Control circuit of camera illuminated by triangular waves of raised preset levels

Abstract

The invention discloses a control circuit of a camera illuminated by triangular waves of raised preset levels. An LED lighting lamp is driven by electrical signals of the triangular waves or sawtooth waves of the raised preset levels to generate a beam of triangular wave-shaped or sawtooth wave-shaped illumination light to be irradiated to an object to be measured so as to generate reflected light; an image sensor receives the reflected light, and transforms the reflected light into a video signal; a video capture card converts the video signal into a digital image signal; a computer obtains frame images of one or more triangular wave or sawtooth wave cycles of the raised preset levels, and carries out sliding-frame cumulative average on the frame images in time lengths to obtain an image signal with a higher gray scale, and outputs an image. In the process that the image senor collects light signals, the noise level is not changed, but the triangular wave signals used as driving are obviously improved at low levels compared with noises because the preset levels are raised, so that the signal-to-noise ratio of the light signals obtained by the image sensor is improved.

Description

technical field [0001] The invention relates to the field of cameras, in particular to a control circuit of a camera using triangular wave illumination with elevated preset levels. Background technique [0002] Cameras are not limited to personal entertainment, but are also widely used in various fields, such as: security cameras all over the city, these security cameras basically rely on LED lighting. [0003] Compared with the luminous efficiency of LED, the electric light source in the past is not the same, and can save huge energy, but after all, each city may be equipped with hundreds of thousands of security cameras and corresponding lighting LED lights, and its energy consumption is still amazing. [0004] In order to improve the quality of the image, the patent application in the prior art whose publication number is CN 104811596 A and whose publication date is July 29, 2015 uses a triangular wave as an excitation signal to improve the quality of the image. [0005...

AI Technical Summary

Problems solved by technology

[0007] Therefore, when a pure triangular wave is used as the excitation signal, the signal-to-noise ratio of the digital signal obtained in the low-level part of the triangular wave is very low, thus affecting the overall signal-to-noise ratio of the image.

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