Imaging
- Created by: Elene
- Created on: 30-11-12 20:47
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- Imaging
- A wave of frequency(f) travelling at speed(v) has a wavelength of ( ?) given by v =f x ?
- Time Period = 1/frequency and vice versa
- Time Period = 1/frequency and vice versa
- Images can be formed with many kinds of signals, including ultrasound and all parts of the electromagnetic spectrum
- E.g. Infrared satellites are able to track growth of vegetation
- Images can be recorded electronically by micro sensors such as the charge coupled device(CCD)
- Images on an atomic scale recorded by scanning methods such as scanning tunneling microscope
- Images can be stored as an array of pixels,each defined by a number(binary)
- Quantities that cover a large ranges of values can usefully be displayed on a logarithmic scale.
- Prefixes of scientific units(e.g. micro, milli, kilo, mega) are chosen at multiples of 1000.
- 1 Bit of information is two choices(1 or 0); 1 byte of info contains 8 bits (256 alternatives); amount of info/ provides N=2^i alternatives
- The eye is like a video camera, sending out a stream of processed signals through detection of edges and movements.
- A converging lens (positive distances) adds a constant curvature to light falling on it. The curvature added is the power of the lens.
- Power of Lens= 1/f
- Image and object distances 1/v = 1/u +1/f
- v = image distance u=object distance (initial image) f= focal length(lens adds this)
- Refractive index = speed of light in a vacuum/speed of light in a material
- Linear magnification is m= image height/object height
- Light takes the same time to travel on all paths from a point on the source to the image via lens or mirror
- A converging lens (positive distances) adds a constant curvature to light falling on it. The curvature added is the power of the lens.
- A wave of frequency(f) travelling at speed(v) has a wavelength of ( ?) given by v =f x ?
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