KR20090011828A - Method of controlling digital image processing apparatus wherein face area is efficiently searched, and digital image processing apparatus adopting the method - Google Patents

Abstract

A method for controlling a digital image processing apparatus in which a facial region is efficiently searched and a digital image processing apparatus are provided to increase an entire processing speed of the digital image processing apparatus by reducing a face searching time efficiently at a live view mode when a facial search mode is set up. When operational power is applied to a digital camera, a digital camera processor performs an initializing process(S1). A digital camera processor carries out a live view mode(S2). When a first step signal from a shutter release button is in an 'ON' state(S3), the digital camera processor carries out a photographing mode(S4). When the signals, which correspond to a setting mode, from the signals inputted from a user input unit(S5), a setting mode for setting up operational conditions according to the inputted signal from the user input unit is carried out(S6). Unless a termination signal is not generated(S7), the digital camera processor judges whether or not a signal converted to another mode is generated(S8). If so, the digital camera mode performs a corresponding mode(S9).

Description

A method of controlling a digital image processing apparatus in which a face region is efficiently searched, and a digital image processing apparatus employing the method. {Method of controlling digital image processing apparatus wherein face area is efficiently searched, and digital image processing apparatus adopting the method}

The present invention relates to a control method of a digital image processing apparatus and a digital image processing apparatus employing the method, and more particularly, to a digital image processing apparatus for searching for a face region in a live-view mode. A control method and a digital image processing apparatus employing the method.

In a typical digital image processing apparatus, for example, a digital camera, when the face search mode is set, the face area is periodically searched in the live-view mode and the detected face area is marked on the display image. The detected face area may be set as a target area for automatic focusing in the shooting mode according to a user's selection.

Well-known face recognition algorithms are used as face regions are periodically searched. Such face recognition algorithms are currently very widely used. For example, it is used in door control systems, time and attendance systems, real time surveillance systems, video conferencing, user authentication, file encryption, toys, and distance education.

Since there are relatively many comparison steps in the face recognition algorithm, the execution time is relatively long. Therefore, when the face search mode is set, the overall processing speed of the digital image processing apparatus may be slowed down as the face region is periodically searched in the live-view mode.

An object of the present invention is to control the face of the digital image processing apparatus can improve the overall processing speed, as the face search time can be efficiently reduced in the live-view mode when the face search mode is set And a digital image processing apparatus.

A method of the present invention for achieving the above object is a control method of a digital image processing apparatus for searching for a face region in a live-view mode. Here, if at least one face region does not exist in the image of the previous frame, the face region is searched only in the set partial region of the current frame.

The digital image processing apparatus of the present invention employs the control method of the present invention.

According to the control method of the digital image processing apparatus and the digital image processing apparatus employing the method of the present invention, when the face searching mode is set, the face searching time can be efficiently reduced in the live-view mode. As a result, the overall processing speed can be improved. This is because, if at least one face region does not exist in the image of the previous frame, there is a high probability that at least one face region does not exist in the image of the current frame. Of course, if at least one face region exists in the image of the previous frame, since there is a high probability that at least one face region exists in the image of the current frame, the face region is searched in the entire region of the current frame.

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

Referring to FIG. 1, in front and above of a digital camera 1 as a digital image processing apparatus according to the present invention, a self-timer lamp 11, a flash 12, a shutter release button 13, and an ASR (Advanced Shake) are provided. Reduction mode button 16, power button 17, lens unit 20, microphone MIC, and speaker SP.

In the self-timer mode, the self-timer lamp 11 operates for a set time from the time when the shutter release button 13 is pressed to the time at which the image starts to be captured. In addition, the self-timer lamp 11 generates auxiliary light according to the user's selection.

The ASR mode button 16 is used to compensate for camera shake. The ASR mode button 16 is also used as a lock button. For example, when the ASR mode button 16 is pressed for less than 1 second, the image stabilization function is performed, and when the ASR mode button 16 is pressed for 1 second or more, the lock function in the playback mode is performed.

The shutter release button 13 has a two-stage structure. That is, when the user operates the wide-angle zoom button 39 _W and the tele-zoom button 39 _T , and presses the shutter release button 13 only one step, the SH1 signal from the shutter release button 13 is turned on. And the second stage is pressed, the SH2 signal from the shutter release button 13 is turned on. In the still image shooting mode and the moving image shooting mode, the image is captured after the SH2 signal is turned on. In the continuous-shooting mode, images are captured continuously while the SH1 signal is on.

