KR100853734B1 - A method for processing a image signal, a method for generating a event and digital video recorder using the methods - Google Patents

Abstract

An image signal processing method, an event generating method, and a DVR detecting a luminance difference for implementing the methods are provided to check whether an image is normally projected to a camera by using an image signal received from the camera, and process and store the image in consideration of the luminance of the image, thereby improving the quality of the stored image. A DVR(Digital Video Recorder)(100) detecting a luminance difference includes a reference information setting unit(110), an encoder, and an interface circuit(150). The reference information setting unit sets a DNN(Day & Night) function for discriminating day and night and a luminance change detecting function for detecting a change of luminance. The encoder includes an image signal processing unit(131), a luminance calculating unit(133), a luminance comparing unit(136), a color filter unit(139), and an event generating unit(140). The image signal processing unit extracts color information and luminance information included into an image signal. The luminance calculating unit calculates the average luminance value of each frame from the luminance information, and calculates a difference value between the average luminance value of a current frame and the average luminance value of a previous frame. The luminance comparing unit compares the average luminance value of the each frame with a first setting luminance value and compares the difference value with a second setting luminance value. The color filter unit outputs the color information and the luminance information if the average luminance value of each frame is greater than the first setting luminance value, and outputs only the luminance information if the average luminance value of each frame is smaller than the first setting luminance value. The event generating unit generates an event if the average luminance value of each frame is smaller than the first setting luminance value or the average luminance difference value is greater than the second setting luminance value. The interface circuit processes the output of the encoder.

Description

A method for processing a image signal, a method for generating a event and Digital Video Recorder using the methods}

1 is a block diagram of a DVR for detecting a luminance difference according to the present invention.

2 is a signal flow diagram illustrating a video signal processing method according to the present invention.

3 is a signal flow diagram illustrating a method of generating an event signal according to the present invention.

The present invention relates to a DVR, and more particularly, to a DVR for detecting a difference in luminance and processing and storing an image signal according to a detection result.

When the camera is equipped with an intensity of brightness sensor, an operation such as controlling the lens operation, correcting an image, and adding an illumination (flash) is performed using the brightness information detected by the brightness sensor. In general, since the luminance sensor is expensive, it is generally mounted on an expensive camera. Therefore, when the brightness sensor is mounted on a CCTV (Closed Cable Television) camera, excessive cost is incurred, and there is an inconvenience in that the brightness detection must be changed according to the darkness or brightness of the place where it is installed.

In the case of a conventional DVR (Digital Video Recorder), the input data is stored without processing. Cameras without a brightness sensor, such as CCTV, operate with a standard level of brightness. Therefore, a video signal taken without sufficient brightness, a video signal taken in bright conditions, or a video signal taken in dark conditions is used. In the case of storing in a conventional DVR, the quality of the playback picture becomes considerably worse.

In addition, when no image is input to the lens of the camera, when the same image is continuously input, when a particularly strong image signal that is difficult to occur in a normal situation is input, or when distorting the image signal to be actually input, such as smoke, When an image signal output from the camera is input to a conventional DVR, abnormal signals are stored.

The technical problem to be achieved by the present invention includes a DNN (Day & Night) function and a brightness change detection function, and determines whether the video signal input from the camera is normal, and processing the video signal according to the determination result An object of the present invention is to provide a DVR for detecting a luminance difference to be stored.

Another technical problem to be solved by the present invention is to process image data output from a camera according to a set value, determine whether a video signal input from the camera is normal or not, and generate an image signal according to the determination result. To provide a processing method.

The DVR for detecting the difference in luminance according to one aspect of the present invention for achieving the above technical problem includes a reference information setting unit, an encoder and an interface circuit. The reference information setting unit sets a DNN (Day & Night) function for distinguishing day and night and a luminance change detection function for detecting a luminance change. The encoder calculates an average luminance value of each frame from the luminance information of the image signal processor and color information and luminance information included in the image signal, and calculates the average luminance difference of the current frame and the average luminance difference value of the previous frame A luminance calculator which compares the average luminance value with a first set luminance value, and compares the average luminance difference value with a second set luminance value, if the average luminance value is larger than the first luminance value. A color filter unit for outputting information and luminance information, and outputting only luminance information when the average luminance value is smaller than the first set luminance value, wherein the average luminance value is smaller than the first set luminance value or the average luminance difference value is set to zero. 2 includes an event generator for generating an event when the set luminance value is greater than the set luminance value. The interface circuit processes the output of the encoder.

