KR101658034B1 - Digital Image Portable electronic apparatus and focus information display method thereof - Google Patents

Abstract

The present invention relates to a digital image processing apparatus and a focus information displaying method thereof, and more particularly, to a digital image processing apparatus and a focus information displaying method thereof, more specifically, to a method of displaying a plurality of subjects by predicting and displaying a degree of focusing on each of a plurality of subjects, To a digital image processing apparatus and a method of displaying the focus information. The digital image processing apparatus predicts the degree of focus of each of a plurality of subject areas based on a focal distance of each of a plurality of subject areas and a depth of field corresponding to a focus area selected from a plurality of subject areas, do.

Description

[0001] The present invention relates to a digital image processing apparatus and a focus information display method thereof,

More particularly, the present invention relates to a digital image processing apparatus and a method of displaying a focus information of the digital image processing apparatus. And a method of displaying the focus information.

Typically, the digital image processing apparatus includes all apparatuses that process images of a digital camera, a PDA (personal digital assistant), a phone camera, a PC camera, or the like and use an image recognition sensor.

The digital image processing apparatus can process an image received through an image pickup device in a digital signal processor, compress the image to generate an image file, and store the image file in a memory.

In addition, the digital image processing apparatus can receive input through an image pickup device or display an image of an image file stored in a storage medium on a display device such as an LCD (Liquid Crystal Display).

In the digital image processing apparatus, the focus lens can be automatically moved to a position where the image can be obtained at each focus lens position while moving the focus lens within a predetermined range, and a clear picture can be obtained therefrom.

The present invention relates to a digital image processing apparatus and a backup location information management method thereof, in which, when a plurality of subjects are photographed, the degree of focus of each of the objects is predicted and displayed, will be.

According to an aspect of the present invention, there is provided a digital image processing apparatus including a focal length calculating unit for calculating a focal length of each of a plurality of subject areas including a plurality of face areas detected from a live view image; A focus area selector for selecting one of the plurality of face areas as a focus area to be a center of focus of the plurality of subject areas; A depth of field calculation unit for calculating a depth of field corresponding to the selected focus area on the basis of a focal length of the focus area and a currently set aperture value; A focus degree prediction value calculation unit for calculating a focus degree prediction value in which the degree of focus of each of the plurality of subject areas is predicted based on the focal distance of each of the plurality of subject areas and the calculated depth of field; And a display unit for displaying a predicted value of focus degree of each of the plurality of subject areas.

More preferably, the plurality of subject areas include areas recognized as a human face from a live view image.

More preferably, the display unit displays a guide line surrounding each of the plurality of subject areas, and displays a predicted value of the focus degree of each of the plurality of subject areas close to the guide lines.

More preferably, the apparatus further includes a focus level predictive value adjuster for changing a predictive value of each focus level according to the changed aperture value when the user changes the aperture value.

According to another aspect of the present invention, there is provided a method for displaying a focus information of a digital image processing apparatus, the method comprising: calculating a focal length of each of a plurality of subject areas including a plurality of face areas detected from a live view image; Selecting one of the plurality of face areas as a focus area to be a center of focus of the plurality of subject areas; Calculating a depth of field corresponding to the selected focus area based on a focus distance of the focus area and a currently set aperture value; Calculating a focal point prediction value in which each of the plurality of subject areas is predicted to be in focus based on a focal distance of each of the plurality of subject areas and the calculated depth of field; And displaying a predicted focus degree value of each of the plurality of subject areas.

More preferably, the plurality of subject areas include areas recognized as a human face from a live view image.

More preferably, the displaying step comprises the steps of displaying guidelines surrounding the plurality of subject areas; And a predicted focus degree of each of the plurality of subject areas in proximity to the guide lines.

More preferably, the method further includes the step of, when the user changes the aperture value, changing the respective focus degree predicted values according to the changed aperture value.

According to the present invention, when a plurality of subjects are photographed, the degree of focus of each of the plurality of subjects is predicted and displayed on the screen, thereby enabling the user to focus on a plurality of subjects and focus on the subject.

