X-Git-Url: http://git.kpe.io/?p=cl-photo.git;a=blobdiff_plain;f=fov.lisp;h=572a55b256652cd2e2dad18d4351de7f3fbdd6c1;hp=6a43317c6131e828c373443bcea690510d79fac1;hb=4c11fbdc404582b4b8590dca68e80db9f19a77b2;hpb=3a9869ff12d0bff6712cfecf52ed40534d64844e

diff --git a/fov.lisp b/fov.lisp
index 6a43317..572a55b 100755
--- a/fov.lisp
+++ b/fov.lisp
@@ -19,11 +19,15 @@
 
 (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 
@@ -35,28 +39,47 @@
     ))
     
   
-(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)))
-
-(defun fov-distance (focal-length frame-width frame-height distance
-                                  &key (projection :rectilinear))
-  "Returns the field of view and image magnificaion ratio at a given distance.
-NOTE: magnification assumes that distance is in the same units as frame size: mm"
-  (multiple-value-bind (fov-width fov-height fov-diagonal)
-      (fov focal-length frame-width frame-height :projection projection)
-    (let* ((d-width (* distance (sin (degrees->radians fov-width))))
-           (d-height (* distance (sin (degrees->radians fov-height))))
-           (d-diagonal (* distance (sin (degrees->radians fov-diagonal))))
-           (mag (/ frame-width d-width))) 
-      (values d-width d-height d-diagonal mag))))
-
-(defun fov-format (focal-length format &key (projection :rectilinear))
+   (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 image-distance (focal-length object-distance)
+  "Returns the image distance for a focused object at distance using the Gaussian 
+Lens Equation."
+  (if (= focal-length object-distance)
+      0
+    (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 (image-distance 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))) 
-    (fov focal-length (car dim) (cdr dim) :projection projection)))
+  (let ((dim (imager-dimensions format))) 
+    (aov focal-length (car dim) (cdr dim) :projection projection)))
+
+(defun magnification (focal-length distance)
+  "Returns the image magnification: the ratio of image size to objecct size."
+  (float (/ focal-length (- distance focal-length))))
+
+(defun bellows-factor (focal-length distance)
+  "Returns the bellows factor, the ratio of effective aperature to actual aperture."
+  (1+ (magnification focal-length distance)))
+