According to another aspect of the present invention, a DVR for detecting a luminance difference includes a reference information setting unit, an encoder, and an interface circuit. The reference information setting unit sets information necessary for sensing the brightness. The encoder calculates an average luminance value for each frame of luminance information included in the image signal, and removes a color signal from the image signal when the average luminance value is lower than a predetermined level. The interface circuit processes the output of the encoder.

According to another aspect of the present invention for achieving the above technical problem, a DVR for detecting a luminance difference includes a reference information setting unit, an encoder, and an interface circuit. The reference information setting unit sets information necessary for sensing the brightness. The encoder calculates an average luminance value of each frame of luminance information included in the video signal, calculates an average luminance difference of a current frame and an average luminance difference of a previous frame using the average luminance value of each frame, and calculates the average luminance. The difference value is compared with the reference luminance change value for detecting the luminance change, and when the average luminance difference value is larger than the reference luminance change value, an event is generated. The interface circuit processes the output of the encoder.

According to another aspect of the present invention, there is provided a video signal processing method including extracting brightness information and color information included in the video signal, and setting the DNN (Day & Night) setting and detecting the brightness change. (B) determining whether at least one is set, calculating (b) calculating an average luminance value for each frame from the luminance information when determining that at least one is set in step (b), and calculating the average luminance value. (D) removing color information from the video signal or generating an event by using the same.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of a DVR for detecting a luminance difference according to the present invention.

Referring to FIG. 1, the DVR 100 according to the present invention includes a reference information setting unit 110, an encoder 130, and an interface circuit 150.

The reference information setting unit 110 generates a control signal CNTR determined according to whether the luminance change detection function is applied, and includes a luminance change setting unit 111, a timer 112, and a setting information storage unit 113. do. The brightness change setting unit 111 sets whether to apply the DNN (Day & Night) function (SET1), whether to apply the brightness change detection function (SET2), and the setting time (C). The DNN function senses a change in brightness to distinguish between the brightness represented by the day and the darkness represented by the night, and to distinguish the brightness from the dark based on a predetermined time (C). can do.

The timer 112 supplies time information Tz according to the setting time C when the DNN function set by the brightness change setting unit 111 is not set to operate in response to the change in brightness. The setting information storage unit 113 stores the values SET1, SET2, and Tz set by the luminance change setting unit 111 and outputs the control signal CNTR corresponding to the stored values and the time information Tz. do.

The control signal CNTR instructs to convert the video signal to color and black and white automatically using the luminance information or time information when the DNN function is applied, and the video signal according to the time information Tz. Indicates whether to save in color only or in color and black and white. The time information Tz corresponds to a preset time for distinguishing night from day.

In addition, the control signal CNTR is a signal instructing to generate an event signal by detecting a case where a uniform image is input by using the brightness information and a case where there is a sudden change in brightness when the brightness change detection function is applied. to be.

By applying the DNN function, the DVR 100 according to the present invention detects a case where the luminance becomes higher or lower than a predetermined level and adaptively adjusts and stores the image. Therefore, by sensing the change in the brightness of the input image it is possible to distinguish and store the image taken in the day (Day) and night (Night). The video signal taken during the day when the lighting is sufficient and transmitted to the DVR may be stored as it is. However, because the lighting is not enough at night, when the image is stored and reproduced in color, the screen is distorted, and in this case, the image signal is processed and converted into black and white and stored.

In addition, the DVR 100 according to the present invention applies a brightness change detection function to detect a case where an image is not input to the camera at all and even an object such as smoke blurs the image, and stores the corresponding video signal in black and white. Or send a constant alert, or event, to the user. In order to disable the camera, a change in luminance of an image signal input from the camera and transmitted to the DVR is detected in preparation for a case where a strong light such as an infrared signal is incident on the lens of the camera. At this time, if a sudden change in luminance is detected, it is determined that this is not a normal situation, and an event corresponding to the situation is generated to alert the user that an abnormal situation has occurred.

The reference information setting unit 110 sets various useful functions described above and controls the operation of the encoder 130 through the control signal CNTR.

The encoder 130 extracts color information U and V and luminance information Y included in the image signal received from the camera according to the instruction of the control signal CNTR, and extracts the extracted color information U and V. And outputs the video signal as a black and white signal or a black and white signal and a color signal to match the state of the video signal using the luminance information (Y). In addition, when the video signal is not received, a case where a uniform video is input and a sudden change in luminance are detected, the corresponding event signals E1 and E2 are enabled.

The encoder 130 includes an image signal processor 131, a luminance information processor 132, a color filter 139, and an event generator 140.

