A Fast Search Method for Infrared Auto Focus

A technology of autofocus and search method, which is applied in the field of infrared autofocus fast search, and can solve problems such as tracking system not working properly, missing targets, and violent

Active Publication Date: 2021-12-31
SHANGHAI INST OF TECHNICAL PHYSICS - CHINESE ACAD OF SCI
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Problems solved by technology

[0002] With the further development of economy and science and technology, the requirements for infrared detection technology are also constantly increasing. The focal length of infrared telescopes is getting longer, the aperture is constantly expanding, and the imaging quality and the ability to detect and track targets are also constantly improving. The problem is that the focus range is wider, the depth of field is shorter, and the blur due to out of focus is more severe
The prerequisite for the detection and tracking of the target by the detection system is to obtain a clear target image. During the process of tracking the target, the relative position and distance between the target and the detection system may be constantly changing. Focusing operation, the image of the target by the detection system may be severely blurred, making the tracking system not work properly or even losing the target

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  • A Fast Search Method for Infrared Auto Focus
  • A Fast Search Method for Infrared Auto Focus
  • A Fast Search Method for Infrared Auto Focus

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Embodiment Construction

[0027] Below in conjunction with accompanying drawing and example, the present invention is described in detail:

[0028] 1. Calculate image sharpness

[0029] The TenenGrad function value uses the Sobel operator to calculate the gradient value in the horizontal direction and the vertical direction, and uses the square operation to enlarge the gradient of the image edge. The evaluation function f(I) is defined as the sum of the squares of the gradient, T is introduced to adjust the sensitivity of the evaluation function, and the expression is formula (1).

[0030] 2. Automatic search algorithm

[0031] ① Initialize momentum m 1 =0,m 2 =0 and acceleration a=0, randomly select the stepping direction d of the focus motor as forward or reverse, and calculate the image sharpness value f before the first focus 0 , such as formula (1), set the basic step size of auto focus as s basic , for the first focusing. Each time the image definition value is calculated, it means that the...

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Abstract

The invention discloses a fast search method for infrared automatic focus. The search algorithm adopts a hill-climbing method with a variable step size, and uses the method of finding the median of the image sharpness multiple times to ensure the accuracy of the sharpness evaluation. The method reduces the instability in the focusing process and reduces the number of steps required for the rough focusing process. The invention effectively solves the problems of inaccurate calculation of image definition, high auto-focus failure rate and slow focusing speed on the infrared telescope by the traditional auto-focus algorithm, and realizes fast and accurate auto-focus on the infrared telescope.

Description

technical field [0001] The invention belongs to the technical field of infrared detection and imaging, and in particular relates to an infrared automatic focusing fast search method, which is applicable to the field of target detection and tracking. Background technique [0002] With the further development of economy and science and technology, the requirements for infrared detection technology are also constantly increasing. The focal length of infrared telescopes is getting longer, the aperture is constantly expanding, and the imaging quality and the ability to detect and track targets are also constantly improving. The problem is that the focus range is wider, the depth of field is shorter, and the blur caused by out-of-focus is more severe. The prerequisite for the detection and tracking of the target by the detection system is to obtain a clear target image. During the process of tracking the target, the relative position and distance between the target and the detecti...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G02B7/36G02B7/38
CPCG02B7/36G02B7/38
Inventor 杨鹏博李洁崔文楠张涛
Owner SHANGHAI INST OF TECHNICAL PHYSICS - CHINESE ACAD OF SCI
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