2, behind the digital camera 1 according to the present invention, the function buttons 15, the camera-status lamp 22, the special-effects button 23, the camera strap 24, the earphone There is a connection 25, a display panel 35, a +/- button 36, a zoom / 9 split / volume button 39, a play / printer button 42, and a mode button 43.

The function buttons 15 are used by the user to perform specific functions of the digital camera 1, are used as direction-shift buttons of the activation cursor on the menu screen of the display panel 35, and are played back in the playback mode. It is used to switch files and recording media.

The camera-state lamp 22 is used to show various operating states of the camera. The special-effect button 23 is used to set special effects on the image to be photographed. The +/- button 36 is used to adjust the shutter speed for night scene photography and the like.

The zoom / 9split / volume button 39 is used to perform a zooming operation in shooting or playback mode, to display nine pictures in a single playback mode, or to adjust the volume of audio. Used for

The play / printer button 42 is used for switching between the play mode and the live-view mode or for direct output to the printer.

The mode button 43 is used to select a PMP (Portable Media Player) mode or various shooting modes.

3 shows the overall configuration of the digital camera 1 of FIG. Referring to Figures 1 to 3, the overall configuration and operation of the digital camera 1 of Figure 1 will be described.

The optical system OPS including the lens unit and the filter unit optically processes light from a subject. The lens unit of the optical system OPS includes a zoom lens, a focus lens, and a compensation lens. When the user presses the zoom / split / volume button 39 included in the user input unit INP in the live-view mode or the video recording mode, a corresponding signal is input to the microcontroller 512. . Accordingly, as the microcontroller 512 controls the lens driver 510, the zoom motor M _Z is driven to move the zoom lens.

Meanwhile, in the auto focusing mode, the focus motor M _F is driven by the main controller embedded in the digital camera processor 507 controlling the driving unit 510 through the microcontroller 512. As a result, the focus lens is moved, and in this process, the position of the focus lens where the high frequency component of the image signal is the largest, for example, the number of driving steps of the focus motor M _F is set. Reference numeral M _A denotes a motor for driving an aperture (not shown).

A photoelectric conversion unit (OEC) of a charge coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) converts light from an optical system (OPS) into an electrical analog signal. Here, the digital camera processor 507 controls the timing circuit 502 to control the operations of the photoelectric converter OEC and the analog-digital converter 501. The CDS-ADC (Correlation Double Sampler and Analog-to-Digital Converter) element 501 as an analog-to-digital converter processes the analog signal from the photoelectric converter (OEC), removes the high frequency noise, and adjusts the amplitude. After that, it is converted into a digital signal.

The real time clock 503 provides time information to the digital camera processor 507. The digital camera processor 507 processes digital signals from the CDS-ADC element 501 to generate digital image data classified into luminance and chroma signals.

The self-timer lamp 11 and the camera-status lamp 22, etc., are provided in the light emitting part LAMP driven by the microcontroller 512 according to control signals from the digital camera processor 507 incorporating the main controller. This includes.

The user input unit INP includes a shutter release button 13, function buttons 15, an ASR mode button 16, a power button 17, a special-effect button 23, a +/- button 36, Zoom / 9 split / volume buttons 39, playback / printer buttons 42, mode buttons 43, and the like are included.

In the DRAM (Dynamic Random Access Memory) 504, digital image data from the digital camera processor 507 is temporarily stored. The EEPROM (Electrically Erasable and Programmable Read Only Memory) 505 stores algorithms necessary for the operation of the digital camera processor 507. In the memory card interface (MCI) 506, a user's memory card is detached. The flash memory FM stores setting data necessary for the operation of the digital camera processor 507. In the memory card interface 506, a plurality of memory cards are detached as recording media of a user.

Digital image data from the digital camera processor 507 is input to the LCD driver 514, whereby an image is displayed on the display panel 35.

In the interface unit 21, the digital image data from the digital camera processor 507 can be transmitted by serial communication via a universal serial bus (USB) connection 21a or an RS232C interface 508 and its connection 21b. It may be transmitted as a video signal through the video filter 509 and the video output unit 21c.

The audio processor 513 outputs the audio signal from the microphone MIC to the digital camera processor 507 or the speaker SP, and outputs the audio signal from the digital camera processor 507 to the speaker SP.

On the other hand, the microcontroller 512 drives the flash 12 by controlling the operation of the flash controller 511 according to the signal from the flash-light amount sensor 19.

4 shows the main algorithm of the digital camera processor 507 of FIG. A main algorithm of the digital camera processor 507 of FIG. 3 will be described with reference to FIGS. 1 to 4 as follows.

