JP3160893B2 - Digital camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital camera capable of converting light from an object to be photographed into a digital signal for recording.

[0002]

2. Description of the Related Art Conventionally, there has been known a digital camera that converts light into an electric signal by an optical sensor such as a CCD, converts the electric signal into digital data, and records the digital data on a recording medium such as a flash memory. Using a digital camera, image data can be stored and various processes can be easily performed by an individual using a personal computer, etc., and film development can be performed by outputting images using a printer for personal computers or directly connected to a digital camera. Photos can be printed without. With the improvement of the printing quality of printers, it has become possible to print high-quality photographs that are almost indistinguishable from silver halide photographs.

[0003]

However, in such a digital camera as described above, a recording time of several seconds to several tens of seconds may be required from the start to the end of the recording of image data, and the next photograph is taken until the recording is completed. I couldn't shoot. Most of the recording time is for writing image data to a recording medium such as a flash memory. Since the writing speed to the flash memory cannot be easily improved, the number of output pixels of the digital camera increases, and as the information amount of the image data increases, the image 1
The recording time per sheet was long. For this reason, continuous shooting cannot be performed in a short time.
There is a problem that the time during which the photographing cannot be performed is long, and there is a risk of missing a photo opportunity.

In order to solve the above problem, a temporary storage memory such as a DRAM capable of writing at a higher speed than a flash memory is provided with a capacity capable of storing a plurality of pieces of image data, so that a plurality of images can be continuously stored. Although a digital camera capable of taking a picture is also known, in this case, there is a problem that a longer recording time to the flash memory is required after the completion of taking a plurality of pictures.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide a digital camera capable of photographing at a desired time at short time intervals.

[0006]

According to the digital camera of the first aspect of the present invention, a temporary storage means capable of temporarily storing a plurality of image data, and image data copied from the temporary storage means are recorded. Recording means, means for instructing the control unit to start photographing , and
A press switch for starting writing . Press switch
By pressing the switch , the image data is recorded in the temporary storage means, a plurality of pictures can be taken continuously, and the pressing of the push switch is released.
Since the timing of writing to the recording means can be designated more , writing to the recording means does not occur against the intention of the user.

According to the digital camera of the second aspect of the present invention, the temporary storage means can write at a higher speed than the recording means, so that after taking one picture, the next picture is taken in a short time. be able to.

[0008] According to the digital camera of the third aspect of the present invention, the compressed image data is stored in the temporary storage means. Therefore, a large number of images can be stored even if the capacity of the temporary storage unit is small.

According to the digital camera of the fourth aspect of the present invention, the control unit has means for writing from the temporary storage means to the recording means when the load is small. Therefore, the free space of the temporary storage means can be sequentially increased, and the processing capacity of the control unit can be effectively used. The time when the load on the control unit is small is, for example, a time when the user does not perform any operation after the photographing is completed.

According to the digital camera of the present invention, it is possible to start photographing when there is at least one image data in the temporary storage means. Even in this case, shooting can be started in a short time.

According to the digital camera of the sixth aspect of the present invention, the means for interrupting the writing from the temporary storage means to the recording means when the photographing start is instructed, and the temporary storage means to the recording means after the photographing is completed. Means for resuming writing. Therefore, even while the data is being written from the temporary storage unit to the recording unit, a new photograph can be taken while holding the already captured image data in the temporary storage unit.

[0012]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, a plurality of embodiments of the present invention will be described in detail with reference to the drawings. (First Embodiment) FIG. 2 is a block diagram for explaining the structure of a digital camera 1 according to a first embodiment of the present invention.
Control unit 11, condenser lens 12, CCD as imaging means
(Charge Coupled Device) 13, A / D converter 14,
R as temporary storage means for temporarily recording image data
AM (Random Access Memory) 15, flash memory 16 as recording means for recording image data, liquid crystal display (LCD) 17 for displaying images, VRAM 1 for storing data for images displayed on the liquid crystal display
8. An interface 19 for outputting the contents of the flash memory 16 to an external device.

