What are the following digitisation processes: frame grabbing, scanning, bit mapping, optical character recognition (OCR)?
Frame Grabbing: Process of capturing a frame from a video and converting it to a bitmap image. Frame grabbing is done by a device known as a frame grabber. A video source is fed to the frame grabber and it captures the frame and converts it to digital form. Modern frame grabbers are able to capture multiple frames at a time from a video. The resulting images can be manipulated to enhance the image or be used for other purposes.
Scanning: Converting a hard copy of a document containing text or image into a digital soft copy. This is achieved using a device called a scanner. The scanner shoots a beam of light at the document, and the light is reflected back onto a photosensitive element, which in most scanners, is a light sensitive electronic circuit known as a charged coupled device (CCD) lined with light sensitive photosites, a single pixel which corresponds to a single pixel in a digital image, which detect varying levels of brightness and accordingly converts into electronic signals which is then converting by the computer into the appropriate file format, e.g. JPEG, PDF etc.
Bit mapping: Image is digitised by the process of bitmapping. Its the relationship between the graphic being displayed onscreen and bits in memory. All graphics are displayed by pixels on screen. Those pixels are represented by a number of bits. The number of bits is known as bit depth. Typically the colour affects the bit depth. The more colours there are, the larger the bit depth. At the basic level, a graphic with a bit depth of one would have two colours, black and white (represented by 1 and 0 respectively)
Optical Character recognition: Or OCR, is converting written text into a digital document that can be edited in a computer. This is done by specialised software. The text to be converted is first scanned, digitised and given to the software. The software scans each individual letter in the text and compares it to a database of shapes of letters. The software matches the letters and represents the information in a digital document. OCR is very useful in scenarios where a text needs to be digitised. Instead of typing the entire text on a computer, it can be digitised using OCR software, saving time and effort. However, one major disadvantage of this is its accuracy with hand written text. Since every one has different handwriting, unlike computer fonts, the software sometimes struggles to identify certain letters and this makes the process not 100% reliable.