The image signal processor 131 extracts the luminance information Y, the difference between the luminance information and the red component U, and the difference between the luminance information and the blue component V included in the input image signal. Separate each of these. Since the luminance information Y is sensitive to an error, the luminance information Y is encoded into a larger number of bits Bit than the color information U and V.

The brightness information processing unit 132 determines whether there is a range of brightness changes or a sudden brightness change in the video signal by using the brightness information Y among the separated image information, and accordingly enables the event signal. And a luminance calculator 133 and a luminance comparator 136.

The luminance calculator 133 calculates an average luminance value Yp of each frame from the separated luminance information Y, and an average luminance value Yp1 of the previous frame and the current frame. And a luminance difference calculating unit 135 for calculating the difference between the average luminance values Yp2 (Ypd = Yp2-Yp1).

The luminance comparison unit 136 includes a first luminance comparison unit 137 and a second luminance comparison unit 138.

The first luminance comparison unit 137 compares the average luminance value Yp of the frame calculated by the average luminance calculator 134 with the first set luminance value Yth1, and the average luminance value Yp is set first. When the luminance value is smaller than Yth1 (Yth1> Yp), the first event signal E1 is enabled. The second luminance comparison unit 138 compares the average luminance difference value Ypd calculated by the luminance difference calculation unit 135 with the second set luminance value Yth2 and sets the average luminance difference value Ypd as the second setting. When larger than the luminance value Yth2 (Ypd> Yth2), the second event signal E2 is enabled.

Here, the first set luminance value Yth1 represents a reference luminance value set to distinguish day and night, and the second set luminance value Yth2 represents a reference luminance change value set to detect a luminance change.

The color filter unit 139 removes the colors U and V included in the video signal in response to the enabled first event signal E1 and corrects the brightness information of the luminance information Y. Generates a black and white image (Yc).

The event generator 140 generates an event in response to the first event signal E1 and the second event signal E2. Here, the event means one of recording of the current image, generating a warning sound, sending a warning message, and warning mail.

The interface circuit 150 includes an image storage unit 151 for processing the processed video signal, a display unit 152 for reproducing the processed video signal, storage of a video signal in response to the event, generation of a warning sound, At least one of an event operation unit 153 taking actual measures such as generating an alert message and sending an alert mail, and a network transmitter 154 for transmitting the output of the encoder 130 to an external device.

Although not shown in FIG. 1, a video signal input unit (not shown) may be further provided to transfer the video signal input from the camera to the encoder 130.

2 is a signal flow diagram illustrating a video signal processing method according to the present invention.

Referring to FIG. 2, the video signal processing method 200 includes a video signal processing step 210, a setting determination step 220, a luminance value calculating step 230, a luminance value comparing step 240, and color information change. Step 250, image information processing step 260 and time determination step 270.

The video signal processing step 210 extracts the luminance information Y and the color information U and V included in the image signal output from the camera and separates the luminance information Y. The setting determination step 220 determines whether the DNN function and the brightness change detection function are set. The luminance value calculating step 230 calculates an average luminance value Yp of each frame from the separated luminance information Y when it is determined in the setting determination step that the DNN function is set (220, Yes). In the luminance value comparison step 240, the calculated average luminance value Yp of the frame is compared with the first set luminance value Yth1.

If the time determination step 270 determines that the DNN function is not set in the setting determination step 220 (220, No), the current time T is compared with a preset time zone Tz. . That is, it is determined whether the current time T enters the night time zone Tz. Here, Tz is described as a night setting time region, but it is also possible to set it to a day setting time region.

In the color information changing step 250, when it is determined that the average luminance value Yp is smaller than the first set luminance value Yth1 (Yth1> Yp) (240, Yes) and the current time is the set time region Tz If it is determined to correspond to (270, Yes), the color information (U, V) is removed from the image information, and the luminance information (Y) is corrected. That is, when the DNN function is set, when the average luminance value Yp is smaller than the first set luminance value Yth1 (Yth1> Yp), the color information is removed from the image information, and the DNN function is not set. When the current time (T) enters the set time zone (Tz: Night Time Zone), the color information (U, V) is removed from the image information, and the processed black and white image is corrected by correcting the brightness information of the luminance information (Y). Produces Yc).

In the image information processing step 260, when the DNN function is not set (220, No) and it is determined that the present day is not night (270, No), the image signal is stored in color, displayed on a display, and transmitted to a network. Perform at least one of the tasks. The image information processing step 260 is performed when the DNN function is set (220, Yes) when the average luminance value Yp is greater than the first set luminance value Yth1 (Yth1 <Yp) (240, No) and When the color signal is removed in the color information changing step 250, at least one of storing the video signal in black and white, outputting the display signal, and transmitting the image signal to the network is performed.

