Target detection in smoke environment using laser active imaging is of great research significance. According to the characteristics of light propagating in smoke environment, the method of laser transmission imaging is adopted and polarization-difference (PD) imaging technology is used to suppress the effect of scattering light on imaging quality. PD imaging method needs to record two target images of different polarization directions and then the two images are subtracted. A correction factor α is used to match the scattering light intensity of the two images, so scattering light can be mostly filtered out. Experiments show that the quality of images obtained by PD imaging method is better than intensity ones. The PD images have big noisy when smoke concentration is high. A method which combines median filtering with multi-scale morphological edge detection is proposed to process images. It can suppress image noise, improve image contrast and edge sharpness effectively.
This paper presents a high frame rate Charge Coupled Device (CCD) image acquisition system. The emphasis is the data
transmission and the data recording technology. The DALSA CCD camera head CA-D6 is utilized as the system imaging
unit. The CA-D6 output 35 pairs and input 2 pairs Low Voltage Differential Signals (LVDS) are analyzed. The switch
from LVDS to TTL signals is implemented. A pair of Agilent data transceivers HDMP-1022/HDMP-1024 is used to
encode/decode the digital image data. The system timing block is designed on Complicated Programmable Logic Device
(CPLD) technology. The internal program is explored on VHDL and schematic combination technology. The optic-fiber
transceiver HFCT-53D5 is applied to complete the data transmission to remote area. The VC++ environment application
software is developed based on data the acquisition card PCI-7300A. The imaging system can work at the frame rate of
up to 955fps. The transmission data rate can reach 1Gbps, and it can transmit the image data beyond 1.5 km area. The
system can be used in remote high-speed image acquisition field such as explosion analysis and radiation diagnosis.
This paper presents high frame rate imaging systems developed in Northwest Institute of Nuclear Technology in recent
years. Three types of imaging systems are included. The first type of system utilizes EG&G RETICON Photodiode Array
(PDA) RA100A as the image sensor, which can work at up to 1000 frame per second (fps). Besides working
continuously, the PDA system is also designed to switch to capture flash light event working mode. A specific time
sequence is designed to satisfy this request. The camera image data can be transmitted to remote area by coaxial or optic
fiber cable and then be stored. The second type of imaging system utilizes PHOTOBIT Complementary Metal Oxygen
Semiconductor (CMOS) PB-MV13 as the image sensor, which has a high resolution of 1280 (H) ×1024 (V) pixels per
frame. The CMOS system can operate at up to 500fps in full frame and 4000fps partially. The prototype scheme of the
system is presented. The third type of imaging systems adopts charge coupled device (CCD) as the imagers. MINTRON
MTV-1881EX, DALSA CA-D1 and CA-D6 camera head are used in the systems development. The features comparison
of the RA100A, PB-MV13, and CA-D6 based systems are given in the end.
KEYWORDS: Video, Cameras, Personal digital assistants, Signal processing, Video processing, Digital signal processing, Analog electronics, Image sensors, High speed cameras, Photodiodes
A digital high speed photodiode array (PDA) camera had been developed in NINT (Northwest Institute of Nuclear Technology). The high speed digital camera was designed compact with high performance that could be applied to conduct area scan. It was constructed by using a high speed PDA as image sensor, which has a fiber optic faceplate coupling to the sensing surface of the device. The camera had a single channel video format that allows video rates up to 1,000 frames per second with exceptional noise immunity and more than 100 times optical dynamic range. Because of the uses of digital signal processing, the quality of image could be made very clearly. We have also adopted the technology, Field Programmable Gate Array, as timing block which makes the camera better work with high reliability. The camera has a wide-range output voltage up to 18 Vp-p, which is suitable for long distance transmission. Advanced features such as frame reset and single work status allows the camera was synchronized to external events. This work details the essential design features and the applications of the high speed PDA camera.
This system basically works by a high frame-rate camera which obtains image signals through a high-speed solid state image sensor array and then memorizes digitally. By connecting the system with computers, various kinds of image processing and displaying can be implemented. In contrast to comparable CCD and CCPD devices, photodiode sensors require no surface electrodes, so there is no interference pattern or light loss and the full inherent sensitivity of a silicon photodiode is obtainable.
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.