PIXEL AND RESOLUTION
Pixels
A pixel is the smallest controllable point of a picture on a computer screen. Every image on a screen is represented by thousands of extremely tiny squares and depending on the resolution of the image, there can even be millions. To establish an image, each pixel is represented by just one colour and - considering these pixels are so small and that there are thousands of them all together - the colours can easily blend together to create any image the computer is told to create.
Colour depth is defined by the number of bits per pixel which are shown on-screen, so the number of colours a pixel can become, is determined by the number of bits which represent it. Data is stored in bits and each bit represents the value 1 or 0 which means it represents 2 colours. in this case, these two colours would be black and white. The more bits per pixel, the more colours the pixel can become. Here are some examples of the colour depth:
1 bit colour = 2 colours
4 bit colour = 16 colours
8 bit colour = 256 colours
16 bit colour = 4,096
24 bit colour = 16,277,216
To work out the number of colours in a 6 bit colour for example, since a bit represents 2 colours, the colour depth of 6 bits would be 2 times itself 6 times so 2x2x2x2x2x2 which equals 64, so a pixel represented by 6-bits would be able to become one of 64 colours.
Digital cameras nowadays all contain sensors. These special sensors convert any light that enters the lens into electrical charges. The lens is used to refract the light and focus it onto the silicon sensor and then these millions of tiny 'photosites' on the sensor take a colour of the light that hits it and a picture is formed. A photosite is commonly known as a pixel which is a very small section of a photo ot image. When thousands or millions of these are together, they are able to construct an image of what is being looked at through the camera. The diagram below explains this process.
Each pixel on the sensor absorbs photons and releases electrons. This process is called the photoelectric effect. Albert Einstein and Heinrich hertz are responsible for discovering this effect. Under the right circumstances, light can be used to push electrons, freeing them from the surface of the solid (which is usually a metal) as a consequence of their absorption energy from electromagnetic radiation of a very short wave length. This could be visible or ultra violet radiation/light.
In most digital cameras, the sensor is called a Charge-coupled device or a CCD but some cameras use what is called a complementary metal oxide semiconductor - CMOS. Both of these technologies are similar in the sense that they convert light into electrons. When the sensor receives light and converts it into electrons, it reads the accumulated charge of every cell within the image. The charge is then taken and converted into what is known as an analogue voltage, which is a voltage that varies in a continuous fashion, which is then amplified. The amplified voltage is then delivered to an Analogue-to-digital converter where it is 'Digitised'. This means it is transformed into a number.
Resolution
This is the term used to describe how many pixels are displayed on an monitor, printer or bit-mapped graphic images. It also describes how sharp and strong one of these items is. Bitmap images are made up of pixels and the resolution of one of these images can be determined by PPI or Pixels Per Inch on a grid. This measurement is used to work out the resolution and to work out the size of the image, the measurements used are Width x Height in inches. These factors can state how many pixels are located in one image.
This is the term used to describe how many pixels are displayed on an monitor, printer or bit-mapped graphic images. It also describes how sharp and strong one of these items is. Bitmap images are made up of pixels and the resolution of one of these images can be determined by PPI or Pixels Per Inch on a grid. This measurement is used to work out the resolution and to work out the size of the image, the measurements used are Width x Height in inches. These factors can state how many pixels are located in one image.
The amount of pixels in an image can be anything from 65,000 to 12 million. The more pixels there are in an image, the higher the resolution and the better the image quality. The fewer the pixels in an image, the less detailed an image can be so the lesser the quality. Some examples of common resolutions are:
256x256 - This has a total of 65,000 pixels and is found mainly of very cheap cameras. The quality is terrible as 65,000 pixels is actually quite a low number pixel-wise.
1600x1200 - This resolution displays almost 2 million pixels and considered 'high resolution'. Images under this resolution have quite a good quality.
4064x2704 - This resolution has 11.1 million pixels and can be found it high end very expensive cameras. The quality of images at this resolution is outstanding and it is possible to create a 13.5x9 inch print with no quality lost.
If you are printing an image however, you need to be aware that each resolution has an optimum size of print. For example, due to lack of quality, images printed with a 256x256 resolution on a large piece of A3 paper will look terrible, but on a much smaller piece, the quality will begin to appear better. The standard for screen displays is 72 PPI and the standard for print is 300 PPI.
256x256 - This has a total of 65,000 pixels and is found mainly of very cheap cameras. The quality is terrible as 65,000 pixels is actually quite a low number pixel-wise.
1600x1200 - This resolution displays almost 2 million pixels and considered 'high resolution'. Images under this resolution have quite a good quality.
