Abstract:The derivation process of Noise Equivalent Temperature Difference (NETD) based on the definition of NETD is presented. The influence of related system parameters on NETD is discussed. Then, the influence of the variation of ambient temperature on NETD is analyzed. Finally, the MATLAB method for calculating the equivalent temperature difference corresponding to the same radiant power difference is given.

Abstract:At present, the hyperspectral imaging technology is widely used in the fields of remote sensing and detection etc. However, in some emerging fields of medicine, material and microelectronics, the passive imaging method has its limitation and unsuitability. A wavelength-tunable staring hyperspectral imaging system is discussed. By using wavelength-tunable monochromatic light, the spectra of an object to be imaged is measured rapidly. In addition, because a grating is used as a light-splitting element, the compatibility and robustness of the system are improved greatly. This research is of reference value to the design of similar imaging systems.

Abstract:In a laser reflective tomography imaging radar system, the narrower the laser pulse is, the higher imaging resolution the system has. But it is difficult to design a large bandwidth and undistorted photoelectric detection circuit. An avalanche photodiode (APD) model and its main parameters are analyzed in detail. An appropriate detector is selected. After the preamplifier, main amplifier and automatic gain amplifying circuits are analyzed, a proper circuit structure is designed. When the GHz-level weak photoelectric signals are being received, they are easy to interfer with the external noise introduced. This may cause the received waveform to be distorted. By using an electromagnetic radiation shielding method to remove the interference, a 1 ns narrow pulse laser signal without distortion is received. The imaging resolution requirement of 0.15 m for the laser reflective tomography imaging radar system is met.

Abstract:An active pixel sensor (APS) for fast target detection and imaging is designed. Unlike the traditional image sensors, this sensor can output the image signals from a part of pixels in an array according to the location of the target signals. So, fast target location and image output can be implemented. The area partitioning principle and area image output control method of the sensor are described. By designing and simulating a 48×48 pixel area array, the fast target location ability of the sensor is verified. The test result shows that this new sensor has a frame rate four times higher than the traditional sensors.

Abstract:A dual-band infrared image fusion algorithm for human visual systems is put forward. First, the source images are decomposed into the multi-scale and multidirectional subbands by using a nonsubsampled contourlet transform method. Then, the highpass subband is fused by selecting the maximum absolute operator and the lowpass subbands is fused by using a method based on region variance. Finally, the fused image is obtained through image reconfiguration. A fusion experiment is made on the dual-band infrared images collected. The method is compared with the gradient pyramid transform and the wavelet transform in fusion effectiveness. The experimental result shows that this dual-band infrared image fusion algorithm for human visual systems is effective and feasible. It can obtain better fusion effectiveness than the common algorithms.

Abstract:To solve the problems present in traditional wavelet denoising methods, such as unexpected oscillation occurring and loss of characteristic information, a novel and effective wavelet denoising method for IR spectrum based on bat algorithm (BA) is proposed. In the method, both threshold and estimation factor are optimized by BA innovatively. Its basic idea is that firstly a certain size of individuals are generated in the solution space randomly and then the velocity and location of each bat are updated according to its distance from the best bat individual. Meanwhile, by using the random walking characteristics of Levy flight search strategy, the search for the whole solution space can be implemented and falling into the local minimum can be avoided. The experimental result of CO gas IR spectrum denoising shows that after the threshold and estimating factor in each layer of wavelet decomposition are optimized by using the proposed wavelet denoising method, the signal-to-noise ratio (SNR) is up to 84.184 and the root square error (RMSE) is 0.0006. Because the characteristic information in the spectral signal is reserved and the unwanted noise information is removed more accurately, the method can be used to improve the accuracy of subsequent qualitative and quantitative analysis.

Abstract:Enough stars for navigation can be detected at infrared wavelengths. Limited by the objective conditions, large quantity of star images can not be obtained in the daytime. To accelerate the development and performance testing of the algorithms for three field-of-view star detection, star point location and star pattern recognition, a method for simulating all-time three field-of-view star images should be studied. The models of three field-of-view sky radiation, system noise and star imaging are established. The software for generating three field-of-view star maps is designed and operated. The result obtained is of importance to the acceleration of development and full performance testing of related algorithms.

Abstract:The feasibility of using an infrared spectral analysis technology to detect cell disruption in the process of electric transfection is studied. Electric transfection is a means commonly used in genetic engineering experiments. It usually uses an electroporation method to incorporate the genes outside a cell into the cell and let them express. In the process of electric transfection, a cell may be perforated and damaged due to the stimulation of strong external voltage. The infrared spectra of porcine kidney cells are obtained before and after their damage respectively. The spectral data in the region from 2200 cm-1 to 2600 cm-1 are analyzed through second derivation combined with a computer software. It is found that the characteristic peaks of the cells before and after their damage are very different in this spectral region. The shape of the characteristic peak of the damaged cell is sharpen and intensive while the shape of the characteristic peak of the normal cell is wider and its intensity is low. This result provides the basis for the identification of cell damage and is of reference value to the further use of infrared spectroscopy in cell damage research.