When operating power is applied to the digital camera 1, the digital camera processor 507 executes initialization (step S1). When this initialization step S1 is executed, the digital camera processor 507 performs a live-view mode (step S2). In this live-view mode, the input image is displayed on the display panel 35.

Next, when the SH1 signal, which is the first-stage signal from the shutter release button 13, is On (step S3), the digital camera processor 507 performs a shooting mode (step S4).

Next, when signals corresponding to the setting mode are input among the input signals from the user input unit INP (step S5), the setting mode for setting the operating conditions according to the input signals from the user input unit INP is performed. (Step S6).

On the other hand, if no end signal is generated (step S7), the digital camera processor 507 determines whether a conversion signal to any other mode has been generated (step S8).

If no conversion signal to any other mode is generated in step S8, the digital camera processor 507 repeats step S2 and subsequent steps. If a conversion signal to any other mode, for example, a playback mode, is generated in step S8, the digital camera processor 507 repeatedly performs the step S2 and subsequent steps after performing the mode (step S9). do.

FIG. 5 is a face searching algorithm that is repeatedly performed frame by frame in the live-view mode performing step S2 of FIG. 4 when the face searching mode is set in the setting mode performing step S6 of FIG. 4. Shows an example.

6 illustrates a pixel structure of a unit frame associated with steps S52 and S53 of FIG. 5. In FIG. 6, reference numeral 601 denotes an entire region of a unit frame, 601 denotes an entire region of a unit frame, R denotes red data, G denotes green data, and B denotes blue data.

FIG. 7 shows that faces are marked on the display image by performing step S55 of FIG. 5. In FIG. 7, reference numeral 35 denotes a color LCD panel, and 701 and 702 denote face marks.

5 to 7, an example of a face search algorithm repeatedly performed in units of frames in the live-view mode performing step S2 of FIG. 4 will be described.

First, the digital camera processor 507 of FIG. 3 determines whether at least one face area exists in the image of the previous frame (step S51).

Here, if at least one face region does not exist in the image of the previous frame, there is a high probability that at least one face region does not exist in the image of the current frame. In this case, the digital camera processor 507 searches for the face area only in the setting partial area 602 of the current frame (step S52).

On the other hand, if at least one face region exists in the image of the previous frame, there is a high probability that at least one face region exists in the image of the current frame. In this case, the digital camera processor 507 searches for the face area in the entire area 601 of the current frame (step S53).

Therefore, as the face search time can be reduced efficiently, the overall processing speed can be improved.

In searching the face region in step S52 or step S53, a well-known face recognition algorithm is used. Various techniques are disclosed as such face recognition algorithms. When a fast recognition speed is required as in the present invention, a face recognition technique using geometric features of a face is suitable. This technique is the most commonly used among various face recognition techniques. This technique uses geometric factors such as the location, size, and distance between facial feature points such as eyes, nose, and mouth to recognize each individual's face. Here, the geometric features are included in the elements that remain when the resolution of the input image is lowered. Therefore, since the face recognition is performed after the resolution of the setting partial region 602 or the entire region 601 of the current frame is lowered in step S52 or S53, the processing speed of steps S52 and S53 can be increased. .

As a result of performing step S52 or step S53, if at least one face area exists in the set partial area 602 of the current frame or the entire area 601 of the current frame (step S54), the digital camera processor 507 determines that face. The area (s) are marked on the display image (step S55, see FIG. 7). For reference, the searched face area (s) may be set as the target area (s) of the automatic focusing in the shooting mode according to the user's selection.

FIG. 8 is a face searching algorithm repeatedly performed in units of frames in the live-view mode performing step S2 of FIG. 4 when the face searching mode is set in the performing setting mode step S6 of FIG. 4. Here is another example.

6 to 8, an example of a face search algorithm repeatedly performed in units of frames in the live-view mode performing step S2 of FIG. 4 will be described.

First, the digital camera processor 507 of FIG. 3 determines whether at least one face area exists in the image of the previous frame (step S81).

If at least one face region does not exist in the image of the previous frame in step S81, the digital camera processor 507 may display the elapsed time (T _PA) from the time point at which the face region was recently searched in the entire region of the frame. ), If the elapsed time T _PA has not reached the set time T _SET , the face area is searched only in the set partial area 602 of the current frame (steps S82 and S83).

In addition, when the elapsed time T _PA has reached the set time T _SET , the digital camera processor 507 searches for the face area in the entire area 601 of the current frame (steps S82 and S84).