4064x2704 - This resolution has 11.1 million pixels and can be found it high end very expensive cameras. The quality of images at this resolution is outstanding and it is possible to create a 13.5x9 inch print with no quality lost.
If you are printing an image however, you need to be aware that each resolution has an optimum size of print. For example, due to lack of quality, images printed with a 256x256 resolution on a large piece of A3 paper will look terrible, but on a much smaller piece, the quality will begin to appear better. The standard for screen displays is 72 PPI and the standard for print is 300 PPI.
The image above shows how the image can appear at different pixel resolutions. As you can see, the higher the resolution, the better the quality. This is because is each image is made out of a grid of squares, the 5x5 image will struggle with sharpness as it can only pick 5 colours in one row, so it will struggle displaying the image correctly each of the 25 squares in the grid can only be one colour, whereas the complex shape in the image cannot be made at such a low resolution. However, on the 100x100 grid, the 10,000 squares on the whole grid are able to construct a much sharper image. This is because there are more pixels and they are much smaller,so the pixels are less visible and find it easier to take a colour depending on where they are in the image. When all together, its higher resolution sharpens the image and makes it much clearer to see and make out.
Raster vs Vector
There are two kinds of computer graphics:
Raster - Which is composed as pixels and more commonly known as bitmap. Raster images use a grid filled with pixels to create an image and each pixel can only be one colour.
Vector - Which is composed of paths. Vector images use mathematical relationships between points and paths connecting them to create an image.
Although there are only two type of computer graphics, any images made in vector will eventually at some point become a raster image at the last part of development by the plate-maker.
In order to remove the jagged appearance on raster images, a tool called 'Anti-aliasing' can be used as it reduces the predominance of jagged lines by adding intermediate shades of grey around the 'stair-steps' or colour depending on what colour/shade the jagged line is. For a smoother appearance in bitmap images, higher resolutions are needed and anti aliasing. However, vector images, due to their mathematically described shape, appear smooth at any resolution. This means that bitmap images are most suitable for photographs whilst vector is best used for illustrations, type or art.
As mentioned before in the previous topic, the total number of pixels can be determined by the number of Pixels Per Inch (PPI) and its size (Width x Height), so a 2 by 3 inch image with a resolution of 400 pixels is (2x400) x (3x400) which is 960,000 pixels. As also mentioned, the more pixels in an image, the more detail is conveyed within the image and the fewer pixels, the less detail the image will have. This is why some Bitmap images are of poor quality, because the pixels are too large, therefore some jagged lines can appear and ruin the picture.
In computer graphics, aspect ratio is used to determine the size of the image. It is the width to the height and stated as 16:9 for example. Width is usually the first number with height being the second. In digital imaging, aspect ratio is expressed with whole numbers. Examples of common ratios are 16:10 3:2 and 4:3. When the width is bigger than the height, this usually means the image is landscape whilst is the height is bigger, this means the image is portrait.
Red, Green and Blue are the primary colours in computer graphics. The colours are mixed together to form secondary colours. In computer graphics, the secondary colours are different to real life colours. As you can see from the diagram below, Yellow, Cyan and Magenta are the Secondary colours in an additive colour diagram. This diagram also shows what is called RBG additive colours. This is because when added together, (The Red, Green and Blue), they create white light
CMYK subtractive colours however are the opposite to additive. The primary colours here are Cyan, Magenta and Yellow. The secondary colours therefore are Red, Green and Blue. They are called subtractive because its wavelength is less than the sum of the wavelengths of its constituting colours. The colour produced this time at the centre is represented as K and is black. This is where all the colours overlap.
So in summary, additive colours combine to create white ans subtractive colours combine to produce black.
File Formats
In computer graphics, various image formats are used as each format has its own advantages:
GIF (Graphics Interchange Format) - Limited to only 256 colours and uses compression for quicker downloads. This format is best used for images with solid colours or creations such as illustrations or logos.
JPEG (Joint Photographic Experts Group) - Use for photogenic image. It can use a full spectrum of colors unlike the previous GIF format. Similarly though to the GIF, JPEG uses compression for quicker downloads too, however, JPEG compression involves discarding some data in the process which means once it is saved to JPEG, the data is permanently lost so cannot be used/edited in the future so to prevent this, you must save the image using no compression.
TIFF (Tagged Image File Format) - Used for bitmap images only and is supported by all graphics applications
EPS (Encapsulated PostScript) - Used for both vector and bitmap and they are unique as they contain a PostScript description of graphic data and you can use them for bitmap, type, vector or pages.
Made in EPS vector format
Adobe PSD - Used for Photoshop documents. Many applications support them and and they are able to keep image elements on layers which can be changed in another app.
