KR101046111B1 - Image capture method - Google Patents

Abstract

The present invention relates to a method for obtaining a still image, in particular in a camera phone.

An image capturing method in a camera phone according to the present invention includes: sequentially storing a plurality of image frames received through a lens unit in a buffer allocated to a plurality of first memory units; Determining whether the camera shutter key is pressed; If the camera shutter key is pressed, extracting and displaying an image frame earlier than the pressed time point from the first memory unit; Compressing the displayed image frame and storing the compressed image frame in a second memory unit.

Camera phone, still image, image

Description

Method of capturing an image}             

1 is a complete block diagram of a mobile phone equipped with a conventional camera.

2 is a flowchart illustrating a method of capturing an image in a conventional camera phone.

3 is a flowchart illustrating a method of capturing an image in a camera phone according to an embodiment of the present invention.

Figure 4 is a flow chart showing a time point to capture and store the image in the camera phone according to an embodiment of the present invention.

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

100: camera unit 116: image compression unit 132: key input unit

102: mobile phone section 118: first memory section 134: fourth memory section

104: interface unit 120: camera control unit (CPU) 142: encoder

106: display unit 122: second memory unit 144: multiplexer (MUX)

108: lens unit 124: third memory unit 146: COMP terminal

110: CMOS sensor 126: RF unit 148: display unit driver

112: ADC 128: mobile phone control unit (MSM) 150: color display unit

114: DSP 130: audio section

The present invention relates to an image capture method for capturing still images coming into a lens unit, in particular in a camera phone.

Recently, the rapid development of the information society has demanded the development of a multi-communication terminal with various functions in addition to a communication terminal that merely delivers voice only.

Accordingly, a portable multi-communication terminal having a video transmission and reception function using a camera has been implemented according to the multimedia era.

In such a multi-communication terminal, a so-called camera phone has been developed in which a digital camera function is implemented in a portable communication terminal (eg, a mobile phone) that a user usually carries.

When a user suddenly wants to capture a certain scene or a subject necessary for work, the user can take a desired scene using the camera phone and store it therein.

1 is an overall block diagram of a mobile phone equipped with a conventional camera.

Referring to FIG. 1, a mobile phone includes a camera unit 100 for capturing an image of a subject, a mobile phone unit 102 for voice call or image transmission and reception, and a display device 106 for displaying an image and a text. And an interface unit 104 for displaying images and characters on the display device 106 under the control of the mobile phone unit 102.

The camera unit 100 includes a lens unit 108, a complementary metal-oxide-semiconductor (CMOS) sensor 110, an analog digital converter (ADC) 112, and a digital signal processor (DSP). (114), JPEG compression unit 116, first memory unit 118, camera control unit 120, second memory unit 122, and third memory unit 124.

The camera unit 100 may be implemented based on a digital still video camera.

The image of the subject is provided to the CMOS sensor 110 through the lens unit 108. The lens unit 108 may include a zoom lens, a focus lens, and an iris, which are typically provided in a digital still video camera.

The CMOS sensor 110 converts and outputs an optical signal of an object that has passed through the lens unit 108 into an electrical signal (imaging image signal), and has functions such as exposure, gamma, gain adjustment, white balance, and color matrix that the camera has. Do this.

The AC 112 converts the captured image signal of one field, which is gain-adjusted by the CMOS sensor 110, into a digital signal and outputs the digital signal to the DS 114.

The DS 114 processes the digitally converted photographed image signal into an NTSC (National Television System Committee) or PAL (Phase Alternation by Line) image signal, and under the control of the mobile phone controller 128, the image signal. To the image compression unit 116 or to the display unit 106 for display on the color graphic display unit 150. Unexplained part 146 is a COMP terminal.                         

2 is a flowchart illustrating a method of capturing an image in a conventional camera phone.

The third memory unit 124 receiving the camera data temporarily stores an image coming through the camera lens unit 108 (S200). The third memory unit is composed of a buffer.

It is determined whether the image temporarily stored in the buffer 124 is to be stored through the image compression unit 116 or displayed on the display unit 150 depending on whether the shutter is applied (S202).

