Nonlinear Scaling Algorithm Research Articles

An imaging algorithm for missile-borne spotlight SAR based on subband compensation

The missile-borne synthetic aperture radar (SAR) often use nonlinear scaling algorithm to improve the focusing effect. However, the nonlinear scaling algorithm cannot be used in missile-borne spotlight SAR because of its own limitations. Aiming at this problem, this paper first puts forward a new method named “sub-band compensation” and combineds it to the missile-borne SAR spotlight imaging algorithm. This new algorithm does not introduce the three phases of operation, so the Doppler frequency rate can be effectively compensated under low PRF. Simulation results and analysis show that compared with the nonlinear chirp scaling algorithm, the proposed one has advantages in computation, results obtained, and applicability.

A Non-linear Scaling Algorithm Based on chirp-z Transform for Squint Mode FMCW-SAR

该文针对调频连续波合成孔径雷达(Frequency Modulated Continuous Wave Synthetic Aperture Radar, FMCW-SAR)在斜视模式下聚焦精度降低的问题，提出一种非线性尺度变换chirp-z 成像算法。该算法利用回波信号在多普勒域中距离向的非线性特性，通过引入一个非线性调频信号对回波信号进行基于chirp-z 的非线性尺度变换，降低距离压缩和距离徙动校正的误差，提高雷达图像分辨率。采用该成像算法对点目标模拟回波的成像结果与原始chirp-z 算法相比，距离向分辨率和图像对比度得到提高，方位向分辨率保持不变。

Non-linear scaling algorithm based on potential energy of color images

Non-linear scaling can maintain the main characteristics and the ratio of the image.Based on the image gradient function,a new potential energy algorithm for color images was proposed in RGB model,and the strong regions were found using potential energy.Fast linear interpolation scaling was used in low energy regions,and it preserved those strong areas in order to protect important features of the image objects.Compared with the traditional image scaling algorithm,the proposed algorithm can overcome the shortcomings of image distortion generated by the scaling effectively.