Adobe Portable Document Format or PDF - Used mainly for electronic documents being published over the internet. They are compact, platform independent, the software to view and print them is free, no fonts have to be installed as they are embedded within the PDF and they can contain hyper-links to pages or videos. It is also worth noting that vector art within the PDF will be of amazing printed quality at any resolution.
Adobe Illustrator Artwork (AI) - This is used in Adobe Illustrator and is mainly used to create vector based images. Many professional programs support AI files. The format is said to be a highly simplified version of EPS and is used a lot for drawing illustrations
Portable Network Graphics PNG - This file format supports lossless data compression which means no data will be lost after the compression process. It supports palette based images with palettes of 24 or 32 bit RBG/RBGA. This type of file format is used for creating or editing Bitmap images.
Windows Bitmap BMP - This is a raster graphics image file format used to store bitmap digital images independently of the display device. It is a very common that many image processing programs can read and write. No compression is used though, so files in this format are usually larger than compressed ones.
Compression
A compression is usually expressed as encoding information using fewer bits than the original representation. Compression can either be classed as either 'lossy' or loss-less. This is because in lossy compression, unnecessary information is deleted. For example, if I created something in Adobe illustrator and compressed the file into something that uses lossy compression, I would not be able to open the document in AI, therefore I would lose the ability to edit the layers I created. This type of compression is usually done on media files such as video, audio and image. However, in loss-less compression, this should not be lost and not as much data is deleted. It recreates the original file in its entirety which ensures that there is no data loss.
Despite loss in some cases, compression can be quite useful for a designer. It reduces storage space meaning even more images can be created and stored. It also reduces the time taken to transfer a file over a network. In the 1970s, people were able to 'archive' files which means they were able to store files in a single package. This makes it easier to send between between computers and means you don't have to send multiple files. This was soon augmented with data compression techniques and the term 'archive' now describes a compressed data file.
"Compressing data involves applying an algorithm that makes some of the repetitive bits unnecessary. It's a bit like a kind of shorthand map that gets stored with the compressed file. When decompressed, the map restores all of the missing bits, reconstituting the complete file."
(From http://www.wisegeek.com/what-is-data-compression.htm)
This technique can be used with text, graphics and multimedia files.
Large files, compressed or not, can be split into pieces before being sent to another device over a network. At the receiving end, the pieces are collected and reassembled. This compression technique is the best at the moment and is called RAR which stands for Roshal ARchive. It can split a large file and create a set of RARs which have the extension .rar. This will create a set so for example you will have part01.rar, part02.rar and part03.rar of a movie. Audio formats also use other data compression techniques to make files smaller. The most common and widely used format in .mp3. In this case though, the file which has been compressed is not an archive, or a collection of files, therefore cannot be decompressed ( return to its original condition and size).
The most popular data compression programs are zip, bzip2, 7-zip and jpeg. Some of these programs support multiple types of compressed files and some are even free to download.
Image Capture devices
Scanner
An image scanner is a device which optically scans images, printed text or an object and converts it into a digital image. It is used a lot in businesses so companies can scan letters and documents so they can either print more out or save them as a file on a computer. Hand-held scanners also exist to scan smaller items and so do 3D scanners to scan 3d objects. Scanners in the modern era usually use a CCD which stands for Charged-Coupled Device or a CIS which stands for Contact image sensor. CIS is where a printed image or text is at close contact to the images sensor and the device uses mirrors to bounce light and detect the image. It is then scanned and converted into a digital image. This method is becoming more popular and is starting to replace CCDs.
CDD - The flatbed CCD scanner usually contains a glass pane with a bright light underneath to light up the glass ,such as a xenon, and a moving optical array. These scanners usually contain 3 arrays or sensors, each one containing either red, green or blue filters.
CIS - This type of scanner usually contains a moving set of LED lights with the colours red, green and blue. To scan an image, the image needs to be placed face down on the glass pane so that the items on the page are facing the internal mechanisms of the device, and a cover is used to put over the device to block out any external light. The array of the colour sensors then move across the pane to scan the entire area. The image reflects the light and therefore an image is constructed by the detector which is then sent up as a digital image to the computer.
