Filtering speed measurement and focus detection method and system and terminal equipment

Abstract

The invention belongs to the technical field of aviation imaging, and provides a filtering speed measurement and focus detection method and system, and terminal equipment, and the method comprises thefollowing steps: enabling a photographed scene to be imaged on a photoelectric detector, and obtaining first to Mth photographed images; controlling a pre-constructed spatial filter to sample the first row to the Nth row of the shot image in sequence to obtain N sampling results, and taking the root mean square of the N sampling results as first to Mth filtering outputs; and selecting the position of the camera focal plane corresponding to the maximum filtering output in the filtering outputs from the first filtering output to the Mth filtering output as the optimal image plane position so asto realize focus detection of the camera. According to the method, sinusoidal variation in SFV signals output by the filter is eliminated, the output of the filter is not affected by images and relative displacement of the filter, when the method is applied to image plane detection of an aerial remote sensing camera, focus detection can be achieved through imaging of a photoelectric detector, anextra focus detection mechanism is not needed, and the structure is simple.

Description

Technical field [0001] The invention relates to the technical field of aerial imaging, in particular to a filtering speed measurement and focus detection method, system and terminal equipment. Background technique [0002] When aerial cameras are imaging in the air, changes in temperature, atmospheric pressure, and camera distance will cause defocusing, which will seriously affect the clarity and resolution of the image, especially for long-focus cameras. Auto-focusing technology has been applied more maturely in ordinary digital cameras, and the reasons for defocusing of aerial cameras are different from ordinary digital cameras. Therefore, the auto-focusing method used in ordinary digital cameras is difficult to realize on aerial cameras. To obtain high-definition images, the camera needs to check and adjust the focus automatically before taking pictures. In recent years, as the research of photodetector's aerial remote sensing camera focusing technology has become more and mo...

AI Technical Summary

Problems solved by technology

In the optical imaging system of aerial remote sensing cameras, the periodic transmission characteristics of spatial filters are simulated by interlaced sampling of images generated by photodetectors. Since spatial filters can be sensitive to higher frequency spatial frequency components, so , when the image is in focus, the spatial filter placed on the image plane of the lens will produce the largest output signal, so that the focus detection of the aerial remote sensing camera can be realized, but because the output signal of the filter will vary with the relative relationship between the image and the filter The displacement changes in a sinusoidal function. The frequency of this sinusoidal function represents the relative moving speed of the image and the filter, which can be used for speed measurement. However, for camera image plane detection, this sinusoidal function change will cause the image itself to contain high frequency components, but the output signal of the filter is very small, and it is impossible to distinguish the position of each image plane, so the use of SFV signals for automatic focus detection of aerial remote sensing cameras is currently not applicable

Images