Ranging Technique Based on Conically Scanned Single Pixel Millimeter Wave Radiometer

Abstract

Passive millimeter wave detection offers great advantages of covertness and anti-interference in surveillance and concealed weapon detection but suffers from disabilities of distance measurement. Based on the conically scanned single pixel millimeter wave radiometer, this paper presents a ranging method via dual-measurement utilizing the relation between the solid angle of the object and its distance from antenna. Both one-dimensional and two-dimensional detections are considered. For one-dimensional detection, the relation between the solid angle of the object and the range is reflected by the pulse width of the radiometer output, and the pulse widths of the radiometer output in two measurements could be extracted by derivative or threshold method. Then the range is calculated since it is inversely proportional to the pulse width, which is demonstrated in simulation. For two-dimensional imaging, a scale extracting algorithm is developed to search the scale between the object sizes of bi-measured images. Experiments are performed using a 94.5GHz total-power radiometer mounted on conically scanning platform. The obtained radiometric images are processed by the developed algorithm and the results indicated that both the scale extracting algorithm and the ranging method are effective and practical.

Object Segmentation for Linearly Polarimetric Passive Millimeter Wave Images Based on Principle Component Analysis

“…Some of them have successfully achieved the fully-polarimetric devices [7][8][9], while others mainly focus on linearly (especially horizontal and vertical) polarized system due to the expensive hardware cost [10][11][12][13][14][15]. In previous work [16][17][18], we fixed a mechanically scanned single pixel 94GHz radiometric imaging system. The radiometer is assembled with a Cassegrain antenna fed by a linearly polarized horn, and is conically scanned in azimuth-elevation coordination to realize large view imaging.…”