BARCODE AND SCANNERS 

Barcodes

• Most barcodes are designed to be symmetrical, which requires an even number of lines. This symmetry involves a key breakthrough between the two sides of the barcode.
• The left-hand side of a barcode typically represents the manufacturing number.
• The right-hand side corresponds to the product number.
• The ‘0’ digit at the beginning of a barcode indicates the start of the bar number.
• The last digit in a barcode is known as the ‘check digit’, used for verification purposes.
• The left-hand side coding for the digit ‘1’ is different from the right-hand side coding for ‘1’. 
• This differentiation is necessary to distinguish between the manufacturer number and the product number.
• The coding pattern on the left-hand side is the opposite of that on the right-hand side.
• If the left-hand side pattern is ‘black white white white’, then the corresponding right-hand side pattern would be ‘white white white black black’. 
• This structure highlights the symmetry in barcodes and the distinct way in which the left and right sides represent different information.

Barcode Scanners

How barcode scanners work:

• Black is on, white is off
• When the scanner scans the barcode, it converts the black and white lines to binary. It then converts the binary code into a denary value.  Each number has a different coloured line, there are 7 lines per number and the left-hand side is the opposite of the right-hand side. 

What happens if the product id matches the denary value?

• A denary value goes into the database, if it matches then it returns as an output (as the price) 
• If it doesn’t work, we keep the number of the barcode along with the barcode as well because if the product id is not found in the database then it will say ‘product is not found’ so you can type the number of the barcode onto the system. 

QR (Quick Response) codes

QR codes are 2D barcodes and can be read by smartphones or tablets

They can contain:

• Links to websites or Information

Uses of QR codes in society. Common uses include:

• Restaurant coupons
• Mobile concert tickets
• Real estate agency boards
• Business cards
• Tourist information
• Advertising posters

Scanners

2D Scanners

These are used to convert a hard/paper copy document or photograph into a computer-readable format. They operate as follows:

• a bright light will illuminate the document to be copied
• a head moves across the document scanning it to produce an image which is sent to a lens
• the focused image then falls onto a light-sensitive sheet made up of thousands of pixels which records the light intensity or color falling on each pixel
• This information is now stored as an image in the computer’s memory

Uses of 2D scanners:

• Airport security cameras use face recognition
  • Specialist software measures and compares the proportions of a person’s face with those stored.

3D Scanners

• 3D scanners are used in both industrial and medical fields
• Many 3D scanners rely on a technology called Tomography which basically means to image something in very thin slices (less than 0.1 mm thick)
• Here a solid cone has been sliced up into several thin slices which when put back together again from the original cone

3D MRI scanning

Digital cameras

• A camera works in much the same way as a scanner
• When a digital camera captures an image it breaks up what it sees through its lens into a grid of pixels
• The shutter opens to let light onto a CCD sensor at the back of the lens
• The intensity or color of light is measured by millions of tiny sensors arranged in a grid on the CCD sensor
• This information is now stored as an image in the camera’s memory