Digital Camera
Most cameras sold today are digital cameras. A typical digital camera will have a lens to gather light, a mechanism to focus the image, an aperture that determines how bright light is and a shutter that determines how long the light enters. These cameras use a solid-state device known as an image sensor. It can either be a CCD or a CMOS (Complimentary Metal-Oxide Semiconductor) sensor. On these extremely small chips, are millions of 'photosensitive diodes' - which convert light into a current or voltage - and each diode captures a single pixel of the photograph being captured of which it needs to be. When an image is taken, the shutter opens for a short moment and the image sensor quickly records the intensity ( or brightness ) of the light that touches it by accumulating an electric charge. The brighter the pixel needs to be, the more of a charge it needs to create. This charge is then measured after the shutter closes and then the device is able to transform this charge into a number. A large series of numbers are created and these numbers are able to construct the image whilst also setting the brightness and contrast.
A process called interpolation was created in 1860 where since daylight is made up of red, green and blue light, RGB filters over individual pixels on an image sensor make it able to create colour images. The camera computes the colours of every pixel but combining the colour it captured with its own filter with the other two colours captured by the pixels around it. Photographic images usually contain what we mentioned before which is RGB Additive colour as when these three colours (Red Green Blue) are equally added together, White is formed, so it can be used whenever light is projected to form colours as it is on the monitor. CMYK subtractive colours are also used to create colour, however, is used less widely as its colour system is used with reflected light.
"To create a full colour image, the camera's image processor calculates, or interpolates, the actual colour of each pixel by looking at the brightness of the colours recorded by it and others around it. Here the full-colour of some green pixels are about to be interpolated from the colours of the eight pixels surrounding them." (From a source)
Tablet/Smartphone
The majority of smartphones and tablets today come with a camera. These cameras however are not as good as most digital cameras. These cameras work extremely similarly to digital cameras and use CMOS images sensors to create the images due to reduced power consumption compared to CCD. The file format used is JPEG and this is saved to your phones memory after you have taken your image. Similarly, both modern day digital cameras and smart phones/ tablets are able to record video, as well as sound on these videos. Digital cameras still have the advantage however when it comes to overall quality. An advantage of smart phones is that images captured can quickly be uploaded to social media sites or sent to friends via the multimedia messaging service.
Sources:
http://www.shortcourses.com/guide/guide1-3.html
http://en.wikipedia.org/wiki/Image_scanner
http://en.wikipedia.org/wiki/Digital_camera
http://en.wikipedia.org/wiki/Camera_phone
Optimisation
Optimisation is the act of improving something to make it to its most optimal standard. When used in digital imaging, it is used to get the image to look as great and professional as possible. There are five types of optimisation and these are:
Target image output
When constructing or editing an image, everybody would want the quality to be as best as it possibly can be and at the right size. If you have a large monitor or are showing a presentation on the smart board, you must make sure that any pictures you have are of a high quality. 1080p is known ad HD due to the fact it uses much more pixels that 720p or 480p. These resolutions are seen commonly on videos and used with digital imaging to try to get the image at an optimal level. 1080p is a set of high-definition video models characterized by 1080 horizontal lines of vertical resolution. It is one of the most common resolutions used today, however, not the most powerful. In digital imaging, editors will be able to use much higher 'ultra high-definition' video modes such as 4320p which is extremely powerful. This is because if they are taking a bitmap image, professional photographers or editors would want this image to be as stunning and fantastic as possible, so these higher video modes will show great benefit.
Image Bit depth
This refers to the colour information stored on the image and the colour of singular pixels within a bitmap image. The higher the bit depth is, the more colours will be available for it to use and store. 1-bit has the most simple bit depth and is hardly ever used nowadays due to the fact it can only store one of two values. These are white which is shown as 0 and black which is shown as 1. However, a 24-bit image can display 16 million colours. Modern image editing software's such as Photoshop offer 32-bit colour and this allows use of 4.292 billion colours for an image making the overall optimisation more vivid and realistic if used. The image below shows a comparison of different bits of colour and their differences.
Image resolution
An important note to take in when trying to get an image to optimal level is the resolution. This is important as if you are using an 8-bit image for a presentation and you have given it a high resolution, the overall image will be very pix-elated and in some cases, poor image quality and high resolutions can make an image unclear. If you are using a high resolution for an image, for example the monitor I'm using uses a resolution of 1920x1080, then you will need the image to be of a good quality and have a larger colour depth. The bigger the image, the higher these things will have to be or the image will not be optimised and will look very poor. The image below has been shown before, but if you imagine one of the lower resolution 'R' images to be enlarged, you will notice that the bigger it gets, the worser it looks. This states that larger images will need higher resolutions to be seen more clearly.
Image dimensions
This section refers to being able to re-size your image in an image editing software. In Photoshop, you are able to change the dimensions to A4, A3, A5 and even more. They can be measured in pixels, but some programs even allow measurements such as millimetres or inches. Dimensions are important when it comes to designing images for objects. For example, games box covers will need to be A4 to get the back and front cover in, but other objects may need specific dimensions in order to fit. Large dimensions for smaller objects will not fix and the quality may be poorer.
