KEYWORDS: Holograms, Digital holography, 3D image reconstruction, Image resolution, Reconstruction algorithms, Digital imaging, Detection and tracking algorithms, Phase shifts, Spatial resolution, Signal to noise ratio
In this paper, the method of recognition and superposition of sub-pixel shifting in digital holograms is investigated. A group of non-scanning holograms is recognized and superposed by using sub-pixel shifting algorithm. Further, spatio-temporal scanning holograms with sub-pixel displacement are recognized and superposed to further improve imaging resolution by combining spatio-temporal scanning digital holography with sub-pixel shifting algorithm. The experimental results verify the feasibility of improving resolution with sub-pixel displacement.
The experiment of volume holographic storage for teaching and training the practical ability of senior students in Applied Physics is introduced. The students can learn to use advanced optoelectronic devices and the automatic control means via this experiment, and further understand the theoretical knowledge of optical information processing and photonics disciplines that have been studied in some courses. In the experiment, multiplexing holographic recording and readout is based on Bragg selectivity of volume holographic grating, in which Bragg diffraction angle is dependent on grating-recording angel. By using different interference angle between reference and object beams, the holograms can be recorded into photorefractive crystal, and then the object images can be read out from these holograms via angular addressing by using the original reference beam. In this system, the experimental data acquisition and the control of the optoelectronic devices, such as the shutter on-off, image loaded in SLM and image acquisition of a CCD sensor, are automatically realized by using LabVIEW programming.
In this paper, a real-time measurement of liquid concentration changing in a Y-type microfluidic chip by digital holography is presented. In the experiments, the different concentrations of salt solution are injected into two channels of the Y-type microfluidic chip as a target object, and then the digital holograms related to the target solutions are recorded. The refractive index of the solution can be obtained from the reconstructed phase image. The experiment results show that the real-time changing of liquid concentration in microfluidic chip can be effectively measured by digital holographic microscopy.
In this paper, a method to measure the flow speed based on microfluidic chip by digital holography in real-time is demonstrated experimentally. The injection pressure of microfluidic device is changed to create different flow rate in microfluidic channels. On this basis, the phase distributions within the microfluidic channels can be reconstructed by using digital holographic microscopy, and then flow rate can be obtain by measuring the phase distributions of cross section. The experiment results show that digital holographic phase image is an effective and real-time detection means for the characteristic parameters of micro-fluid such as flow rate and injection pressure. In addition, the chip calibration is made to ensure the validity of the experimental results.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.