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 ;;;; *************************************************************************
23 (defun coc-format (format &key (lpm 5) (minimum-distance 250)
24 (viewing-distance 250)
25 (print-size (format-dimensions :8x10in)))
26 "Returns circle of confusion in mm and print magnification for a format.
27 Default resolving power is 5 lpm at 25cm."
29 (let* ((format-size (format-dimensions format))
30 (format-diagonal (diagonal (car format-size) (cdr format-size)))
31 (print-diagonal (diagonal (car print-size) (cdr print-size)))
32 (resolution-factor (/ (* lpm print-diagonal minimum-distance)
33 (* format-diagonal viewing-distance)))
34 (coc (/ 1.0d0 resolution-factor))
35 (print-magnification (/ print-diagonal format-diagonal)))
36 (values coc print-magnification)))
38 (defun coc-sensor (format nx ny)
39 "Returns circle of confusion based on pixel size."
40 (let* ((dim (format-dimensions format))
41 (pixel-width (/ (car dim) nx))
42 (pixel-height (/ (cdr dim) ny)))
43 (values (float (* 2 pixel-width))
44 (float (* 2 pixel-height)))))
46 (defun coc-sensor-camera (camera &key (format :aps))
47 (let ((dim (sensor-dimensions camera :format format)))
48 (coc-sensor format (car dim) (cdr dim))))
50 (defun sensor-dimensions-megapixels (format megapixels)
51 (let* ((dim (format-dimensions format))
52 (aspect-ratio (/ (car dim) (cdr dim)))
53 (width (round (sqrt (* aspect-ratio 1000000 megapixels)))))
54 (cons width (round (/ width aspect-ratio)))))
57 (defun sensor-dimensions (sensor-spec &key (format :aps))
58 "Returns the number of pixels for a sensor.
59 CAMERA-SPEC is either a keyword designating the camera or
60 the number of megapixels of the sensor.
61 FORMAT should be defined if the CAMERA-SPEC is the number of megapixels
62 so the proper aspect ratio is used."
63 (etypecase sensor-spec
67 (:d2x (cons 4288 2848))
68 (:d100 (cons 3037 2024))
69 (:d2h (cons 2464 1632))
70 (:d70 (cons 3008 2000))
73 (:1d (cons 2464 1648))
74 (:1d2 (cons 3504 2336))
75 (:1ds (cons 4064 2704))
76 (:1ds2 (cons 4992 3328))
80 (sensor-dimensions-megapixels format sensor-spec))))
82 (defun coc-airy (f-stop)
83 "Return the circle of confusion based on the airy disk."
84 (let ((airy (/ f-stop 1500)))
87 (defun dof-mm (focal-length f-stop distance coc &key (pupil-factor 1))
88 "Returns depth of field based on focal-length, f-stop, distance, and coc.
89 Six values are returned:
90 near dof, far dof, total dof, near point, far point, magnification,
91 blur size at infinity (mm).
92 Circle of confusion can either be a number or keyword designating format."
93 (let* ((aperture (/ focal-length f-stop))
94 (numerator-1 (* (- pupil-factor 1) (- distance focal-length)
96 (numerator-2 (* pupil-factor aperture focal-length distance))
97 (denominator-1 (* pupil-factor coc (- distance focal-length)))
98 (denominator-2 (* pupil-factor aperture focal-length))
99 (near (/ (+ numerator-1 numerator-2)
100 (+ denominator-1 denominator-2)))
101 (far (/ (- numerator-1 numerator-2)
102 (- denominator-1 denominator-2)))
103 (mag (float (/ focal-length (- distance focal-length))))
104 (infinity-blur-diameter (/ (* mag focal-length) f-stop))
105 (depth (- far near)))
106 (values near far depth mag infinity-blur-diameter)))
108 ;; Simplified calculation for symmetric lens
109 (defun dof-symmetric-mm (focal-length f-stop distance coc)
110 "Returns depth of field based on focal-length, f-stop, distance, and coc.
111 Six values are returned:
112 near dof, far dof, total dof, near point, far point, magnification,
113 blur size at infinity (mm).
114 Circle of confusion can either be a number or keyword designating format.
115 Pupil factor is the ratio of the exit to enterance pupil diameters."
116 (let* ((aperture (/ focal-length f-stop))
117 (numerator (* distance coc (- distance focal-length)))
118 (factor-1 (* focal-length aperture))
119 (factor-2 (* coc (- distance focal-length)))
120 (near (- distance (/ numerator (+ factor-1 factor-2))))
121 (far (+ distance (/ numerator (- factor-1 factor-2))))
122 (mag (magnification focal-length distance))
123 (infinity-blur-diameter (/ (* mag focal-length) f-stop))
124 (depth (- far near)))
125 (values near far depth mag infinity-blur-diameter)))
127 (defun dof (focal-length f-stop distance coc &key (units :mm) (pupil-factor 1))
128 (multiple-value-bind (near-point far-point total-dof mag blur)
129 (dof-mm focal-length f-stop (length->mm distance units) coc
130 :pupil-factor pupil-factor)
131 (values (mm->length near-point units)
132 (mm->length far-point units)
133 (mm->length total-dof units)
136 (defun hyperfocal (focal-length f-stop coc &key (units :mm))
138 (+ focal-length (/ (* focal-length focal-length) f-stop coc))
141 (defun magnification (focal-length distance)
142 (float (/ focal-length (- distance focal-length))))
144 (defun bellows-factor (focal-length distance)
145 (1+ (magnification focal-length distance)))
147 (defun effective-aperture (focal-length distance aperture)
148 (* aperture (bellows-factor focal-length distance)))