FIG. 1 is a rear view showing a rear external appearance of a digital camera, which is an embodiment of a digital image processing apparatus according to the present invention.
2 is a block diagram of a control device of a digital camera, which is an embodiment of a digital image processing apparatus according to the present invention.
3 is a block diagram of a digital camera, which is a preferred embodiment of the digital image processing apparatus according to the present invention.
FIG. 4 is a flowchart illustrating a method of displaying a predicted value of focus degree of a digital image processing apparatus according to the present invention.
5 is a flowchart illustrating a process of displaying a predicted value of a degree of focus in a digital camera according to an exemplary embodiment of the present invention.
6A to 6C are views illustrating an example of displaying on a screen of a digital camera according to an embodiment of the present invention.

The above objects, features and advantages will become more apparent from the following detailed description in conjunction with the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

On the other hand, when an element is referred to as "including " an element, it does not exclude other elements unless specifically stated to the contrary.

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

FIG. 1 is a rear view showing a rear external shape of a digital camera 100, which is an embodiment of a digital image processing apparatus according to the present invention.

Referring to FIG. 1, a direction button 21, a menu-OK button 22, a wide angle-zoom button W, a telephoto-zoom Zoom button T and a display panel 25 may be provided.

The direction button 21 may include a total of four buttons including an up button 21a, a down button 21b, a left button 21c, and a right button 21d. The direction button 21 and the menu-OK button 22 are keys for inputting various menus related to the operation of the portable electronic device such as a digital camera.

Wide angle-zoom button W or telephoto-zoom button T widens the view angle or narrows the view angle depending on the input. In particular, it can be used to change the size of the selected exposure area. As the display panel 25, an image display device such as a liquid crystal display (LCD) may be used.

The display panel 25 may be included in the display unit 350 (FIG. 3) in which the input image captured from the outside and input from the stored image file can be displayed.

As an embodiment of a portable electronic device to which the present invention can be applied, a digital camera, a control device thereof, and a control method thereof are disclosed in U.S. Patent Application Publication No. 2004/0130650 (titled: automatic focusing using a quadratic function of a camera Method, a method of automatically focusing using a quadratic function in camera.

The digital camera, its control device, and control method disclosed in the U.S. application are incorporated herein, and a detailed description thereof will be omitted.

Fig. 2 is a block diagram of the control device 200 of the digital camera shown in Fig. The controller 200 of the digital camera according to the present embodiment may be mounted inside the digital camera 100 of Fig.

Referring to FIG. 2, an optical system (OPS) including a lens unit and a 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 wide-zoom button W or telephoto-zoom button T included in the user input unit INP, a corresponding signal is input to the microcontroller 212. Accordingly, as the microcontroller 212 controls the lens driving unit 210, the zoom motor M _Z is driven to move the zoom lens.

When the wide angle-zoom button (W) is pressed, the focal length of the zoom lens is shortened and the angle of view is widened so that the input image is reduced. When the telephoto-zoom button T is depressed, the focal length of the zoom lens becomes long, The input image is enlarged and input.

Meanwhile, in the auto focusing mode, the main controller built in the digital signal processor 207 controls the lens driving unit 210 through the micro controller 212, so that the focus motor M _F is driven do. That is, the focus motor M _F is driven to move the focus lens to a position where the sharpest picture can be obtained.

The compensation lens compensates for the overall refractive index and is not driven separately. Reference symbol M _A denotes a motor for driving an aperture (not shown).

In the filter section of the optical system (OPS), an optical low pass filter removes optical noise of a high frequency component. Infra-red cut filter blocks the infrared component of incident light.

The photoelectric conversion unit OEC may include an image pickup device such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal-Oxide-Semiconductor). The photoelectric conversion unit OEC converts light from the optical system OPS into an electrical analog signal.

The analog-to-digital conversion unit may include a CDS-ADC (Correlation Double Sampler and Analog-to-Digital Converter) The analog-to-digital converter processes the analog signal from the photoelectric converter (OEC), removes the high-frequency noise, adjusts the amplitude, and converts the analog signal into a digital signal. Here, the digital signal processor 207 controls the timing circuit 202 to control the operations of the photoelectric conversion unit (OEC) and the analog-digital conversion unit 201.

The optical system OPS, the photoelectric conversion unit OEC, the CDS-ADC 201, and the like may be included in the image input unit 330 of FIG. 3 according to the present invention.

