Method, system and terminal equipment for filter speed measurement and focus detection

Abstract

The invention belongs to the technical field of aerial imaging, and provides a method, system and terminal equipment for filtering speed measurement and focus detection, including: imaging the captured scene on a photoelectric detector to obtain the first to Mth captured images; controlling the pre-built space The filter sequentially samples the first row to the Nth row of the captured image to obtain N times of sampling results, and uses the root mean square of the N times of sampling results as the first to Mth filter outputs; select the first The position of the focal plane of the camera corresponding to the maximum filtered output from the filtered output to the Mth filtered output is the best image plane position, so as to realize the focus check of the camera. This method eliminates the sinusoidal change in the SFV signal output by the filter, so that the filter output is not affected by the relative displacement of the image and the filter. When it is applied to the image plane detection of the aerial remote sensing camera, the focus can be detected by imaging with the photodetector The obvious advantages of this method are that no additional focusing mechanism is needed, and the structure is simple.

Description

Technical field [0001] The invention relates to the technical field of aerial imaging, in particular to a method, a system and terminal equipment for filtering, speed measurement and focus detection. technical background [0002] When aerial cameras are imaging in the air, the changes of temperature, atmospheric pressure and photographic distance will cause defocus, which will seriously affect the clarity and resolution of images, especially for long focal length cameras. Auto-focus detection technology has been widely used in ordinary digital cameras, but the reason of defocusing of aerial cameras is different from that of ordinary digital cameras. Therefore, the auto-focus detection method used in ordinary digital cameras is difficult to realize in aerial cameras. In order to obtain high-definition images, it is necessary for the camera to automatically check and focus before taking pictures. In recent years, with the deepening of the research on focusing technology of aerial r...

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

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