The control unit 11 includes a CPU and the digital camera 1
That stores programs for performing various controls
M or flash memory and input / output means.
The condenser lens 12 is provided with a diaphragm 121 for adjusting the amount of light input to the condenser lens 12. CCD1
3, C (Cyan), M (Magenta), Y (Yello
w), a color image can be taken by using the CCD 13 in which a plurality of image pickup devices having complementary color filters of G (Green) are arranged in a matrix. The complementary color filter may have three colors of C, M, and Y in some cases. R (Red
), G (Green) and B (Blue) primary color filters may be used.

The A / D converter 14, the control section 11, and the program recorded in the control section 11 constitute a conversion means for converting an output signal from the CCD 13 into image data. .

As the RAM 15, a DRAM (Dynamic RAM) having a self refresh function is used. As shown in FIG. 3, an area 151 for storing at least one image data and an area 1 for storing a plurality of compressed image data are provided.
52, 153, and 154. A plurality of uncompressed image data may be stored. Further, the RAM 15 may store only the compressed image data.

The flash memory 16 is a rewritable recording medium capable of holding recorded contents without power supply. The flash memory 16 is built in the digital camera 1 or is detachably attached to a card slot 20 of the digital camera 1. Have been. As the flash memory 16, for example, a PC
Memory card conforming to MCIA standard or PCMC
By using a memory card that can be attached to the IA card adapter, the contents of the flash memory 16 can be directly read and written by a personal computer having a PCMCIA card slot.

FIGS. 4 and 5 show a digital camera 1 according to this embodiment.
0 is a plan view and a rear view. The photographing is started by pressing a shutter button 101 as a photographing start instruction means. The control unit 11 includes a shutter button 101
`` Half-pressed '' by pushing to the middle position of the movable range,
It is possible to discriminate and recognize the “full press” that has been pressed to the limit of the movable range or to the vicinity of the limit. When the shutter button 101 is fully depressed while pressing the image recording standby switch 107 as a depressing switch for instructing the writing time from the temporary storage unit to the recording unit, the control unit 11 stores the image data in the RAM 15 and then stores the image data in the RAM 15. When the recording standby switch 107 is released, copying (writing) of image data from the RAM 15 to the flash memory 16 starts.

The user uses the mode switching dial 102 to switch the mode of the LCD 17 to “View”,
One of four modes of “On”, “Play”, and “Off” is selected. The “View” mode is
In this mode, shooting is performed using the LCD 17 as a finder. The “On” mode is a mode in which the LCD 17 is not displayed in order to save power consumption of the digital camera 1 and a photograph is taken while looking through the optical viewfinder 101. "P
The “lay” mode is a mode in which an image based on image data that has already been captured and recorded in the flash memory 16 is displayed on the LCD 17.
Mode. When the mode switching dial is set to “Off”, the power of the digital camera 10 is turned off.

Next, the operation of the digital camera 1 of this embodiment will be described. Set the mode switching dial 102 to “Pla
y ”, the LCD 1 is controlled by the control unit 11.
7 displays an image based on the image data in the flash memory 16. Pressing the first arrow key 104 displays the previous image, and pressing the second arrow key 105 displays the next image.

When the select key 106 is pressed, a menu display mode is set, and various settings such as date and image quality can be made. First arrow key 104 and second arrow key 10
By selecting an item to be set with 5 and pressing the select key 106 again, the setting can be changed. Here, conditions such as numerical values can be changed using the first arrow key 104 and the second arrow key 105. By pressing the ESC key 103, it is possible to return to the previous screen.

FIG. 1 is a flowchart showing the processing performed by the digital camera 1 when the mode switching dial 102 is at the "View" or "On" position. In step S101, the control unit 11 detects the position of the mode changeover switch 102, and sets the mode to the View mode or the On mode.
It is determined whether to continue the mode.

In step S102, it is determined whether or not the RAM 15 has image data that has not been recorded in the flash memory 16. If there is unrecorded image data in the RAM 15, the process proceeds to step S103. If there is no unrecorded image data, the process proceeds to S105.

In step S103, it is determined whether or not the flash memory 16 has a sufficient free space. If the free space in the flash memory 16 is larger than the amount of compressed image data in the RAM 15 + the amount of data of one compressed image data, the process proceeds to S104. If there is less free space in the flash memory 16, the process proceeds to S110.

In step S104, it is determined whether or not the image recording standby switch 107 has been pressed. If the image recording standby switch 107 has not been pressed, the process proceeds to step S110, and if it has been pressed, the process proceeds to S105.

