Real-time holography for optical processing using photorefractive crystals

1999 ◽  
Author(s):  
Nickolai V. Kukhtarev ◽  
Tatiana V. Kukhtareva ◽  
Ruth D. Jones ◽  
JaChing Wang ◽  
Partha P. Banerjee
Keyword(s):  
Real Time ◽  
Optical Processing ◽  
Photorefractive Crystals

Pseudo-Color Coded Optical System Based on the Spatial Light Modulator and Charge-Coupled Device

2012 ◽  
Author(s):  
S. N. Zhao ◽  
H. Chang ◽  
J. Wei ◽  
Z. Wei
Keyword(s):  
Real Time ◽  
Optical System ◽  
Spatial Light Modulator ◽  
Processing System ◽  
Optical Processing ◽  
Gray Scale ◽  
Light Modulator ◽  
Time Modulation ◽  
Gray Scale Image ◽  
Pseudo Color

A new pseudo-color coded optical system based on the liquid crystal spatial light modulator (LC-SLM) and a digital camera (CCD) is proposed. The SLM is used to replace the holographic grating with gray-scale image information, a gray-scale image in real-time modulation methods is proposed by synthesizing phase hologram and Ronchi grating, combined with the 4f coherent optical processing system and spatial filtering. For the high resolution gray image processed with existing digital pseudo-color method, the color sensitivity is low, algorithm is very complex. For traditional optical pseudo-color method, the gray scale image needs chemical pretreatment. The process is complex and time-consuming, and the real-time modulation could not be achieved. Our new method has enhanced the flexibility and adaptability of the optical pseudo-color, and give full play to the high sensitivity, high-capacity, rich colors and other features of the optical processing mode. At the same time, it overcomes the disadvantages of pure optical system which could not perform real-time processing. Therefore, it can be widely used in the field of remote sensing, biomedical, environmental monitoring, public security and criminal investigation, etc.

scholarly journals EARLINET: potential operationality of a research network

2015 ◽  
Vol 8 (7) ◽  
pp. 6599-6659 ◽  
Author(s):  
M. Sicard ◽  
G. D'Amico ◽  
A. Comerón ◽  
L. Mona ◽  
L. Alados-Arboledas ◽  
...  
Keyword(s):  
Real Time ◽  
Research Network ◽  
Lidar Data ◽  
Optical Processing ◽  
Special Events ◽  
Aerosol Classification ◽  
The Common ◽  
First Time ◽  
Cloud Screening ◽  
Different Levels

Abstract. In the framework of ACTRIS summer 2012 measurement campaign (8 June–17 July 2012), EARLINET organized and performed a controlled exercise of feasibility to demonstrate its potential to perform operational, coordinated measurements and deliver products in near-real time. Eleven lidar stations participated to the exercise which started on 9 July 2012 at 06:00 UT and ended 72 h later on 12 July at 06:00 UT. For the first time the Single-Calculus Chain (SCC), the common calculus chain developed within EARLINET for the automatic evaluation of lidar data from raw signals up to the final products, was used. All stations sent in real time measurements of 1 h of duration to the SCC server in a predefined netcdf file format. The pre-processing of the data was performed in real time by the SCC while the optical processing was performed in near-real time after the exercise ended. 98 and 84 % of the files sent to SCC were successfully pre-processed and processed, respectively. Those percentages are quite large taking into account that no cloud screening was performed on lidar data. The paper shows time series of continuous and homogeneously obtained products retrieved at different levels of the SCC: range-square corrected signals (pre-processing) and daytime backscatter and nighttime extinction coefficient profiles (optical processing), as well as combined plots of all direct and derived optical products. The derived products include backscatter- and extinction-related Ångström exponents, lidar ratios and color ratios. The combined plots reveal extremely valuable for aerosol classification. The efforts made to define the measurements protocol and to configure properly the SCC pave the way for applying this protocol for specific applications such as the monitoring of special events, atmospheric modelling, climate research and calibration/validation activities of spaceborne observations.

Sign in / Sign up

Export Citation Format

Share Document