Use of a Millimeter Wave Radiometer for Detecting Pedestrian and Bicycle Traffic

Abstract

A total-power radiometer at 48 GHz has been constructed and used for detecting pedestrian and bicycle traffic. The high operating frequency was selected in order to obtain a high angular resolution. The best way to distinguish a human being from the background is to direct the antenna to the road from above in an angle of 40-70 degrees. Hereby the road reflects the cold sky and thus the brightness temperature of the road is low. On the other hand, the brightness temperature of a human being at millimeter waves is almost the same as his physical temperature. Cars among human beings can be detected radiometrically because the brightness temperature versus the car position has a specific feature. First the front of the car reflects the high brightness temperature of the surroundings and then the top reflects the low brightness temperature of the sky.

Review of Basic Research in Bicycle Traffic Science, Traffic Operations, and Facility Design

“…Since detection is required for actuated control, studies of bicycle detection technology apply, including those on standard loop detectors (40,41). Several studies also were found on more advanced detection systems, such as pattern recognition and classification (42)(43)(44).…”

A new method towards traffic flow control by millimeter wave radiometers

“…According to astrophysics, the universe has a temperature around 3 K. and the brightness temperature of the earth is about 280 K. Other objects with high absorption such as asphalt, (1)Possible radio-brightness contrast grass-metal; (2)Absorption of electromagnetic waves in the atmosphere sands, grass and trees have radio-brightness temperature T back ranging from 280 K to 300 K due to the different emissivity and surrounding objects [7,13,14]. Unlikely, metal and other similar objects are able to reflect the radiation that they receive.…”

“…It is well known that automobile roofs can reflect the cold sky (smaller than -200 • C) whereas construction materials like asphalt and concrete are considered as warm objects [6,7]. By comparing the different radio-brightness temperatures, automobiles can be detected and recognized [8][9][10].…”

Estimation of number of people in crowded scenes using perspective transformation

“…To normalize the coefficients is to preserve the relation in distribution of gray level that the scale of gray level will be ignored. The average th coefficient for each class , is calculated by (2) where is the number of input images. As shown in Fig.…”