JP2002125188A - Digital camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital camera with a new function that can directly access optional image data stored in an image buffer. SOLUTION: The digital camera having an image buffer storing image data obtained by photographing by n (n is an integer of 2 or over) frames and a recorder recording the stored image data onto a recording medium, is provided with a counter whose count is incremented every time the image data are stored, a management information table that consists of n-sets of management information areas used individually to manage the image data of n-frames and on the management information areas of which at least the count and a delete flag denoting whether deletion of the corresponding image data is permitted or inhibited is recorded, a 1st delete flag setting means that sets the delete flag on the basis of the count stored in the management information areas, and a controller that selectively records the stored image data onto the recording medium on the basis of the value of the delete flag as its control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital camera having an image buffer for storing a plurality of frames of image data obtained by imaging a subject, and a recording device for recording the image data stored in the image buffer on a recording medium. About the camera.

[0002]

2. Description of the Related Art In a conventional digital camera, image data obtained by imaging a subject is temporarily stored in an image buffer in consideration of the slow writing speed of a memory card as a recording medium, and then stored in the memory card. I was writing. For example, a high-speed continuous shooting function has been realized by storing image data for a plurality of frames in an image buffer.

[0003]

However, a conventional digital camera has a function of storing image data for a plurality of frames in an image buffer and recording the image data in a memory card. However, any digital image stored in the image buffer can be used. There was no direct access to the data. Therefore, it has been difficult to selectively delete the image data stored in the image buffer or record the image data in a memory card.

[0004] It is an object of the present invention to provide a digital camera having a new function by enabling direct access to arbitrary image data stored in an image buffer.

[0005]

According to the present invention, there is provided an image buffer for storing n (n is an integer of 2 or more) frames of image data obtained by imaging a subject. A digital camera having a recording device for recording image data stored in a buffer on a recording medium, wherein a counter increases or decreases each time image data is stored in the image buffer;
The management information area includes n management information areas for individually managing image data of a frame, and the management information area records at least a value of the counter and a deletion flag indicating whether deletion of the corresponding image data is permitted or prohibited. Management information table, first deletion flag setting means for setting the deletion flag based on the value of the counter stored in the management information area, and image data stored in the image buffer as the value of the deletion flag. And a control device for controlling the recording means so as to selectively record the data on a recording medium based on the information.

Further, the control device, if the deletion flag is a value indicating deletion permission, enables the corresponding image data to be deleted in order to store image data generated in response to a new photographing, and sets the deletion flag. Is a value indicating deletion prohibition, the recording apparatus is controlled to record the corresponding image data on a recording medium.

[0007] Further, a two-stage release switch is connected to the control device. When the control device detects that the first stage of the two-stage release switch is pressed, the control device transfers image data to the image buffer. A storage start is instructed to the image buffer, and when it is detected that the second stage of the two-stage release switch is pressed, the deletion flag setting means is operated.

Further, when the control device detects that the second stage of the two-stage release switch is pressed, the controller sets the deletion flag corresponding to image data newly stored in the image buffer to a value indicating prohibition of deletion. Operating the second deletion flag setting means for setting the flag.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a functional block diagram showing a digital camera according to an embodiment of the present invention. The imaging device 1 includes an optical lens and an imaging element, and converts light from a subject (not shown) into an image signal. The image signal is AD
The data is converted into a digital signal by the converter 2 and is written as uncompressed image data in the image buffer 3 composed of an SDRAM. The image data is once read out from the image buffer 3, a YUV signal necessary for JPEG compression processing is created in the signal processing circuit 4, and JPEG compression is performed in the compression circuit 5. The data is written and stored in the image buffer 3. The stored compressed image data is finally recorded on the memory card 6. On the other hand, a two-stage release switch 9 is connected to the control circuit 10, and controls the imaging device 1, the signal processing circuit 4, and the compression circuit 5, controls the image buffer 3 via the image buffer controller 7, and The memory card 6 is controlled via a controller. Details will be described later.

