1. Digital imaging or digital image acquisition is the creation of digital images. The term
is often assumed to imply or include the processing, compression, storage, printing,
and display of such images. The most usual method is by digital photography with a
digital camera but other methods are also employed.
Digital imaging was developed in the 1960s and 1970s. As digital technology became
cheaper in later decades it replaced the older film methods for many purposes. An
image changed on the computer would be called a digital image e.g. If a photograph
was taken (which would be a natural photo) and then the person who took the photo
wanted to tweak it, he would have to put it on a computer. After he finishes tweaking
the photo it becomes a digital image instead of a natural image.
2. Raster Images
A raster image, also called a bitmap, is a way to represent digital images. The raster
image takes a wide variety of formats, including the familiar .gif, .jpg, and .bmp. A
raster image represents an image in a series of bits of information which translate
into pixels on the screen. These pixels form points of colour which create an overall
finished image.
When a raster image is created, the image on the screen is converted into pixels.
Each pixel is assigned a specific value which determines its colour. The raster image
system uses the red, green, blue (RGB) colour system. In photographs with subtle
shading, this can be extremely valuable.
3. Vector Images
Vector images are created on a computer using mathematical calculations. Vector images
are used for simple geometric shapes like lines and arcs. These shapes can be combined
to make squares and circles.
Vector graphics is based on images made up of vectors which lead through locations
called control points. Each of these points have a position on the x and y axes of the work
plan. Each point, as well, is a variety of database, including the location of the point in
the work space and the direction of the vector (which is what defines the direction of the
track. This does not affect the size of the files in a substantial way because all information
resides in the structure; it describes how to draw the vector.
4. Raster VS Vector
Usually when choosing one of these image types the user would choose Vector images over
Raster. This would usually be the case because Raster images are bury when magnified
while Vector images are usually defined. As you can see with the image below Raster
images have a blurred edge.
5. Image file Formats
Image file formats are standardize means of organizing and storing digital images. Image
Files are made up of digital data which can be rasterized for use on a computer display. An
image file format can store data in uncompressed, compressed or vector formats. Once an
image is formed the image becomes a grid of pixels, each of which has a number of bits to
designate its colour equal to the colour depth of the device displaying it. A raster image file
format can be displayed in many different formats, e.g.
Jpeg, Exif, Tiff, Raw, Png, Gif,Bmp, Ppm, Webp, Jpeg 2000.
6. Jpeg file format
The Jpeg file format is one of the most common image file formats used around the world.
One of the main advantages of the Jpeg file format is that it is smaller in file size then most
other image file formats. A disadvantage of the jpeg file format is that due to its small size it
loses depth and quality.
Gif file format
Gif was the first image file format introduced into the world wide web. One of the
advantages of having the Gif file format is that it is html supported. One of the
disadvantages of the Gif File format is that it has restricted file colours.
7. Tif File format
The Tiff file format is an image file format that mainly graphic designers use. It is a
flexible and adaptable file format. The Tiff file is widely used as a bitmapped file
format, which stores graphics in CMYK or RGB colour model. One of the
advantages of using the Tiff format is that it is good for storing information for
printing. A disadvantage. of using the Tiff format is that it takes up quite a lot of
room up on the hard drive compared to other file formats.
