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Eye fundus photography control circuit applying triangular wave illumination capable of raising preset level

A technology of preset level and control circuit, applied in applications, ophthalmoscopes, equipment for testing eyes, etc., can solve the problems of low signal-to-noise ratio of digital signals and affect the signal-to-noise ratio of images, and achieves low device and process requirements, The effect of improving the signal-to-noise ratio and improving the quality

Inactive Publication Date: 2017-01-11
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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.

Method used

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  • Eye fundus photography control circuit applying triangular wave illumination capable of raising preset level
  • Eye fundus photography control circuit applying triangular wave illumination capable of raising preset level
  • Eye fundus photography control circuit applying triangular wave illumination capable of raising preset level

Examples

Experimental program
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Effect test

Embodiment 1

[0034] see figure 1 , the fundus photography control circuit using triangular wave illumination with raised preset level, comprising: connecting eyepiece and objective lens 2, semi-transparent and semi-reflective prism 3, illuminating lens group 4, imaging objective lens 5, image sensor 6, LED lighting lamp 7 and Computer 8, wherein, the eyepiece and objective lens 2, half-reflective prism 3, imaging objective lens 5 and image sensor 6 are arranged in sequence, and an illuminating lens group 4 is arranged between the half-reflective prism 3 and the LED lighting lamp 7;

[0035] Among them, the LED lighting lamp 7 is driven by a triangular wave or sawtooth wave electrical signal with a preset level to generate a beam of triangular wave or sawtooth waveform lighting light, and the triangular wave or sawtooth waveform lighting light passes through the lighting lens group 4, transflective and transflective in turn. The prism 3, the eyepiece and the objective lens 2 irradiate the f...

Embodiment 2

[0056] see figure 2 , the fundus photography control circuit that uses the triangular wave illumination that raises the preset level, the difference between the illumination light control circuit and embodiment 1 is that the image sensor 6 is specifically a CCD image sensor 61, and the illumination light control circuit includes: an eyepiece and an objective lens 2, semi-transparent and semi-reflective prism 3, illumination lens group 4, imaging objective lens 5, CCD image sensor 61, LED lighting lamp 7 and computer 8, wherein, connect eyepiece and objective lens 2, semi-transparent and semi-reflective prism 3, imaging objective lens 5 and CCD image sensors 61 are arranged in sequence, and an illuminating lens group 4 is arranged between the half-transparent prism 3 and the LED illuminating lamp 7;

[0057] Among them, the LED lighting lamp 7 is driven by a triangular wave or sawtooth wave electrical signal with a preset level to generate a beam of triangular wave or sawtooth...

Embodiment 3

[0062] see image 3 , the fundus photography control circuit that uses the triangular wave illumination that raises the preset level, the difference between the illumination light control circuit and embodiment 1 is that the image sensor 6 is specifically a CMOS image sensor 62, and the illumination light control circuit includes: an eyepiece and an objective lens 2, semi-transparent and semi-reflective prism 3, illumination lens group 4, imaging objective lens 5, CMOS image sensor 62, LED lighting lamp 7 and computer 8, wherein, connect eyepiece and objective lens 2, semi-transparent and semi-reflective prism 3, imaging objective lens 5 and The CMOS image sensors 62 are arranged in sequence, and an illuminating lens group 4 is arranged between the half-transparent mirror 3 and the LED illuminating lamp 7;

[0063] Among them, the LED lighting lamp 7 is driven by a triangular wave or sawtooth wave electrical signal with a preset level to generate a beam of triangular wave or s...

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Abstract

The invention discloses an eye fundus photography control circuit applying triangular wave illumination capable of raising preset level. According to the control circuit, light reflected back from eye fundi of detected human eyes passes through an eyepiece and objective lens a half-transparent and half-reflecting prism and an imaging lens sequentially to be imaged in an image sensor; the image sensor acquires one or more video images in the period of the triangular wave or sawtooth wave and transmits the video images to a computer, gliding frame accumulative average is performed on the video images within the time length, and an eye fundus image signal with higher definition is obtained; during image acquisition of the image sensor, noise level is not changed, but the triangular wave signal as a drive unit is improved remarkably at the low level part compared with noise due to the fact that the preset level is improved, the signal-to-noise ratio, acquired by the image sensor, of the images is increased at the low level section of the triangular wave signal, and accordingly, the precision of the video images input into the computer is improved.

Description

technical field [0001] The invention relates to the field of fundus photography, in particular to a fundus photography control circuit using triangular wave illumination with elevated preset levels. Background technique [0002] During the fundus examination, it is necessary to observe the retina, optic nerve and macula inside the eye through the pupil. When light hits the eye, the pupil naturally narrows to accommodate the light, which hinders the examination of the fundus. In order to solve this problem, the eyes are generally anesthetized in advance so that the pupils will not change with the change of light. [0003] In practical application, it is found that after the subjects dilate their pupils, the recovery time is relatively long. At this time, if encountering strong light, the human eyes will be very uncomfortable and even damage the retina. Therefore, in recent years, the fundus photography technology without mydriasis has been developed. , this technology uses ...

Claims

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Application Information

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IPC IPC(8): A61B3/12A61B3/14
CPCA61B3/0008A61B3/0025A61B3/12A61B3/14A61B2576/02
Inventor 李刚于悦林凌
Owner TIANJIN UNIV
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