1 ;;;; -*- Mode: LISP; Syntax: ANSI-Common-Lisp; Base: 10; Package: photo -*-
2 ;;;; *************************************************************************
3 ;;;; FILE IDENTIFICATION
6 ;;;; Purpose: Depth of field functions for cl-photo
7 ;;;; Programmer: Kevin M. Rosenberg
8 ;;;; Date Started: April 2005
12 ;;;; This file, part of cl-photo, is Copyright (c) 2005 by Kevin M. Rosenberg
14 ;;;; cl-photo users are granted the rights to distribute and use this software
15 ;;;; as governed by the terms of the GNU General Public License v2
16 ;;;; (http://www.gnu.org/licenses/gpl.html)
18 ;;;; *************************************************************************
22 (defun coc (imager-size &key (lpm 5) (minimum-distance 250)
23 (viewing-distance 250)
24 (print-size (output-dimensions :8x10in)))
25 "Returns circle of confusion in mm and print magnification for a format.
26 Default resolving power is 5 lpm at 25cm."
28 (let* ((imager-max (max (car imager-size) (cdr imager-size)))
29 (imager-min (min (car imager-size) (cdr imager-size)))
30 (print-max (max (car print-size) (cdr print-size)))
31 (print-min (min (car print-size) (cdr print-size)))
32 (magnification (max (/ print-max imager-max) (/ print-min imager-min)))
33 (resolution-factor (/ (* magnification lpm minimum-distance) viewing-distance))
34 (coc (/ 1.0d0 resolution-factor)))
35 (values coc magnification)))
37 (defun coc-format (format &key (lpm 5) (minimum-distance 250)
38 (viewing-distance 250)
39 (print-size (output-dimensions :8x10in)))
40 "Returns circle of confusion in mm and print magnification for a format.
41 Default resolving power is 5 lpm at 25cm."
43 (let* ((format-size (imager-dimensions format))
44 (format-diagonal (diagonal (car format-size) (cdr format-size)))
45 (print-diagonal (diagonal (car print-size) (cdr print-size)))
46 (resolution-factor (/ (* lpm print-diagonal minimum-distance)
47 (* format-diagonal viewing-distance)))
48 (coc (/ 1.0d0 resolution-factor))
49 (print-magnification (/ print-diagonal format-diagonal)))
50 (values coc print-magnification)))
52 (defun coc-pixels (imager pixels)
53 "Returns lpm and circle of confusion based on pixel size."
54 (when (and (consp imager) (consp pixels))
55 (let ((coc-w (float (* 2 (/ (car imager) (car pixels)))))
56 (coc-h (float (* 2 (/ (cdr imager) (cdr pixels))))))
57 (values coc-w coc-h (/ 1. coc-w) (/ 1. coc-h)))))
59 (defun coc-pixels-format (format)
60 "Returns circle of confusion based on pixel size."
61 (coc-pixels (imager-dimensions format) (pixel-dimensions format)))
63 (defun coc-airy (f-stop &optional (wavelength 0.000512))
64 "Return the circle of confusion based on the airy disk."
65 (float (/ 1 (rayleigh-limit f-stop wavelength))))
67 (defun rayleigh-limit (f-stop &optional (wavelength 0.0005))
68 "Returns the rayleigh limit in line pairs per mm (MTF 9%) as well as the MTF50"
69 (let ((rayleigh (float (/ 1 1.22 f-stop wavelength))))
70 (values rayleigh (* 0.46 rayleigh))))
72 (defun maximum-sharpness-aperture (format &optional (wavelength 0.0005))
73 (multiple-value-bind (coc-w coc-h lpm-w lpm-h) (coc-pixels-format format)
74 (declare (ignore coc-w coc-h))
75 (/ 1. (* 1.22 wavelength (/ (min lpm-w lpm-h) 0.46)))))
77 (defun dof-mm (focal-length f-stop distance coc &key (pupil-factor 1))
78 "Returns depth of field based on focal-length, f-stop, distance, and coc.
79 Six values are returned:
80 near point, far point, total dof, magnification, blur size at infinity (mm).
81 Circle of confusion can either be a number or keyword designating format."
82 (let* ((aperture (/ focal-length f-stop))
83 (numerator-1 (* (- pupil-factor 1) (- distance focal-length)
85 (numerator-2 (* pupil-factor aperture focal-length distance))
86 (denominator-1 (* pupil-factor coc (- distance focal-length)))
87 (denominator-2 (* pupil-factor aperture focal-length))
88 (near (/ (+ numerator-1 numerator-2)
89 (+ denominator-1 denominator-2)))
90 (far (/ (- numerator-1 numerator-2)
91 (- denominator-1 denominator-2)))
92 (mag (float (/ focal-length (- distance focal-length))))
93 (infinity-blur-diameter (/ (* mag focal-length) f-stop))
95 (values near far depth mag infinity-blur-diameter)))
97 ;; Simplified calculation for symmetric lens
98 (defun dof-symmetric-mm (focal-length f-stop distance coc)
99 "Returns depth of field based on focal-length, f-stop, distance, and coc.
100 Six values are returned:
101 near dof, far dof, total dof, near point, far point, magnification,
102 blur size at infinity (mm).
103 Circle of confusion can either be a number or keyword designating format.
104 Pupil factor is the ratio of the exit to enterance pupil diameters."
105 (let* ((aperture (/ focal-length f-stop))
106 (numerator (* distance coc (- distance focal-length)))
107 (factor-1 (* focal-length aperture))
108 (factor-2 (* coc (- distance focal-length)))
109 (near (- distance (/ numerator (+ factor-1 factor-2))))
110 (far (+ distance (/ numerator (- factor-1 factor-2))))
111 (mag (magnification focal-length distance))
112 (infinity-blur-diameter (/ (* mag focal-length) f-stop))
113 (depth (- far near)))
114 (values near far depth mag infinity-blur-diameter)))
116 (defun dof (focal-length f-stop distance coc &key (units :mm) (pupil-factor 1))
117 "Returns the Depth of Field.
118 Input: FOCAL-LENGTH, F-STOP, DISTANCE, CIRCLE-OF-CONFUSION.
119 Output: NEAR-POINT, FAR-POINT, TOTAL-DOF, MAGNIFICATION, BLUR-SIZE-OF-INFINITY-POINT-IN-MM."
120 (multiple-value-bind (near-point far-point total-dof mag blur)
121 (dof-mm focal-length f-stop (length->mm distance units) coc
122 :pupil-factor pupil-factor)
123 (values (mm->length near-point units)
124 (mm->length far-point units)
125 (mm->length total-dof units)
128 (defun hyperfocal (focal-length f-stop coc &key (units :mm))
129 (mm->length (+ focal-length (/ (* focal-length focal-length) f-stop coc)) units))
131 (defun effective-aperture (focal-length distance aperture)
132 (* aperture (bellows-factor focal-length distance)))
134 (defun mtf-scanner (freq dscan-freq &optional (order 3))
135 (abs (expt (kmrcl:sinc (* pi (/ freq dscan-freq))) order)))