Cao Jianzhong

An Adaptive Two-Point Non-uniformity Correction Algorithm Based on Shutter and Its Implementation

Because of the non-uniform response of infrared focal plane arrays (IRFPA), non-uniformity correction is a key technology in IRFPA application. The two-point correction algorithm is widely used in practical applications, but there are some disadvantages. The detectors response will drift with time and temperature, correction parameters will drift with this accordingly. In order to acquire good quality images, the correction parameters need to be recalibrated periodically. It is inconvenient for user. This paper proposed an adaptive non-uniformity correction algorithm based on the two-point correction, which can update the correction parameters automatically. And this paper else introduced the approach of the algorithm. Results showed that the algorithm is effective to compensate the response drift influenced by time and temperature.

Research and approach on video stabilization algorithm

This paper presents a video stabilization algorithm based on Scale Invariant Feature Transform and the improved RANdom SAmple Consensus (RANSAC) algorithm. Feature points of the video images are extracted using the SIFT algorithm, and then a compensation matrix is obtained using the improved RANSAC algorithm. Pre-detection is used to accelerate the computation by discarding those temporary models that are not candidate models. The experiment result shows that this algorithm largely reduces the amount of computation, as well as improves the speed of video stabilization without changing the accuracy notably.

Real time H.264 high definition videos encoding based on TMS320DM368 and a video quality evaluation framework

This paper presents a framework for evaluating quality of video encoding algorithms. This technique works by collecting source videos, encoding the source videos with a given algorithm, and decoding the compressed sequences. The decoded video shall be measured with the original sources in a specific evaluation method and feedback to the algorithm. Under the guidance of this framework, an implementation based on embedded device is achieved. Firstly, we collect test source videos in two ways: the commonly used standard sequences and actual scenes captured by camera. Secondly, a popular video encoding standard, H.264, is realized on TMS320DM368, a digital media system-on-chip produced by TEXAS INSTRUMENTS (TI). Finally, peak signal-to-noise ratio (PSNR) is implemented and computed among different test sequences. In the experiments, we achieve the real time compression of high definition videos with an acceptable PSNR. The video quality framework also can be easily extended to other encoding algorithms.

Low-memory-usage and high-speed image wavelet transform

Discrete wavelet transform (DWT) is being broadly used in processing digital image, but the large requirement of memory and the time delay limit the DWT usage. For instance, when the image is processed in the space, the realtime processing, low power consumption, reduced complexity and low memory consumption are required. Lifting-based DWT is implemented to lessen complexity. And then the coefficients of the lifting filters are turned to be binary and the filters are therefore implemented efficiently without using any multiplier. In this way the frequency of DWT can be improved and the architecture is simplified. When 2-dimensional DWT is carried out, the line-based wavelet transform is able to save memory in a larger sense. The architecture of line-based wavelet can also be executed in a parallel way. Both horizontal transform and vertical transform can be executed at the same time. This paper takes 9/7 wavelet as an example and compares with others its architecture and performance. The advantages of this design include real-time performance improvement, memory reduction and architecture simplification.

Camera design in ultra-low temperature vessel

According to special application, surveillance camera working in the ultra-low temperature and high pressure vessel is designed. By request of optics and electronics system on temperature, research focus on the design from selection of the structure material, thermal insulation, the adaptability of optical system in the ultra-low temperature and high pressure environment. Finally, It is confirmed that opto-Mechanical structure with double layers thermal insulation of PIPA and ITO optical window have benefit on thermal insulation for the camera working in this ultra-low temperature(-196°C) and high pressure(0.5MPa) environment. All the opto-Mechanical material which may be contact with ultra-low high pressure liquid can also be consistent with liquid.

A New Algorithm for Auto-Exposure Based on the Analogy Histogram

A calculation of exposure time based on the light measurement often refer to errors in the deepness space detection duo to darkness background of deepness space and over hundreds of kilometers between the camera and the target. However, the use of based on an auto-exposure statistic and compensation method overcome those defects that mentioned before. Consequently, average gray level in the object area could be successfully adjusted to the excellent gray scale. Scientifically speaking, the application of auto-exposure method has benefits to promote the impact of exposure unknown size or light target in the darkness background.