Step S105 is a state of waiting for photographing, in which the condenser lens 12 is set every one-second to several tenths of a second.
The light condensed on the CCD 13 is converted into an electric signal and converted into digital image data. In the case of the View mode, the image data is transferred to the VRAM 18, and the shooting target is displayed on the LCD 17 as a moving image. The exposure at the time of photographing is changed by the control unit 11 controlling the aperture 121 and the shutter speed of the condenser lens 12, that is, the accumulation time of the CCD 13, based on data output from the CCD 13. Exposure automatically set by the control unit 11 is referred to as automatic exposure. The shutter of the digital camera 10 is a shutter that physically blocks light or a CCD 13.
Electronic shutter, or both. The user presses the shutter button 1 of the digital camera 1
When the shutter button 10 is pressed halfway, appropriate exposure and focus are set for the image recognized by the CCD 13 and the shutter button 10
Exposure and focus are fixed while 1 is half-pressed.

If it is recognized in step S106 that the user has fully pressed the shutter button 101, the flow advances to step S107. If the shutter button 101 has not been pressed, the flow returns to step S101.

In step S107, image data is created and stored in the RAM 15 as follows. First, CC
All the charges accumulated in D13 are once discharged, and then the light collected by the condenser lens 12 is input to the CCD 13. In the CCD 13, the light is converted into electric charges according to the amount of light. The electric signal output from the CCD 13 is converted into a digital signal by the A / D converter 14. The digital data output from the A / D converter 14 is D
The address is directly designated and stored in the RAM 15 by a direct memory access (MA) without passing through the control unit 11.
The data stored in the RAM 15 is subjected to various image corrections such as white balance adjustment, interpolation processing, and color correction, and then JPEG (Joint Photographic E) is performed to increase the number of images recorded in the RAM 15 and the flash memory 16.
xperts Group) to generate image data with a small capacity. JPEG is a commonly used image compression method capable of handling an image of about 16.7 million colors, and the stored image quality can be adjusted by changing the compression ratio. The JPEG compression is performed by the control unit 11 using software, and a dedicated circuit can be used for speeding up. RAM 15
In addition to the area for storing the output of the A / D converter 14, the memory has a capacity capable of storing at least a plurality of compressed image data.

If it is determined in step S108 that the image recording standby switch 107 has not been pressed, or if it is determined in step S109 that there is no free space in the RAM 15 for at least one JPEG-compressed image data, the process proceeds to step S108. Proceed to S110. In step S110,
The JPEG-compressed image data is stored in the flash memory 16
And the process proceeds to step S111. Step S11
In step 1, it is determined whether or not the free space in the flash memory 16 is smaller than one compressed image data. If the flash memory 16 has little free space, the user is notified by a warning sound, a display on the LCD 17, or the like that no further photographing is possible, and the View mode or the On mode is terminated.

In step S108, it is determined that the image recording standby switch 108 has been pressed, and in step S109, the RA
If it is determined that there is an empty space in M15 for one or more JPEG-compressed image data, the process returns to step S101 and the next photograph can be taken.

Since the photographing is performed according to the above-described process, if the photographing is performed by pressing the shutter button while pressing the image recording standby switch 107, it is not necessary to write the image data to the flash memory immediately after the photographing is completed. A photograph can be taken. Further, by releasing the pressing of the image recording standby switch 107, the flash memory 1 is removed from the RAM 15 which takes a long time.
Since the timing of writing to 6 can be determined by the user's intention, it is possible to prevent a situation where photographing cannot be started for a long time against the user's intention.

When the mode switch 102 is set to "On"
, The LCD 17 is not energized and the LC 17
D17 is always in a non-display state. Normally, the CCD 13 is not energized, and the user presses the shutter button 1
The operation of the CCD 13 starts when 01 is half-pressed. Other operations are the same as those in the “View” mode.

(Second Embodiment) A digital camera according to a second embodiment of the present invention has a configuration similar to that of the first embodiment shown in FIGS. In the second embodiment, the shutter button 101
Even if is pressed all alone, the image data after JPEG compression is temporarily stored in the RAM 15 in the same manner as when the shutter button 101 is pressed while pressing the image recording standby switch 107 in the first embodiment.

