Method for calibrating external parameters of monitoring camera by adopting reference height

Abstract

The invention discloses a method for calibrating external parameters of a monitoring camera by adopting reference height, which comprises the following steps of: far vanishing point and lower vanishing point-based vision model description and related coordinate system establishment; projected coordinate calculation of reference plumb information-based far vanishing points and lower vanishing points in an image plane; reference height calibration-based camera height, overhead view angle and amplification factor calculation; design of a reference plumb direction-based horizon inclination angle calibration tool; and design and use of perspective projection model-based three-dimensional measurement software and three tools for three-dimensional measurement, namely an equal height change scale, a ground level distance measurement scale and a field depth reconstruction framework. The calibrating method is simple and convenient in operation, quick in calculation and high in measurement precision. The reference can be a pedestrian, furniture or an automobile; and a special ground mark line is not needed. The method allows the camera to be arranged at a low place, and the shooting overhead view angle is slightly upward as long as the bottom of the reference can be seen clearly in the video and the ground level coordinate system is definite.

Description

technical field [0001] The invention belongs to the technical field of intelligent video monitoring, and particularly relates to a method for calibrating external parameters of a camera by using the height of a reference object in a monitoring environment, and is mainly used for precise calibration of external parameters of a camera in a video monitoring environment. Background technique [0002] With the development of computer technology, the modern monitoring system is gradually developing in the direction of networking, intelligence and multi-source. Among them, intelligent video analysis technology, as an important means to realize the intelligence of video surveillance system, has become the research focus of many universities, companies or scientific research institutions. In recent years, with the continuous improvement of computer performance, intelligent video technology has been widely used in various indoor and outdoor application environments such as intelligent...

AI Technical Summary

Problems solved by technology

Since the camera calibration is carried out in the image, the image resolution itself affects the calibration accuracy, which brings inevitable errors

In addition, the error of the selection point when the staff calibrates will also affect the calibration results

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