Compression
Compression for images is very important in digital imaging. If files are left uncompressed, transferring them could take a lot of time. One example I found on the internet made me realize that textures in games would alter the size of the game if textures and images were left uncompressed. In consoles, this may lead to slower loading times and lag in the game especially in RPGs due to the fact that the console will have to load so many large textures.
http://en.wikipedia.org/wiki/1080p
http://en.wikipedia.org/wiki/High-definition_video
http://etc.usf.edu/techease/win/images/what-is-bit-depth/
http://en.wikipedia.org/wiki/Image_resolution
Storage and Asset Management
Within the games industry, storage and asset management would be quite important. Asset management would be very important as game elements would need proper names or else level designers would have no idea what any of the objects the 3D modellers have made would be for example. This and other variations would happen a lot to various roles within the games industry if items, textures or objects are not managed properly. The three main areas which need to be recognised are:
Naming conventions
As stated before, this is where naming digital files, textures or objects within a computer are named correctly for level designers for example would quickly be able to understand what each file is. Having done some of my own level design for Fallout 3 and New Vegas in a level editor known as the 'G.E.C.K.', these file names are clearly evident within the objects panel. Research has also shown me that various companies also do the same thing the GECK does when it comes to naming conventions. They do not name objects such as a chair as 'Chair', a typical file name for such an object would include where abouts it is within the game world for example, a chair within the GECK is called 'EnclaveChair01R'. This states that the chair is specially designed to be in 'Enclave' ( A faction within the game) territory, that it is a chair, it is the '01' (or 1st) model of the chair and the character enters the chair from the 'R' which means Right side. The image below is one I personally took to show some of the file names of chairs within the GECK. Some other examples of naming conventions would be Wall_wooden_broken_01 which states that it is a wall which is wooden, broken and is the first model.
Considering in the games industry, hundreds of elements within a game would have to be made, storage needs to be managed. One computer should not hold all game files as it would be too big in some cases and if the computer is damaged, it is lost forever. Backing it up on external hard drives is usually done so that data is kept safe all the time and there will always be a backup of it. In a games studio, it would be wise to connect all the computers on to a kind of network so that each computer level designer for example could easily get the resources they need. They could also make it so that each computer will have to save all the data on the 'master' computer so that each computer in the facility will be able to back it up and have its own copy of the data.
No sources were used for this section.
Raster vs Vector
There are two kinds of computer graphics:
Raster - Which is composed as pixels and more commonly known as bitmap. Raster images use a grid filled with pixels to create an image and each pixel can only be one colour.
Vector - Which is composed of paths. Vector images use mathematical relationships between points and paths connecting them to create an image.
Although there are only two type of computer graphics, any images made in vector will eventually at some point become a raster image at the last part of development by the plate-maker.
In order to remove the jagged appearance on raster images, a tool called 'Anti-aliasing' can be used as it reduces the predominance of jagged lines by adding intermediate shades of grey around the 'stair-steps' or colour depending on what colour/shade the jagged line is. For a smoother appearance in bitmap images, higher resolutions are needed and anti aliasing. However, vector images, due to their mathematically described shape, appear smooth at any resolution. This means that bitmap images are most suitable for photographs whilst vector is best used for illustrations, type or art.
As mentioned before in the previous topic, the total number of pixels can be determined by the number of Pixels Per Inch (PPI) and its size (Width x Height), so a 2 by 3 inch image with a resolution of 400 pixels is (2x400) x (3x400) which is 960,000 pixels. As also mentioned, the more pixels in an image, the more detail is conveyed within the image and the fewer pixels, the less detail the image will have. This is why some Bitmap images are of poor quality, because the pixels are too large, therefore some jagged lines can appear and ruin the picture.
In computer graphics, aspect ratio is used to determine the size of the image. It is the width to the height and stated as 16:9 for example. Width is usually the first number with height being the second. In digital imaging, aspect ratio is expressed with whole numbers. Examples of common ratios are 16:10 3:2 and 4:3. When the width is bigger than the height, this usually means the image is landscape whilst is the height is bigger, this means the image is portrait.
Red, Green and Blue are the primary colours in computer graphics. The colours are mixed together to form secondary colours. In computer graphics, the secondary colours are different to real life colours. As you can see from the diagram below, Yellow, Cyan and Magenta are the Secondary colours in an additive colour diagram. This diagram also shows what is called RBG additive colours. This is because when added together, (The Red, Green and Blue), they create white light
CMYK subtractive colours however are the opposite to additive. The primary colours here are Cyan, Magenta and Yellow. The secondary colours therefore are Red, Green and Blue. They are called subtractive because its wavelength is less than the sum of the wavelengths of its constituting colours. The colour produced this time at the centre is represented as K and is black. This is where all the colours overlap.
