Image Capture

In this modern day, most of our lives on digital and this means we need a way to capture images to put on a computer.This is called image capture and there are many different ways to do this ranging from camera's to capture devices.

Camera's
A camera works by recording images which can be transferred in different ways. They do this my by capturing the light with the lens with an aperture at one end for the light to enter. There used to be no way to get the image from the camera but it developed over the years.  When it used a film to store the pictures it was impossible still to put it onto a computer. Recently the pictures have started to be stored on flash memory which can be transferred to a computer and stored on a hard drive or flash memory. Since you can put the files on a computer , it makes it so you can edit them using various software such as photoshop. The default file extention is for images of this type is J-PEG.  As camera's get more advanced they will have more detailed pictures with more "megapixels" in addition to taking more frames in a still image.

There are various versions of camera's. Heres some of the more known ones.

Sony's Cyber-shot digital camera

• Camera Phone
• Digital Camera
• Movie Camera
• Pocket Camera
• Traffic Camera
• Video Camera

Scanners
Scanners are devices which can capture an image and transfere it onto a computer.It can scan images, printed text , drawings and objects. There are different types of scanners but the most common is CCD scanner. The different types just define the way it works. A CCD scanner is known as a flatbed scanner. This consists of a glass pane to put your picure on for example where under there is a light which lights up the picture. This light moves along the picture and using 2 mirrors, the capture device "scans" your picture and makes it a digital image.


Flatbed scanner

Diagram of CCD Scanner



Image Optimisation and storage

Image optimisation is when you make the image an appropriate size to fit a model. Textures need to use the power of two rule. If you don't scale the image to a power of two then the image won't fit properly and be missing.If you don’t optimize textures then the game has to reposition the textures to make them fit which makes them go out of line and blury.

If you don’t use the power of two rule then then engine has to reposition and expand the texture to make it fit. This means the engine has to do more processes which in turn will slow down the game and lower the fps. It lowers the fps because the processing power needs to be used for a lot of other things.Interpolation is when there is extra data needed to fill in the gaps so it makes up extra pixels and that’s where the blurring comes from – filling in the missing data. Loss-less compression is where you save a file which will increase the file size to compress it better. This means it won’t resize the image but will increase the file size. A file format such as JPEG is a file format described as lossy. All game engines don’t physically resize textures but some do such as the unity game engine.

Pixels and image resolution

Pixels
Pixels per inch or pixel density. The word pixel comes from picture and element. A pixel is the smallest thing in a digital image. We create pixels using different software such as photoshop or paint. It can be presented on a television such as a LCD screen. Pictures can be took using a camera or a scanner and it contains pixels. Digital images are always rectangles or squares. They are constructed of pixels. There's a horizontal and vertical number of pixel size of an image. A million pixels is called a megapixel. E.g 1920 x1080 has 2,073,600 pixels which is 2.07 megapixels.There are two types of images which is screen and print. Screen is the pixels on the monitor and the resolution is 72ppi (pixels per inch). A print is a image which is printed off and has 300dpi (dots per inch) which is basically the same thing. When people are making games for phones they have to consider the ppi of the phone. Such as the iPhone 3gs has 165ppi.

Image Resolution
The image resolution is a term that descrives the detail the image hold. This term applist to digital images , film images and other type of images. The resolution can be lines per mm (LP/mm) or lines per inch (LP/Inch). A resolution can consist of loads of different amount of pixels. For example HD us 1280x720 pixels. Whereas full HD is either 1440x1080 or 1920x1080 depending of the input.

Bit is conflation of 2 words - Binary and digit. Origin of the word is attributed to John W Tukey who first written on Bell Labs memo on 9th of January 1947 in contracted "binary digit" to simplify "bit"

In computing a bit can only have 2 possible values 0 or 1 , yes or no , true or false , + or - etc.

A byte is a group of 8 bits. Bytes or multiples thereof, are almost always used to speicfy the sizes of computing files and the capacity of storage uinits. Most modern compiter and peripheral devices are designed to manipulate data whole bytes or groups of bytes rather than individual bits.A nibble is 4 bits or half a byte. 2 to the power of 8 is 256 bits. Bit depth specifies how much each pixel is an image. The more bits of information per pixel , the more available colours and more accuraate colour representaion.

An image with 1 pixel has 2 values black and white. An image with a bit depth of 8 has 2(8) or 256 possible values grayscale mode images with bit depth of 8 have 256 possibe gray values.

RGB images ae made of three colour channels. An 8 bit per pixel RGB image has 256 possible values fir each channel which means it has over 16 million pissible colour values. RGB images with 8 bits per channel (bpc) are sometimes called 24 bit images (8 bits x 3 channels = 24 bits of date for each pixel).