# US 2014/0192203 A1 · System and method for focusing an electronic imaging system

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- Number: US 2014/0192203 A1
- Document ID: US20140192203A1
- Status: Published application
- Kind: A1
- Application number: 14/239,544
- Filed: 2012-02-02
- Published: 2014-07-10
- Earliest claimed: 2012-02-02
- Assignees: Aselsan Elektronik Sanayi Ve Ticaret Anonim Sirketi
- Inventors: Emre Turgay
- Web page: https://patentgrep.com/patent/US20140192203A1

## CPC

- H04N 23/673: {based on contrast or high frequency components of image signals, e.g. hill climbing method}
- H04N 23/23: from thermal infrared radiation
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

The present invention relates to the field of image processing and methodologies to passively focus an image automatically, using the electronic sensor signal. The method comprises the steps of; receiving a pixel image, generating at least two histograms of the received image using at least two different frequency components, finding widths of acquired histograms and storing them as a focus measure, finding the difference between last received frame's highest frequency component histogram width and at least one previously received frame's histogram width corresponding to the same component, is there a meaningful difference?, and using the difference to determine the focus direction signal. The system comprises; an image sensor to acquire an electronic pixel image; an image processing unit configured to receive an image and implement the method using this image and output a focus direction signal found by the method; and a memory unit configured to store image histogram widths.

## Claims

### Claim 1

A method for focusing an electronic imaging system, the method comprising the steps of:
receiving a pixel image;
generating at least two histograms of at least one region of the pixel image using at least two different frequency components;
finding widths of acquired the histograms and storing them as a focus measure;
finding a difference between last received frame's highest frequency component histogram width which is not previously taken into account, and at least one previously received frame's histogram width corresponding to the same frequency component;
determining whether there is a meaningful difference; and
determining a focus direction signal using the meaningful difference.

### Claim 2 (depends on 1)

The method for focusing an electronic imaging system according to claim 1, wherein one of the frequency components used in order to obtain the histograms is a high frequency component, and the other one is a lower frequency component than the high frequency component.

### Claim 3 (depends on 2)

The method for focusing an electronic imaging system according to claim 2, wherein the meaningful difference is a difference other than zero.

### Claim 4 (depends on 2)

The method for focusing an electronic imaging system according to claim 2, wherein the histograms with the lower frequency component are differentiated if there is no meaningful difference.

### Claim 5

A system for focusing an electronic imaging system, comprising:
at least one image sensor which is capable of acquiring at least one electronic pixel image;
at least one image processing unit which is capable of:
receiving at least one image from the image sensor,
generating at least two histograms in at least one region of the image by using at least two frequency components,
finding the histogram widths and store them as focus measure,
finding a difference between the highest frequency component histogram width of the last received frame which is not previously taken into account and the previously received frame's histogram width corresponding to the same frequency component,
questioning the difference between the two histogram widths and determining a focus direction signal according to the result of this query, and
transmitting the determined focus direction signal to a lens drive mechanism;
at least one memory unit which is capable of connecting to a image processing unit and storing the image histogram widths in order to determine the focus direction signal output for focusing an electronic imaging system.