Large-field-angle detection image acquisition method for electronic white board and device

Abstract

The invention discloses a large-field-angle detection image acquisition method for an electronic white board. The large-field-angle detection image acquisition method includes following steps: a, forming a small-field-angle camera by long-focus lenses and an image sensor; b, placing convex lenses or concave lenses in front of the lenses of the camera by certain distances, and leading each convex lens or concave lens to be located in a view finding range of the camera; and c, selecting the appropriate shape parameters of the convex lenses or concave lenses, adjusting the directions and the angles of the camera and the convex lenses or concave lenses, and leading a space with the shot white board space to be imaged on the image sensor of the camera by the aid of reflection of the convex lenses or concave lenses. Large-field-angle image acquisition is realized by the small-field-angle camera, and brightness decay of an edge is avoided; and the shapes of the surfaces of the convex lenses or concave lenses are properly designed, low distortion can be realized, the problems of keystoning and the like are eliminated, images can be properly stretched, so that pixel utilization rate of the camera is improved, and finally resolution ratio of a system is finally increased.

Description

technical field [0001] The invention relates to an image acquisition method and device in an electronic whiteboard system using a real-time image detection method for pen positioning, in particular to an image acquisition method and a corresponding electronic whiteboard device in the case of a large viewing angle. Background technique [0002] In the current electronic whiteboard technology, the use of image detection to realize handwriting positioning and tracking is one of the mainstream technologies. There is a lot of room for development of such products. The electronic whiteboard technical solution using real-time image detection for pen positioning is involved in a large number of patent documents, such as patent number ZL011080477, invention patent publication number CN1305143A, and the name "system and method for computer coordinate and control information input" The Chinese invention patent, and the Chinese invention patent application with the patent publication n...

AI Technical Summary

Problems solved by technology

[0004] At present, such products are already in use, but there are the following problems: 1. The edge attenuation of the image is serious, resulting in a decrease in edge sensitivity, and increasing the overall sensitivity leads to a decrease in anti-interference ability

[0005] 2. The edge of the image is distorted greatly, causing the resolution of the edge to drop rapidly, resulting in a decrease in the overall resolution of the whiteboard

[0006] 3. Generally, this type of lens needs to be composed of multiple lenses, which is costly and bulky. The typical case is a fisheye lens

[0007] 4. According to the principle of physical optics, the filtering characteristics of multilayer interference filters change with the incident angle of light. In order to ensure the transmission of light at different angles, the width of the light transmission window of the filter must be increased, which results in the anti-interference ability of the system. decline

For this reason, in the prior art, it is theoretically impossible to achieve high-performance bandpass filtering

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