The real-time clock 203 provides time information to the digital signal processor 207. The digital signal processor 207 processes digital signals from the CDS-ADC device 201 to generate digital image signals classified into luminance (Y value) and chromaticity (R, G, B) signals.

A self-timer lamp, an auto-focus lamp, a mode indicating lamp, a flash standby lamp, and the like are connected to the light emitting unit (LAMP) driven by the microcontroller 212 under the control of the main controller incorporated in the digital signal processor 207 .

The digital signal processor 207 and / or the microcontroller 212 may be included in the controller (320 of FIG. 3) according to the present invention. In addition, the user input inputted by the operation of the user operation unit 360 of FIG. 3 according to the present invention is input to the digital signal processor 207 and / or the micro controller 212 through the user input unit INP, The work can be performed accordingly.

A digital image signal from the digital signal processor 207 is temporarily stored in a DRAM (Dynamic Random Access Memory) 204. An EEPROM (Electrically Erasable and Programmable Read Only Memory) 205 stores algorithms and setting data such as a boot program and a key input program necessary for the operation of the digital signal processor 207. In the memory card interface 206, a user's memory card can be attached and detached.

The memory card recognized through the DRAM 204 or the memory card interface 206 may store the input image or the stored image file, which is photographed and input from the outside, temporarily or nonvolatilely, ).

That is, the storage unit 340 is provided with a flash memory or a removable memory (not shown), such as a DRAM 204 or a cache memory, in which an input image or an edited image captured from an externally imaged or input image file is temporarily or non- Card, and the like.

The digital image signal from the digital signal processor 207 is input to the display panel driver 214, thereby displaying an image on the display panel 215. [ The display panel 215 may be driven by the display panel driver 214 under the control of the digital signal processor 207.

The display panel 215 and the display panel driving unit 214 may be included in the display unit 350 of FIG. 3 in which an input image input from an image file photographed from the outside and stored or stored according to the present invention may be displayed.

On the other hand, the digital image signal from the digital signal processor 207 can be transmitted by serial communication through a USB (Universal Serial Bus) connection part 31a or an RS232C interface 208 and its connection part 31b, 209 and the video output unit 31c as video signals. Here, the digital signal processor 207 may incorporate a micro controller therein.

The audio processor 213 outputs the audio signal from the microphone MIC to the digital signal processor 207 or the speaker SP and outputs the audio signal from the digital signal processor 207 to the speaker SP.

3 is a block diagram of a digital camera 300, which is a preferred embodiment of the digital image processing apparatus according to the present invention.

3, the digital camera 300 according to the present embodiment may include a control unit 320, an image input unit 330, a storage unit 340, a display unit 350, and a user operating unit 360.

The control unit 320 extracts a plurality of subject areas from the live view image, and predicts the degree of focus of each of the plurality of subject areas.

The control unit 320 may include a focal length calculation unit 322, a focus area selection unit 324, a depth of field calculation unit 326, and a focus accuracy prediction unit 328.

The focal length calculating unit 322 calculates the focal length of each of the plurality of subject areas.

In the present embodiment, a plurality of subject areas may be recognized as human faces from a live view image and include detected areas.

Conventional face recognition algorithms can be used for recognizing and detecting a human face from a live view image.

The focus area selector 324 selects a focus area to be the center of focus of the plurality of subject areas.

The focus area may be selected by a user's designation or automatically selected as an area located nearest to the center of the live view image among a plurality of subject areas, but the present invention is not limited thereto.

The depth-of-field calculation unit 326 calculates the depth of field corresponding to the selected focus area on the basis of the focal length and the aperture value of the focus area.

The focal length of each of the plurality of subject areas including the focus area can be calculated as shown in Equation (1) using the table shown in FIGS. 4A to 4B.

Equation 1 in this embodiment corresponds to (focal distance of the subject area) = (second preservation value) / (current focus position - infinity focus position) + (first preservation value).

The focal length of each of the plurality of subject areas is obtained by taking the first preservation value and the second preservation value from the table shown in Fig. 4A, taking the infinite focus position from the table shown in Fig.

