Principal point (PP)

the geometric center of the image

Conjugate Principle point (CPP)

the principle point of image B on image A in a photo series

RF

Representative fraction

Focal length

distance to the focal plane from the lens inside a camera

Focal length and flying height ratio for scale

RF=f/H

Common focal length

6" or 152.598 mm

Nadir

the point directly below the sensor

Elevation at Nadir

the distance from sea level to the nadir on the ground

Find the scale with this info:

Flight altitude = 3048m

Elevation at Nadir = 259m

Focal Length = 15.2cm

RF = (15.2cm) / (3048m-259m) x 100

RF = 15.2 / 278,900

RF = 1 : 18,348

Photo and ground distance ratio for scale

RF = PD/GD

Equation to derive flying Height (H)

H = Flight Altitude - Elevation at Nadir

Equation to find object height where relief displacement is clear. what are all the variables?

h = (d x H) / r

r is distance from the principle point

h is building height

H is flying height

d is the building height in the image

Equation to find object height where relief displacement isn't clear.

tana = height/length

Relief displacement

causes tall objects to lean away from the center of the image towards the edges of the photo

Wein's Law

the peak wavelength of radiation emission is inversely related to the temperature of an object. (hotter objects emit shorter wavelengths)

Stefan Boltzmann Constant

In a black body, the total intensity of radiation emitted increases across wavelengths

Planck's Law

hotter objects emit more light and brighter

Visible light spectrum

0.38-0.7 μm