In the present embodiment, the elapsed time T _PA is the number of elapsed frames and the set time T _SET is the number of setting frames.

If, as a result of performing step S83 or step S84, at least one face area exists in the set partial area 602 of the current frame or the entire area 601 of the current frame (step S85), the digital camera processor 507 determines that face. The area (s) are marked on the display image (step S86, see FIG. 7).

As described above, according to the control method of the digital image processing apparatus and the digital image processing apparatus employing the method according to the present invention, when the face search mode is set, the face is effectively in the live-view mode. As the search time can be reduced, the overall processing speed can be improved. This is because, if at least one face region does not exist in the image of the previous frame, there is a high probability that at least one face region does not exist in the image of the current frame. Of course, if at least one face region exists in the image of the previous frame, since there is a high probability that at least one face region exists in the image of the current frame, the face region is searched in the entire region of the current frame.

The present invention is not limited to the above embodiments, but may be modified and improved by those skilled in the art within the spirit and scope of the invention as defined in the claims.

1 is a perspective view showing the front and top appearance of a digital camera as a digital image processing apparatus employing a control method according to the present invention.

FIG. 2 is a rear view illustrating a rear shape of the digital camera of FIG. 1.

3 is a diagram illustrating the overall configuration of the digital camera of FIG. 1.

4 is a flow chart showing the main algorithm of the digital camera processor of FIG.

FIG. 5 is a flowchart illustrating an example of a face searching algorithm that is repeatedly performed in units of frames in a live-view mode performing step of FIG. 4 when the face searching mode is set in the performing of the setting mode of FIG. 4. to be.

FIG. 6 is a diagram illustrating a pixel structure of a unit frame related to steps S52 and S53 of FIG. 5.

FIG. 7 is a diagram illustrating that faces are marked on a display image by performing step S55 of FIG. 5.

FIG. 8 illustrates another example of a face searching algorithm that is repeatedly performed frame by frame in the live-view mode performing step of FIG. 4 when the face searching mode is set in the performing of the setting mode of FIG. 4. It is a flow chart.

 <Explanation of symbols for the main parts of the drawings>

1 ... digital camera, 11 ... self-timer lamp,

12 ... flash, 13 ... shutter release button,

15 ... function buttons, 16 ... ASR mode buttons,

17 ... power button, 19 ... flash-light sensor, 20 ... lens section, 22 ... camera-status lamp,

23 ... special-effect buttons, 24 ... camera strap,

25 ... earphone connection, MIC ... microphone,

SP ... speakers, 35 ... color LCD panels,

36 ... + /-buttons, 39 ... Zoom / 9 split / volume buttons,

42 ... play / print button, 43 ... mode button,

OPS ... optical system, OEC ... photoelectric converter, M _Z ... zoom motor, M _F ... focus motor,

M _A ... aperture motor, 501 ... analog-to-digital converter,

502 timing circuit, 503 real time clock,

504 ... DRAM, 505 ... EEPROM, 506 ... memory card interface, 507 ... digital camera processor, 508 ... RS232C interface, 509 ... video filter, 21a ... USB connection, 21b ... RS232C connection, 21c ... video output, 510 ... lens driver, 511 ... flash controller, 512 ... microcontroller, INP ... user input, LAMP ... light emitter, 513 ... audio processor, 514 ... LCD driver, 62 ... flash memory, 601 ... entire area of the unit frame,

602 ... Settings partial area.

Claims (6)

A control method of a digital image processing apparatus for searching for a face region in a live-view mode, And searching for the face area only in the set partial area of the current frame, if at least one face area does not exist in the image of the previous frame. The method of claim 1, If at least one face region exists in the image of the previous frame, the face region is searched for in the entire region of the current frame. The method of claim 2, And the at least one face area is marked on a display image when at least one face area exists in the entire area or the set partial area of the current frame. The method of claim 2, (a) if there is no at least one face region in the image of the previous frame, measuring an elapsed time from a time point at which the face region was recently searched in the entire region of the frame to the current time point; (b) searching for the face area only in the set partial area of the current frame if the elapsed time has not reached the set time in step (a); And and (c) searching for a face area in the entire area of the current frame when the elapsed time reaches the set time in step (a). The method of claim 4, wherein in steps (a) to (c), And the elapsed time is the number of elapsed frames and the set time is the number of set frames. A digital image processing apparatus for searching for a face area in a live-view mode, And searching for the face region only in the set partial region of the current frame when there is no at least one face region in the image of the previous frame.

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