Digital Imaging is a process where an electronic photograph, scanned document, or image is converted into a series of electronic dots called pixels. Pixels is an acronym for "picture elements".After the image is converted, or digitized, it is stored on a memory storage device which may be a hard drive or some sort of electronic storage device such as a memory stick. The pixels are stored in a compressed format to save storage space. As each pixel is being created it is assigned a color value, called a tonal value, of black, white,shades of grey, or an actual color. These pixels must be processed by a piece of software in order for them to be called up and viewed as an actual image later.
Traditional cameras capture images onto film while digital cameras use an electronic chip known as a Charged Coupling Device (CCD). The CCD is actually a grid of miniature lightsensitive diodes. These diodes convert photons (light) that strikes them into electrons(electrical impulses). The technical name for these diodes is 'photosite'. The brighter the light is that hits the photosite the stronger the electrical charge is that's produced.
After converting the photons into electrons, a mini-computer, located inside of the camera,reads the stored electrical value in each photograph. Then a built-in analog-to-digital converter turns the stored electrical value into a digital value. These digital values are then stored on the cameras memory storage device. When these digital values are recalled by software, and displayed on a screen, they reproduce the image that was originally captured by the camera or digital input device.
Graphic File Formats
.PNG-Portable Network Graphic
-Our favorite for Powerpoint. The Best!
-Does not lose any information
-Works with all the different numbers of colors (256, 16 bit, 24 bit, grayscale)
-A compressed file (smaller filesize, especially 256 color files)
-Widely compatible
-Takes very little time to de-compress in Powerpoint
.JPG-Joint Photographic Expert Group
-Loses information. But you do have control when you save it how much information is lost
-Only works with 24 bit colors (16 million)
-A highly compressed file (very small files)
-Widely compatible
-Takes longer to compress in powerpoint than .PNGs
-Also puts a higher load onto the processor to de-compress
.BMP-Windows Bitmap
-Does not lose any information
-Works with all the different number of colors
-Can be compressed but not 24 bit colors
-Widely compatible
-Very fast to load and display in Powerpoint
.GIF-Graphics Interchange Format
-Loses information as it can only have a maximium of 256 colors
-Only works with 256 colors
-Compressed format
-Widely compatible
-Doesn't take anytime to de-compress as it's not compressed
