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TABLE 1 
rms 
Range Camera Focal Move- Error in 
(m) Separate. Length ment 3D 
(m) (mm) Speed Vector 
(m/s) (mm) 
1.5 0.45 50 0.12 0.981 
1.85 0.45 25 0.06 1.935 
1:85°(° 045 2525455912 |! 2200 
1.85 0.45 50 0.12 0.974 
1.85 0.45 50 0.18 3.096 
1.85 0.75 25 0.06 1.354 
2.5 0.45 50 0.06 3.537 
2.5 0.45 50 0.12 3.094 
2.5 0.75 50 0.12 2.509 
  
  
  
  
  
  
  
3.2 Rotating Head Vision System 
The present research focuses on producing 
line-scan images by introducing rotation of the 
camera head with respect to a stationary object. 
Details of the hardware used to accomplish this 
have been provided in the following sections and a 
block diagram is presented in Figure 15. 
3.2.1 Rotating Stage The rotational movement 
of the line-scan cameras relative to the object of 
interest is achieved by using a rotary stage. A 
stepper motor provides the motion and a worm and 
wheel assembly transmits the primary drive to the 
rotary table top, via an 18:1 gearbox. A central 
aperture is provided through the centre of this 
table arrangement and this is used to pass control 
to and picture information from the cameras. 
The stepping motor providing the camera motion 
is adjusted via a microprocessor based dedicated 
controller. This provides control over rotation 
speed, acceleration, etc.. 
It is necessary for this research to allow the 
cameras to rotate continuously. To achieve this, a 
36-way slip-ring assembly has been used to 
electrically connect the cameras to the external 
electronic arrangement. 
OBJECT OF 
INTEREST 
     
INTERFACE 
CIRCUITRY 
         
  
  
ROTRTION 
CONTROL 
  
  
  
INTERFRCE 
CIRCUITRY 
IBM CLONE PC 
OVERRLL 
CONTROL PROCESSOR 
  
  
FRAME- 
STORE 
  
  
  
  
FRRHESTORE 
CONTROL 
PROCESSOR 
IF RRME- 
STORE 
  
  
  
  
MONITOR MONITOR 
  
  
  
  
  
Figure 15 
3.2.2 Image Capture The picture information 
returning from the cameras is controlled and 
stored in a stand-alone framestore. This provides 
sufficient storage memory to retain two 1024 
pixels by 1024 lines by 8 bits deep images. The 
images are viewed using standard display 
technology, ie: a PAL signal providing a 512 pixel 
by 512 line picture of the original image. A roam 
facility can be used to move the 512 x 512 window 
to view any quadrant of the 1024 by 1024 image. 
3.2.3 Controlling Environment The framestore 
and rotating stage controller are themselves linked 
to an IBM compatible PC. This principally 
provides the operator with direct control over the 
testing environment variables, eg: speed of 
rotation, start point for image capture, etc., and 
also allows dedicated software to be developed for 
specific tasks.