A laboratory measurement device and method for the point spread function of a spaceborne push-broom camera

Abstract

The invention discloses a laboratory measurement device and method for satellite-borne push-broom camera point spread functions. The device comprises a light source system, a target, a collimator, a TDI CCD camera and an image collecting system, wherein the target is arranged on a focal plane of the collimator, the collimator and the optical axis of the TDI CCD camera are coaxial, the target is illuminated by uniform light generated by the light source system, by means of the collimator and the TDI CCD camera, an image is formed on the focal plane of the TDI CCD camera, the image of the target is formed, and frame collecting and processing are carried out on the imaging result through the image collecting system. Phase position alignment is taken into consideration in target design, experiment methods and data processing, PSF measurement precision can be guaranteed, and the device and method can be used for measurement of the PSFs in multiple integral numbers and fill in the blank of a PSF measurement method of a satellite-borne TDI CCD camera.

Description

technical field [0001] The invention belongs to the technical field of aerospace optical remote sensing, and relates to a laboratory measuring device and method for point spread function of a spaceborne push-broom camera, in particular to target design, experimental method and experimental data processing method. Background technique [0002] In the ideal state of the optical system, the light energy emitted by a point in the object space is also concentrated on a point in the image space, but when the actual optical system is imaging, due to the influence of diffraction, aberration and other processes, the light emitted by a point in the object space is concentrated in the image space. The space is distributed in a certain area, and its distribution curve is called the point spread function PSF. The modulation transfer function (MTF) is an important indicator for objectively evaluating the imaging quality of the optical system. At present, in order to quantitatively evaluat...

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Problems solved by technology

At present, the commonly used MTF test methods include the following three. The first one is the contrast rectangular target method, which can be used for the MTF test of area array or push-broom cameras. A high-contrast rectangular target test method is given in the article "Research on MTF Test Technology of Remote Sensors". This method is affected by the sampling phase and has a large test error. The low-frequency target method in this article is not sensitive to phase, but is easily affected by noise; The second is the oblique edge target method, which is only suitable for the MTF ground test of the area array CCD. In 2006, Zhang Xiaohong et al. published the "Area Array CCD Camera" at the 19th Academic Conference of the Space Detection Professional Committee of the Chinese Society for Space Science. The article "MTF Test Technology" introduces the experimental method and data processing algorithm. This processing method increases the sampling points, but cannot accurately locate the initial phase; the third method is the point source or slit test method, which is currently only used for the MTF of the area array CCD. Wu Haiping's master's degree thesis "Research on MTF Testing Technology of Point Source Method" introduced the point source method experimental system in detail. The experimental method is to image the point light source. Accurate precision requirements are high, and it is necessary to ensure that the point light source is imaged within one pixel

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