The non-uniformity response in infrared focal plane array (IRFPA) detectors has a bad effect on images with fixed pattern noise. At present, it is common to use shutter to prevent from radiation of target and to update the parameters of non-uniformity correction in the infrared imaging system. The use of shutter causes „freezing‟ image. And inevitably, there exists the problems of the instability and reliability of system, power consumption, and concealment of infrared detection. In this paper, we present an efficient shutter-less non-uniformity correction (NUC) method for infrared focal plane arrays. The infrared imaging system can use the data gaining in thermostat to calculate the incident infrared radiation by shell real-timely. And the primary output of detector except the shell radiation can be corrected by the gain coefficient. This method has been tested in real infrared imaging system, reaching high correction level, reducing fixed pattern noise, adapting wide temperature range.
In this paper we present a novel method to record high spatial resolution far-infrared(FIR) hologram. This method takes advantage of the photo-induced phase transition characteristic of vanadium dioxide(VO<sub>2</sub>) film. The light path is off-axis digital hologram recording path, while the VO<sub>2</sub> film is kept in constant temperature in front of the recording high resolution CMOS sensor. In the setup, the far infrared light from CO<sub>2</sub> laser changes the partial transmittance of VO<sub>2</sub> film to visible light, then a read-out visible laser is used to measure the transmittance of VO<sub>2</sub> film, and subsequently the results are recorded by a high resolution CMOS sensor. So that with utilizing the photo-induced phase transition of VO<sub>2</sub> film, we can use CMOS sensor to record far-infrared digital hologram. As the pixel pitch of CMOS sensor is much smaller than tradition FIR sensor, the recorded FIR digital hologram has been much improved. Moreover, the transition speed of VO<sub>2</sub> film is in nanosecond scale which means that far-infrared fast-moving object recording and hologram video could be achieved. In our experiments we used different objects to compare the spatial recording resolution and the experiments prove that our method can record higher spatial spatial resolution than traditional FIR digital hologram. It has the potential to become a more effective FIR digital hologram record method. Further research will focus on the simplified light path and FIR hologram video record and process.
Restricted by the detector technology and optical diffraction limit, the spatial resolution of infrared imaging system is
difficult to achieve significant improvement. Super-Resolution (SR) reconstruction algorithm is an effective way to solve
this problem. Among them, the SR algorithm based on multichannel blind deconvolution (MBD) estimates the
convolution kernel only by low resolution observation images, according to the appropriate regularization constraints
introduced by a priori assumption, to realize the high resolution image restoration. The algorithm has been shown
effective when each channel is prime. In this paper, we use the significant edges to estimate the convolution kernel and
introduce an adaptive convolution kernel size selection mechanism, according to the uncertainty of the convolution
kernel size in MBD processing. To reduce the interference of noise, we amend the convolution kernel in an iterative
process, and finally restore a clear image. Experimental results show that the algorithm can meet the convergence
requirement of the convolution kernel estimation.
Recent studies have shown that compressed sensing is capable of recover sparse signals with much few measurements. Meanwhile, it provides a new idea for super resolution imaging. However, previous compressed sensing super resolution imaging methods use digital micro-mirror device or coded aperture as the measurement matrix, which makes the method inefficient. In this paper, we propose a super-resolution method via parallel compressed sensing, the proposed method using scattering medium as the measurement matrix, which we can get enough measurement values at once. Each measurement values contains global information about the object. Experiment simulation results show the effectiveness of the proposed method.