JP3237627B2 - Image display method and digital camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an image display method and a digital camera.

[0002]

2. Description of the Related Art Conventionally, there has been known a digital camera which converts light into an electric signal by an optical sensor such as a CCD, converts the electric signal into digital data, and stores the digital data in a storage medium such as a flash memory. Many digital cameras are equipped with a liquid crystal display (LCD), and the shooting range can be accurately determined by using the LCD as a finder during shooting. In addition, since the photographing is completed and the image stored in the flash memory can be reproduced on the LCD, the user can confirm the photographed image immediately after photographing the subject without performing processing such as development. it can.

Since image data stored in a flash memory is stored as compressed image data compressed in a file format such as JPEG, the compressed image data is expanded in a VRAM and displayed on an LCD.
The LCD has 640 x 480 pixels and 320 x
While the image data is composed of 240 pixels and the like, the number of pixels of the image data is 1600 × 1200 pixels, 1280 × 960
Since the number of pixels is 1024 × 768 pixels, 640 × 480 pixels, etc., it is necessary to reduce image data in accordance with the number of pixels of the LCD in order to display an image on the LCD.
Since the expansion and contraction of the compressed image data are performed every eight lines and transferred to the VRAM, an image based on the image data is displayed on the LCD from top to bottom every eight lines.

[0004]

However, in a circuit using a CPU having a relatively low processing capability, such as a digital camera, the processing time for rewriting one display image to the next display image is long, and the compression image When data is developed and reduced for every eight lines and displayed on the LCD, it takes about two seconds to change the display from top to bottom of one image display to the next image. When continuously reproducing several to several tens of images on the LCD of the digital camera, the shooting of which is completed,
While it is desired to display one image in a stationary state for 3 to 5 seconds, the processing time for rewriting to the next image is about 2 seconds, and the image rewriting process lacks smoothness.

It is an object of the present invention to provide an image display method capable of smoothly rewriting an image when displaying the image continuously.

Another object of the present invention is to provide a digital camera which can improve the processing speed and does not increase the manufacturing cost.

[0007]

Means for Solving the Problems According to the first aspect of the present invention.
3. An image display method according to claim 1, or the digital camera according to claim 2.
According to this, the n-th (n is a natural number) image is displayed
In the meantime, the (n + 1) th compressed image data is stored in a plurality of areas.
Divide, expand and reduce to a displayable image size (n +
1) Create the image data of the sheet and store it in the temporary storage medium
You. Creation and temporary creation of (n + 1) th display image data
When the storage on the storage medium is completed, the
(N + 1) th display image data is
Transferred to the data storage medium. Therefore, stored in the storage unit
The image based on the compressed image data
Rewrite images in a short time when displaying continuously
be able to.

Also, while displaying the n-th image,
Display image data for displaying the (n + 1) th image
To rewrite images in a short time.
Can be. Therefore, a new section is required to rewrite the image.
Product, for example, to improve the display processing speed of the reproduced image
Equipped with a high-speed CPU, or add new parts
You don't have to. Therefore, the production cost increases,
It does not incur additional manufacturing steps.

[0009]

[0010]

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

A digital camera 1 according to one embodiment of the present invention.
0 is shown in FIGS.

As shown in FIG. 1, a digital camera 10
Is a control unit 11, a condenser lens 12, a CCD (Charge Cou
imaging device having a pled device (Pled Device) 14 and an A / D converter 15, and an LCD (Li) as an image display unit for displaying an image.
(Quad Crystal Display) 16, RAM (Random Access Memory) as a temporary storage medium for temporarily storing image data
mory) 17, a flash memory 18 as a storage unit for storing captured image data, a VRAM (Video RAM) 19 as a display image data storage medium for storing data for images to be displayed on the LCD 16, and a flash memory 18. It comprises an interface 20 for outputting the contents to an external personal computer or the like. The control unit 11 includes a CPU (Central Processing Unit) (not shown), a ROM in which programs for performing various controls of the digital camera 10 are recorded, and an input unit 13. Further, the control unit 11, the LCD 16, the RAM 17, the flash memory 18 and the VRAM 19 constitute an image display device.

The CPU of the control unit 11 expands the compressed image data stored in the flash memory 18 according to a computer program stored in the ROM or the flash memory 18, reduces the expanded image data, and writes it in the RAM 17. Digital camera 10 such as processing for transferring image data written in RAM 17 to VRAM 19 and displaying an image based on the image data on LCD 16.
Control and processing. The input unit 13 includes a shutter button 2 as an instruction unit for inputting execution of photographing.
1 and input buttons for operating various functions of the digital camera 10.

The digital camera 10 is operated by power supplied from a power source (not shown). As a power supply source, for example, a primary battery such as an alkaline battery, a secondary battery such as a nickel metal hydride battery, an AC power supply via an AC adapter, or the like can be used.

