INTRODUCTION
In many cases the choice of the technique used in recording building
depends on the historical value, the available instrument and the field
circumstance for this building. Many techniques used for documenting buildings,
photogrammetry is one of these techniques. Photogrammetry has been defined
by the American Society for Photogrammetry and Remote Sensing as the art,
science and technology of obtaining reliable information about physical
objects and the environment through processes of recording, measuring
and interpreting photographic images and patterns of recorded radiant
electromagnetic energy and other phenomena (Mofitt and Mikhail, 1980;
Wolf and DeWitt, 2000; Atkinson, 2001). In photogrammetry the object is
recorded on an intermediate medium, such as photographs and the measurements
are carried out later in the office. Photogrammetry is generally accepted
technique for collection of the threedimensional representations of the
environment. This technique has also been extensively used for documentation
different building (Karara and AbdelAziz, 1974; Nutto and Ringle, 2001).
Closerange photogrammetry can be achieving the photos by Metric camera
or NonMetric camera. In last years, NonMetric cameras were very common
for documenting buildings. Nonmetric cameras are defined as cameras that
are not specifically designed for photogrammetric purposes or a camera
whose interior orientation is completely or partially, unknown and unstable.
Offtheshelf, amateur and professional cameras fall into this category.
Jechev describes some problems for using nonmetric cameras for photogrammetric
purposes and the solving of these problems by using three different methods
(Jechev, 2004).
To recreate the shape of buildings, we need at least one Stereomodeltwo
photographs for each building. In this paper we will evaluate both of
the effect of the number of control points as well as the effect of the
ratio of the base line distance (B) over the object distance (D) [(B/D)
ratio] on the accuracy the data acquisition obtained from NonMetric photographs.
EXPERIMENTAL WORK
In this case, we choice a wall which about 20 m height and 48 m width
(Fig. 1) of Moid Shikh historical mosque located in
Ghoria, beside Bab Ziwala, Cairo, Egypt (Fig. 2) to
apply our study. Sixtyfour targets (20x20 cm) were fixed on the wall
of Moid Shikh historical mosque (Fig. 1, 3).

Fig. 1: 
The two groups (I) and (II) of targets points on historical
wall 

Fig. 2: 
Sketch of Moid Shikh historical mosque and the locations
of the observation stations 
The intersection method was used to calculate the ground coordinates
(X_{G}, Y_{G}, Z_{G}) which have been assumed
to be a corrected coordinates (i.e., coordinates without error), according
to the next assumption:
• 
The Theodolite used in the observations was a calibrated onesecond
Theodolite (wild T2) with accuracy (±0.8") 
• 
The angles have been measured at four positions of directions (i.e.,
the angles were measured eight times) 
• 
The good experience of the observer 

Fig. 3: 
Sketch for fixed target at the historical wall of Moid
Shikh mosque 
• 
The weather through the fieldwork was clear and suitable to get
accurate measurements and consequently to obtain high accuracy 
• 
The data reduction used to get the ground coordinates was designed
to obtain high accuracy 
• 
The all data was adjusted with least square adjustment 
The observations of Theodolite (i.e., The intersection Method) had been
done by occupying the available three station points (A, B, C) as shown
in Fig. 2, while in the nonmetric camera we choose
the exposure stations as close as possible to the stations A, B and C.
The coordinates of the station points (A, B, C) were obtained using a
calibrated ordinary total station SOKKIApowerset 3000 (No. 22518D21810),
which have technical specifications as follows; Standard measuring up
to 3 km, Accuracy in measuring distance (± (2+2 ppm *D) mm), accuracy
in measuring the horizontal and vertical angles (±3"), minimum
reading in measuring distance (1 mm) and minimum reading in measuring
angles (1"/5").