After the storage of the image data in the RAM 15 is completed, when the load on the control unit 11 is small, such as when the user is not in a standby state in which no operation such as image capturing and reproduction is performed, the RA
Writing from M15 to the flash memory 16 is executed.

FIG. 6 is a time chart showing processing performed by the control unit according to the comparative example and the present embodiment. In the conventional digital camera according to the comparative example, when the shutter button 101 is pressed to take one photographic image, image data is generated on the RAM 15 from the signal read by the CCD 13 as shown in FIG. Flash memory 16
The writing of image data is performed. After the writing to the flash memory 16 is completed, the next photograph image can be taken by pressing the shutter button 101 again. Shutter button 10 to take the first shot
The interval t1 from when the user presses 1 to the time when the shutter button 101 can be pressed to take the second image is determined by the sum of the writing time of the image data to the RAM 15 and the writing time to the flash memory 16. Is also longer.

On the other hand, in the present embodiment, when the shutter button 101 of the digital camera 10 is pressed while the first image data is being written to the flash memory 16 as shown in FIG. If there is enough free space to store the first image data, the writing of the first image data to the flash memory 16 is suspended, and the second image data is written to the RAM 15. The control unit 11 stores the position of the data for which the writing to the flash memory 16 has been interrupted.
After the storage in the AM 15 is completed, writing of the first image data into the flash memory 16 is restarted. Therefore, the shutter button 101 is used for the first photographing.
The interval t2 from when is pressed until the shutter button 101 is pressed to take the second image can be made smaller than the interval t1 in (A).

If there is not enough free space in the RAM 15 to store one image data, the shutter button 10
Even if 1 is pressed, the control unit 11 does not start the photographing process,
Writing from the M15 to the flash memory 16 is performed with priority.

In the above embodiments of the present invention, a digital camera having an LCD has been described. However, the present invention can be applied to a digital camera without an LCD. Further, it is also possible for a single digital camera to operate both the first embodiment and the second embodiment by changing the setting by the user.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a procedure for recording an image by a digital camera according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a digital camera according to a first embodiment of the present invention.

FIG. 3 is a diagram illustrating a digital camera according to a first embodiment of the present invention;
It is a schematic diagram which shows the content of AM.

FIG. 4 is a plan view showing the digital camera according to the first embodiment of the present invention.

FIG. 5 is a rear view showing the digital camera according to the first embodiment of the present invention.

FIG. 6 is a time chart showing a process performed by a control unit of the digital camera according to the second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 digital camera 11 control unit 12 condenser lens 121 aperture 13 CCD (imaging means) 14 A / D converter (conversion means) 15 RAM (temporary storage means) 16 flash memory (recording means) 17 liquid crystal display device (LCD, display Means) 18 VRAM 19 interface 20 card slot 101 shutter button 107 image recording standby switch 108 optical viewfinder

Continuation of the front page (56) References JP-A-6-86203 (JP, A) JP-A-10-178615 (JP, A) JP-A-7-95507 (JP, A) JP-A-10-32775 (JP) JP-A-6-169426 (JP, A) JP-A-7-334467 (JP, A) JP-A-8-16445 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB Name) H04N 5/222-5/257 H04N 5/91

Claims (6)

(57) [Claims] An imaging unit configured to convert light from an imaging target into an electric signal; a conversion unit configured to convert an output signal from the imaging unit into image data; and a temporary storage capable of temporarily storing a plurality of image data. Means, recording means for recording image data copied from the temporary storage means, a control unit for controlling the imaging means, conversion means, temporary storage means and recording means, and means for instructing the control unit to start photographing Start writing to the recording means when not pressed.
And a pressing switch . 2. The digital camera according to claim 1, wherein said temporary storage means is writable at a higher speed than said recording means. 3. A device for compressing the image data,
The digital camera according to claim 1, wherein the compressed image data is stored in the temporary storage unit. 4. The digital device according to claim 1, wherein the control unit includes a unit that writes data from the temporary storage unit to the recording unit when a load is small. camera. 5. The digital camera according to claim 1, further comprising a unit that can start photographing when the temporary storage unit has a space for at least one image data. . 6. A means for interrupting writing from said temporary storage means to said recording means when a photographing start is instructed, and means for resuming writing from said temporary storage means to recording means after photographing is completed. 6. The method according to claim 5, wherein
A digital camera according to claim 1.