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Digital Image Types and Application Areas An image is the end product of a computer graphics process. An imaging system consists of a graphics device or systems used for the storage, processing, display and the transmission of images. Basically three standard types of image systems exists, 1. Optical Image 2. An Analog-Electronic image 3. Digital image The application areas of digital image processing are tremendously wide and are briefly mentioned. A comprehensive coverage of digital imaging applications can be found in other resources. In general the digital image processing techniques are extensively used in areas such as photography, remote sensing, medical imaging, astronomy, forensics, transportation and military applications. 1.4 Characteristics of Digital Images A digital image is an electronic file and forms into square picture elements called pixels when displayed on a device such as the monitor. The displayed image is a two-dimensional matrix of thousands of millions of pixels each having their own address, size, and color representation. For instance, digitizing a photograph means to capture its mage and converting it electronically using a scanner or a digital camera. Digital image processing software allows us to manipulate images like magnifying the pixels, reduce the size, change effects, shading, etc. The resolution of digital images is represented by using two standard terminologies: dpi (dots per inch) and ppi (pixels per inch). DPI measures the capturing detail and also called spatial resolution. The other characteristic of a digital image is the tonal resolution which provides details on color, bit-depth and dynamic range. Digital images are used in many ways like viewing them in many devices (computer monitors, mobile devices, etc) and they can be transmitted to other systems using the normal data transfer protocols over a network. Digital images can be stored in most of the storage media such as CDs, DVDs, computer hard drives, flash drives, etc. The characteristics of digital images include, Physical Size: The size of the captured image as a measure of inches or pixels. File Size: The actual size of the digitized image file stored in the computer, measured in kilobytes or in megabytes. Pixels: An image captured using a digital camera is made up of Pixels (short for picture elements). A pixel is a smallest element of the digital image and also called dot or a point. The numbers of pixels in the image make up the resolution and the amount of information contained while we view it. In general, if the image is made up of large number of pixels, it will appear more sharp and clear. It is important to note that when the image is enlarged the individual pixels that make up the image is no longer clear and sharp as shown in the illustration in figure 1B. Megapixel: Megapixels means one million pixels. We often discuss the sharpness of an image we refer to the number of mega pixels that make up the image. Digital camera specifications are mentioned in megapixel.ls (eg., 3 MP, 4 MP, etc.), and this is a measure of quantity and not quality. It is also important to note that having a higher number of megapixels in a digital camera may not always produce a better picture. Resolution: Resolution in an image is determined by the number of pixels and is determined by the number of pixels. The higher the resolution, the better the image will look. A low-resolution image (640 x 480 pixels) can appear great on a web page, but may appear fuzzy when enlarged or printed. Images with resolutions such as 1280 x 1024 pixels are of high resolution and they contain enough pictorial information namely sharp contrasts, rich colors, depth and more details. To summarize if the megapixels is more, larger print size print size is possible while maintaining good quality. However, print quality is determined by certain other factors as mentioned above. ImageCapture Suite combines a image acquisition library and webcam library SDK into one control.
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