* 10 -
t
f=F+n+s (3)
E fn] = (4)
E [s] = (5)
n is called noise or uncorrelated component and s is the signal
or correlated part or f, Correspondingly, the noise covariance
matrix Cnn (usually) is a diagonal matrix, whilst the signal
covariance matrix Css is rather packed. In general, noise and
signal are not correlated with each other (Che = 0).
In the present case of self calibrating block adjustment the
noise represents the purely random errors of the photogrammetric
data. The signal s however, is interpreted as the effect of the
additional parameters p on the image or model coordinates:
s = Bp (6) e e
The additional parameters p themselves are assumed as random
variables with the expectation zero.
E T5910 (7)
With (7) the signal (6) meets the requirement (5). If the
covariance matrix of the additional parameters p is denoted by
Cpp» the signal covariance matrix Css follows from (6) as:
Css "B Cup BT (8)
The problem is solved by least squares. For that purpose the
residual vectors vj, and v5 are attached to n and p. Considering
(3) and (6) we then obtain:
Ax - (f + (n+v; ) + B (p+v2)) =
Ax. Wm Buuirof o0 (9)
The minimum condition to be satisfied reads:
T T.-1 Sa
Vat à + VC ppY2 - min | (10)
Equation (9) represents a conditioned adjustment with unknown
parameters, which however, is equivalent to the observation
equation system (1a), (1b): This can be shown by back substi-
tution of (1b) into (1a) which directly leads to formula (9),
For a detailed proof see Schwarz |17|. Because of (4) and (7)
the obtained results x, vj and v», are unbiased,
The additional parameters usually are common to many images or
models occasionally. In this case formulation (1a), (1b) is
superior to formulation (9), because it leads to normal equa-
tion matrices of more favourable structure (banded bordered
system) and of better numerical condition (see |18]).