1. Lenses Information storage
before the lens + Curvature added by lens
Curvature of light after lens = Curvature
Image Manipulation
Curvature added = 1/f In computers voltages are stored: Greyscale Image 256 shades of grey
Dioptres (D) Voltage either ON or OFF 106 pixels per image
1 0
Smoothing Sharp edges 1 pixel needs 1 byte
Lens Formula: Binary Numbers:
24 23 22 21 20
Rule: Replace Memory needed = 1 million bytes
each value by the 1=1+1 1 1 0 1 1
Total = 27 (1MB)
mean of its value v u f
and those of No. of alternatives 16 8 0 2 1
Colour needs 3 bytes per pixel
surrounding
256 = all letters = capitals + symbols, no. 1-9
pixels. m = v/u (magnification) I = amount of information (No. of BITS)
u = - number 0-255 Number of alternatives = 2I eg I = 8 = (1
Removing noise byte) No. of alternatives = 28 = 256
Replace each pixel 27 26 25 24 23 22 21 20
by the median of 1 extra bit doubles the no. of
its value and the 1 1 1 1 1 1 1 1
alternatives.
surrounding pixel Chapter 1
values.
Imaging Scanning Tunnelling Microscope
Support and control and
Finding Edges
Wavelength (m) control arm scans in zig-
Speed (m/s) zags across surface
-1
Ultra sharp needle point
-1 +4 -1
-1
v = fλ
Atoms in material
Subtract the N, S, E and W pixel values from
Time period of Frequency (Hz)
4 times the value of each pixel.
a wave (sec)
• Tip is close to atoms electrons tunnel across gap
1
Numbers can be Resolution: smallest detail
T = /f electric current between surface and tip
• Tip moved up and down keeping tunnelling current
manipulated distinguishable, size of one constant.
• The movements of tip are recorded
Darker Region -
larger number Set of numbers 1 number = Picture element (Pixel)