Here, the DNN (Day & Night) function means a function of distinguishing between Day and Night.

In the above description, the time determining step 270 may be selectively used by the user. That is, the DNN may be performed by detecting only a change in the luminance value, but the DNN function may be performed by using a setting time defining night or day. The setting of the DNN function used in the above description is limited to detecting night and day automatically by detecting only a change in luminance value, and in a special case in which a problem occurs when a change in luminance value is detected and automatically operated. In other words, it means that it can be compensated by using the set time manually. Therefore, the user can set the two technologies to perform functions more fully by using them separately or simultaneously.

3 is a signal flow diagram illustrating a method of generating an event signal according to the present invention.

Referring to FIG. 3, the event signal generating method 300 includes a video signal processing step 310, a setting determination step 320, a luminance value calculating step 330, a luminance difference calculating step 340, and a luminance difference comparison. Step 350, the event generation step 360 and the brightness value storage step 370.

The video signal processing step 310 extracts color information U and V and luminance information Y included in the video signal output from the camera. The setting determination step 320 determines whether an event is set.

When it is determined that the event is set (320, Yes), the luminance value calculating step 330 calculates an average luminance value Yp of each frame from the separated luminance information Y. The luminance difference calculating step 340 calculates a difference Ypd between the average luminance value Yp1 of the current frame and the average luminance value Yp2 of the previous frame of the image information. In the luminance difference comparing step 350, the average luminance difference value Ypd is compared with the second set luminance value Yth2.

The event generating step 360 generates an event when it is determined that the average luminance difference value Ypd is greater than the second set luminance value Yth2 (Ypd> Yth2) (350, Yes). The event generating step 360 generates an event when there is a sudden change in the luminance of the signal input to the camera, for example, when the signal input to the camera is suddenly cut off, or when the camera input is uneven due to an external environment. Let's do it.

In the luminance value storing step 370, the average luminance difference value Ypd is smaller than the second set luminance value Yth2 (350, No) or after the event occurs in the event generating step 360, the average luminance value of the current frame. Save (Yp1).

If the event is not set (320, No) or if the event is set and the luminance value is stored (370), the video signal Yp1 corresponding to the above setting is output.

In the above description, the technical idea of the present invention has been described with the accompanying drawings, which illustrate exemplary embodiments of the present invention by way of example and do not limit the present invention. In addition, it is apparent that any person having ordinary knowledge in the technical field to which the present invention belongs may make various modifications and imitations without departing from the scope of the technical idea of the present invention.

As described above, the DVR, the image signal processing method, and the event signal generation method for detecting the luminance difference according to the present invention take into account whether the normal image is being projected to the camera using the image signal received from the camera, and the light and the darkness of the illumination are considered. By processing and storing the image, the image quality of the stored image can be improved, and by enabling the event signal according to a certain condition, the user can be warned of an abnormal situation in the area where the camera is shooting.

Claims (18)

