This document discusses digital imaging and different types of image files. It explains that digital images are composed of pixels and can be raster images made of grids of pixels or vector images made of mathematical shapes. Raster images are best for photos while vector images are more flexible but must be converted to pixels for screens. Common file formats like JPEG, GIF, TIFF and PNG each have advantages like file size or quality that make them suited to different uses like websites versus high-quality printing. The document provides examples and details on digital imaging concepts.
2. What is Digital Imaging?
• Digital images are objects which communicate
meaning or information.
• If an image is used or to be used on a
computer it is in digital form
• A photograph from a camera is a natural
image however once on a computer it is
manipulated into digital format.
3. What are Raster Images?
• Raster images can also be referred to as
bitmap images
• They are created on a computer with the use
of pixels
• Pixels are arranged in a small grid formation
where their colours and tones combine to
produce an image
• They are best for complex images or
photographic images
Example
Raster Image -
4. What are Vector Images?
• Vector images are created using mathematical
calculations on a computer
• Vector uses both line direction and magnitude
to create simple shapes i.e. lines, arcs
• These shapes can also be joined (combined)
together to make squares and circles as an
example.
Example
Vector
Image -
5. Advantages/Disadvantages for Raster
Images
Advantages:
• Ideal for professional photographic images which
contain a lot of colour
• More editing tools available to the consumer
• Can easily edit colour by seeing the individual
pixels making the image.
Disadvantages:
• Resolution dependent, can have pixels become
visible when the quality has been reduced
• The size will determine how much can be altered
6. Advantages/Disadvantages for Vector
Images
• Advantages
• More Flexible than raster images
• Smaller than raster files as they produce less information
when displayed/ edited
• Disadvantages
• To be viewed on computer they must be transformed into
pixels.
• Computer monitors can only show pixels so the computer
has to re-calculate the vector images to fit on the screen.
• The Computer must re-calculate the vector image every
time it refreshes.
7. What are Image file formats?
• Image file formats are the organizing of digital
images which allows a computer to tell what type
of data is stored in the current file selected.
• There are 5 types of Image file formats:
• .bmp – Bitmap
• .tif
• .gif
• Jpeg
• png
8. Advantages / Disadvantages of the
image file formats
• Used for: Natural Photographical images
• Name : JPEG
• Advantages:
• Compressed and take up less room
• Are a common file accepted by most websites
• Make the file smaller so they can be used in an email
JPEG – Disadvantages:
• The colour is slightly degraded once conversion from
normal image
• Designed for mainly websites and emails.
9. Advantages / Disadvantages of the
image file formats continued
• Used for Can be animated, used for large areas / solid
colours
• Name :GIF
• Advantages
• Great for websites
• Can make amusing images which are created from
movie clips
• Cross platform usage and made for online purposes
• Disadvantages
• Limited Colour availability
• Definitely not suited for high photographic images
10. Advantages / Disadvantages of the
image file formats continued
• Use: To save images to be read by multiple devices and to
get the max resolution and quality for the image.
• Name:TIFF
• Advantages
• High Quality images
• Saves the pristine full colour of the original photograph on
the camera
• Great for printing out large canvas prints of desired image
• Disadvantages
• Not suitable for most websites
• Extremely large file sizes from the colour
11. References
• Images:
• Vector Paris Image visited : 14/3/12
http://trialx.com/curetalk/wp-content/blogs.dir/7/files/2011/05/diseases/Vector-
3.jpg
• Raster Linux Head Image visited : 14/3/12
http://keithp.com/~keithp/talks/xr_ols2003/html/tux_head_raster_4x.png
Information:
Applied It 2A Moodle groups website Visited throughout the week of Week 8
Used the documents:
Raster Vector
Colour
Digital Imaging
Also visited:
http://amath.colorado.edu/computing/graphics/understand_fmts.html
14/3/12