For example, taking the wide end of the 18-55 mm lens as an example, the focal length of the subject area can be calculated by calculating 52533 / (current focal position - 389) + 60.

Here, the current focus position means the number of steps of the lens, and in this embodiment, a value between 389 and 628 may be a target (refer to FIG. 4B).

For example, the focal length of the subject area when the current focus position is 500 can be calculated as about 533 mm.

4C, the boundary values of the depth of field corresponding to the focal length and the aperture value of the focus area among the plurality of subject areas, that is, Near and Far values are obtained.

Assuming that the focal distance of the focus area belongs to the depth of field set by the Near and Far values, the degree of focus is 100%.

The focal-point prediction unit 328 calculates a focal-plane predictive value that predicts the degree of focus of each of the plurality of subject areas based on the focal length of each of the plurality of subject areas and the depth of field corresponding to the focal area.

The predicted value of the focus degree can be calculated by the following equation (2).

Equation 2 in this embodiment corresponds to (focal point,%) = ((focal distance of subject area) / (focal distance of depth of field corresponding to the focus area)) * 100-100.

For example, when the focal distance satisfies 100%, that is, when the focal length of the selected one of the plurality of subject areas belongs to the depth of field set by the Near and Far values, Can be predicted as shown in Equation (3) below.

Equation 3 in this embodiment corresponds to (focus degree,%) = ((focal distance of subject area) / (focal distance of focus area)) * 100-100.

For example, when the subject area is located at a focal distance of 500 mm, 575 mm, 625 mm, and 750 mm, respectively, and a subject area having a focal length of 500 mm is selected as the focus area, the degree of focus of each subject area is 100% %, 75%, and 50%, respectively.

In addition, the digital camera 300 may further include a focus degree predictive value adjuster (not shown) that changes a predicted value of each focus degree according to the changed aperture value when the user changes the aperture value.

The image input unit 330 may receive an input image captured from the outside or input from an image file.

As described above, the image input unit 330 receiving the input image may include an optical system (OPS), a photoelectric conversion unit (OEC), a CDS-ADC device 201, etc. of FIG. At this time, the optical system (OPS) may include various lenses including a zoom lens. The CDS-ADC element 201 may be included in an image pickup element that receives an input image input through a lens.

The storage unit 340 may store an image file or an image file of an input image captured and input from the outside, and a database file that stores metadata of the image file. The storage unit 340 may include a DRAM (204 in FIG. 2) for temporarily storing data or a cache memory or a flash memory or a memory card in which data is stored in a non-volatile manner.

The display unit 350 displays the photographed input image, the stored input image, and the edited image to be edited. In particular, in this embodiment, the predicted value of the degree of focus of each of the plurality of subject areas is displayed.

More preferably, the display unit 350 is configured to display a guide line surrounding each of the plurality of subject areas, and to display a predicted value of the focus degree of each of the plurality of subject areas in proximity to the guide lines.

Here, in the case where the user who views the predicted value of the focus degree changes the aperture value by referring to the predicted value, the focus degree predicted value adjustment unit (not shown) adjusts the focus value based on the changed aperture value, The focal plane predicted value of each of the pixels is changed.

Equation 4 in this embodiment corresponds to f (x, F) = 100 - (100 - x) / (FF ₀ +1) (where F> = F ₀ ) , F) = 100 - (100 - x) / (FF ₀ +1) (where F <F ₀ ).

Equation (4) is to obtain a changed focus degree predicted value when the aperture value is increased, and Equation (5) is used to obtain the changed focus degree predicted value when the aperture value is decreased.

In the equations (4) to (5), F ₀ denotes the aperture value before the change, F denotes the aperture value after the change, x denotes the focus degree before the change, and f to be.

The focus degree prediction value adjustment unit (not shown) adjusts the focus degree prediction value based on the changed aperture value using Equation 2 or 3 instead of adjusting the focus degree prediction value using Equations 4 to 5 when the aperture value is changed And then adjust it again.

The user operation unit 360 can be operated by a user so as to input a desired command from the outside. The directional buttons (21 in Fig. 1), the menu-OK button (22 in Fig. 1), the shutter release button (26 in Fig. 1), and the power switch .