As the CCD 14, for example, C (Cyan), M (Magenta), Y (Yellow), G (Gre
By using a CCD in which a plurality of pixels having a complementary color filter of en) are arranged in a matrix, a color image can be taken. R (Red), G (Green), B
In some cases, a CCD having a (Blue) primary color filter is used.

The electric signal output from the CCD 14 is A /
The digital data converted into a digital signal by the D converter 15 and output from the A / D converter 15 are directly designated by an address of the RAM 17 by a direct memory access (DMA) without using the control unit 11 for speeding up. Be recorded. As the RAM 17, a DRAM having a self-refresh function can be used. The image data recorded in the RAM 17 is subjected to various image corrections such as white balance adjustment, interpolation processing, and color correction by the control unit 11.

The corrected image data is compressed by a method such as JPEG (Joint Photographic Experts Group) in order to increase the number of images to be recorded in the flash memory 18 as image storage means, thereby generating small-capacity image data. JPEG is about 167 of 256 gradations of each color of R, G, B.
This is a generally used irreversible image compression method capable of handling images of 10,000 colors, and the stored image quality can be adjusted by changing the compression ratio. JPEG compression is
In addition to the control unit 11 using software, a dedicated circuit can be used for speeding up. The compressed image data is stored in the flash memory 1 as a JPEG file.
Record in 8. The flash memory 18 is a rewritable recording medium capable of storing recorded contents without power supply, and is built in the digital camera 10 or is detachably attached to the digital camera 10.

As a means for inputting image data shot to a personal computer, a method of connecting a JPEG file in a flash memory to a personal computer by connecting to an interface 20 of a digital camera 10 via a serial cable or the like, or a method of using a flash memory 18 If it is detachable and formatted in a format compatible with a personal computer, the JPEG recorded on the flash memory 18 via the adapter
The file can be read directly by a personal computer.

As shown in FIGS. 2 and 3, the digital camera 10 operates a dial switch 22 provided at an upper portion to switch a photographing mode and operate a power supply. When the dial switch 22 is in the “Off” mode,
The power of the CCD 14 and the LCD 16 of the digital camera 10 is turned off, and photographing cannot be performed.
When the dial switch 22 is in the “On” mode, the CCD
The power of the LCD 14 and the digital camera 10 is on, but the power of the LCD 16 is off, so that the user takes a picture while looking at the viewfinder 24.
When the dial switch 22 is in the “View” mode, C
Since the power supplies of the CD 14, the LCD 16 and the digital camera 10 are all on, the user can take a picture while watching the LCD 16. Further, when the dial switch 22 is set to the “Play” mode, it is possible to reproduce an image which has been photographed before and stored in the flash memory 18. In the “On” mode, the power of the LCD 16 is off, and the power consumed by the LCD 16 can be saved.

Next, an image display method for continuously reproducing an image based on the image data stored in the flash memory 18 on the LCD 16 using the digital camera 10 will be described.

An image based on photographed image data is converted to an LC
In the case of playback with D16, when the dial switch 22 provided on the upper part of the digital camera 10 is set to the “Play” mode, the L switch provided on the back of the digital camera 10 is set.
An instruction screen for the user to instruct a reproduction method is displayed on the CD 16. The user instructs a reproduction method from input means 13 such as buttons provided on the digital camera 10 according to the instruction screen. When the "slide show" mode for continuously displaying and reproducing a plurality of shot images is selected, the following processing is performed.

Here, the image is composed of 1280 × 96 pixels.
An image based on image data of 0 has a pixel number of 640 × 480.
The case of displaying on the LCD 16 will be described. n is 1
Any number above. The 0th image is the above-described instruction screen.

The n-th compressed image data compressed and stored in the flash memory 18 is expanded in units of eight lines to create image data having 1280 × 8 pixels.

When the image data in units of 8 lines is expanded, the number of pixels in the horizontal direction is set to 6 according to the number of pixels of the LCD 16.
The image data is reduced to 40, and the reduced image data is written to the RAM 17.

The processing described above is repeated until all the n-th image data is expanded in the RAM 17 to create image data having 640 × 480 pixels.

All the n-th image data is stored in the RAM 1
7, the black image data is written into the VRAM 19, and the (n-1) th image displayed on the LCD 16 is erased.

When the erasing of the LCD 16 is completed, the developed nth image data is transferred to the VRAM 19, and an image based on the nth image data is displayed on the LCD 16.

When the transfer of the n-th image data to the VRAM 19 is completed, the operations of (1) to (n + 1) -th image data are repeated.

In the above-described image display method, while the n-th image data is processed in the RAM 17 by
At (D16), the (n-1) th image is displayed. The time required for is about 2 seconds, and the time required for is about 0.5 seconds. Since one image is displayed in a stationary state for 3 seconds to 5 seconds, the n-th image is developed in the RAM 17 while the (n-1) -th image is displayed on the LCD 16. Then, the reduction process can be completed. The above processing is performed by the control unit 11.

