KR101677394B1 - Image acquiring system and image acquiring method therefor - Google Patents

Image acquiring system and image acquiring method therefor Download PDF

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Publication number
KR101677394B1
KR101677394B1 KR1020150142599A KR20150142599A KR101677394B1 KR 101677394 B1 KR101677394 B1 KR 101677394B1 KR 1020150142599 A KR1020150142599 A KR 1020150142599A KR 20150142599 A KR20150142599 A KR 20150142599A KR 101677394 B1 KR101677394 B1 KR 101677394B1
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KR
South Korea
Prior art keywords
image
shutter time
motion
interest
region
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KR1020150142599A
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Korean (ko)
Inventor
이규홍
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주식회사 아이닉스
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    • H04N5/225—
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
    • H04N19/167—Position within a video image, e.g. region of interest [ROI]
    • H04N5/2254—
    • H04N5/2353—

Abstract

An image acquiring system comprises: an image photographing unit for photographing an image; an image synthesizing unit for synthesizing a first image outside a preset region of interest and a second image inside the region of interest by using the image photographed by the image photographing unit; a movement detecting unit for detecting a movement inside the region of interest; and a control unit for controlling a shutter time of image photographing by the image photographing unit. The image acquiring system uses a wide dynamic range (WDR) technology for setting the region of interest, and maximizing a contrast of the image by differently controlling an exposure time of the inside and the outside of the region of interest.

Description

TECHNICAL FIELD [0001] The present invention relates to an image acquisition system,

The present invention relates to an image acquisition system and an image acquisition method thereof, and more particularly, to an image acquisition system and an image acquisition method using the WDR (Wide Dynamic Range) technique that maximizes the contrast of images by setting an area of interest and controlling exposure times within and / An image acquiring system and an image acquiring method thereof.

Figure 1 illustrates a general WDR scheme.

A typical WDR (Wide Dynamic Range) technique is a technique for acquiring a long shutter time image and a short image for the entire image area, and then synthesizing all two images to output a backlight corrected image.

In other words, the WDR function is used to correct the backlight caused by strong light during daytime. It determines whether the current situation is night or day, and automatically turns off the WDR function at night, Can be corrected.

However, if a long image and a short image having the same shutter time are collectively acquired for all the regions in a state where the degree of backlight differs from that of the entire image region, and then the entire two images are combined, A motion ghost phenomenon may occur.

Korean Patent No. 10-1501678: Apparatus and method for photographing a vehicle using exposure control (March 15, 2015)

An object of the present invention is to solve the technical problems as described above, and to provide a method and apparatus for adjusting the exposure time within and outside the area of interest by using WDR (Wide Dynamic Range) And an object thereof is to provide an image acquisition system and an image acquisition method thereof.

An image acquisition system of the present invention includes: an image capturing unit for capturing an image; An image synthesizing unit synthesizing a first image outside a predetermined region of interest and a second image within the region of interest using the image photographed by the image capturing unit; A motion detector for detecting motion within the ROI; And a control unit for controlling the shutter time of the image taking by the image taking unit.

Specifically, the image capturing unit may be configured to capture the image by the first shutter time; And photographing the image by the target shutter time set using the second shutter time or the degree of motion within the ROI detected by the motion detecting unit.

In addition, the image synthesizing unit may include a first image outside the region of interest, of the image photographed by the first shutter time; And a second image inside the region of interest of the image photographed by the second shutter time or the target shutter time set using the degree of motion within the ROI detected by the motion detection unit . Here, the first shutter time may be longer than the second shutter time.

The control unit may control the image capturing unit to capture an image by the second shutter time when the motion detecting unit does not detect a motion within the area of interest. The control unit may control the image capturing unit to capture an image at a target shutter time set using the degree of motion within the region of interest, when motion within the region of interest is detected by the motion detector desirable.

An image acquisition method of the present invention comprises the steps of: (a) detecting motion within a region of interest; (b) capturing an image by a first shutter time; (c) capturing an image with a target shutter time set using a second shutter time or a degree of motion within the ROI detected in the step (a); And (d) a target shutter time which is set using a first image outside the region of interest and a second shutter time of the image photographed by the first shutter time or a degree of motion within the region of interest detected by the motion detection unit, And synthesizing a second image within the ROI among the images captured by the ROI. Here, the first shutter time is longer than the second shutter time.