In this embodiment, the user inputs through the user manipulation unit 360 an input specifying a focus area to be selected from among a plurality of subject areas, or a user viewing the predicted focus degree of a plurality of subject areas, Can be configured to be able to change input.

5 is a flowchart illustrating a method of displaying a focus information (S500) of a digital image processing apparatus according to an exemplary embodiment of the present invention. The focus information display method (S500) of the digital image processing apparatus according to the present embodiment can be implemented in the control device 200 of the digital camera shown in FIG. 2 and / or the digital camera 300 shown in FIG. Therefore, the same items as those in the description of the control device 200 of the digital camera of Fig. 2 and the digital camera 300 of Fig. 3 are referred to.

Referring to FIG. 5, when the photographing mode is entered (S501), a subject is recognized and detected from the live view image (S502).

The subject in this embodiment includes a face of a person, and in this case, the subject can be recognized and detected through a conventional face recognition algorithm.

As in the live view image illustrated in FIG. 6A, when the number of subjects is greater than 1 (S503), that is, when a plurality of subjects are recognized and detected in operation S502, the focal length of each of the plurality of subjects is calculated S504).

A focus area of one of the plurality of subjects is selected (S505).

In step S505, the depth of field is calculated based on the focal length and the aperture value of the focus area selected in step S505.

In step S507, a depth-of-focus estimated value that predicts the degree of focus of each of a plurality of subjects based on the depth of field calculated in step S506 and the focal length of each of the plurality of subjects is calculated.

As illustrated in FIG. 6B, the area is displayed through a guide line for each of a plurality of subjects, and a predicted focus degree value of each of a plurality of subjects is displayed beside the displayed area (S508).

In a case where the aperture value is changed by the user who confirmed the focus degree prediction value of each of the plurality of subjects (S509), the process of setting the new focus degree prediction value based on the changed aperture value can be repeatedly performed (S506 to S508).

Or by adjusting and displaying the predicted value of the degree of focus before the change based on the changed diaphragm value as shown in Equations (4) to (5).

As shown in FIG. 6B, when a plurality of subjects each displays a predicted value of the degree of focus predicted with respect to the degree of focus, the user views a plurality of subjects in a uniformly focused image on all of the subjects So that it can be easily and conveniently photographed.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, You will understand. Accordingly, the true scope of protection of the present invention should be determined only by the appended claims.

Claims (8)

A focal length calculating unit for calculating a focal length of each of a plurality of subject areas including a plurality of face areas detected from a live view image;
A focus area selector for selecting one of the plurality of face areas as a focus area to be a center of focus of the plurality of subject areas;
A depth of field calculation unit for calculating a depth of field corresponding to the selected focus area on the basis of a focal length of the focus area and a currently set aperture value;
A focus degree prediction value calculation unit for calculating a focus degree prediction value in which the degree of focus of each of the plurality of subject areas is predicted based on the focal distance of each of the plurality of subject areas and the calculated depth of field; And
And a display unit configured to display a predicted value of focus degree of each of the plurality of subject areas. delete The method according to claim 1,
The display unit
A guide line surrounding each of the plurality of subject areas is displayed and a predicted focus degree value of each of the plurality of subject areas is displayed in proximity to the guide lines. The method according to claim 1,
Further comprising a focus degree prediction value adjuster for changing a focus degree estimate value according to the changed aperture value when the user changes the aperture value. Calculating a focal length of each of a plurality of subject areas including a plurality of face areas detected from a live view image;
Selecting one of the plurality of face areas as a focus area to be a center of focus of the plurality of subject areas;
Calculating a depth of field corresponding to the selected focus area based on a focus distance of the focus area and a currently set aperture value;
Calculating a focal point prediction value in which each of the plurality of subject areas is predicted to be in focus based on a focal distance of each of the plurality of subject areas and the calculated depth of field; And
And displaying a focus degree prediction value of each of the plurality of subject areas. delete 6. The method of claim 5,
The display step
Displaying guiding lines surrounding the plurality of subject areas; And
And displaying the predicted focus degree of each of the plurality of subject areas in proximity to the guide lines. 6. The method of claim 5,
Further comprising the step of, when the user changes the diaphragm value, changing a predicted value of each focus degree according to the changed diaphragm value.

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