A high-performance long-wave IR zoom sensor capable of 20× magnification using a 480×6 linear detector has been developed. The system magnification can be continuously adjusted by simply moving two lens groups, which also provides the means of athermalization of the images. The sensor image can be displayed in the 16 : 9-aspect-ratio high-definition TV format, which allows longer detection and recognition range than normal 4 : 3 TV format images without any loss of field of view. In order to correct the nonuniformity of the detector arrays, the two-point correction method has been applied using a thermoelectric cooler. Additionally, a new histogram processing technique suitable for characterization of the contrast distribution of thermal imagery has been proposed to enhance the image contrast and improve the detection capability.
The developing multi-channel stabilized commander's sighting system which can be operated by day and night consists of 2nd generation LWIR thermal imager, daylight TV camera, eyesafe 1.54μm Raman shifted Nd:YAG laser rangefinder and direct view telescope for outstanding observation and fire control capabilities. The high performance thermal imager which uses a 480x6 HgCdTe array detector has dual field of views such as 3x2.25° in NFOV and 10x7.5° in WFOV. Daylight TV camera which employs 768x494 color CCD has 4.0cycles/mrad resolution and the same dual FOV. For an eyesafe operation, 1.54μm Raman shifted Nd:YAG laser rangefinder with InGaAs APD detector is incorporated into direct view optics to provide range data to commander and fire control computer with an accuracy of 10 meter. Multi channel EO/IR sensors for day and night views are integrated into the stabilized head mirror. In this paper, the performances of multi channel EO/IR sensors for the commander's sight has been analyzed for a tactical ground application.
A new second generation advanced thermal imager, which can be used for battle tank sight has been developed in Korea. The IR optics has dual field of views such as 2.67×2° in NFOV and 10×7.5° in WFOV. This system uses a 480×6 TDI HgCdTe detector, operating in the 8-12μm wavelength, made by Sofradir. In order to correct non-uniformity of detector array, the two point correction method has been developed by using the thermo electric cooler. Additionally, to enhance the image of low contrast and improve the detection capability, the new technique of histogram processing has been proposed. Through these image processing techniques, we obtained the high quality thermal image.
The development of a compact and high performance MWIR zoom camera based on the 320 X 240 staring focal plane array (FPA) is described. The camera has 20 magnification zoom optics with the maximum 40°x 30° of super wide field of view and 7.6 cycles/mrad of resolving power with the operation of attached microscanning system. In order to correct non-uniformities of detector arrays, we have proposed the multi-point correction method using the defocusing technique of the optics and acquired the highest quality images. The MRTD of our system shows good results below 0.05 °K at spatial frequency 1 cycles/mrad at narrow field of view.
KEYWORDS: Image processing, Sensors, Signal processing, Digital filtering, Signal detection, Digital signal processing, Digital image processing, Analog electronics, Signal to noise ratio, Electronic filtering
This paper describes the digital image processing techniques of a thermal observation system, which is a serial/parallel scan and standard TV display type using a SPRITE (Signal PRocessing In The Element) detector. The designed digital electronics has two major signal processing stages: a high speed digital scan converter and an autoregressive (AR) filter. The digital scan converter is designed with analog-to-digital converter (ADC) and dual port RAM that can carry out reading and writing simultaneously, thus enabling compact scan conversion. The scan converter reformats the five parallel analog signals generated from the detector elements into serial digital signals compatible with RS-170 video rate. For the improvement of signal-to- noise ratio and compensation for the gamma effect of the monitor, we have implemented a real time 1st order AR filter that adopts frame averaging method. With the look-up-table (LUT) ROM that contains the frame averaging factors and the gamma coefficients, this digital filter performs the noise reduction and the gamma correction at the same time. This digital image processor has been proven to provide excellent image quality and superior detection capability for distant targets at night time.
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.