PRACTICAL INTEGRATION OF VISION METROLOGY AND CAD IN SHIPBUILDING 
George W. Johnson, Quality Engineer, Bath Iron Works Corporation 
700 Washington Street, Bath, Maine-USA 
email: gwjohns@biw.com phone (207) 442-2083 
Invited Paper, Commission V, Working Group V/3 
KEY WORDS: CCD Sensor, Digital, Close-Range, Measurement, CAD, Visualization 
ABSTRACT: 
Photogrammetry, the science of obtaining precise coordinate measurements from images, has until recently been 
dominated by the use of photographs taken with specially designed, film based cameras. With the development of high 
resolution solid state video imaging sensors, the era of digital photogrammetry has arrived. Digital based systems 
provide far faster results and greater flexibility than their film based counterparts, which has led to more widespread use 
of photogrammetry in the shipbuilding industry. This paper will provide a brief introduction on Bath Iron Works 
Corporation (BIW) emergence into the Digital Close-Range Photogrammetry (DCRP) field, then present measurement 
techniques for applications representing different stages of construction within the ship yard; located in Bath, Maine. 
Implementation of vision metrology stresses the linking of shop floor measurements with Engineering's Computer Aided 
Design (CAD) design and graphic visualization functionality to compliment the use of ‘traditional’ Surveyors optical 
tooling equipment (theodolites, transits, optical micrometers, right angle prisms/optical squares, etc..). All savings and 
benefits provided are from real services being performed in production. Long term expectations are summarized by 
noting plans to apply Total Quality Management (TQM) principles and/or Statistical Process Control (SPC) techniques 
to achieve strategic improvement goals. 
1. INTRODUCTION results (Maas and Kersten 1994) proved beyond a doubt 
that measurement accuracies from the KODAK 
1.1 Background DCS200mi camera and off the shelf components were 
well within tolerances required in the shipbuilding industry 
The Shipbuilding Industry has many diverse meas- for a wide range of applications. In 1994 an ongoing 
urement applications all performed under a wide range of dialogue with Geodetic Services Inc. resulted in the 
operating conditions. Traditionally theodolites and optical acceptance and subsequent implementation of the first 
micrometers have been the standard tools. This equip- Digital Photogrammetry Measurement System (DPMS) in 
ment is accurate and reliable, but one dimensional. Over shipbuilding. This event changed the way BIW 
the last ten years the emergence of three dimensional approaches Dimensional Control for many reasons but 
measurement systems is having a significant impact on two stand above the rest. First and foremost is the 
the way ships are manufactured. One of the most technological ability to measure rigid bodies quicker, 
promising technologies is Photogrammetry (Fraser and more accurately, and with less impact to surrounding 
Brown 1986) which offers stereo and convergent workers than ever before. Secondly is the versatility of 
techniques. Both enable the user to economically the software in handling data. 
measure large numbers of points in an off line manner. 
1.3 Direct Benefits 
1.2 Digital Emergence in Shipbuilding 
The significant benefits derived from these features has 
In 1992 BIW assembled a highly skilled and diverse proven to be both economical and social in nature. 
group of employees, representing the various divisions of Simply stated one can typically obtain three dimensional 
the company, and initiated a Continuous Process data (versus one dimensional) in about one half the time 
Improvement (CPI) project to determine the “Cost for selected jobs requiring thirty or more points to be 
effectiveness and feasibility of utilizing photogrammetry measured. Savings are maximized when the number of 
for shipyard processes requiring precision measurement" points to be measured is increased. At BIW this is readily 
(Johnson 1993). The following year brought about being achieved by refocusing and combining many of the 
extensive testing of many different types of existing Quality Inspection and production service checks. 
measurement systems (photogrammetry, laser based Socially (yet still very positively linked to the economy) is 
theodolites, and light pen technology). At the same time the improvements in shop floor productivity through 
research and development of using charged coupling enhanced visualization of measurement results utilizing 
device (CCD) cameras instead of the existing film based CAD. The old adage “one picture is worth a thousand 
types was being pursued in a cooperation with Prof. words" is quite applicable here. Another reason is the 
Armin Gruen and researchers at the Swiss Federal pride associated with using the first Digital Measurement 
Institute of Technology (ETH) in Zurich, Switzerland. The System and experiencing a true 'change of pace' from 
264 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B5. Vienna 1996 
years of 
is of high 
improvec 
there ha 
integratic 
final coo 
floor will 
analysis 
high cos 
effort be 
delimited 
between 
suremen 
data use 
and caf 
dicators 
improver 
2.1 Stru 
Tradition 
focused 
plate au 
visualiza 
drawings 
shipyard 
purposes 
delivery. 
measure 
to paper 
one at a 
being d 
measure 
delimitec 
being us 
actual m 
program 
code poi 
networki 
evolving 
Increase 
has resu 
Manufac 
suremen 
2.2 Mea 
In addi 
visualiza 
more to 
benefits 
same de 
initial tar 
operator 
sequenc 
coordina 
instill a 
each ar 
wasted : 
data car 
increase 
the appr