Source Code for Module pyvision.other.optics

 1  ''' 
 2  Created on Mar 22, 2013 
 3   
 4  @author: David S. Bolme 
 5  Oak Ridge National Laboratory 
 6  ''' 
 7   
 8 -def diffractionLimit(distance,wavelength,aperture): 
 9      ''' 
10      This function computes the Diffraction limit of an optical system.  It 
11      returns the smallest resolvable pattern at a given wavelength and  
12      aperture.  
13       
14      @param distance: distance to the target in meters. 
15      @param wavelength: the wavelength of the light in nanometers 
16      @param aperture: the size of the aperture in meters. 
17      @returns: the resolution limit in meters 
18      ''' 
19      # Convert the wavelength of the  
20      wavelength = 1.0e-9*wavelength 
21       
22      # Compute the resolution 
23      resolution = distance * 1.220*(wavelength/aperture) 
24      return resolution 
25   
26 -def apertureComputation(distance,wavelength,resolution): 
27      ''' 
28      This function computes the Diffraction limit of an optical system.  It 
29      returns the smallest resolvable pattern at a given wavelength and  
30      aperture.  
31       
32      @param distance: distance to the target in meters. 
33      @param wavelength: the wavelength of the light in nanometers 
34      @param resolution: the resolution on target in metes. 
35      @returns: the aperture size in meters. 
36      ''' 
37      # Convert the wavelength of the  
38      wavelength = 1.0e-9*wavelength 
39       
40      # Compute the resolution 
41      aperture = (distance * 1.220* wavelength) / resolution  
42       
43      return aperture 
44   
45 -def fNumber(focal_length,aperture): 
46      N=focal_length/aperture 
47      return N 
48       
49 -def depthOfField(hyperfocal,distance): 
50      ''' 
51       
52      ''' 
53      H = hyperfocal 
54      s = distance 
55      Dn = (H*s)/(H+s) 
56      Df = (H*s)/(H-s) 
57      return Dn,Df,Df-Dn 
58       
59 -def hyperFocalDistance(focal_length,fnumber,circle_of_confusion,definition=2): 
60      ''' 
61      http://en.wikipedia.org/wiki/Hyperfocal_distance 
62       
63      Definition 1: The hyperfocal distance is the closest distance at which a  
64      lens can be focused while keeping objects at infinity acceptably sharp.  
65      When the lens is focused at this distance, all objects at distances from  
66      half of the hyperfocal distance out to infinity will be acceptably sharp. 
67       
68      Definition 2: The hyperfocal distance is the distance beyond which all  
69      objects are acceptably sharp, for a lens focused at infinity. 
70      '''         
71      return (focal_length**2)/(fnumber*circle_of_confusion) 
72