A Fast Adaptive Autofocus Method

An automatic focusing and self-adaptive technology, applied in installation, optics, instruments, etc., can solve the problems of focusing failure and time-consuming focusing, and achieve the effect of eliminating the influence of image noise, reducing the probability of focusing failure, and fast and accurate automatic focusing.

Active Publication Date: 2017-07-14
BEIJING INST OF ENVIRONMENTAL FEATURES
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Problems solved by technology

But when the imaging target and imaging conditions are poor, focusing often takes a long time and often fails

Method used

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  • A Fast Adaptive Autofocus Method
  • A Fast Adaptive Autofocus Method
  • A Fast Adaptive Autofocus Method

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Embodiment Construction

[0037] The specific application object of the present invention is an infrared thermal imager automatic focusing system, and its image signal processor hardware platform is constructed by TMS320C6416 DSP produced by TI Company. The fast self-adaptive auto-focusing technology proposed by the present invention is realized by programming in special C language of TMS320C6416 DSP, which is solidified on the image signal processor hardware after compilation, and the DSP automatically loads the program to run after power-on.

[0038] The present invention proposes an improved hill-climbing algorithm combined with an automatic focus algorithm combined with traversal search, the process is as follows image 3 shown. Accurate focusing of the thermal imager is achieved by calculating the gradient of the image; first, the focus area is selected according to the monitoring target, and the gradient is calculated for the image in the focus area at different positions by moving the focus moto...

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Abstract

The invention belongs to the field of photoelectric product application technology, and in particular relates to a fast self-adaptive autofocus method. Accurate focusing of the thermal imager is achieved by calculating the gradient of the image; first, the focus area is selected according to the monitoring target, and the gradient is calculated for the image in the focus area at different positions by moving the focus motor, and by comparing the gradient value, the motor is moved, Until the maximum gradient is obtained, the position of the motor is the clear imaging position of the target. It is mainly used in the automatic focusing system of infrared thermal imaging cameras. It adaptively selects an area with sufficient size in the field of view as the focusing area, so that the scene in this area has obvious edge and texture features. The improved laplace function is used to improve the clarity of the imaging Evaluate the degree, optimize the search strategy, adopt the combination of fixed step size and variable step size, the combination of improved hill climbing method and traversal search, and improve the focusing rate under the premise of ensuring the focusing accuracy, so as to realize the rapid and accurate positioning of the infrared thermal imager. Auto focus.

Description

technical field [0001] The invention belongs to the field of photoelectric product application technology, and in particular relates to a fast self-adaptive autofocus method. Background technique [0002] In the process of image acquisition, whether automatic focusing can obtain a clear image is the first step in image analysis and processing. The traditional manual focusing method mainly relies on human visual inspection and manual adjustment, which is not only cumbersome and time-consuming, but also the adjustment accuracy is greatly affected by human subjectivity. Therefore, it is of great significance to choose a focusing method with good anti-interference, high precision, strong stability and good real-time performance. [0003] Autofocus methods mainly include methods based on distance measurement and methods based on image processing. The intelligent method based on image processing has the advantages of small size, fast speed and high precision, and has broad appli...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G02B7/36
CPCG02B7/36
Inventor 张挺朱敏杨桦杨金宝
Owner BEIJING INST OF ENVIRONMENTAL FEATURES
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