When the camera shutter is applied, the image captured by the camera lens unit 108 is stored in the first memory unit 118 via the image compression unit 116 (S204).

On the other hand, when the camera shutter is not applied, the image signal output from the DSP 114 is temporarily stored in the third memory unit 124 through the camera controller 120, and then the camera controller 120, the DSP 114, and the multiplexer ( MUX) 144 and the display unit 150 are displayed on the display unit 150 via the path of the driving unit 148 of the display device 106 (S206).

As described above, when taking a picture, a user generally wants to store an image shown on the display unit 150 of the camera phone.

However, since there is no difference between the image displayed on the display unit 150 and the image stored when the image is captured, there is no difference between the image to be taken and the stored image. If it is faster than), the video that is different from the video you want to take is stored.

Accordingly, an object of the present invention is to temporarily store the moving image in each buffer for each frame image, and then compress and store the image frame before the time when the camera shutter is pressed.

In addition, when the camera shutter is pressed, another purpose is to compress and store the first stored image frame as the image frames stored in the plurality of buffers.

In addition, another purpose is to store image frames in a plurality of buffers in sequence and display each image frame in turn on the display unit.

According to a preferred aspect of the present invention to achieve the above object, in the image capture method in the camera phone,

Storing image frames received through the lens unit in order in each buffer in a plurality of allocated first memory units;

Determining whether the camera shutter key is pressed;

If the camera shutter key is pressed, extracting and displaying an image frame earlier than the pressed time point from the first memory unit;

And compressing the displayed image frame and storing the compressed image frame in a second memory unit.                     

The display may include displaying an image frame of a buffer stored first among storage points of each image frame stored in a first memory unit when the camera shutter key is pressed.

Preferably, the first memory unit is allocated to a plurality of buffers using program logic.

Preferably, when the image frame is stored in the first memory unit, the image frame stored in the first memory unit is further characterized in that the step of displaying on the display unit after the RGB conversion.

Preferably, the image frame stored in the first memory unit is stored as a time difference for each image frame.

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

3 is a flowchart illustrating a modified method of storing an image in a camera phone according to an embodiment of the present invention.

Since the basic operation principle of the camera phone is the same, the image signal according to the present invention is stored in the first memory unit 118 through the image compression unit 116 or the display device 106 with reference to each component of FIG. 1. Describes the specific operation sent to

In a situation where the camera shutter key is not applied in the camera use mode, the image signal output from the DS 114 temporarily stores image frames having a plurality of intervals in the third memory unit 124 through the camera controller 120 for a predetermined time. The display is sequentially displayed on the display unit 150 via the camera control unit 120, the DPS 114, the multiplexer (MUX) 144, and the driving unit 148 of the display device 106.

The subject entering the camera lens through the display unit 150 is identified by the user.

On the other hand, when the camera shutter key is applied in the camera use mode, the image compression unit 116 converts the captured image signal provided from the DS 114 to JPEG format under the control of the camera control unit 120 and compresses it at a predetermined ratio. 1 is stored in the memory unit 118.

In the JPEG format, the input data format of the camera is usually YUV / YCbCr, and the format cannot display data on the display unit 150 displaying the RGB format. Thus, the YUV is converted into RGB or YCbCr is converted into RGB. It says display on 150.

The YUV / YCbCr is a color space derived from the color reference of the PAL TV, where Y is a luminance channel, U is a blue channel, and V is a red channel.

In order to take a frame that the user wants to shoot through the camera, the data of YUV / YCbCr format coming from the camera is stored. If it is temporally determined, the data when the camera shutter key is pressed must be stored.

In other words, the image is not compressed in the new YUV / YCbCr format, but in the previous frame, that is, in YUV / YCbCr format data stored in another RGB buffer.

Then, the compressed image stored in the first memory unit 118 is decompressed and provided to the DSP 114 under the control of the camera controller 120.

The image compressor 116 compresses a 640 × 480 size VGA (Video Graphics Array) signal to about 1/8 size to reduce the size of the image. For example, the image size of the 640 × 480 size is about 300KB. It is about (Kilo Byte), if the image is compressed to 1/8 in the image compression unit 116 is about 40KB size.

