Image Processing Reference
In-Depth Information
[p2,msk2]=phaseproc(dir2,TH,FILTER);
dp=p1-p2;
msk=msk1.*msk2;
dp=dp.*msk;
6.5 Noise Removal from Differential Phase
As can be seen, the phase map (
Figure 18
) has very low contrast and object topography is not
clear. This is because of phase mistakes with very large or very small values. Hence, we im-
proved the previous phase map using the following ilter:
dp(abs(dp)>15 | dp>-4)=0;
dpf=abs(dp);
After erasing these mistakes, we can see the much improved object topography in the phase
FIGURE 19
Phase map after filtering.
There are yet some phase errors especially at the edges. We can correct these errors using a
ilter previously used in phase computation. Like with phase computation, we can apply this
ilter several times by which we obtain the further improved phase map of
Figure 20
.
FIGURE 20
Final phase map with modulated height information.
a=medfilt2(dpf,[1 7]);
7]);c=filter2([1 2 3 0 3 2 1]/12,dpf);
b=abs(a-dpf)>.5;
dpf=dpf.*~b+c.*b;
6.6 How to Make RGB Texture Image from Projected Fringe
Pattern Images
RGB=(projected fringe patern1+projected fringe patern2+projected fringe patern3)/3
As can be seen from the texture image of
Figure 21
, there are some unwanted periodic pat-
terns and these could be removed by using phase filtering techniques in the frequency do-
main. However, a beter method is possible as a result of binary code patern unwrapping be-
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