Tanagra Theater and the Fishbowl Mermaid

In the early 20th century, an optical arrangement started appearing at exhibitions, fairs, and department stores that produced a convincing illusion of miniaturized people walking on a tiny stage. It could be viewed from a variety of angles and gave a convincing illusion of a three-dimensional figure. This was named Tanagra Theater after “Tanagra”, a location in Greece where miniature figures had recently been discovered. How did they create the illusion so convincingly? How do you produce the same effect if you’re a sideshow operator with little access to precision optics and no optical training?

Inelastic hyperspectral lidar for aquatic ecosystems monitoring and landscape plant scanning test

We have developed an aquatic inelastic hyperspectral lidar with unrestricted focal-depth and enough sensitivity and spatio-temporal resolution to detect and resolve position and behavior of individual sub-millimeter aquatic organisms. We demonstrate ranging with monitoring of elastic echoes, water Raman signals and fluorescence from chlorophyllbearing phytoplankton and dye tagged organisms. The system is based on a blue CW diode laser and a Scheimpflug optical arrangement.

Synchronous Measurement of Three-Dimensional Deformations Using Tri-Channel Spatial-Carrier Digital Speckle Pattern Interferometry

Spatial-carrier digital speckle pattern interferometry (SC-DSPI) has proven to be a competitive tool for full-field deformation measurement. Comparing with traditional phase-shifting digital speckle pattern interferometry, SC-DSPI has the advantage of rapid measurement which guarantees that dynamic deformations can be precisely measured. In this article, a tri-channel SC-DSPI that measures three-dimensional deformations synchronously is introduced. Measuring algorithm as well as optical arrangement is described in detail. Experiments are carried out to verify the validity and evaluate the performance of the proposed technique.

Optical Technique Using Nano-Spark Lightsource for Macro and Microscale Image Acquisition to Study Diesel Spray Atomization

Atomization and fuel-air mixing is an important process in diesel combustion. It directly affects the combustion and emission of diesel engine. Optical technique has the advantage of being unobtrusive in nature when compared to other technique. nanospark unit that has spark duration of 30ns was used as a lightsource to capture high resolution spray image using still film camera. The very short duration of the spark freeze the fast movement of the spray droplet, and sharp image of fuel droplet to be successfully captured by the camera, and then analyzed for sizing and spatial distribution. In addition, by using a more elaborate optical setup, dual image of the same spray can be captured, with a very short time interval between each of them. This provides the means to study dynamic behaviors of the diesel spray and also the droplets, as the progression of the spray and trajectory and velocity of the droplet can be analyze from these images. With the proposed optical technique and optical arrangement, microscopic detail of the diesel engine spray can be captured. Critical data such as droplet sizing can be extracted from this high resolution image. Furthermore, by introducing a more sophisticated optical arrangement coined dual-nano spark photography method, the droplet dynamic behaviors such as flying angle and velocity can be study.