The first memory unit 118 is a memory for storing the compressed image output from the image compression unit 116 and is implemented as a flash memory, and the amount of the captured image is adjusted according to the memory capacity.

The camera controller 120 is implemented as a central processing unit (CPU) and controls the overall operation of the camera unit 100.

In addition, when a signal corresponding to various keys input from the key input unit 132 of the mobile phone unit 102 under the control of the mobile phone controller 128 included in the mobile phone unit 102 is transmitted under the control of the mobile phone controller 128. It performs various operations accordingly.

The second memory unit 122 connected to the camera controller 120 is a memory that stores programs for performing various operations of the camera controller 120 and is typically implemented as a static random access memory (SRAM).

The third memory unit 124 connected to the camera controller 120 is a plurality of buffers for temporarily storing an image received through the camera lens, and is typically implemented as a dynamic random access memory (DRAM).

On the other hand, while the camera control unit 120 and the mobile phone control unit 128 is shown as being configured separately, it can be implemented as a single chip using a single CPU.

Referring to FIG. 3, when YUV / YCbCr format camera data comes in real time through the camera lens unit 108 (S300), a plurality of third memory units 124 may be allocated to a plurality of buffers that are mutually toggled. Image frames having time differences are sequentially stored in respective buffers (S302).

For example, the third memory unit 124 may be equally divided into the first buffer and the second buffer using the logic of the program according to the time difference between the frames.

In other words, the image frames sequentially stored in the respective buffers in step 302 are sequentially displayed by the camera → the first buffer → the RGB conversion → the display section, and the camera → the second buffer → the RGB conversion → the display section.

After step 302, the controller 120 of the camera phone determines whether the camera shutter is pressed by the user (S304), and when the camera shutter is pressed, extracts image data from a plurality of buffers before the shutter is pressed (S306). ).

Thereafter, the extracted image data is displayed on the display unit and compressed and stored in the memory (S308).

However, if the camera shutter is not pressed by the user in step 304, the image data of the lens unit 108 is displayed on the display unit 150 as it is.

4 is a flowchart illustrating a time point of capturing and storing an image in a camera phone according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the image data is input through the camera lens unit 108 so that the control unit 120 determines whether the camera shutter is pressed by the user. Same process as 304.

Then, when it is determined that the camera shutter is pressed by the user, the controller 120 compares the time points of storing the images stored in the plurality of buffers (S406).

For example, when taking the moving image of the first stored image frame sequentially stored in the first buffer and the second buffer in which the third memory unit 124 is equally divided, it is close to the time when the shutter is pressed by the user. This is essentially the image you want to capture.

Then, in step 406, the image of the first stored buffer is compressed and stored in the memory (S408).

However, if the camera shutter is not pressed by the user in step 404, the image data of the lens unit 108 is displayed on the display unit 150 as it is.

The image capturing method described above is not only applied to a camera phone but is applicable to everything having a subject photographing function such as a digital camera.

Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible.

Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

As described above, the method of obtaining a still image in the camera phone according to the present invention is a quality because the user can take and store the image shown in the display unit of the camera phone as well as the moving image as well as the moving image (quality Excellent effect can be obtained in terms of).

Claims (5)

Storing image frames received through the lens unit in order in each buffer in a plurality of allocated first memory units; Determining whether the camera shutter key is pressed; If the camera shutter key is pressed, extracting and displaying an image frame earlier than the pressed time point from the first memory unit; Compressing the displayed image frame and storing the compressed image frame in a second memory unit. The method of claim 1, In the displaying step, when the camera shutter key is pressed, an image frame of the first stored buffer of the image frames stored in the first memory unit is displayed. The method of claim 1, And the first memory unit is allocated to a plurality of buffers using program logic. The method of claim 1, And after the storing of the image frame in the first memory unit, converting the stored image frame into RGB and sequentially displaying the stored image frame in the display unit. The method of claim 1, And an image frame stored in the first memory unit is stored at a time difference for each image frame.

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