In the DVR (Digital Video Recorder) for detecting the difference in brightness of the video signal input from the camera, A reference information setting unit for setting a DNN (Day & Night) function for distinguishing day and night and a brightness change detection function for detecting a brightness change; An image signal processor which extracts color information and luminance information included in the image signal, and calculates an average luminance value of each frame from the luminance information, and calculates an average luminance difference of the current frame and an average luminance difference value of the previous frame. A luminance comparison unit which compares the average luminance value of each frame with a first set luminance value and compares the average luminance difference value with a second set luminance value, wherein the average luminance value of each frame is a first set luminance value; If it is larger than the first set luminance value, and outputs the color information and luminance information, and if the average luminance value of each frame is less than the first set luminance value, the color filter unit for outputting only the luminance information, the average luminance value of each frame than the first set luminance value An encoder including an event generator for generating an event when the average luminance difference value is smaller than or greater than a second set luminance value; And Digital video recorder (DVR) for detecting the difference in brightness, characterized in that it comprises an interface circuit for processing the output of the encoder. The method of claim 1, The first set luminance value is a luminance value set to distinguish day and night, and the second set luminance value is a luminance change value set to detect a luminance change. Recorder). The method of claim 1, The reference information setting unit (DVR) for detecting a luminance difference, characterized in that it comprises a timer for providing time information for distinguishing day and night when the DNN (Day & Night) function is not set. In the DVR (Digital Video Recorder) for detecting the difference in brightness of the video signal input from the camera, A reference information setting unit for setting information necessary for detecting luminance; An encoder for calculating an average luminance value for each frame of luminance information included in the image signal and removing a color signal from the image signal when the average luminance value is lower than a predetermined level; And Digital video recorder (DVR) for detecting the difference in brightness, characterized in that it comprises an interface circuit for processing the output of the encoder. The method of claim 4, wherein the reference information setting unit, A brightness change setting unit configured to set at least one of a DNN (Day & Night) function and a brightness change detection function; And Digital video recorder (DVR) for detecting a luminance difference, characterized in that it comprises a timer for providing time information for distinguishing day and night when the DNN (Day & Night) function is not set in the brightness change setting unit. The method of claim 4, wherein the encoder, An average luminance calculator for calculating an average luminance value for each frame of luminance information included in the video signal; A first luminance comparison unit comparing the average luminance value with a reference luminance value for distinguishing day and night; And And a color filter unit for outputting color information and luminance information if the average luminance value is larger than a reference luminance value and outputting luminance information if the average luminance value is smaller than the reference luminance value. (Digital Video Recorder). The method of claim 6, wherein the color filter unit, Digital video recorder (DVR) for detecting the luminance difference, characterized in that for outputting a black and white signal correcting the brightness of the luminance information. The method of claim 6, wherein the encoder, A luminance difference calculator configured to calculate an average luminance difference value of a current frame and an average luminance value of a previous frame by using the average luminance value of each frame; A second luminance comparison unit comparing the average luminance difference value with a reference luminance change value for detecting a luminance change; And And an event generator for generating an event when the average luminance value is smaller than the reference luminance value or the average luminance difference value is larger than the reference luminance change value. The method of claim 6, wherein the event, Digital video recorder (DVR) for detecting the difference in brightness, characterized in that at least one of the recording of the current video, generating a warning sound, sending a warning message and warning mail. The method of claim 4, wherein the interface circuit, An image storage unit for storing the processed image signal; A display unit for reproducing the activated video signal; An event operation unit which takes practical measures such as storing a video signal, generating an alarm sound, generating an alarm message, and sending an alarm mail in response to the event; And Digital video recorder (DVR) for detecting the difference in brightness characterized in that it comprises at least one of the network transmission unit for transmitting the output of the encoder (130) to an external device. delete In the DVR (Digital Video Recorder) for detecting the difference in brightness of the video signal input from the camera, A reference information setting unit for setting information necessary for detecting luminance; The average luminance value of each frame of luminance information included in the video signal is calculated, the average luminance difference value of the current frame and the average luminance difference of the previous frame are calculated using the average luminance value of each frame, and the average luminance difference value is calculated. An encoder for generating an event when the average luminance difference value is greater than a reference luminance change value compared to a reference luminance change value for detecting a luminance change; And An interface circuit for processing the output of said encoder, The encoder, The average luminance value of each frame is compared with a reference luminance value distinguishing day and night, and when the average luminance value of each frame is larger than the reference luminance value, color information and luminance information are output, and the average luminance value of each frame is a reference luminance value. If smaller, DVR (Digital Video Recorder) for detecting the difference in luminance, characterized in that to remove and output the color information. In the method for processing the video signal input from the camera, (a) extracting luminance information and color information included in the video signal; (b) determining whether at least one of the Day & Night (DNN) setting and the luminance change detection setting is set; (c) calculating an average luminance value for each frame from the luminance information when it is determined that at least one is set in the step (b); And and (d) removing color information or generating an event from the video signal by using the average luminance value. The method of claim 13, wherein step (c) comprises: When it is determined in step (b) that at least one is set, the average luminance value of each frame is calculated from the luminance information, and if the luminance change detection is set, the average luminance value of the current frame is used by using the average luminance value of each frame. And calculating an average luminance difference value of the previous frame. The method of claim 14, wherein step (d) And comparing the average luminance difference value with a reference luminance change value for detecting a luminance change and generating an event when the average luminance difference value is larger than the reference luminance change value. The method of claim 15, wherein after step (d), And storing the average luminance value of the current frame. The method of claim 13, wherein step (d) If it is determined in step (b) that the DNN (Day & Night) function is set, the average luminance value is compared with a reference luminance value for distinguishing day and night, and if the average luminance value is smaller than a reference luminance value, color information And outputs the color information, and outputs the color information and the luminance information if the average luminance value is larger than the reference luminance value. The method of claim 13, wherein step (d) If it is determined in step (b) that the DNN (Day & Night) function is not set, the video signal comprises removing color information from the video signal when it corresponds to a set time region for distinguishing day and night. Processing method.

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