The wideband radar system is usually exploited to obtain the 3-D image of the target under test. However, the wide bandwidth increases the system complexity and cost. Emerging techniques, such as the reconfigurable reflectarrays, reconstruct a near 3-D image via using single-frequency millimeter-wave (MMW) and near-field focusing of the beam, which greatly simplifies the system design, whereas the near-field focusing can only achieve a poor range resolution and a limited depth of focus. In this letter, we propose a multifocus image fusion method based on the criterion of minimum entropy, which can further be utilized for any kind of the MMW imaging system working at a single frequency. Simulations and experiments are presented to verify the effectiveness of the proposed method.

中文翻译：

---

通过多焦点图像融合实现近场单频毫米波3-D成像

通常利用宽带雷达系统来获取被测目标的3D图像。但是，宽带宽增加了系统的复杂性和成本。诸如可重构反射阵列之类的新兴技术通过使用单频毫米波（MMW）和光束的近场聚焦来重建近3D图像，这大大简化了系统设计，而近场聚焦可以只能实现较差的范围分辨率和有限的焦点深度。在这封信中，我们提出了一种基于最小熵准则的多焦点图像融合方法，该方法可进一步用于以单一频率工作的任何类型的MMW成像系统。仿真和实验表明该方法的有效性。