So in summary, additive colours combine to create white ans subtractive colours combine to produce black.
File Formats
In computer graphics, various image formats are used as each format has its own advantages:
GIF (Graphics Interchange Format) - Limited to only 256 colours and uses compression for quicker downloads. This format is best used for images with solid colours or creations such as illustrations or logos.
JPEG (Joint Photographic Experts Group) - Use for photogenic image. It can use a full spectrum of colors unlike the previous GIF format. Similarly though to the GIF, JPEG uses compression for quicker downloads too, however, JPEG compression involves discarding some data in the process which means once it is saved to JPEG, the data is permanently lost so cannot be used/edited in the future so to prevent this, you must save the image using no compression.
TIFF (Tagged Image File Format) - Used for bitmap images only and is supported by all graphics applications
EPS (Encapsulated PostScript) - Used for both vector and bitmap and they are unique as they contain a PostScript description of graphic data and you can use them for bitmap, type, vector or pages.
Made in EPS vector formatAdobe PSD - Used for Photoshop documents. Many applications support them and and they are able to keep image elements on layers which can be changed in another app.
Adobe Portable Document Format or PDF - Used mainly for electronic documents being published over the internet. They are compact, platform independent, the software to view and print them is free, no fonts have to be installed as they are embedded within the PDF and they can contain hyper-links to pages or videos. It is also worth noting that vector art within the PDF will be of amazing printed quality at any resolution.
Adobe Illustrator Artwork (AI) - This is used in Adobe Illustrator and is mainly used to create vector based images. Many professional programs support AI files. The format is said to be a highly simplified version of EPS and is used a lot for drawing illustrations
Portable Network Graphics PNG - This file format supports lossless data compression which means no data will be lost after the compression process. It supports palette based images with palettes of 24 or 32 bit RBG/RBGA. This type of file format is used for creating or editing Bitmap images.
Windows Bitmap BMP - This is a raster graphics image file format used to store bitmap digital images independently of the display device. It is a very common that many image processing programs can read and write. No compression is used though, so files in this format are usually larger than compressed ones.
Compression
A compression is usually expressed as encoding information using fewer bits than the original representation. Compression can either be classed as either 'lossy' or loss-less. This is because in lossy compression, unnecessary information is deleted. For example, if I created something in Adobe illustrator and compressed the file into something that uses lossy compression, I would not be able to open the document in AI, therefore I would lose the ability to edit the layers I created. This type of compression is usually done on media files such as video, audio and image. However, in loss-less compression, this should not be lost and not as much data is deleted. It recreates the original file in its entirety which ensures that there is no data loss.
Despite loss in some cases, compression can be quite useful for a designer. It reduces storage space meaning even more images can be created and stored. It also reduces the time taken to transfer a file over a network. In the 1970s, people were able to 'archive' files which means they were able to store files in a single package. This makes it easier to send between between computers and means you don't have to send multiple files. This was soon augmented with data compression techniques and the term 'archive' now describes a compressed data file.
"Compressing data involves applying an algorithm that makes some of the repetitive bits unnecessary. It's a bit like a kind of shorthand map that gets stored with the compressed file. When decompressed, the map restores all of the missing bits, reconstituting the complete file."
(From http://www.wisegeek.com/what-is-data-compression.htm)
This technique can be used with text, graphics and multimedia files.
Large files, compressed or not, can be split into pieces before being sent to another device over a network. At the receiving end, the pieces are collected and reassembled. This compression technique is the best at the moment and is called RAR which stands for Roshal ARchive. It can split a large file and create a set of RARs which have the extension .rar. This will create a set so for example you will have part01.rar, part02.rar and part03.rar of a movie. Audio formats also use other data compression techniques to make files smaller. The most common and widely used format in .mp3. In this case though, the file which has been compressed is not an archive, or a collection of files, therefore cannot be decompressed ( return to its original condition and size).
The most popular data compression programs are zip, bzip2, 7-zip and jpeg. Some of these programs support multiple types of compressed files and some are even free to download.