As described above, according to the embodiment, the image data once expanded and reduced in the RAM 17 is stored in the VRAM 1.
9, the compressed image data is decompressed and transferred to the LCD 16
The total time (approximately 3 seconds) required to display the
This is longer than the time (about 2.5 seconds) for directly writing the image data expanded from the compressed image data to the VRAM 19 as in the related art. However, since the (n + 1) th image can be expanded in the RAM 17 while the nth image is being displayed on the LCD 16, the display of (n + 1) is completed in a short time when the display of the nth image is completed. ) The image data of the sheet is stored in VRAM1
9 and displayed on the LCD 16. Accordingly, the apparent image rewriting time for the user is reduced, and the time required for image rewriting can be increased even with a circuit using a CPU having relatively low processing capability. Also, a RAM 1 conventionally mounted for use in compressing image data at the time of photographing and at the time of image processing.
7, it is not necessary to add a new component.

In the above embodiments, the case where the image display device is applied to a digital camera has been described. However, as long as the device has the image display device, the present invention is not limited to the digital camera. Also, a method of reducing image data and displaying the image data on the LCD has been described. However, image data having a smaller number of pixels than the number of pixels of the LCD can be enlarged.
Further, in the case of image data having the same number of pixels as the number of pixels of the LCD, it is possible to omit the processing of reducing and enlarging.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a digital camera according to an embodiment of the present invention.

FIG. 2 is a plan view showing a digital camera according to one embodiment of the present invention.

FIG. 3 is a rear view showing the digital camera according to one embodiment of the present invention.

FIG. 4 is a digital camera CC according to an embodiment of the present invention.
It is a schematic diagram which shows D.

[Explanation of symbols]

Reference Signs List 10 digital camera 11 control unit (image display device, compressed image data creation unit) 12 condenser lens (imaging unit) 13 input unit 14 CCD (imaging unit) 15 A / D converter (imaging unit) 16 LCD (image display device) , Image display unit) 17 RAM (image display device, temporary storage medium) 18 Flash memory (image display device, storage unit) 19 VRAM (image display device, display image data storage medium) 20 interface

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ identification symbol FI H04N 5/907 G09G 5/00 555G // H04N 101: 00 (58) Fields surveyed (Int.Cl. ⁷ , DB name) H04N 5/76-5/781 H04N 5/907-5/956 H04N 101: 00 G09G 5/00

Claims (2)

(57) [Claims] 1. A storage unit for storing compressed image data.
And the compressed image data stored in the storage unit.
Storage medium for storing display image data developed from
And the display image data transferred from the temporary storage medium.
Having a display image data storage medium for storing data
Image based on the display image data stored in the data storage medium.
Image display unit capable of displaying an image.
An image display method, wherein the image display unit stores n (n
Is a natural number)
The first process for displaying the n-th image based on the display image data
And while the n-th image is displayed on the display unit,
(N + 1) th compressed image stored in the storage unit
Dividing the data into a plurality of areas, one of the plurality of areas
Create image data expanded for the area of
The data is reduced according to the number of pixels of the image display unit,
A second step of storing the data in a temporary storage medium, and compressing the (n + 1) -th piece divided into the plurality of areas.
Repeat the second step for all regions of the image data
And a third step of creating the (n + 1) th display image data
And when the third step is completed, the image is displayed on the image display unit.
Delete the image based on the n-th display image data
And the (n + 1) -th table stored in the temporary storage medium.
Display image data is temporarily transferred to the display image data storage medium.
A fifth step of transmitting the (n +) transferred to the display image data storage medium.
1) Displaying an image based on the first display image data in the image
And a sixth step of displaying the image on a section . 2. A storage section in which compressed image data is stored.
And the compressed image data stored in the storage unit.
Storage medium for storing display image data developed from
And the display image data transferred from the temporary storage medium.
Having a display image data storage medium for storing data
Image based on the display image data stored in the data storage medium.
Digital camera with an image display unit that can display images
In the image display unit, n (n
Is a natural number)
The n-th image based on the display image data is displayed
In the meantime, the (n + 1) -th pressure stored in the storage unit
Dividing the reduced image data into a plurality of areas;
Create expanded image data for one area of
The image data is reduced according to the number of pixels of the image display unit.
Stored in the temporary storage medium and divided into the plurality of areas.
Of the (n + 1) th compressed image data
Creates the developed image data for the area and
Data according to the number of pixels of the image display unit, and
Time storage medium, repeatedly (n + 1) sheets
Means for creating the display image data of the eyes, and creation of the (n + 1) th display image data is completed
And the display of the n-th sheet displayed on the image display unit.
Delete the image based on the image data, and
The stored (n + 1) th display image data is stored in the
Means for temporarily transferring to the display image data storage medium, and (n +
1) Displaying an image based on the first display image data in the image
Digital camera, characterized in that it comprises means for displaying the section, the.