More specifically, in the step (c), when motion in the ROI is not detected in the step (a), the image is captured by the second shutter time. The step (c) may further include capturing an image at a target shutter time, which is set using the degree of motion within the region of interest, when motion within the region of interest is detected in the step (a) do.

According to the image acquiring system and the image acquiring method of the present invention, it is possible to maximize the contrast of images by setting the region of interest and controlling the exposure time in and out of the region of interest differently.

1 is an explanatory diagram of a general WDR technique.
2 is a configuration diagram of an image acquisition system according to an embodiment of the present invention;
3 is a timing diagram of an image acquisition system according to a preferred embodiment of the present invention;
4 is an explanatory diagram of a video synthesizing method by the video synthesizing unit of the present invention.
Fig. 5 is an exemplary view of a video in the case where no motion within the region of interest is detected; Fig.
Fig. 6 is an exemplary view showing a case where a motion within a region of interest is detected; Fig.
FIG. 7 shows a general scene in which a region of interest is not set and a final image of the present invention.
8 is a photograph of a gray-scale chart shot through a backlight.
9 is an explanatory diagram of a motion ghost phenomenon.

Hereinafter, an image acquisition system and an image acquisition method according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

It should be understood that the following embodiments of the present invention are only for embodying the present invention and do not limit or limit the scope of the present invention. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

The image acquiring system 100 and the image acquiring method of the present invention can be applied to an image acquiring system 100 and a method of acquiring an image of a subject by setting a position and a size of a region of interest Wide Dynamic Range) application technology. In the present invention, it is preferable that the region of interest is located in a region that is saturated due to light and is not visible. Inside the region of interest, an image that is not saturated by controlling a short exposure time (i.e., shutter time) Image control), and the image outside the region of interest at the next time is controlled to a long exposure time to acquire an image in which the shadow area is secured (Long Image control). The image acquisition system 100 and the image acquisition method of the present invention combine images obtained in two areas in which exposure correction is completed, and output final images.

2 is a block diagram of an image acquisition system 100 according to an embodiment of the present invention.

2, the image acquisition system 100 according to an exemplary embodiment of the present invention includes an image capturing unit 110, an image synthesizing unit 120, a motion detecting unit 130, and a controller 140 .

The image capturing unit 110 serves to capture an image.

The image synthesizing unit 120 synthesizes a first image outside the predetermined region of interest and a second image within the region of interest using the image photographed by the image capturing unit 110. Here, it is preferable that the region of interest is set in advance on the window representing the entire image region using a circle, an ellipse, or various polygons by the user.

The motion detection unit 130 serves to detect a motion within a region of interest.

Detection of motion can be implemented by various conventional techniques. Typically, motion detection is classified into a method of extracting information of a moving object and a method of inferring shape information of a moving object by analyzing a difference image. A method of extracting information of a moving object is a method of extracting information about a motion object by sensing a group of points or regions having a similar velocity vector. The difference image technique is a method of inferring the movement form for a moving object by analyzing difference images constructed by the difference in brightness between the (i-1) -th and i-th images adjacent to each other.

The control unit 140 controls the shutter time of the image capturing by the image capturing unit 110.

FIG. 3 shows a timing diagram of an image acquisition system 100 in accordance with a preferred embodiment of the present invention. The image acquisition system 100 according to the preferred embodiment of the present invention will be described in detail with reference to FIG.

The image capturing unit 110 captures an image at the first shutter time t1 and is set using the second shutter time t2 or the degree of motion within the region of interest detected by the motion detecting unit 130 The image is photographed by the target shutter time tg alternately. For example, when the motion within the ROI detected by the motion detector 130 is detected, the target shutter time tg is determined by the range of the lower limit shutter time at the preset upper limit shutter time, The target shutter time tg may be set to be longer when the movement within the ROI detected by the camera is continuously detected to determine a more accurate movement.

4 is an explanatory diagram of an image synthesizing method by the image synthesizing unit 120 of the present invention.

4, the image synthesizing unit 120 generates a first image and a second shutter time t2 of the image photographed by the first shutter time t1 outside the region of interest or the first shutter time t2 or the motion detector 130, The second image within the ROI is synthesized with the target shutter time tg set by using the degree of motion within the ROI detected by the ROI detection unit.