Sources:
http://www.lostsaloon.com/technology/what-is-data-compression-and-why-use-it/
http://www.wisegeek.com/what-is-data-compression.htm
http://www.wisegeek.com/what-is-data-compression.htm
Image Capture devices
Scanner
An image scanner is a device which optically scans images, printed text or an object and converts it into a digital image. It is used a lot in businesses so companies can scan letters and documents so they can either print more out or save them as a file on a computer. Hand-held scanners also exist to scan smaller items and so do 3D scanners to scan 3d objects. Scanners in the modern era usually use a CCD which stands for Charged-Coupled Device or a CIS which stands for Contact image sensor. CIS is where a printed image or text is at close contact to the images sensor and the device uses mirrors to bounce light and detect the image. It is then scanned and converted into a digital image. This method is becoming more popular and is starting to replace CCDs.
CDD - The flatbed CCD scanner usually contains a glass pane with a bright light underneath to light up the glass ,such as a xenon, and a moving optical array. These scanners usually contain 3 arrays or sensors, each one containing either red, green or blue filters.
CIS - This type of scanner usually contains a moving set of LED lights with the colours red, green and blue. To scan an image, the image needs to be placed face down on the glass pane so that the items on the page are facing the internal mechanisms of the device, and a cover is used to put over the device to block out any external light. The array of the colour sensors then move across the pane to scan the entire area. The image reflects the light and therefore an image is constructed by the detector which is then sent up as a digital image to the computer.
Digital Camera
Most cameras sold today are digital cameras. A typical digital camera will have a lens to gather light, a mechanism to focus the image, an aperture that determines how bright light is and a shutter that determines how long the light enters. These cameras use a solid-state device known as an image sensor. It can either be a CCD or a CMOS (Complimentary Metal-Oxide Semiconductor) sensor. On these extremely small chips, are millions of 'photosensitive diodes' - which convert light into a current or voltage - and each diode captures a single pixel of the photograph being captured of which it needs to be. When an image is taken, the shutter opens for a short moment and the image sensor quickly records the intensity ( or brightness ) of the light that touches it by accumulating an electric charge. The brighter the pixel needs to be, the more of a charge it needs to create. This charge is then measured after the shutter closes and then the device is able to transform this charge into a number. A large series of numbers are created and these numbers are able to construct the image whilst also setting the brightness and contrast.
A process called interpolation was created in 1860 where since daylight is made up of red, green and blue light, RGB filters over individual pixels on an image sensor make it able to create colour images. The camera computes the colours of every pixel but combining the colour it captured with its own filter with the other two colours captured by the pixels around it. Photographic images usually contain what we mentioned before which is RGB Additive colour as when these three colours (Red Green Blue) are equally added together, White is formed, so it can be used whenever light is projected to form colours as it is on the monitor. CMYK subtractive colours are also used to create colour, however, is used less widely as its colour system is used with reflected light.
"To create a full colour image, the camera's image processor calculates, or interpolates, the actual colour of each pixel by looking at the brightness of the colours recorded by it and others around it. Here the full-colour of some green pixels are about to be interpolated from the colours of the eight pixels surrounding them." (From a source)
Tablet/Smartphone
The majority of smartphones and tablets today come with a camera. These cameras however are not as good as most digital cameras. These cameras work extremely similarly to digital cameras and use CMOS images sensors to create the images due to reduced power consumption compared to CCD. The file format used is JPEG and this is saved to your phones memory after you have taken your image. Similarly, both modern day digital cameras and smart phones/ tablets are able to record video, as well as sound on these videos. Digital cameras still have the advantage however when it comes to overall quality. An advantage of smart phones is that images captured can quickly be uploaded to social media sites or sent to friends via the multimedia messaging service.
Sources:
http://www.shortcourses.com/guide/guide1-3.html
http://en.wikipedia.org/wiki/Image_scanner
http://en.wikipedia.org/wiki/Digital_camera
http://en.wikipedia.org/wiki/Camera_phone
Optimisation
Optimisation is the act of improving something to make it to its most optimal standard. When used in digital imaging, it is used to get the image to look as great and professional as possible. There are five types of optimisation and these are:
Target image output
When constructing or editing an image, everybody would want the quality to be as best as it possibly can be and at the right size. If you have a large monitor or are showing a presentation on the smart board, you must make sure that any pictures you have are of a high quality. 1080p is known ad HD due to the fact it uses much more pixels that 720p or 480p. These resolutions are seen commonly on videos and used with digital imaging to try to get the image at an optimal level. 1080p is a set of high-definition video models characterized by 1080 horizontal lines of vertical resolution. It is one of the most common resolutions used today, however, not the most powerful. In digital imaging, editors will be able to use much higher 'ultra high-definition' video modes such as 4320p which is extremely powerful. This is because if they are taking a bitmap image, professional photographers or editors would want this image to be as stunning and fantastic as possible, so these higher video modes will show great benefit.
