A novel optical encryption technique that uses oscillations on a liquid lens surface and random phase masks to encode images is presented. Excited liquid surface patterns can encode optical wave fronts, making the optical transfer function of the system a function of time. This allows for possible protection against known and chosen plaintext attacks and potentially enables more flexible realizations of random phase mask security systems. However, the periodic nature of liquid surface oscillations and the geometry of the patterns can potentially place constraints on the efficacy of such a system. Simulation results show that the entropy of encrypted images depends on the liquid surface mode shape and the recording duration of the encrypted image. Additionally, it is shown that mistiming the liquid system during decryption gives significant error in the recovered images. The simulations presented here use a model of a commercial available liquid lens, giving the possibility for future comparison with experimental results.
Piezo devices made of lead-zirconium-titanate (PZT) are known for driving mechanical device for positioning control and vibration actuation. Here we present a new rapid prototyped PZT actuator for potential 2D scanner application. The proposed 5-μm thick film PZT actuator is made by directly deposited on a thin 100 μm thick stainless steel substrate by using an aerosol deposition (AD) method. The actuator features a stable linear vibration and frequency response. Fabrication results, electrical impedance and mechanical response will be presented and discussed.
The objective of this study is to develop an RGB-D (video + depth) camera that provides three-dimensional image data for use in the haptic feedback of a robotic underwater ordnance recovery system. Two camera systems were developed and studied. The first depth camera relies on structured light (as used by the Microsoft Kinect), where the displacement of an object is determined by variations of the geometry of a projected pattern. The other camera system is based on a Time of Flight (ToF) depth camera. The results of the structural light camera system shows that the camera system requires a stronger light source with a similar operating wavelength and bandwidth to achieve a desirable working distance in water. This approach might not be robust enough for our proposed underwater RGB-D camera system, as it will require a complete re-design of the light source component. The ToF camera system instead, allows an arbitrary placement of light source and camera. The intensity output of the broadband LED light source in the ToF camera system can be increased by putting them into an array configuration and the LEDs can be modulated comfortably with any waveform and frequencies required by the ToF camera. In this paper, both camera were evaluated and experiments were conducted to demonstrate the versatility of the ToF camera.
A new lead-zirconium-titanate (PZT) actuator design for a micro scanning illuminating device is being developed. The thin PZT film is deposited directly on stainless steel by using an aerosol deposition machine. The aerosol deposition method enables inexpensive, quick, room temperature fabrication while producing high quality PZT films. The presented scanners would be attractive for endoscopic device applications, where inexpensive systems with high resolution would be a move toward disposal endoscopes. The design of this scanning illuminator and fabrication method are presented. Measurements of the PZT layer surface roughness and the aerosol deposited PZT powder particle diameter are presented. Ongoing work and fabrication challenges are discussed.