(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
))
-(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-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 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 fov-format (focal-length format &key (projection :rectilinear))
+(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)))
+ (aov focal-length (car dim) (cdr dim) :projection projection)))