Multiple sensor tracking area

Hi TD programmers,
I am setting up a interactive project using 2 Hokuyo sensors and need some advices for defining the tracking area of each sensors. From my point of view, my method requires lots of calibration by hand and setting-up time, but the result is still not quite precise.

Here is how I did it:
I use Hokuyo CHOP to input data, then visualize them by rendering a texture for each sensor. Next, I connected each texture to a Fit TOP (to synchronize 2 textures), then a Crop TOP (to limit the tracking area of each sensor). Finally a Composite TOP merges 2 textures together. The position data is achieved through a Blob Track TOP.
Multi_Sensor.4.toe (11.5 KB)

Can some pro help me with a more optimized solution to limit the tracking area of each sensor or any comment on the method?
Thanks a lot.