An improved Surendra background update algorithm for moving targets detection is proposed in this paper, which is
beneficial to the background update and can automatically change threshold. Firstly, the initial background frame can be
obtained through the arithmetic average to the first few frame images. Secondly, The OTSU method is used for adaptive
threshold selection to background updating, so that the moving objects can be obtained by morphological processing.
Experiments show that the improved Surendra background updating algorithm can detect the moving targets effectively
and overcome the original method's shortcoming which needs to manually intervene the threshold. The impact of such
background disturbances and illumination changes to moving targets detection has a good inhibition.
Proc. SPIE. 7658, 5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronic Materials and Devices for Detector, Imager, Display, and Energy Conversion Technology
A small-molecular red-fluorescent dye of [7-diethylamino-3-(2-thienyl)chronmen-2-ylidene]-2,2-dicyanoviny-lamine
(ACY) has been blended into blue-emitting poly(N-vinylcarbazole) (PVK) by using different solvents of chloroform and
1,2-dichloroethane. Photoluminescence characteristic of solvent effects were investigated mainly from the aspect of
solvent polarity. To demonstrate the solvent effects in organic light emitting devices (OLEDs), devices with a structure
of indium-tin-oxide (ITO)/PVK: ACY (x wt %)/tris(8-quinolinolato) aluminum (Alq3)/Mg: Ag were fabricated, in which
the weight doping ratios are x = 0.3, 0.5 and 0.7. Using spin coating method, a blending system of PVK: ACY is
dissolved in both chloroform and 1,2-dichloroethane with various doping concentrations. As a result, by choosing
chloroform as solvent, a high electroluminescent (EL) performance device with a maximum luminance of 7698 cd/m2 at
a driving voltage of 15.5 V was obtained, with a concentration proportion of PVK: ACY at 1000: 7. In the EL spectra of
the OLEDs, red and green fluorescence of ACY and Alq3 were detected. It was found that by using 1,2-dichloroethane as
a solvent, fluorescent quenching emerged with the enhancement of doping concentration. Energy transfer and Alq3
cations quencher theories were used to discuss different solvent effects on OLEDs.
ITO (Indium tin oxide) film has been widely used as transparent electrode for organic light-emitting diodes (OLEDs).
Higher conductibility and transparency, smoother surface morphology and higher work function are indispensable for the
fabrication of high performance OLEDs, especially for transparent and double-side devices. Therefore, it is necessary to
deposit ITO films at low temperature to protect the organic films of OLED from damaging during fabrication process. In
this work a novel transparent electrode ITO/Ag/ITO was introduced to the OLED device. This kind of transparent
electrode was used to reduce the sheet resistance of electrode and raise the performance of OLED device. By theoretical
simulation, the optimum film thickness of three organic layers was obtained. ITO and Ag films were prepared by DC
magnetron sputtering at room temperature. The transparent electrode with low sheet resistance of 6.3 Ω/sq and high
transmittance of 87% at 550 nm was achieved. OLED consisted of this multilayer film was developed. The relationship
between the thickness of Ag film and photoelectric performance of multilayer films was also discussed.
A novel kind of multilayer blue organic light-emitting diode (OLED) was developed via vacuum thermal deposition method. Host and dopant materials were co-deposited to fabricate as an emissive layer (EML) simultaneously. The film thickness of each layer was controlled with a quartz crystal microbalance. Typical device structure was ITO/CuPc (20 nm)/NPB (60 nm)/B-host (40 nm) : dopant (X wt%)/Alq3 (20 nm)/LiF (1 nm)/Al (100 nm), where X% stands for the doping concentration in the EML of OLED. The weight ratio was changed from 1% to 4%. Optical and electronic performance including current, bias voltage, brightness, efficiency and spectra of the devices varied with doping concentration was characterized. The results showed the turn-on voltage of the device with 1% doping concentration was lower than that of others, which was only 3.5 V. When X wt% was 3%, the brightness of the device reached to be 9,500 cdm-2 at a driving voltage of 20 V with blue emission spectrum peak 472 nm corresponding to the CIE coordinates of x=0.147, y=0.215 and a maximum luminance efficiency of 2.92 lmW-1. The brightness of the device increased linearly with the bias voltage ranging from 3.5 to 52 V. The results also showed that the doping OLED was very steady under high driving voltage at ambient atmosphere.
Ultra-wideband (UWB) signals are widely used in radar, navigation and satellite communications. It is rather difficult to process UWB signals. In this paper we adopt dechirp pulse compression method to process the received UWB linear frequency modulated (LFM) signals. UWB signals are converted into signals with frequency components that are proportional to the relative range between the target and the reference target. It means to select low-speed analog-to-digital converters (ADC) for sampling UWB signals. The simulation results show that LFM signal with 600MHz center frequency, 200MHz bandwidth and 30usec pulse width can be processed under 70MHz sampling frequency by means of the method.