At this time, the target shutter time tg set by using the first shutter time t1 or the second shutter time t2 or the degree of motion within the ROI detected by the motion detector 130 It is preferable that one of the images photographed by the first camera is stored in a buffer so that it can be used for synthesis with another image processed later.

In the image acquisition system 100 of the present invention, it is desirable that the region of interest is saturated in light and is located in a region (High Light) that is not visible. Therefore, the inside of the region of interest is controlled by a short exposure time It is preferable to take an image in which the shadow area is ensured by taking an image that is not a shadow area and controlling the area outside the area of interest to be a long exposure time in the next time. That is, the first shutter time t1 is preferably longer than the second shutter time t2.

The control unit 140 controls the image capturing unit 110 to capture an image at the second shutter time t2 when the motion detector 130 detects no motion within the region of interest. In addition, when motion within the ROI is detected by the motion detector 130, the controller 140 controls the imaging unit 130 to photograph the image at a target shutter time tg set using the degree of motion within the ROI, (110).

5 is an illustration of an image in the case where no motion within the ROI is detected. (a) shows an image taken at a first shutter time t1, (b) shows an image taken at a second shutter time t2, and (c) shows a final synthesized image.

Fig. 6 is an exemplary view of an image in the case where motion within the ROI is detected. Fig.

(a) shows the final composite image using the image photographed by the second shutter time t2 without considering the motion inside the region of interest, (b) shows the target shutter time tg ), Respectively. ≪ / RTI > It can be seen that the final composite image using the image photographed by the target shutter time tg is superior in contrast to the object expression in consideration of the movement within the region of interest.

The image acquisition system 100 of the present invention can divide an area so as to have different exposure correction for one image and can adjust attributes of the polygonal area of interest through a simple operation of the user. Inside and outside of the set area of interest, images with different exposure times are replaced with images with proper exposure compensation, instead of the usual fusion / tone mapping method of WDR. There is no temporal motion ghost phenomenon as shown in FIG.

Specifically, the differentiated functions of the image acquisition system 100 of the present invention will be summarized as follows.

(1) Exposure control by area: Backlight compensation area setting

7 (a) and 7 (b) respectively show a general scene in which a region of interest is not set and a final image of the present invention.

The image acquisition system 100 of the present invention has n interest areas that can be adjusted by a user for an area requiring short image control and is capable of directly confirming a scene through OSD (On Screen Display) Area can be located. Attributes that can control the area of interest include the use, location, and size of the area.

(2) Improved image contrast

8 is a photograph of a gradation chart projected through a backlight.

(a) shows an image according to a general WDR technique without setting a region of interest, and (b) shows an image according to the present invention. The area of interest is a scene placed on a gradation chart illuminated through a backlight.

In comparison with the histogram, it can be seen that the present invention has better contrast in the long and short regions than the general WDR function. In general WDR, the brightness level that can be expressed in Tone Mapping process is compressed when synthesizing Long Image and Short Image. On the other hand, the present invention replaces an image of a region with reference to an image obtained at different exposure times for each region, and since there is no tone loss since the Tone Mapping process is not performed, the contrast is relatively good.

(3) motion ghost (Motion Ghost) phenomenon

9 is an explanatory diagram of the motion ghost phenomenon. (a) shows an image according to a general WDR technique without setting a region of interest, and (b) shows an image according to the present invention.

WDR has a time difference in taking a long / short image. In the case of a general WDR, both images are appropriately synthesized. On the other hand, since the present invention replaces only the images inside and outside the ROI by referring to the acquired Long / Short Image, the motion ghost phenomenon occurs with respect to the temporally moving object Do not.

(4) Backlight compensation function for daytime use only

The WDR function is used to correct backlight caused by strong light during the day. Therefore, the image acquisition system 100 of the present invention preferably determines whether the current situation is night or day, and automatically turns off the WDR function at night to perform exposure correction so as to obtain a more effective image.

It should be understood that the image acquisition method according to the preferred embodiment of the present invention includes all the features of the image acquisition system 100 of the present invention because the image acquisition system 100 of the present invention is used.

The method of acquiring an image according to the preferred embodiment of the present invention includes the steps of detecting motion within a region of interest (S10), capturing an image at a first shutter time t1 (S20) (step S30) of photographing an image at a target shutter time tg set using the degree of motion of the inside of the ROI detected in step S10.