Fig. 4: 
Plan for location of the station points (A, B, C) 
In this study the three axes X, Y and Z were chosen to be as follows:
The X and Z axes represent the horizontal plane and the X and Y axes represent
the vertical plane.
By Assuming the coordinates of station A = (1000 E, 10 N, 500 Z) and
measuring the length and the bearing angle of lines AB and BC tenth times
to get the most probable value for stations B and C ( Fig.
4 ).
Theodolite measurements: The measurements have been taken using
a calibrated wild T2 onesecond theodolite with accuracy = ±0.8".
The intersection technique was used to calculate the ground coordinates
(X_{G}, Y_{G}, Z_{G}) of each target which have
been assumed as a corrected coordinates.
The object (the historical wall of Moid Shikh mosque) has been divided
into two groups, group (I), which includes twentyone targets and group
(II), which includes fortythree targets (Fig. 2). Three
stations (A, B, C) have been established in the field to apply the intersection
technique for the two groups (Fig. 4).
The base line AB was used to obtain the ground coordinates of the targets
of group (I) and the base line BC was used to obtain the ground coordinates
of the targets of group (II). To obtain the ground coordinates for any
target we measure the base distance (B), the horizontal angles (φ_{A},
φ_{B} ) and the vertical angels (θ) at each end of the
base line (Fig. 5).
The most probable values and their mean square errors (m.s.e) for the
horizontal angles have been measured at four positions of directions (0,
45, 90 and 135°), for each position the angle had been measured face
left and face right (i.e., each angle had been measured eight times).
The most probable values of the horizontal angles and their m.s.e were
founded for group I and II. In group I one target was not observed, while
in group II eight targets were not observed because of some obstacles
in pointing these targets. The mathematical model of coordinate computations
is based on the following three equations:

Fig. 5: 
Explain the intersection method, which used to obtain
the space coordinates of the targets 
Where:
A, B 
: 
The two end points of the base line 
X_{A}, Y_{A}, Z_{A} 
: 
The ground coordinates of point (A) 
X_{B}, Y_{B}, Z_{B} 
: 
The ground coordinates of point (B) 
L_{AB} 
: 
The base line length (measuring accuracy ± 2.0 mm) 
φ_{A} 
: 
The horizontal angle measured from point (A) (measuring accuracy
± 5") 
φ_{B} 
: 
The horizontal angle measured from point (B) (measuring accuracy
± 5") 
φ_{AB} 
: 
The bearing angle for base line (AB) (measuring accuracy ±
5") 
θ 
: 
The vertical angle measured from point (A) (measuring accuracy ±
5") 
h_{i} 
: 
The height of Theodolite 
To simplify the calculations, an Excel program was achieved INTERSECTION
program features can be summarized as follows:
• 
The result of the mathematical model of computing the coordinates
is given in Eq. 13 
• 
It can accept the measured horizontal and vertical angles to each
target, as measured from the two ends of the base line 
Accuracy of the coordinates is estimated using the theorem of error propagation.
According to error propagation theorem Eq. 13 must
be partially differentiated with respect to each measured variable (L_{AB},
φ_{A}, φ_{B} and θ).
According to Eq. (46), we can get the standard errors
of the space coordinates. A computer program was designed to apply the
above formulas to obtain the accuracy of the space coordinates. Additionally,
the mean square error (m.s.e) in different planes can be calculated by
the forms;
The final results for space coordinates (X_{G}, Y_{G},
Z_{G}) and the final mean square errors (m.s.e) {σ(X_{G}),
σ(Y_{G}), σ(Z_{G}), σ_{R}} for
twenty targets of group (I) and for thirtyfive targets of group (II)
were shown in Table 1 and 2, respectively.
Photogrammetric procedures with two nonmetric photographs: We
use Yashka (EZS70) non metric camera and Kodak film speed is 100 ASA.
(American Standard Association), film speed describes film`s threshold
sensitivity to light to take many photographs of the historical wall of
Moid Shikh Mosque. The focal length (f) is 50 mm and the image format
of the roll film is 24x36 mm. The only available way for getting digital
image is the use of a Personal Computer (PC) and a good scanner using
resolution 1000 dpi while the storage used area in hard disk for one photograph
about 70 MB. The basic function of a scanner is to convert a hardcopy
photograph to digital format (that is, softcopy format).
Scanners are used to reflect the image paper print or the film to models
in the computer. The photographs were converted to digital format by using
Genius advanced scanner color pageHR6X.
Table 1: 
The ground coordinates (m) for group (I) of targets
points and their m.s.e (mm) of the historical wall 

Table 2: 
The ground coordinates (m) for group (II) of targets
points and their m.s.e (mm) of the historical wall 

