Perception

What is perception in HCI?

Perception is what allows the user to see and feel when using a human computer interface. In order to understand and allow the users to see and feel, designers use colours, patterns and objects.

Colour

When building a human computer interface it is important that the designer takes note and thinks whether the user of the interface will be able to navigate around it and use it with ease. In order to resolve such issue and ensure that the user will be able to use the interface, the designer should draw up colour charts with a mixture of backgrounds and text colours which can be seen by the user or any user that uses the interface.

It is always a good idea to make sure the colours chosen for the HCI are suitable for all types of users and offers a way to change the colour if required. For example some users do find and will find that yellow is easy to see and read on a white background though for others it would appear fuzzy and difficult to see and read. Some users that are hoping to use the HCI may be found with dyslexia that would require them and the designer to offer different colour overlays and also people with colour diffusion often confuse red and green or blue and yellow, while others see only in monochrome; this means that there is quite a lot that the designer has to take into consideration when building a HCI.

Luminance is when you are able to see a colour above another layer / colour. It's known that people tend to have troubles seeing text above another layer as designers do not take in to consideration that users and screen brightness of peoples computer monitors. Also as above, some people find it hard to read yellow text on a blue background, so what the designer needs to do is make sure that the colour of the text is easy for every reader to read.

The pop-out effect is when you are able to make one image stand out more than the other images around it by using a different shape, colour or size. It gives the illusion that something is popping out of the screen and the images around it are further away or hidden. 

Pattern

Pattern is made up of 6 sections which consist of Proximity, Continuity, Symmetry, Similarity, Common groupings and Connectedness. However, what are these sections and what do they means? 

• Proximity - This is a way of saying that we view things which are close together as a group or look closer than they actually are. An example of this would be to look in a wing-mirror on a car and notice how cars seem closer than they actually are when you look back at the car behind. Warning signs are placed on such mirrors notifying them that objects would appear closer than they actually are to the humans eye.
• Continuity -  This means that we take more of an interest in straight smooth lines rather than lines that are rigid and constantly change shape / size. 
• Symmetry - This is when a shape or object is repeated on both sides to make it an mirror image / copy. It's proven that us humans are capable of seeing patterns better when they are symmetrical.
• Similarity - This is when a group of objects and shapes are placed together because they look similar to one another, whereas dissimilar objects tend to be seen as individuals.
• Common groupings - This is when us humans notice and see a set of images and group them together if they are related or closely related to one another.
• Connectedness - This is when we see objects that are related to one another joined together by a continuous straight line.

Objects

When we look at an interface the designer needs to think about and take note of the size and shape of a particular object so when a user goes to see this object and interact with it, it doesn't take long for the user to click on it. Objects in a GUI (Graphical User Interface) would include Geons and Gross 3D. 

• Geons - These are 2D shapes which can be easily viewed and given a perspective of 3D. They are quickly recognizable and are also cheap to produce and doesn't take as much time to produce. The shapes are broken up and arranged to give the illusion of being a 3D object. 

• Gross 3D- These are 2D shapes that also give the illusion of being 3D, however it can be difficult for some users to interact with and look at, in order to make the illusion of it being 3D the shape is copied and placed slighter higher or lower on the page. 

Bibliography
http://www.colourtherapyhealing.com/colour/colour_perception.php
http://www.skidmore.edu/~hfoley/Perc5.htm