SBIR-STTR Award

The ability to store and analyze a continuous sequence of high resolution images of a ballistic event has tremendous benefits in determining the ballistic limits for laminated carbon fiber materials. When the ability to store these images in a 3-D format is introduced, the volume of data that can be extracted from each image is far more than any single photograph. Unlike photography or direct digital imaging, holography offers the ability to store these events in a 3-D format so that high resolution images can be digitized at different depths of field and viewpoints. To meet this need, North Dancer Labs, Inc. (NDL) proposes in Phase I to develop a unique Multiple-view Holographic Cinematography (MHC) recorder capable of capturing 3-D images and interferograms at kHz repetition rates. These can be played back, scanned through depth, and digitized for tomographic analysis to evaluate the displacement, true trajectory and velocity of projectiles and particles, as well as target deformation. A holographic movie can also be played back for viewing with stereo glasses on a monitor so that the viewers can see the event in 3-D while adjusting the image to scan the event in depth. During Phase I, NDL will conduct tests at Wright-Patterson AFB Labs of actual shots to demonstrate proof of principle of a Multiple-view Holographic Cinematography camera and establish a design for Phase II.

Spatial mapping of target fragment field during ballistic events requires time sequenced, ultra-high resolution images containing three dimensional information. A sufficient recording repetition rate is also needed to record and track the debris field generated by penetrating projectiles. NDL has recently pioneered the development of a single view holographic recorder capable of repetition rates up to 500 kHz, based on a spinning film disk approach. In this Phase II work, NDL will develop an ultra-high resolution, (15 microns or better over a 100 mm x 100 mm field), multiple view system capable of recording four (or more) perspective views with a 30 kHz, (50 kHz option) recording rate. The playback system will be capable of digitizing the recorded images for viewing as a movie and for tomographic particle field analysis. It is important to understand why NDL is using a holographic approach to recording images instead of conventional high speed photography such as a Cordin camera. Although high speed cameras can offer higher recording rates (1 million frames per second) they cannot offer the resolution or depth information required to document the fine spall fragment field which is generated in carbon fiber panels. High speed cameras offer 125 microns resolution over a 100 mm x 100 mm image area, whereas the MHC system will provide 15 microns (nearly a factor of 10 increase in resolution) with the added ability to record four simultaneous views. Several of these high speed cameras may be combined to produce multiple views, but the resolution is still poor and serious logistic problems are introduced. MHC (because it is a holographic based system) will also provide the ability to record holographic interferometry for material deformation and shockwave analysis.