Passive auto-focusing method and device

An automatic focusing and passive technology, applied in the field of image processing, can solve the problems of slow focusing speed and achieve the effects of increased speed, accurate video automatic focusing, and good subjective visual effects

Active Publication Date: 2014-01-15
ZTE CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a passive automatic focusing method and device to solve the problem of slow focusing speed

Method used

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  • Passive auto-focusing method and device
  • Passive auto-focusing method and device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] This embodiment introduces a passive auto-focus method, such as figure 1 shown, including the following steps 110-160:

[0043] Step 110, obtaining original image data;

[0044] Step 120, performing sharpness calculation to obtain the sharpness value of the original image data;

[0045] Preferably, before calculating the sharpness, in order to obtain a better result, the acquired original image data is firstly subjected to denoising processing.

[0046] Step 130, determine the current effective focus range according to the current zoom value;

[0047] Step 140, judging whether the current position of the lens is within the current effective focus range, if not, then perform step 150, if it is, then perform step 160;

[0048] Step 150, adjust the position of the lens using a large-step coarse focus strategy, and return to step 140, the large-step coarse focus strategy includes: using the first step to move the lens until the current position of the lens is within the cu...

Embodiment 2

[0053] This embodiment introduces the device for realizing the method of Embodiment 1, such as figure 2 As shown, it includes an image acquisition module, a definition calculation module, and an analysis and adjustment module, where:

[0054] The image acquisition module is used to acquire original image data;

[0055] The sharpness calculation module is used for calculating the sharpness to obtain the sharpness value of the original image data;

[0056] The analysis and adjustment module is used to determine the current effective focus range according to the current zoom value. If the current position of the lens is not within the current effective focus range, the large-step coarse focus strategy is used to adjust the lens position until the current position of the lens is within the current effective focus range. Within the effective focus range, adjust the lens position with a small-step fine-tuning strategy; if the current position of the lens is within the current effe...

Embodiment 3

[0064] This embodiment is a concrete description of the method of embodiment 1, as image 3 shown, including the following steps:

[0065] Step 210, obtaining raw image data from the camera;

[0066] Step 220, denoising is carried out to the acquired original image data, and the image data after processing is carried out sharpness calculation, obtains sharpness value;

[0067] For example, use a gradient operator or a method such as contrast to calculate the sharpness.

[0068] The steps of sharpness calculation are here only for example, and may not be performed here, but may be calculated later whenever necessary.

[0069] Step 230, using the zoom value of the current lens, the position of the current lens and the sharpness value of the image to determine the moving direction and the moving step of the lens, and finally obtain the best sharpness value and the best focus position of the lens;

[0070] In the following automatic focusing process, every time the lens positio...

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Abstract

The invention discloses a passive auto-focusing method and a device so as to solve the problem of slow focusing speed. The method provided by the invention comprises the following steps: original image data is acquired; sharpness is calculated to obtain sharpness value of the original image data; current valid focusing range is determined according to current zoom value, the position of a lens is adjusted by a large-step rough-focusing strategy if the current position of the lens is not within the current valid focusing range, and the position of the lens is adjusted by a small-step fine-focusing strategy when the current position of the lens is within the current valid focusing range; and if the current position of the lens is within the current valid focusing range, the position of the lens is adjusted by a small-step fine-focusing strategy. The large-step rough-focusing strategy is as follows: a first-step shift lens is adopted until the current position of the lens is within the current valid focusing range. The small-step fine-focusing strategy is as follows: a step shift lens with step being less than the first step is used until the calculated sharpness value is the best sharpness value.

Description

technical field [0001] The invention relates to the technical field of image processing, in particular to a passive automatic focusing method and device. Background technique [0002] Auto Focus (AF) technology means that the lens automatically adjusts the focus on the object being photographed, so as to obtain the clearest image. This technology has been widely used in video cameras (Video Camera), digital still cameras (Digital Still Camera), mobile phones (Mobile Phone) and other imaging products. [0003] There are mainly two types of video auto-focus technologies for cameras: active focus and passive focus. Active focusing measures the distance and orientation of the target by receiving actively emitted light waves or reflected waves of sound waves, and then controls the automatic focus through the computer. Passive focusing collects a series of images through the lens and CCD / CMOS sensor, processes each frame of image in real time, judges whether it is in focus, and ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02B7/36G03B13/36H04N5/232
Inventor 杜昕欧阳典勇贾少华任江涛
Owner ZTE CORP
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