(aov-one-dim focal-length (diagonal frame-width frame-height)
:projection projection :magnification magnification)))
-(defun image-distance (focal-length object-distance)
+(defun gaussian-lens (&key object-distance image-distance focal-length (units :mm))
+ "object-distance is in units. image-distance and focal-length are in mm."
+ (cond
+ ((and object-distance image-distance (not focal-length))
+ ;; Return focal length
+ (float (/ 1 (+ (/ 1 (length->mm object-distance units)) (/ 1 image-distance)))))
+ ((and object-distance focal-length (not image-distance))
+ ;; Return image distance
+ (cond
+ ((= focal-length (length->mm object-distance units))
+ most-positive-double-float)
+ ((> focal-length (length->mm object-distance units))
+ :error)
+ (t
+ (float (/ 1 (- (/ 1 focal-length) (/ 1 (length->mm object-distance units))))))))
+ ((and image-distance focal-length (not object-distance))
+ ;; Return object distance
+ (cond
+ ((= focal-length image-distance)
+ most-positive-double-float)
+ ((> focal-length image-distance)
+ :error)
+ (t
+ (mm->length (float (/ 1 (- (/ 1 focal-length) (/ 1 image-distance)))) units))))
+ (t
+ (error "Must specify two, and only two, of the parameters: focal-length, image-distance, object-distance"))))
+
+
+(defun image-distance-magnification (focal-length magnification)
"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))))))
+ (* focal-length (1+ magnification)))
-(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)))
+(defun %fov (focal-length frame-width frame-height object-distance image-distance units
+ &optional (projection :rectilinear))
+ "Returns the field of view (units), magnification ratio, object-distance (units),
+and image distance (mm) for a given image (mm) and object distance (mm)."
+ (unless (numberp image-distance)
+ (return-from %fov image-distance))
+ (unless (numberp object-distance)
+ (return-from %fov object-distance))
+ (let ((mag (/ image-distance (length->mm object-distance units))))
(multiple-value-bind (aov-width aov-height aov-diagonal)
(aov focal-length frame-width frame-height :projection projection
- :magnification magnification)
+ :magnification mag)
(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)))))
+ (values d-width d-height d-diagonal mag object-distance image-distance)))))
+
+(defun fov (focal-length frame-width frame-height
+ &key object-distance image-distance magnification
+ (units :feet)
+ (projection :rectilinear))
+ (cond
+ ((and object-distance (not image-distance) (not magnification))
+ (setq image-distance (gaussian-lens
+ :focal-length focal-length
+ :object-distance object-distance
+ :units units)))
+ ((and (not object-distance) image-distance (not magnification))
+ (setq object-distance (gaussian-lens
+ :focal-length focal-length
+ :image-distance image-distance
+ :units units)))
+ ((and (not object-distance) (not image-distance) magnification)
+ (setf image-distance (image-distance-magnification focal-length magnification)
+ object-distance (when (numberp image-distance)
+ (mm->length (/ image-distance magnification) units))))
+ (t
+ (error "Must set one, and only one, of the parameters: image-distance, object-distance, or magnification.")))
+
+ (%fov focal-length frame-width frame-height object-distance image-distance units
+ projection))
(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 (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 magnification (&key focal-length object-distance image-distance (units :feet))
+ "Returns the image magnification: the ratio of image size to object size.
+focal-length and image-distance are in mm, object-distance is in units"
+ (when object-distance
+ (setq object-distance (length->mm object-distance units)))
+ (cond
+ ((and (not focal-length) object-distance image-distance)
+ (if (zerop object-distance)
+ :error
+ (float (/ image-distance object-distance))))
+ ((and focal-length object-distance (not image-distance))
+ (cond
+ ((eql object-distance focal-length)
+ most-positive-double-float)
+ ((< object-distance focal-length)
+ :error)
+ (t
+ (float (/ focal-length (- object-distance focal-length))))))
+ ((and focal-length (not object-distance) image-distance)
+ (cond
+ ((eql image-distance focal-length)
+ most-positive-double-float)
+ ((< image-distance focal-length)
+ :error)
+ (t
+ (float (1- (/ image-distance focal-length))))))
+ (t
+ (error "Must set two, and only two, of the parameters: image-distance, object-distance, and focal-length."))))
+
+(defun close-up (&key focal-length object-distance image-distance magnification (units :feet) &aux bellows-factor)
+ "Computes the parameters for focusing closer than infinity.
+Requires two, and only two, of the input parameters.
+Returns: focal-length object-distance image-distance magnification bellows-factor."
+ (cond
+ ((and focal-length object-distance (not image-distance) (not magnification))
+ (setq magnification (magnification :focal-length focal-length
+ :object-distance object-distance
+ :units units))
+ (setq image-distance (gaussian-lens :focal-length focal-length
+ :object-distance object-distance
+ :units units)))
+ ((and focal-length (not object-distance) image-distance (not magnification))
+ (setq magnification (magnification :focal-length focal-length
+ :image-distance image-distance
+ :units units))
+ (setq object-distance (gaussian-lens :focal-length focal-length
+ :image-distance image-distance
+ :units units)))
+ ((and (not focal-length) object-distance image-distance (not magnification))
+ (setq magnification (magnification :object-distance object-distance
+ :image-distance image-distance
+ :units units))
+ (setq focal-length (gaussian-lens :object-distance object-distance
+ :image-distance image-distance
+ :units units)))
+ ((and focal-length (not object-distance) (not image-distance) magnification)
+ (setq image-distance (image-distance-magnification focal-length magnification))
+ (setq object-distance (gaussian-lens :focal-length focal-length
+ :image-distance image-distance
+ :units units)))
+ ((and (not focal-length) object-distance (not image-distance) magnification)
+ (setq image-distance (* magnification (length->mm object-distance units)))
+ (setq focal-length (gaussian-lens :image-distance image-distance
+ :object-distance object-distance
+ :units units)))
+ ((and (not focal-length) (not object-distance) image-distance magnification)
+ (setq object-distance (mm->length (float (/ image-distance magnification)) units))
+ (setq focal-length (gaussian-lens :image-distance image-distance
+ :object-distance object-distance
+ :units units)))
+ (t
+ (error "Must set two, and only two input parameters: focal-length, image-distance, object-distance, magnifcation.")))
+ (values focal-length object-distance image-distance magnification (1+ magnification)))
-(defun bellows-factor (focal-length distance)
+(defun bellows-factor (focal-length object-distance)
"Returns the bellows factor, the ratio of effective aperature to actual aperture."
- (1+ (magnification focal-length distance)))
+ (1+ (magnification :focal-length focal-length :object-distance object-distance)))