More specifically, in step S30, if motion within the ROI is not detected in step S10, the image is captured by the second shutter time t2 (S31). In step S30, when motion in the ROI is detected in step S10, the image is captured using the target shutter time tg set using the degree of motion inside the ROI (S32).

In addition, in the image acquisition method of the present invention, the first image outside the ROI and the second shutter time t2 of the image photographed by the first shutter time t1 or the degree of motion within the ROI in step S10 (S40) of synthesizing a second image inside the ROI among the images photographed by the target shutter time tg set by the target shutter time tg.

The first shutter time t1 is longer than the second shutter time t2.

The surveillance security camera is installed in a fixed position, and the majority of viewers are looking at a scene. Therefore, factors that greatly affect the image exposure correction appear at the same position. Backlighting due to strong light causes deterioration of image quality, and saturated or invisible images can be a fatal problem in surveillance security cameras. The WDR function serves as a wide-area backlight compensation to prevent degradation of image quality due to these factors. However, due to the problem of loss of grayscale appearing in the process of synthesizing images, a more unnatural image is output.

The image acquisition system 100 and the image acquisition method of the present invention are exposure correction application technologies for each backlight region that can correct a specific region by directly setting a region of interest that is a cause of image quality degradation. So that it is possible to see a contrast-free image having no grayscale loss relatively. In addition, an appropriate exposure compensation technique targeting an object detected through motion detection within the set region of interest may have a characteristic of Local AE (Auto Exposure).

As described above, according to the image capturing system 100 and the image capturing method of the present invention, it is possible to maximize the contrast of an image by setting an area of interest and controlling exposure times in and out of the area of interest differently.

100: Image acquisition system
110: image capturing unit 120:
130: Motion detection unit 140:

Claims (11)

An image capturing unit for capturing an image;
An image synthesizing unit synthesizing a first image outside a predetermined region of interest and a second image within the region of interest using the image photographed by the image capturing unit;
A motion detector for detecting motion within the ROI; And
And a control unit for controlling the shutter time of the image capturing by the image capturing unit,
Wherein the image capturing unit captures an image by a first shutter time; And photographing the image by the target shutter time set using the second shutter time or the degree of motion within the ROI detected by the motion detecting unit.
Wherein the image combining unit comprises: a first image outside the region of interest of the image photographed by the first shutter time; And a second image inside the region of interest, the image being photographed by a second shutter time or a target shutter time set using the degree of motion within the ROI detected by the motion detection unit ,
Wherein the first shutter time is longer than the second shutter time,
Wherein the control unit controls the image capturing unit to capture an image by the second shutter time when motion within the area of interest is not detected by the motion detector,
Wherein the control unit controls the image capturing unit to capture an image at a target shutter time set using the degree of motion within the area of interest when motion within the area of interest is detected by the motion detection unit Image acquisition system. delete delete delete delete delete (a) detecting movement within a region of interest;
(b) capturing an image by a first shutter time;
(c) capturing an image with a target shutter time set using a second shutter time or a degree of motion within the ROI detected in the step (a); And
(d) a target shutter time which is set using a first image outside the region of interest and a second shutter time of the image photographed by the first shutter time or a degree of motion within the region of interest detected by the motion detector And synthesizing a second image within the ROI among the ROI images,
Wherein the first shutter time is longer than the second shutter time,
Wherein, in the step (c), when motion in the ROI is not detected in the step (a), the image is captured by the second shutter time,
Wherein, in the step (c), when motion in the ROI is detected in the step (a), the image is captured using a target shutter time set using the degree of motion within the ROI Acquisition method. delete delete delete delete
KR1020150142599A 2015-10-13 2015-10-13 Image acquiring system and image acquiring method therefor KR101677394B1 (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20140111858A (en) * 2013-03-12 2014-09-22 삼성테크윈 주식회사 Apparatus and method for processing image
KR101501678B1 (en) 2014-03-28 2015-03-12 재단법인 다차원 스마트 아이티 융합시스템 연구단 Image Picturing Apparatus for Vehicle using Controlling Exposure and Method thereof

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR20140111858A (en) * 2013-03-12 2014-09-22 삼성테크윈 주식회사 Apparatus and method for processing image
KR101501678B1 (en) 2014-03-28 2015-03-12 재단법인 다차원 스마트 아이티 융합시스템 연구단 Image Picturing Apparatus for Vehicle using Controlling Exposure and Method thereof

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