This scanner has true optical
resolution up to 600 dpi with interpolation up to 19200 dpi. It includes
a transparency adapter (TPA) with autodensity technology; this technology
can automatically adjust and enhance the scan color of slides and films
to create high quality.
Scanner specifications
• 
Scanner type Genius HR6X color page 
• 
True optical resolution: 600x1200 dpi 
• 
Transparency adapter (TPA) included for multiple positive and negative
scanning 
• 
Scanning bit depth: 48bit input hardware color depth output 
• 
Supported with USB interface 
• 
Supported Windows XP/Me/2000/98 
Personal computer specifications
• 
Processor intel PIII 2.8 GH 
• 
RAM: 256 MB 
• 
Monitor 17 inch 
• 
Display adapter: svga 32 MB 
• 
Hard disk 80 GB 
• 
Operation system Windows 98 
This personal computer is compatible with IBM computer and with the scanner
software. The measurements of the image coordinates for the points obtained
from AutoCAD version (14) computer program and recording in EXCEL program
RMS manual for three models and their image coordinates will be shown
later.
In this stage, a computer program using the bundle adjustment with selfcalibration
technique was applied to calculate the space coordinates (X_{ph},
Y_{ph}, Z_{ph}) and the root mean square errors for the
target points. Three computer programs were used to fulfill the above
requirements. These programs are Bundle adjustment with selfcalibration
(BSC) program, AutoCAD14 and Computer programs written with SQL language
(Excel).
The BSC program developed by Novak 1991, which was designed by (c) under
Unix programming language. This program solved the photogrammetric triangulation
problem by bundle adjustment with selfcalibration technique. Figure
6 shows the structure of BSC program.
The BSC program was used by providing it with a file containing the photo
coordinates of all points in the stereopair (*.icf), a file containing
the space coordinates of all control point (*.gcf), a file containing
the camera parameters (*.cam) and a file containing the approximations
for the orientation parameters (*.apx).

Fig. 6: 
Structure of BSC program 
The output of the program is a
DXF file containing the space coordinates of all the points (control and
check). We can get the coordinates for checkpoints by using AutoCAD program
and write these coordinates in RMS Excel program to find the difference
in X, Y and Z directions.
Thirty photographs were taken with different locations taking into consideration
the object distance (D). From each location, we take five photographs
for the same part of the historical wall of Moid Shikh mosque and the
best clear one had chosen to be used in this study.
Three models have been chosen from the available photographs with different
overlap ratio. The object distance (D) was chosen to be 16 m because it
is the only available distance in the site of the field work:
First model: This model contain two photographs No. (001, 012),
each one have 21 targets and the base distance (B) between the two stations
was 15 m, then the overlap ratio was 65%.
Second model: This model contain two photographs No. (015, 025),
which have 17 and 13 targets respectively and the base distance (B) between
the two stations was 24 m, then the overlap ratio was 83%.
Third model: This model contain two photographs No. (002, 034),
each one has 21 targets and the base distance (B) between the two stations
was 7 m, then the overlap ratio was 59%.
The print format obtained the print of the nonmetric camera is 15x10
cm.

Fig. 7: 
(a) The left nonmetric photograph No. 001 and (b)
The right nonmetric photograph No. 012 

Fig. 8: 
(a) The positions of the targets for No. 001 and (b)
the positions of the targets for No. 012 
This print photographs were scanned using Genius HR6X color page scanner
with high resolution 1000 dot per inch (dpi) to change the photographs
from print to digital format (pixel format). These digital photographs
were transferred to the AutoCAD program. The final digital format obtained
in AutoCAD program were equal the same size of the negative film format
24x36 mm to be compatible with the used camera focal length (f = 50 mm).
The photo coordinates which are used, as input data of the BSC computer
program should be measured from the principal point of the metric camera,
but in our study because, we use a nonmetric camera we measured the photo
coordinates from the point of symmetry (center of each photograph) by
using AutoCAD program. For example, Fig. 7a and b show the nonmetric photographs and Fig. 8a and b show the positions of the targets using in model one.
ANALYSIS OF EXPERIMENTAL WORK
The number of control points: The main objective of this test
is to investigate the effect of increasing the number of control points
on the RMS in X, Y and Z directions as well as space length (L), this
study will be done for the three models.
Where:
(RMS)_{X} 
: 
The root mean square errors of the targets in the X direction 
n 
: 
No. of targets 
Similar formulas were used for Ydirection, the Zdirection and the space
length (L) to compute the root mean square error values for each direction.
Many relations have been done in this study, we choose for each model
two deferent positions, position (1) and position (2) for the control
points. The final results of the accuracy obtained from the study were
shown in Table 35 for models 1, 2 and 3, respectively.
Figure 911a, b show the relationship between the number
of control points and RMS for models 1, 2 and 3 at two positions (1) and
(2) for every model, respectively.
According to the Fig. 911, we can see that in each
model:
• 
The relations are approximately constant for all the models and
all the positions. 
Table 3: 
The RMS in cm for (X, Y, Z) directions and space vector
(R) for model one (overlap 65%) 