Next, the details of the image buffer 3 will be described with reference to FIGS. The image buffer 3 is composed of an SDRAM, and as shown in FIG. 2, a non-compressed image data area 31 for storing the non-compressed image data from the AD converter 2, a management information table 32, and a compressed image from the compression circuit 5. The data is mapped to a compressed image data area 33 having a capacity to store data for n (n is an integer of 2 or more) frames, and the like. The other is a work area used when the control circuit 10 performs an operation. FIG. 2 shows a state in which compressed image data for one frame is written in the compressed image data area 33, s_ad indicates the start address of the compressed image data area 33, and p_ad indicates the next compressed image data. Indicates the compressed image data storage address, which is the start address, and e_ad indicates the end address of the compressed image data area 33.

As shown in FIG. 3, the information management table 32 stores an image management information area 320 in the compressed image data area 3.
3, the same number of frames as the number of frames of compressed image data that can be stored. In the present embodiment, it is for n frames. Each image management information area 320 includes a deletion flag area 321 for storing a deletion flag indicating permission or prohibition of deletion of the corresponding compressed image data, and a serial number that increases each time the compressed image data is written to the compressed image data area 33. Related to the serial number area 322 for storing, the storage address area 323 for storing the storage address of the corresponding compressed image data in the compressed image data area 33, the size area 324 for storing the file size of the corresponding compressed image data, and the corresponding compressed image data. It comprises a JPEG information area 325 for storing JPEG information as sub-information.

The JPEG information is sub-information added when JPEG compression of image data is performed by the compression circuit 5, and is, for example, an aperture value or a shutter speed in the imaging apparatus 1.

Next, the photographing operation of the digital camera controlled by the control circuit 10 will be described with reference to the flowcharts shown in FIGS. In this embodiment, photographing and writing of the compressed image data to the image buffer 3 are performed even before the second stage of the two-stage release switch 9 is pressed.
In other words, it realizes a new function that enables pre-shooting and does not miss a photo opportunity.

When the photographing operation is started, first, initial settings are made (S1). That is, the maximum size of the compressed image data generated by the compression circuit 5 is set to max, and the start address of the compressed image data area 33 of the image buffer 3 is set to s_
The value of s_ad is substituted for the compressed image data storage address p_ad, which is the head address where the next compressed image data is written, and the end address of the compressed image data area 33 is set to e_ad
And the value of a counter p_no for generating a serial number is 1,
The number of pre-images is set in a variable N. Although the size of the compressed image data generated by the compression circuit 5 varies depending on the subject, the maximum size max can be determined based on the resolution (number of pixels) of the image to be captured and the compression ratio in the compression circuit 5. it can. The pre-shooting number is the number of image data to be written to the memory card 6 without being deleted from image data taken before the second stage of the two-stage release switch 9 is pressed.

When the first-stage depression of the two-stage release switch 9 is detected, photographing A is started (S2, S3),
By the steps S4 and S5, the photographing A is repeatedly performed while the first stage of the second-stage release switch 9 is pressed without being pressed. Note that, when the release of the first-stage press is detected in step S5, the control circuit 10 ends the photographing operation.

FIG. 5 is a flowchart showing photographing A. First, the maximum size of the compressed image data is max, rather than the difference between the end address e_ad of the compressed image data area 33 and the compressed image data storage address p_ad, which is the start address where the next compressed image data is written. It is determined whether or not it is larger (S31). If it is larger, the value of p_ad is set to the start address s_ad of the compressed image data area 33 of the image buffer 3.
(S32). That is, after the shooting A is repeated, the compressed image data is stored in the compressed image data area 33 for n frames, and then the compressed image data storage address p_
By setting ad as the start address s_ad of the compressed image data area 33, the compressed image data area 33 is continuously written with compressed image data while leaving the latest n frames of compressed image data like a flight recorder. Control.

Next, the value of the address of the image buffer 3 is p_
Deleteable compressed image data included in the range from ad to (p_ad + max) is deleted from the image buffer 3 (S33).
Therefore, even when compressed image data for n frames is stored, an area for writing new compressed image data is secured. Whether or not the compressed image data stored in the image buffer 3 can be deleted is determined using the value of a deletion flag described later.

