IGCSE Scanners and Cameras

Which statement about a scanner's operation does not belong?

• A bright light illuminates the document

• A head moves across the document. Scanned image is sent to lens

• A light-sensitive sheet gets the focused image

• Sheet is made up of a dozen pixels which record the light intensity

Face recognition software works in this way:

• It measures & compares proportions of a person’s face with those stored

• It measures & compares proportions of a person’s face with a passport photo

• It measures nose, eyes and hair and compares with stored values

Which statement about a 3D scanner's operation does not belong?

• Moving laser projects beam of laser light onto object

• Two sensor cameras record changing distance and shape of laser in 3D

• Shape of object appears as millions of points known as a “dot cloud"

• Point cloud data is merged into a 3D representation of the object

Tomography means...

• To image something by analysing the object in very thin slices

• To use a tomograph laser for 3D scanning

• Scanning in 3D or 2D using an advanced mological laser

Which statement about a camera's operation does not belong?

• Breaks up what it sees through its lens into a grid of pixels

• Shutter opens to let light onto a DVD sensor at the back of the lens

• Intensity or colour of light is measured by millions of tiny sensors

• Information is stored as an image in the camera’s memory

Not a common kind of barcode:

• UPC-A

• Code 128

• CP 256

To represent letters and numbers in a barcode, use

• UPC-A

• Code 128

• Code 99-A

The bars on the sides and middle of a UPC-A barcode are called

• Guard bars

• Security bars

• Side rails

• Double lines

The number 3 on the LHS of a barcode is shown below. What would it look like on the RHS

• 
• 
• 

Which statement about a barcode scanner's operation does not belong?

• Scanner shines a light at barcode

• Microprocessor interprets data from digital values

• Photoelectric cells detect light

• Pattern of lines is beamed out