Figure 5 
Points that must be measured 
between on the transmission case 
  
PENN VIDEO LIGHTING ADVISOR 
— Conclusions: 
The list of suggested solutions is as follows: 
Possible lighting technique: STRUCTURED FRONT 
LIGHT - LIGHT FIELD AND TRIANGULATION. USE 
SHADOW CASTING IF POSSIBLE. 
Possible light source: FIBER OPTIC BUNDLE WITH 
APERTURE AND LENS, QUARTZ HALOGEN LIGHT 
SOURCE. 
Possible lens choices: THE CALCULATED FOCAL 
LENGTH IS 113.4. USE A 75mm FIXED FOCAL 
LENGTH LENS. USE A ZOOM LENS WITH A FOCAL 
LENGTH OF 113.4mm IN ITS USABLE RANGE. 
**End - RETURN/ENTER to continue 
  
  
  
  
  
  
  
Figure 6 
Lighting Advisor's suggested 
solutions to the application 
The lighting technique used at the time of the 
application consists of a structured light 
source to detect the raised surface position 
with respect to the backlit hole. An 
unstructured light source could not reveal 
depth information to the two dimensional 
camera. The same application was described to 
the Lighting Advisor expert system. The 
results from Lighting Advisor are shown in 
figure 6. 
  
PENN VIDEO LIGHTING ADVISOR 
  
STRUCTURED LIGHTING (Raised Surface) 
Structured lighting provides a means of lighting only a 
portion of a part or scene. It is achieved by shaping a 
beam of a light with apertures and lenses, or by using 
lasers. Below are two ways structured lighting is used. 
1. To reduce the complexity of a scene by only project- 
ing light on the features of interest. 
2.To light a three-dimensional form in a way that 
extracts two-dimensional information. For example, 
a slit can be projected at an angle to a part to deter- 
mine the presence of a raised surface. 
**End- RETURN/ENTER to continue 
  
  
  
  
  
  
Figure 7 
An explanation of structured lighting 
  
Structured 
1 Lighting 
Camera (Raised Surface) 
  
Press ENTER to continue 
  
  
  
Figure 8 
A graphic representation of 
structured lighting 
This conclusion offers structured light as the 
major lighting technique. Figures 7 and 8 show 
a full explanation and graphic representation 
of structured lighting. The results also 
suggest triangulation (figures 9 and 10) and 
shadow casting as alternate techniques. These 
secondary techniques are suggested because the 
information input to the system matches rules 
that lead to this set of conclusions. 
  
PENN VIDEO LIGHTING ADVISOR 
  
TRIANGULATION: 
Triangulation is used to determine the height of a surface. 
A spot of light is projected on the surface at a low angle. If 
the surface height changes, the spot moves relative to 
the camera. 
**End- RETURN/ENTER to continue 
  
  
  
  
  
  
Figure 9 
An explanation of triangulation 
  
Structured 
Lighting 
(Triangulation) 
   
    
  
Camera 
Light 
+ Position ‘A’ 
/ 
Position ‘B’ 
Surface ‘A’ 
Surface 'B' j : À. 
  
Press ENTER to continue 
  
  
  
Figure 10 
A graphic representation of 
triangulation 
The tec 
simila 
suggest 
the tw 
The lic 
shaped 
produc 
positi 
light E 
expert 
image 
transmi 
spots 
convent 
  
The fi 
expert 
have I 
usefuln 
are enc 
system 
knowl ed 
With re 
continu 
Applyin 
amount 
expert 
systems 
many a 
expansi 
and suj 
where t 
system 
optimiz 
and mac 
promisi