Table 4: 
The RMS in cm for (X, Y, Z) directions and space vector
(R) for model two (overlap 83%) 

Table 5: 
The RMS in cm for (X, Y, Z) directions and space vector
(R) for model three (overlap 59%) 

• 
The relations are semi parallel for each position; that`s mean the
relations are nearly the same for all figures. 
• 
These relations approved that, when the number of control points
increasing, the RMS is decreasing and consequently the accuracy is
increasing. 
The ratio of the base distance (B) to the object distance (D): We can
conclude from Table 6, when B =15 m and D = 16 m, (B/D
1.0) in model one (overlap 65%), we get the best accuracy for the computed ground
coordinates. When B = 24 m and D = 16 m (B/D
1.5) in model two (overlap 83%), we get the worst accuracy in the computed ground
coordinates. While the accuracy comes in between for the computed ground coordinates
when B = 7 m and D = 16 m (B/D
0.5) in model three (overlap 59%).
According to Fig. 12, which shows the relations between
B/D ratio against RMS in X, Y, Z and R directions, we can see that:

Fig. 9: 
The relationship between the number of control points
and RMS in check points for model one (a) position (1) and (b) position
(2) 
• 
The relations between the values of B/D ratio and RMS are nearly
the same for Y, Z and R direction. 
• 
The relations are directly proportionally in the range of 0.5≤
(B/D) ratio ≤ 1.0 (i.e., when the values B/D ratio is increasing,
the accuracy is increasing), while the relations are inversely proportionally
in the range of 1.0≤ (B/D) ratio ≤ 1.5 (i.e., when the value
of B/D ratio is increasing, the accuracy is decreasing). 
• 
The relation in Xdirection approved that, when the values of B/D
in the range 0.5≤ (B/D) ratio ≤ 1.0 the relation between B/D
ratio and RMS is inversely proportionally (i.e., when the value of
B/D ratio is increasing, the accuracy is decreasing). While the relation
is directly proportionally when the values of B/D in the range 1.0≤
(B/D) ratio ≤ 1.5 (i.e., when the values of B/D ratio is increasing,
the accuracy is increasing). 
• 
From the above observations we see that, the relation in Xdirection
is the only one which is not matched with the other relations and
that may be due to the big effect of the angle of convergence (φ)
on the accuracy in Xdirection. 

Fig. 10: 
The relationship between the number of control points
and RMS in check points for model two (a) (position (1) and (b) position
(2) 

Fig. 11: 
The relationship between the number of control points
and RMS in check points for model three (a) position (1) and (b) position
(2) 
Table 6: 
The most probable values of the exterior orientation
parameters and calculate average of RMS in X, Y, Z as well as Rdirections
of nonmetric camera and (B/D) ratio 


Fig. 12: 
The relationship between B/D ratio against the RMS in
X, Y, Z and R directions 
CONCLUSIONS AND FUTURE WORK
This study evaluates both of the effect of the number of control points
as well as the effect of the ratio of the base line distance (B) over
the object distance (D) [(B/D) ratio] on the accuracy obtained from the
ground coordinates using nonmetric photographs for documenting historical
buildings. We choose a wall of Moid Shikh historical mosque located in
Ghoria, beside Bab Ziwala, Cairo, Egypt as a test object. From the previous
analysis we can conclude that for evaluated the effect of the number of
control points on the accuracy obtained from nonmetric photographs for
documenting historical buildings, when the number of control points increasing,
the accuracy is increasing. The effect of the ratio of the base line distance
(B) over the object distance (D) [(B/D) ratio] on the accuracy obtained
using NonMetric photographs for documenting historical buildings, the
relations Y, Z and R direction are directly proportionally in the range
of 0.5≤ (B/D) ratio ≤ 1.0, while the relations are inversely proportionally
in the range of 1.0≤ (B/D) ratio ≤ 1.5. Only the relation in Xdirection
is not matched with the other relations, that is may be due to the big
effect of the angle of convergence (φ) on the accuracy in Xdirection.
Future works will be focused on the effect of the angle of convergence
(φ) on the accuracy, as well as the effect of more number of control
points on the accuracy.