. Digital image is a picture that may be stored in, displayed on, processed by a computer. • As mentioned, bitmap is composed of a matrix elements called pixels • Each pixel can be in a specific colour and each pixel consists of two or more colors. 6

Bitmaps Image • The range of these colours is known as the colour depth. • The color depth determined “How much data in bits used to determined the number of colors”. • Colour depth is measured in bits per pixel – Remember: a bit (binary digit) is either 1 or 0 and that there are eight (8) bits in a byte 7

Colour depth • 1 bit per pixel = 2 colours (monochrome) • 2 bits per pixel = 4 colours • 4 bits per pixel = 16 colours • 8 bits per pixel = 256 colours – Generally good enough for colour images • 16 bits per pixel = 65536 colours – Better quality for photograph-like images, also known as high colour • 24 bits per pixel = >16 million possible colours – Used to recreate photo realistic images, also known as true colour 8

Bitmaps Image • The more colours that are allowed per pixel, the greater the size of the image • The number of pixels is related to the size of file that required to store an image. • Remember, two factors effect the size file bitmap are: – Resolution – Color Depth 9

Bitmaps images Original image Shown magnified 10

Image (Bitmap) pixel 11

Image – – – 1 bit (bw) 1 byte (greyscale) 1 byte (256 color) 2 byte (64 K color) 3 byte (16 M color) Pixel H (horizontal number of pixel) V (vertical number of pixel) • Total number of pixels is Hx. V • Every pixel represented by IWAN SONJAYA, ST. MMT, MT 12

Greyscale Image (1 byte per pixel) • Image 500 x 400 pixel • Total number of pixel is 200. 000 pixel • Each pixel represented by 1 byte • Total image capacity 200. 000 x 1 byte = 200. 000 byte Pixel-2 = 1 byte Pixel-1 13 Pixel-n

Color Image (true color, 3 byte per pixel) • Image 400 x 500 pixel • Total number of pixel is 200. 000 pixel • Each pixel represented by 3 byte • Total image capacity 200. 000 x 3 byte = 600. 000 byte Pixel-1 Pixel-2 = 1 byte 14 Pixel-n

Color vs Greyscale vs BW Black and White Color Greyscale 15

Black and White (1 bit per pixel) 8 pixels = 1 byte 8 pixels Greyscale 16 Black & White

Calculating the size of a raster image • Where: – Width of the images measured in pixels – Height of the images measured in pixels – Colour depth is the number of bits used for color measured in bits per pixel • Remember: – 1024 bytes = 1 kilobyte (KB) – 1024 kilobytes = 1 megabyte (MB) 17

Example • A 640 x 480 pixel image in 24 -bit colour would require how much disk space? 18

Popular bitmap formats • Microsoft bitmap (. bmp) – Used in microsoft windows • TIFF - Tagged Image File Format (. tif) – Used for faxing images (amongst other things) • JPEG - Joint Photographic Expert Group (. jpg) – Useful for storing photographic images • GIF - Graphics Interchange Format (. gif) – Used a lot on web sites • PNG - Portable Network Graphics (. png) – A new format for web graphics • PCD – Kodak photo CD – A new format for store image in a compressed form on a CD 19

Advantages and Disadvantages of using bitmap images • Advantages – Convey detail of information quickly – Real life • Disadvantages – Depend on a Resolution – Effect to the image quality – Size file is big 20

Software to create bitmap images • Popular PC packages include: – Microsoft Paint • Included with microsoft windows – Microsoft Photo. Draw 2000 • http: //www. microsoft. com/office/photodraw/ – Adobe Photoshop • http: //www. adobe. com/products/photoshop/main. html – Paint Shop Pro • http: //www. jasc. com/psp 6. html – Macromedia Fireworks • http: //www. macromedia. com/software/fireworks/productinfo/ 21

Vector images • Vector images are stored as the set of graphic primitives required to represent the image • A graphic primitive is a simple graphic based on drawing elements or objects such as shape – e. g. square, line, ellipse, arc, etc. • The image consists of a set of commands (mathematical equations) that are drawn the object when needed. 22

Vector images • Storing and representing images by mathematical equations is called vector graphics or Object Oriented graphics. • Each primitive object has various attributes that go to make up the entire image – e. g. x-y location, fill colour, line style, etc. • Example: – RECTANGLE : rectangle top, left, width, height, color is ( 0, 0, 200, red) – CIRCLE : circle top, left, radius, color – LINE : Line x 1, y 1, x 2, y 2, color 23