After securing an area for writing new compressed image data in the image buffer 3 in step S33, the imaging device 1 is controlled to take in uncompressed image data into the image buffer 3 (S34), and the signal processing circuit 4 By operating the compression circuit 5, the uncompressed image data is JPEG-compressed to create compressed image data (S35). And
The created compressed image data is written into the compressed image data area 33 of the image buffer 3, and the file size size of the compressed image data is calculated (S36, S37). Further, a management information table 32 corresponding to the compressed image data
A deletion flag having a value indicating that deletion is possible is written in the deletion flag area 321 of the image management information area 320, the value of p_no is written in the serial number area 322, the value of p_ad is written in the storage address area 323, and the size area 324 is written.
Write the value of size and write JPE to JPEG information area 325
The G information is written (S38).

Next, a value obtained by adding the value of the file size size of the compressed image data to the compressed image data storage address p_ad which is the head address where the next compressed image data is written is set as a new compressed image data storage address p_ad (S3).
9) Increment the value of the counter p_no for generating a serial number (S40), and return to the original routine.

That is, by repeatedly executing photographing A, the compressed image data is continuously written into the compressed image data area 33 while leaving the latest n frames of compressed image data.

Returning to FIG. 4, the description of the operation will be continued. If it is detected in step S4 that the second stage of the two-stage release switch 9 has been pressed, the serial number value is changed from (p_no-N) to (p_no-1) for the compressed image data obtained in shooting A.
In order to write the compressed image data to the memory card 6 later, the deletion flag recorded in the deletion flag area 321 of the management information area 320 corresponding to the compressed image data is deleted with a value indicating deletion prohibition. Change to a flag (S6). Then, the value of the serial number w_p_no of the compressed image data to be written into the memory card 6 is set to (p_no-N-1) (S7), and the photographing B is started (S8).

FIG. 6 is a flowchart showing photographing B. First, the maximum size of the compressed image data is max, rather than the difference between the end address e_ad of the compressed image data area 33 and the compressed image data storage address p_ad, which is the start address where the next compressed image data is written. It is determined whether or not it is larger (S81). If it is larger, the value of p_ad is set to the start address s_ad of the compressed image data area 33 of the image buffer 3.
(S82) That is, even if photographing A and photographing B are repeated, the compressed image data storage address p_ad does not exceed the end address e_ad of the compressed image data area 33 and the compressed image data is recorded continuously. Controlling.

The value of the address of the image buffer 3 is
Whether or not there is any compressed image data whose deletion is prohibited in the range from p_ad to (p_ad + max) is detected based on the deletion flag (S83). If there is any compressed image data whose deletion is prohibited, shooting B is performed. End and return to the original routine. If not, the value of the address of the image buffer 3 is changed from p_ad to (p_ad +
The compressed image data that can be deleted included in the range of (max) is deleted from the image buffer 3 (S84). Therefore, even if compressed image data for n frames is stored,
An area for writing new compressed image data is secured.

After securing an area for writing new compressed image data in the image buffer 3 in step S84, the imaging device 1 is controlled to take in uncompressed image data into the image buffer 3 (S85), and the signal processing circuit 4 The compression circuit 5 is controlled to perform JPEG compression on the uncompressed image data to create compressed image data (S86). Then, the created compressed image data is written into the compressed image data area 33 of the image buffer 3, and the file size size of the compressed image data is calculated (S87, S88). Further, a management information table 32 corresponding to the compressed image data
Deletion flag area 321 of the image management information area 320
Unlike the step S38 of the photographing A, a deletion flag having a value indicating deletion prohibition is written in the serial number area 32.
2 is written with the value of p_no, and p_no is stored in the storage address area 323.
The value of ad is written, the value of size is written in the size area 324, and the JPEG information is written in the JPEG information area 325 (S89). That is, it is set so that all the compressed image data obtained by the photographing B is written to the memory card 6 later.

Next, a value obtained by adding the value of the file size size of the compressed image data to the compressed image data storage address p_ad which is the head address where the next compressed image data is written is set as a new compressed image data storage address p_ad (S9).
0), the value of the counter p_no for generating a serial number is incremented (S91), and the process returns to the original routine.

