MTF (Modulation Transfer Function) parameter testing method under condition of nonideal target

Abstract

The invention relates to an MTF (Modulation Transfer Function) parameter testing method under the condition of a nonideal target. The method is characterized by comprising the following steps of: (1) establishing a weight map for a special remote sensing image containing margins on the basis of image features; (2) setting a starting point and a terminating point on the margin, and calculating the shortest path from the starting point to the terminating point in the weight map on the basis of dynamic planning; (3) sampling the image grey value to form a margin spread function at a certain distance in the direction vertical to the shortest path, fitting and solving the margin spread function to obtain the line spread function, and carrying out Fourier transform on the line spread function to obtain an MTF curve; (4) repeating the steps 1-3 several times, and taking average values multiple times to reduce error. The invention not only can be used under the ideal conditions of having a target and a margin, but also can extract an MTF parameter by utilizing the targets with irregular shapes, ,thereby enabling the margin selection to be convenient, flexible and accurate.

Description

technical field [0001] The invention relates to the technical field of electronic information, in particular to a method for testing MTF parameters under the condition of non-ideal targets. Background technique [0002] At present, the methods for extracting MTF (Modulation Transfer Function, satellite image modulation transfer function) parameters of orbiting satellites all require matching targets on the ground or images with very regular edges. The ground target must be set in advance in the area where the satellite passes, and the image acquisition is greatly affected by the weather and the satellite orbit. If the edge of other ground objects is used, the requirements for the edge shape and imaging quality are high, and it is difficult to find a very good target in many cases. The flat and ideal edge of the ground object, and during the operation of the satellite, due to equipment aging and other influences, the performance of the sensor is constantly changing, so it is ...

AI Technical Summary

Problems solved by technology

The ground target must be set in advance in the area where the satellite passes, and the image acquisition is greatly affected by the weather and the satellite orbit. If the edge of other ground objects is used, the requirements for the edge shape and imaging quality are high, and it is difficult to find a very good target in many cases. The flat and ideal edge of the ground object, and during the operation of the satellite, due to equipment aging and other influences, the performance of the sensor is constantly changing, so it is very important to frequently test the MTF parameters of the satellite in orbit, but at the same time the MTF parameters Testing also becomes very tedious and difficult due to the need to set targets

For example: when the selected target image is not a straight line but a curved line, it is not feasible to extract the MTF parameters by the traditional edge method and obtain a reasonable line extension function.

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