JPH04354482A - Electronic still camera device - Google Patents

Abstract

PURPOSE:To relieve the limit of the processing of a CPU and the load by recording head start position information and number information of a unit recording area so as to store a number data of a cluster required for the recording to a RAM work area of the CPU when a picture data is continuously recorded to the unit recording area. CONSTITUTION:It is noted that there are many consecutive clusters forming one packet when a picture data is recorded by the MAT system, then an area 29 representing 5 clusters required for the data and available cluster numbers 1-5 is allocated to a most significant bit D15 of a data storage area 32 as consecutive information. The CPU built in the camera main body increments the cluster number by a designated consecutive cluster number based on the consecutive information, calculates an address in response to the number and records the data to a memory card. Thus, a RAM work area 30 requiring 10 bytes is reduced to an area 31 in 4 bytes.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an electronic still camera device that converts a photographed optical image into digital image data, compresses the data by a predetermined amount, and records the data on a recording medium such as a semiconductor memory.

0002

2. Description of the Related Art Currently, cameras that are widely used use silver halide film as a recording medium, and after photographing, this film is developed by chemical processing to produce a single photograph. Therefore, the captured image cannot be viewed immediately.

[0003] In order to meet this demand, an electronic photographic system that converts an optical image into an electrical signal and displays the image on a television receiver has been developed, for example, as disclosed in Japanese Patent Laid-Open No. 49-52192. was developed and commercialized in recent years. In such a system, if the acquired optical image is digital image data, it is conceivable to use a semiconductor memory as the recording medium.

[0004] In particular, in recent years, with the advancement of semiconductor element mounting technology, memory cards with built-in semiconductor memory have come into practical use, and development for using this memory card as a recording medium is progressing. It is being actively carried out.

By the way, in the conventional electronic still camera device that uses a memory card as a recording medium as described above, a video signal is converted into digital data, and the data is further band-compressed and recorded in a semiconductor memory. Therefore, the data length for one still image varies depending on the content of the photographed image, the compression ratio specified by the user, and the like. In addition, the memory stores the first image in the order in which it was taken,
Still image data is written sequentially, such as the second image, etc.

For this reason, if the data of the n-th still image becomes unnecessary and is deleted during shooting, the data length of the n-th still image or more will be stored in the storage area after the deletion. Still images cannot be recorded. Therefore, unless there is a still image taken after the nth still image whose data length is shorter than the data length of the nth still image, the recording area after deletion will not be used at all and will be wasted. It ends up. This causes a problem that the storage capacity of the memory cannot be used effectively.

In order to solve this problem, the storage capacity of the memory card is divided into a plurality of unit storage areas (hereinafter referred to as clusters), and data of captured still images is stored as a collection of several clusters (hereinafter referred to as packets). A memory card recording management system has been proposed. In addition, the memory includes a MAT (
This method is called the MAT method because a memory allocation table (memory allocation table) area is provided.

[0008]

[Problem to be Solved by the Invention] When recording image data using the above-mentioned MAT method, which is a memory card management method, the CPU (Central Processing Unit) built into the camera body cannot record image data in the MAT area. It is necessary to refer to the information in the database and secure the clusters necessary for recording. In this case, the shorter the cluster length or the longer the data length to be stored, the greater the number of clusters to be secured. In the MAT method, the actual address for recording on the memory card is determined by referring to the cluster number. For this reason, all necessary cluster number data must be temporarily stored in the work area of the CPU's RAM (read/write memory). Therefore, the RAM work area is occupied to store this data, which limits the processing of the CPU and increases the load.

Therefore, the present invention was made to solve the above problems, and when recording data in a memory using the MAT method, the cluster number data required for recording is
It is an object of the present invention to provide an electronic still camera device that can be rationally stored in the RAM work area of a PU and that can reduce processing constraints and loads on the CPU as much as possible.

0010

[Means for Solving the Problems] An electronic still camera device according to the present invention converts a photographed optical image into electrical still image data, divides a recording area of a recording medium into a plurality of unit recording areas, and divides the recording area of a recording medium into a plurality of unit recording areas. In an electronic still camera device in which the still image data is distributed and recorded in a plurality of unit recording areas, when the still image data is continuously recorded in the unit recording areas, the continuous unit recording areas and information on the number of successive unit recording areas below on the recording medium.

[0011]

According to the above means, when data is recorded on a memory card, the area occupied by the RAM work area of the CPU can be reduced compared to when usable cluster information is stored for each number. Particularly in the case of a one-chip CPU with a limited RAM work area, processing constraints and loads are significantly reduced.