Vector images • Vector image or vector graphics can be resized without losing the integrity of the original image. • Scaling a vector is a mathematical operation - only the attributes change, the image is unaffected 24

Primitive geometric drawing objects • Basic – – Line Polyline Arc Bezier curve • Text – Font, weight • Shapes – – – – Circle Ellipse Rectangle Square Pie segment Triangle Pentagon, hexagon, heptagon, octagon, etc 25

Scaling vector graphics Original image Shown magnified 26

Advantages and Disadvantages of using vector image • Advantages – Relatively small amount of data required to represent the image. – Therefore, it does not required a lot of memory to store – Easier to manipulate • Disadvantages – Limited level of detail than can be presented in an image 27

Software to create images • Graphics programs are tools that allow an artist to create and edit designs used in multimedia applications. • Generally, graphics programs can be categorized as: – Drawing programs • Creating draw type graphics • Provide freehand. Example geometric shape • Example : Adobe Illustrator, Corel Draw, Macromedia Freehand – Paint programs • Those creating bitmaps • Useful in creating original art • Example: Paint Shop Pro – Image editing programs • Making changes to existing images, such as manipulating the brightness or contrast, applying textures, patterns • Examples : Adobe Photoshop, Corel Photo. Paint 28

Vector formats • Windows metafile (. wmf) – Used by Microsoft Windows • SVG - Scalable Vector Graphics (. svg) – A new format devised for the web • CGM - Computer Graphics Metafile (. cgm) – Older format commonly used for clip art • Adobe Post. Script (. ps) – A page description language used to control printers • Adobe Portable Document Format (. pdf) – A page description language common on the web • Drawing Exchange Format (. dfx) – Store 3 D image created by design program Auto. CAD • Encapsulated Post. Script (. epf) – Professional printing: Illustration program, Adobe Systems, Desktop Publishing programs 29

3 -Dimensional Graphic models • A 3 D model is a variation on the vector format • The location of a 3 -dimensional object is specified using x, y and z co-ordinates X • Further primitives can be found in 3 D models 3 D model – Cube, sphere, pyramid, etc. – Camera, spotlight, texture, shading etc. Y Z 30

3 -Dimensional Graphic models • 3 D graphics offer the photorealistics effects that have you seen in TV, Computer Games • Examples, Motion Picture films such as: – Jurassic Park, Terminator 2, Lost World and Toy Story • Examples 3 D programs: – Carigali Truespace – 3 D Studio Max – Infini-D 31

3 -Dimensional Graphic models 32

Hardware used to acquire images • Scanners and digital imaging products • Many forms of scanner – – Drum Flat-bed Negative / slide Hand-held • Important to check the optical resolution of the scanner – measured in dots per inch (DPI) 33

Hardware used to acquire images • Digital camera – Uses digital memory instead of film – Images are transferred to computer via a cable – Can be very high resolution • Stills from a camcorder or PC “webcam” type camera – Home products tend to be low resolution 34

Hardware used to create / edit images • Graphics tablet and pen – Preferred by digital artists – Pressure sensitivity Tablet and pen • Digitiser tablet – Preferred by technical artists – Mouse has accurate crosshair to help digitise drawings Digitiser 35

Converting image formats True. Type / Post. Script Type font Render as bitmap Contour trace Vector image Text Optical Character Recognition (OCR) Bitmapped image Bitmapped font 36

Working With Graphics • Considerations and guidelines when we are working with graphics: – Choose the graphic depend on your work – Choose the correct software – Use minimum color depth – Delivery Systems 37

How graphics/images can be used effectively • Different types of graphics are used in different ways: – Line drawing are graphical representations of physical objects. There are 3 kinds of line drawings: • Isometric - represent 3 -D objects without realistic perspective • Orthographic - are 2 -D representations of objects • Perspective - represent objects in their most realistic form 38

How graphics/images can be used effectively ? • Graphs and Tables – In just a glance, graphs can provide specific data, show general trends in data or depict the relationships between data and data trends • Diagrams – Help users conceptualize a process, flow or interrelationship. Examples of diagrams include: Flow charts, Schematic Drawings and Block Diagrams. 39

Advantages and Disadvantages of using images • Advantages – – Convey a lot of information quickly Add visual simulation and colour Can communicate across language borders Enhance other media • Disadvantages – Do not provide in-depth explanations • Graphics rarely suffice to convey a whole message in business, technical or safety settings – Can be misinterpreted • Graphics should be used carefully to make sure the message is not ambiguous or cryptic 40

Irian. . . Cendrawasih 41

Sekian. . . Dan Terimakasih. . . 42