As explained in the article “Liquid lenses for fast focusing in machine vision”, the best way to combine the liquid lenses with other optical modules is to design them inside.
This way, the position of the liquid lens in the optical system can be optimized, the aberrations can be minimized and the assembly tolerances can be limited. This is the approach followed in the case of the total body scanner.
The desired specifications
The optical module for the iToBoS scanner needs to be compact to add a minimal amount of weight and rotational inertia to the camera system which will be moving and turning to image the full body of the patient. Moreover, due to safety considerations, the whole moving camera system will be located several tens of centimeters from the patient, so the working distance needs to match that distance. Next, we want to be able to acquire high-resolution images, so the focal distance needs to be designed to provide sufficient magnification. Finally, all these specifications need to be achieved throughout the whole visible spectrum and limit the aberrations and tolerances that occur when a theoretical design is physically fabricated.
The table below summarizes the most important specifications of the custom camera module:
Figure 1. CAD design of the custom lens module for the total body scanner. The liquid lens is designed inside the module to optimize the geometry and performance of the system.
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