0012

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of an electronic still camera device according to the present invention. That is, this electronic still camera is comprised of a camera body 4 and a memory card 6 that is removably attached to the camera body 4. The camera body 4 includes a lens barrel 3, a finder 2, and a shutter button 1, as well as an opening 5 into which a memory card 6 is inserted, like a normal camera.

FIG. 2 shows the internal structure of the camera body 4. As shown in FIG. That is, numeral 7 in the figure is a lens disposed within the lens barrel 3, and the lens 7 projects a subject image onto a solid-state imaging device 8, such as a CCD, disposed on the back surface of the lens 7. The solid-state image sensor 8 outputs an analog electric signal (video signal) depending on the brightness of the image projected through the lens 7.
This outputs the following.

The electrical signal output from the solid-state image sensor 8 is supplied to an image processing circuit 9 and subjected to predetermined signal processing, and then input to an analog/digital (hereinafter referred to as A/D) conversion circuit 10. The image data is then converted into digital image data. Image data output from the A/D conversion circuit 10 is input to a band compression processing circuit 11 and compressed by a predetermined amount of data, and then supplied to a memory interface circuit 15.

Here, 13 in FIG. 2 is a CPU, which performs overall control of the entire electronic still camera including the memory card 16. For example, the CPU 13 controls the memory interface circuit 15 to write image data output from the band compression processing circuit 11 to the memory card 16 or read data from the memory card 16. The CPU 13 controls the data amount compression rate of the band compression processing circuit 11 based on the operation of the operation section 14 provided in the camera body 4, and also controls the display section 12.

Further, voice is input to the microphone 17 , and the voice output from the microphone 17 is input to the voice processing section 18 and code-converted, and then supplied to the memory interface circuit 15 . As a result, the audio processing section 18
The audio data output from the CPU 13 is recorded on the memory card 16 under the control of the CPU 13 . Image data taken with the electronic still camera is recorded on a memory card using the MAT method, which is one of the recording management methods. FIG. 3 shows a recording format based on the MAT method.

Each piece of data constituting the header area 19 in the figure is for managing the entire recorded data recorded on the memory card 16 shown in FIG.
detects the data content in this area when a memory card is inserted, and determines the identity of the inserted memory card.

Image data is recorded in packets using the MAT method. Furthermore, this packet records not only image data but also other data such as audio data. M
In the AT method, the entire data is expressed in units of packets, so index information of the contents of each packet is recorded in the packet information area 20. The directory area 21 is an area in which an address map indicating where a packet exists in the memory card is recorded.

The MAT area 22 is an area for recording the connections and order of clusters indicating subdivided unit storage areas. By reading the data in this MAT area 22, each cluster making up one packet can be confirmed.

The packet data area 23 is an area where data such as images is actually stored. The card area 24 is an area in which data representing the type of memory constituting the memory card is recorded. Below, with reference to FIG.
The operation of recording image (or audio) data in the format shown in FIG.

[0022] When the recording operation is started (step S1)
, the required number of clusters N is calculated from the data length of the data to be stored in the memory card 16 (step S2). This number N of clusters is compared with the number of remaining clusters (step S3), and it is determined whether the number of remaining clusters is less than the number N of clusters required for recording (step S3).
4). If there is a shortage (Yes), a warning is issued (step S5) and the operation is ended (step S6). Through the above operations, it is checked whether the data to be recorded at present can actually be recorded on the memory card.

If it is determined that the number of remaining clusters is not less than the number N of clusters required for recording (No) and it is possible to record on the memory card, the number of packets is read from the header area 19 and the number of used packets is checked. (Step S7). Furthermore, the number of clusters is read from the header area 19, and the number of used clusters is checked (step S
8). Then, based on the check results in steps S7 and 8, a storage packet number A and a storage start cluster number B are determined (step S9).

Next, the contents of cluster number A are checked with reference to the MAT area 22 (step S10), and it is determined whether cluster number A is vacant (step S11). If it is determined that cluster number A is vacant (Yes), subtract 1 from the number of clusters N calculated in step S2 to obtain a new number of clusters N (step S12), and check whether this number of clusters is 0 or not. is determined (step S13). If it is determined that the subtracted number of clusters is not 0 (No), 1 is added to the cluster number A to make it a new cluster number A (step S14), and the process returns to step S10. On the other hand, if it is determined in step S11 that the cluster number A is not vacant (No), processing is performed in step S14. Through the above operations, the clusters necessary to record the data of the number of clusters calculated in step S2 are secured. Then, usable class areas are detected (step S15). Data is sequentially recorded in the usable clusters detected in this way (step S16).

