# US 2014/0153839 A1 · Apparatus and method for calculating flicker-evaluation value

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- Number: US 2014/0153839 A1
- Document ID: US20140153839A1
- Status: Published application
- Kind: A1
- Application number: 14/080,894
- Filed: 2013-11-15
- Published: 2014-06-05
- Earliest claimed: 2012-12-04
- Assignees: Samsung Techwin Co., Ltd.
- Applicants: Samsung Techwin Co., Ltd.
- Inventors: Takeru TSUZUKI
- Web page: https://patentgrep.com/patent/US20140153839A1

## CPC

- H04N 23/745: Detection of flicker frequency or suppression of flicker wherein the flicker is caused by illumination, e.g. due to fluorescent tube illumination or pulsed LED illumination
- H04N 23/741: by increasing the dynamic range of the image compared to the dynamic range of the electronic image sensors
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

An apparatus and a method for calculating a flicker-evaluation value through a wide dynamic range (WDR) system. The apparatus includes: a first calculator configured to calculate a first difference between a pixel value of a long exposure image of a current frame and a pixel value of a long exposure image of a previous frame; an average calculator configured to calculate an average of the pixel value of the long exposure image of the current frame and the pixel value of the long exposure image of the previous frame; a second calculator configured to calculate a second difference between a pixel value of a short exposure image of the current frame and the average calculated by the average calculator; and a flicker-evaluation value calculator configured to calculate a flicker-evaluation value which indicates a flicker strength using the first difference and the second difference.

## Claims

### Claim 1

An apparatus for calculating a flicker-evaluation value, the apparatus comprising:
a first calculator configured to calculate a first difference between a pixel value of a long exposure image of a current frame and a pixel value of a long exposure image of a previous frame;
an average calculator configured to calculate an average of the pixel value of the long exposure image of the current frame and the pixel value of the long exposure image of the previous frame;
a second calculator configured to calculate a second difference between a pixel value of a short exposure image of the current frame and the average calculated by the average calculator; and
a flicker-evaluation value calculator configured to calculate a flicker-evaluation value which indicates a flicker strength using the first difference and the second difference.

### Claim 2 (depends on 1)

The apparatus of claim 1, further comprising:
a mixing ratio controller configured to control a mixing ratio of the long exposure image of the current frame to the short exposure image of the current frame using the flicker-evaluation value.

### Claim 3 (depends on 2)

The apparatus of claim 2, further comprising:
a synthesizer configured to synthesize the long exposure image of the current frame and the short exposure image of the current frame according to the mixing ratio controlled by the mixing ratio controller.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein the flicker-evaluation value calculator calculates the flicker-evaluation value to be inversely proportional to the first difference.

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein the flicker-evaluation value calculator calculates the flicker-evaluation value to be proportional to the second difference.

### Claim 6 (depends on 2)

The apparatus of claim 2, wherein the mixing ratio controller controls the mixing ratio of the long exposure image of the current frame to the short exposure image of the current frame to be proportional to the flicker-evaluation value.

### Claim 7

A method of calculating a flicker-evaluation value, the method comprising:
calculating a first difference between a pixel value of a long exposure image of a current frame and a long exposure image of a previous frame;
calculating an average of the pixel value of the long exposure image of the current frame and the pixel value of the long exposure image of the previous frame;
calculating a second difference between a pixel value of a short exposure image of the current frame and the calculated average; and
calculating a flicker-evaluation value which indicates a flicker strength through the first difference and the second difference.

### Claim 8 (depends on 7)

The method of claim 7, further comprising controlling a mixing ratio of the long exposure image of the current frame to the short exposure image of the current frame using the flicker-evaluation value.

### Claim 9 (depends on 8)

The method of claim 8, further comprising synthesizing the long exposure image of the current frame and the short exposure image of the current frame according to the mixing ratio controlled.

### Claim 10 (depends on 7)

The method of claim 7, wherein the flicker-evaluation value is calculated to be inversely proportional to the first difference.

### Claim 11 (depends on 7)

The method of claim 7, wherein the flicker-evaluation value is calculated to be proportional to the second difference.

### Claim 12 (depends on 8)

The method of claim 8, wherein the mixing ratio of the long exposure image of the current frame to the short exposure image of the current frame is controlled to be proportional to the flicker-evaluation value.