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Chul Bum KIM Doo Hyung WOO Yong Soo LEE Hee Chul LEE
For real time image processing, a readout circuit for an infrared focal plane array (IRFPA) involving a new edge detection technique has been proposed in this letter. A non-uniformity correction unit (NUC), essential in an IRFPA because of bad non-uniformity characteristics of IR sensors is eliminated in this circuit by using a noise tolerant edge detection technique. In addition, real time edge detection can be possible, because of pixel-level integration and parallel processing. The proposed readout circuit shows an approximately three to nine times better edge error rate than other available methods using pixel-level parallel processing.
Hyeok Jun SON Il Woong KWON Yong Soo LEE Hee Chul LEE
In this paper, Poly(3,4-ethylenedioxythiophene): Poly (Styrenesulfonate) (PEDOT:PSS) thin films for application in a bolometer, a type of uncooled infrared image sensor, are presented. In addition, the TCR and 1/f noise dependencies of PEDOT:PSS thin films on the thermal treatment conditions are demonstrated. It is also shown that an appropriate thermal treatment can suppress the 1/f noise of PEDOT:PSS thin films while maintaining the resistivity and TCR. A high TCR value over -4%/ (within 10 ohmcm) through chemical treatment is also presented. The results of this study show that PEDOT:PSS thin films have potential for use as a bolometric material.
Dong-Heon HA Chi Ho HWANG Yong Soo LEE Hee Chul LEE
A new readout integrated circuit is developed for application in an amorphous silicon-based microbolometer array with a pixel pitch of 35 µm. The proposed circuit lowers the power dissipation for a pixel-level analog-to-digital converter (ADC), which uses a comparator and a counter for its data conversion. The infrared current of a microbolometer is proportional to the resistivity changes of the microbolometer. Thus, the required number of counter operations for the pixel ADC can be determined according to the microbolometer current variation. The counting number precisely determines how much infrared flux is absorbed. A 14 bit counter should normally be used for the pixel ADC for this kind of operation. However, when the proposed current skimming scheme is adopted, the total bits for the counter in the pixel ADC can be reduced to 12 bits. Due to the proposed mechanism, the required operational speed of the comparator can lower than that of a conventional circuit. Consequently, the overall power dissipation in the comparator and counter is less than that of a conventional structure. This low power approach is very suitable in the pixel-level ADCs of microbolometers.