Connection information of the used cluster is recorded in the MAT area (step S17), and the start cluster number A is placed in the position of packet B in the directory area 21.
is recorded (step S18). Finally, the contents of the header area 19 are updated (step S19), and the recording operation ends (step S20).

The problem with the above recording operation is that the MAT
Browse the area to find a free available cluster,
Now is the time to secure the clusters necessary for recording. In the MAT method, the address for actually recording on the memory card is calculated based on the cluster number. Conventionally, all usable clusters in a memory card are temporarily stored in a number format in the RAM work area of the CPU of the camera body. For this reason, when an attempt is made to record image data with a large amount of data, such as uncompressed data, it occupies a considerable amount of the RAM work area, and in some cases, there may be a situation where the RAM work area becomes insufficient. In such a case, the recording process must be performed while referring to the MAT area and searching for a usable cluster several times. This not only places a burden on the processing of the CPU, but also affects the recording processing time. If the recording processing time becomes long, for example, high-speed continuous shooting becomes impossible.

Therefore, in the present invention, when photographed image data is actually recorded, the recording process is performed by paying attention to the fact that many clusters constituting one packet are continuous. That is, information indicating how many consecutive clusters is added after the first consecutive cluster number is stored in the RAM work area of the CPU built into the camera body.

[0028] This will be explained below with reference to FIG. 29 in the diagram
shows the five clusters required by the data to be stored and the usable cluster number detected from within the memory card.

Reference numeral 30 shows a state in which all of the five clusters mentioned above are stored in the RAM work area as in the conventional case. In this case, a total of 10 bytes of area is occupied.

31 shows how the five clusters described above are stored in the RAM work area using the recording method according to the present invention. In this case, it suffices to occupy only 4 bytes, 2 bytes to store the start cluster number and 2 bytes to store the number of consecutive clusters.

[0031] In this way, when storing five clusters, conventionally it occupied a RAM work area of 10 bytes, but according to the recording method according to the present invention, it occupies a 4-byte work area. All you have to do is do it.

When recording data using the recording method shown in 31, the most significant bit D1 of the data storage area shown in 32
5 is assigned continuous information. That is, if the clusters are continuous, "1" is assigned to indicate that continuous information exists.

Based on this continuous information, the CPU built into the camera body increments the cluster number one by one by the specified number of consecutive clusters, calculates an address corresponding to that number, and stores the data in the memory card. will be recorded. Furthermore, referring to FIG. 6, one packet is composed of 8 clusters, and the number of usable clusters in the memory card is 33.
Let's explain the case where it is distributed as shown in .

As in the case explained with reference to FIG. 5, when all clusters are recorded, they occupy an area of 16 bytes, such as 34. In contrast, according to the recording method according to the present invention, only 14 bytes need to be occupied.

[0035] In this way, when saving usable clusters of a memory card in the CPU, the cluster numbers are not saved one by one, but if the clusters are consecutive, the starting cluster number and the number of consecutive clusters are saved. I have to. This makes it possible to reduce the amount of RAM work area occupied.

[0036]

According to the electronic still camera device described above, when recording image data in a memory using the MAT method, cluster number data required for recording is stored in the RA of the CPU.
It is possible to rationally store the information in the M work area and reduce the processing constraints and load on the CPU as much as possible.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an electronic still camera device according to the present invention.

FIG. 2 is a configuration diagram showing the camera body 4 shown in FIG. 1.

FIG. 3 is a diagram showing the recording format of the MAT method.

FIG. 4 is a flowchart for explaining how data is recorded.

FIG. 5 is a diagram for explaining how data is recorded.

FIG. 6 is a diagram for explaining how data is recorded.

[Explanation of symbols]

1... Shutter button, 2... Viewfinder, 3... Lens barrel, 4...
Camera body, 5... Aperture, 7... Lens, 8... Solid-state imaging device, 9... Imaging processing circuit, 10... A/D conversion circuit, 11...
Band compression processing circuit, 12...Memory interface circuit, 13...CPU, 14...Camera body, 15...Memory interface circuit, 16...Memory card, 17...Microphone, 18...Audio processing section.

Claims (1)

[Claims] 1. Converting a photographed optical image into electrical still image data, dividing a recording area of a recording medium into a plurality of unit recording areas, and distributing the still image data among the plurality of unit recording areas. In an electronic still camera device configured to record, when the still image data is continuously recorded in the unit recording area, the start position information of the head of the continuous unit recording area and the subsequent unit recording An electronic still camera device, characterized in that information about the number of areas is recorded on the recording medium.