Returning to FIG. 4, the description of the operation will be continued. As shown in FIG. 4, the photographing B is repeated until the compressed data recording area of the image buffer 3 is filled with the compressed image data of which deletion is prohibited, or until the release of the second-stage release switch 9 from the second stage is detected. Execute (S9, S10). Finally, writing to the memory card 6 is performed (S11). Note that the compressed image data written to the memory card 6 in step S11 is compressed image data having image management information with serial numbers of w_p_no to p_no-1 and is stored in the management information table 32 in ascending order of the serial numbers. A storage address and a file size in the buffer 3 are obtained, and JPEG information is added to each compressed image data and written to the memory card 6.

As described above, in this embodiment, the image buffer 3 compresses the latest n frames until the first stage of the two-stage release switch 9 is depressed and the second stage is depressed. By storing the compressed image data continuously while leaving the image data, and by setting the latest N frames in the compressed image data stored up to that point when the second stage is pressed, deletion is prohibited. The compressed image data of N frames immediately before the second stage of the two-stage release switch is pressed and (nN) frames after the second stage release switch is pressed can be written to the memory card 6.

In this embodiment, n is stored in the image buffer 3.
The image data stored in the frame is JPEG compressed, but may be uncompressed image data. Further, the information management table 32 including the n image management information areas 320 is provided in a part of the image buffer 3, but may be provided in another memory.

[0029]

According to the present invention, it is possible to directly access arbitrary image data stored in the image buffer, so that, for example, the first stage of the two-stage release switch is pressed and the second stage is pressed. Until the image data is accumulated, the image data is continuously stored in the image buffer while leaving the latest n frames of image data. Of the latest N frames are set to delete prohibition, so that the image data of the N frame immediately before the second stage of the two-stage release switch is pressed and the image data of the (n−N) frames after the second stage are pressed are recorded on the recording medium. It is possible to provide a digital camera that can easily realize recording, and the effect is great.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram showing details of a digital camera that is an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing details of a digital camera that is an embodiment of the present invention.

FIG. 4 is a flowchart showing an operation of the digital camera according to the embodiment of the present invention.

FIG. 5 is a flowchart showing an operation of the digital camera according to the embodiment of the present invention.

FIG. 6 is a flowchart showing an operation of the digital camera according to the embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 imaging device 2 AD converter 3 image buffer 32 management information table 320 image management information area 321 deletion flag area 322 serial number area 5 compression circuit 6 memory card 9 two-stage release switch 10 control circuit

Continued on the front page F term (reference) 2H054 AA01 BB11 5C022 AA13 AB68 AC31 AC69 5C053 FA08 FA14 FA27 GB05 GB06 GB36 HA29 HA33 JA24 KA04 KA24 LA01

Claims (4)

[Claims] 1. An image buffer for storing n (n is an integer of 2 or more) frames of image data obtained by imaging a subject, and a recording device for recording the image data stored in the image buffer on a recording medium. A digital camera having a counter for increasing or decreasing a value each time image data is stored in the image buffer;
The management information area includes n management information areas for individually managing image data of a frame, and the management information area records at least a value of the counter and a deletion flag indicating whether deletion of the corresponding image data is permitted or prohibited. Management information table, first deletion flag setting means for setting the deletion flag based on the value of the counter stored in the management information area, and image data stored in the image buffer as the value of the deletion flag. A control device for controlling the recording means so as to selectively record the data on a recording medium based on the digital camera. 2. The control device according to claim 2, wherein the deletion flag is a value indicating a deletion permission, and the corresponding image data can be deleted in order to store image data generated according to a new photographing, and the deletion flag can be stored. 2. The digital camera according to claim 1, wherein the controller controls the recording device to record the corresponding image data on a recording medium if the value indicates a deletion prohibition. 3. The control device is connected with a two-stage release switch. When the control device detects that the first stage of the two-stage release switch is pressed, the control device transmits image data to the image buffer. 3. The deletion flag setting unit is operated when an accumulation start is instructed to the image buffer, and when it is detected that a second stage of the two-stage release switch is pressed, the deletion flag setting unit is operated. Digital camera. 4. When the control device detects that the second stage of the two-stage release switch has been pressed, the control device sets a deletion flag corresponding to image data newly stored in the image buffer to a value indicating prohibition of deletion. 4. The digital camera according to claim 3, wherein a second deletion flag setting unit that sets the flag is operated.