X-Git-Url: http://git.kpe.io/?a=blobdiff_plain;f=fov.lisp;h=9b5ac79d1e8acc1216cee3663899ad01ab2e5228;hb=01efbdaa2981abb7f7a399f5a7f7ff3c431432d5;hp=6cc5bb3a8a5095717bf4338faf4dc10dc229253e;hpb=2502270d59bbf71c29d82486997d38a3981b307c;p=cl-photo.git

diff --git a/fov.lisp b/fov.lisp
index 6cc5bb3..9b5ac79 100755
--- a/fov.lisp
+++ b/fov.lisp
@@ -9,18 +9,25 @@
 ;;;;
 ;;;; $Id$
 ;;;;
-;;;; This file, part of cl-photo, is Copyright (c) 2005 by Kevin Rosenberg.
-;;;; Rights of modification and redistribution are in the LICENSE file.
+;;;; This file, part of cl-photo, is Copyright (c) 2005 by Kevin M. Rosenberg
+;;;;
+;;;; cl-photo users are granted the rights to distribute and use this software
+;;;; as governed by the terms of the GNU General Public License v2
+;;;; (http://www.gnu.org/licenses/gpl.html)
 ;;;;
 ;;;; *************************************************************************
 
 (in-package #:photo)
 
-(defun fov-one-dim (focal-length frame-size 
-                                 &key (projection :rectilinear))
+(defun aov-one-dim (focal-length frame-size 
+                                 &key (projection :rectilinear)
+                                 (magnification 0))
+  "Returns the angle of view in one dimension. Default is infinity which
+has an magnification of 0."
   (ecase projection
     (:rectilinear
-     (radians->degrees (* 2 (atan (/ frame-size 2 focal-length)))))
+     (radians->degrees (* 2 (atan (/ frame-size 2 focal-length
+                                     (1+ magnification))))))
     (:equisolid 
      (radians->degrees (* 4 (asin (/ frame-size 4 focal-length)))))
     (:equidistance 
@@ -32,37 +39,35 @@
     ))
     
   
-(defun fov (focal-length frame-width frame-height
-                         &key (projection :rectilinear))
-  "Returns the angle of field of view for a focal length and frame size at infinity"
+(defun aov (focal-length frame-width frame-height
+                         &key (projection :rectilinear)
+                         (magnification 0))
+  "Returns the angle of field of view for a focal length and frame size. 
+Default is infinity (magnification 0)"
   (values
-   (fov-one-dim focal-length frame-width :projection projection)
-   (fov-one-dim focal-length frame-height :projection projection)
-   (fov-one-dim focal-length (diagonal frame-width frame-height)
-                :projection projection)))
+   (aov-one-dim focal-length frame-width :projection projection :magnification magnification)
+   (aov-one-dim focal-length frame-height :projection projection :magnification magnification)
+   (aov-one-dim focal-length (diagonal frame-width frame-height)
+                :projection projection :magnification magnification)))
 
-(defun fov-format (focal-length format &key (projection :rectilinear))
-  "Returns the angle of field of view for a focal length and frame size at infinity"
-  (ecase format
-    (:aps-c
-     (fov focal-length 22.7 15.1 :projection projection))
-    (:aps
-     (fov focal-length 24 18 :projection projection))
-    (:35mm
-     (fov focal-length 36 24 :projection projection))
-    (:4.5x6
-     (fov focal-length 45 60 :projection projection))
-    (:6x6
-     (fov focal-length 60 60 :projection projection))
-    (:6x7
-     (fov focal-length 60 70 :projection projection))
-    (:6x9
-     (fov focal-length 60 90 :projection projection))
-    (:4x5
-     (fov focal-length (* 4 +inches->mm+) (* 5 +inches->mm+)
-          :projection projection))
-    (:8x10
-     (fov focal-length (* 8 +inches->mm+) (* 10 +inches->mm+)
-          :projection projection))
-    ))
+(defun gaussian-lens (focal-length object-distance)
+  "Returns the image distance for a focused object at distance."
+  (float (/ 1 (- (/ 1 focal-length) (/ 1 object-distance)))))
+
+(defun fov (focal-length frame-width frame-height object-distance
+                         &key (projection :rectilinear))
+  "Returns the field of view and image magnificaion ratio at a given distance."
+  (let* ((image-distance (gaussian-lens focal-length object-distance))
+         (magnification (/ image-distance object-distance)))
+    (multiple-value-bind (aov-width aov-height aov-diagonal)
+        (aov focal-length frame-width frame-height :projection projection
+             :magnification magnification)
+      (let* ((d-width (* 2 object-distance (tan (degrees->radians (/ aov-width 2)))))
+             (d-height (* 2 object-distance (tan (degrees->radians (/ aov-height 2)))))
+             (d-diagonal (* 2 object-distance (tan (degrees->radians (/ aov-diagonal 2))))))
+        (values d-width d-height d-diagonal magnification)))))
 
+(defun aov-format (focal-length format &key (projection :rectilinear))
+  "Returns the angle of field of view for a focal length and frame size at infinity"
+  (let ((dim (format-dimensions format))) 
+    (aov focal-length (car dim) (cdr dim) :projection projection)))