Image Bit depth
This refers to the colour information stored on the image and the colour of singular pixels within a bitmap image. The higher the bit depth is, the more colours will be available for it to use and store. 1-bit has the most simple bit depth and is hardly ever used nowadays due to the fact it can only store one of two values. These are white which is shown as 0 and black which is shown as 1. However, a 24-bit image can display 16 million colours. Modern image editing software's such as Photoshop offer 32-bit colour and this allows use of 4.292 billion colours for an image making the overall optimisation more vivid and realistic if used. The image below shows a comparison of different bits of colour and their differences.
Image resolution
An important note to take in when trying to get an image to optimal level is the resolution. This is important as if you are using an 8-bit image for a presentation and you have given it a high resolution, the overall image will be very pix-elated and in some cases, poor image quality and high resolutions can make an image unclear. If you are using a high resolution for an image, for example the monitor I'm using uses a resolution of 1920x1080, then you will need the image to be of a good quality and have a larger colour depth. The bigger the image, the higher these things will have to be or the image will not be optimised and will look very poor. The image below has been shown before, but if you imagine one of the lower resolution 'R' images to be enlarged, you will notice that the bigger it gets, the worser it looks. This states that larger images will need higher resolutions to be seen more clearly.
Image dimensions
This section refers to being able to re-size your image in an image editing software. In Photoshop, you are able to change the dimensions to A4, A3, A5 and even more. They can be measured in pixels, but some programs even allow measurements such as millimetres or inches. Dimensions are important when it comes to designing images for objects. For example, games box covers will need to be A4 to get the back and front cover in, but other objects may need specific dimensions in order to fit. Large dimensions for smaller objects will not fix and the quality may be poorer.
Compression
Compression for images is very important in digital imaging. If files are left uncompressed, transferring them could take a lot of time. One example I found on the internet made me realize that textures in games would alter the size of the game if textures and images were left uncompressed. In consoles, this may lead to slower loading times and lag in the game especially in RPGs due to the fact that the console will have to load so many large textures.
http://en.wikipedia.org/wiki/1080p
http://en.wikipedia.org/wiki/High-definition_video
http://etc.usf.edu/techease/win/images/what-is-bit-depth/
http://en.wikipedia.org/wiki/Image_resolution
Storage and Asset Management
Within the games industry, storage and asset management would be quite important. Asset management would be very important as game elements would need proper names or else level designers would have no idea what any of the objects the 3D modellers have made would be for example. This and other variations would happen a lot to various roles within the games industry if items, textures or objects are not managed properly. The three main areas which need to be recognised are:
Naming conventions
As stated before, this is where naming digital files, textures or objects within a computer are named correctly for level designers for example would quickly be able to understand what each file is. Having done some of my own level design for Fallout 3 and New Vegas in a level editor known as the 'G.E.C.K.', these file names are clearly evident within the objects panel. Research has also shown me that various companies also do the same thing the GECK does when it comes to naming conventions. They do not name objects such as a chair as 'Chair', a typical file name for such an object would include where abouts it is within the game world for example, a chair within the GECK is called 'EnclaveChair01R'. This states that the chair is specially designed to be in 'Enclave' ( A faction within the game) territory, that it is a chair, it is the '01' (or 1st) model of the chair and the character enters the chair from the 'R' which means Right side. The image below is one I personally took to show some of the file names of chairs within the GECK. Some other examples of naming conventions would be Wall_wooden_broken_01 which states that it is a wall which is wooden, broken and is the first model.
Directory
A directory is a set of folders named correctly in order to convey that they contain certain game elements and those elements only. As well as level design, I also mod games therefore I have seen some of these directories. One game I mod is called Half Life 2 and this games files contain a large directory involving different elements within the game. These directories are set up in order for the games designers to be able to easily find where game objects such as textures or even maps are place. The image below was print screened by me and it shows that within the 'half-life 2' folder, there are a large set of folders which contain many game elements. An example would be the 'models' section. This folder contain all of the games models and makes it easier for people to be able to find such items. If every element was just in one folder, finding one thing would be very difficult. The directory path here is:
F:\Steam\steamapps\benakin999\half-life 2\hl2
Storage
Considering in the games industry, hundreds of elements within a game would have to be made, storage needs to be managed. One computer should not hold all game files as it would be too big in some cases and if the computer is damaged, it is lost forever. Backing it up on external hard drives is usually done so that data is kept safe all the time and there will always be a backup of it. In a games studio, it would be wise to connect all the computers on to a kind of network so that each computer level designer for example could easily get the resources they need. They could also make it so that each computer will have to save all the data on the 'master' computer so that each computer in the facility will be able to back it up and have its own copy of the data.
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