Calibrating method for CCD (Charge Coupled Device) imaging lateral laser radar

Abstract

The invention discloses a calibrating method for a CCD (Charge Coupled Device) imaging lateral laser radar. The method comprises the following steps of: enabling an optical axis (1) of a CCD camera to be vertical to the plane of a calibration table (2), firstly acquiring a CCD image of the calibration table (2) by use of the CCD camera (3), and then calculating the offset angle (alpha) and angle width (d alpha) of each pixel according to a table number in the CCD image of the calibration table (2) and a pixel number with a same dimension as the table number increment in the table; and after placing the CCD camera (3) at the lateral adjacent part of an emitted light beam (5) of the laser radar, firstly determining the vertical distance(D) between the CCD camera (3) and the emitted light beam (5) of the laser radar by adopting a three-point positioning method, then substituting the offset angle (alpha) and angle width (d alpha) of each pixel as well as the vertical distance (D) between the CCD camera (3) and the emitted light beam (5) of the laser radar into a lateral laser radar equation P(alpha)=P0KA / D *TtTrbeta(alpha)dalpha, and performing inversion calculation by use of the offset angles (alpha), the angle widths (d alpha) and the vertical distance (D) so as to obtain atmospheric parameters. The calibrating method disclosed by the invention is high in measurement accuracy and wide in application range, and can be widely used for measuring the spatial distribution of atmospheric aerosol of a surface layer.

Description

technical field [0001] The invention relates to a laser radar calibration method, in particular to a CCD imaging lateral laser radar calibration method. Background technique [0002] At present, in order to realize the measurement of atmospheric visibility or extinction coefficient, lidar is often used. For example, the Chinese invention patent application CN 102621102 A published on August 1, 2012 a "Measurement method of horizontal visibility based on CCD lidar". The invention patent application document discloses a continuous laser as the emission light source, using the optical receiving component composed of a CCD camera and a filter in series to receive the laser echo signal from within several kilometers, and analyze the laser echo image through the computer After processing, the atmospheric extinction coefficient is obtained, so as to obtain the size of the atmospheric horizontal visibility. However, there are deficiencies in this measurement method. First of all, ...

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Problems solved by technology

However, there are deficiencies in this measurement method. First of all, the CCD camera is required to be at a small angle with the laser, and what the CCD receives is only the backscattered light of the laser in the atmosphere, making it only suitable for laser scattering angles of approximately 180 degrees. Measurement; secondly, although the distribution of the laser echo signal with different distances is obtained through distance geometric correction, it is not considered that the CCD camera is composed of multiple pixels, and the incident angles of the beams of scattered light irradiating different pixels are not the same The characteristics of different pixels are used to calibrate the corresponding opening angle, which makes the measurement results have certain errors; finally, only the atmospheric extinction coefficient in the horizontal direction of the surface can be measured, and the atmospheric extinction coefficient at different heights cannot be measured.

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