JPH04290390A - Electronic still camera - Google Patents

Abstract

PURPOSE:To reduce the processing burden of a CPU and to shorten processing execution time by recording information showing a leading idle area where one bucket of picture data is to be recorded in a bucket unit on a semiconductor memory. CONSTITUTION:The CPU reads the content of a leading unused bucket number recording area 28h in a header area 28 and detects the number of clusters of the unused bucket. The CPU compares the number of clusters for the picture data to be newly recorded with that of the detected clusters, and discriminates whether or not the detected number of clusters is fewer the number of required clusters. When the number of clusters is fewer, the CPU retrieves an idle cluster from the content of a MAT area 31, and the picture data is newly recorded on the idle cluster. Thus, the CPU can easily recognize the position of the idle cluster.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to an electronic still camera device that converts an optical image of a photographed subject into digital data and stores it in a semiconductor memory, and in particular, it is possible to easily search for an empty storage area of the semiconductor memory. Concerning what has been made possible.

0002

[Prior Art] As is well known, a typical camera forms an optical image taken on a silver halide film, so unless the film is chemically treated and developed, the photographed image cannot be viewed. is not possible. In recent years, however, electronic photographic systems have been developed that eliminate the need for troublesome chemical processing by converting the captured optical image into an electrical image signal and displaying the image on a television receiver. It is becoming popular. An example of such an electronic photographic system is a still image recording and reproducing system.

[0003] In this still image recording and reproducing system, a tape, disk, drum, or the like made of magnetic material is mounted in a camera body as a recording medium in the form of a cassette or cartridge. After taking a picture and recording the image signal on a recording medium, the recording medium is removed from the camera body and attached to a playback device, and the still image is displayed on a television receiver connected to the playback device. It is. However, in this type of still image recording and playback system,
Since the recording medium is made of a magnetic material, a magnetic head, a drive mechanism for the recording medium, etc. are required to perform recording and reproduction, which results in a more complicated and larger configuration and increases power consumption.

[0004] For this reason, in recent years, electronic stills have been designed to convert image signals into digital data and store it in semiconductor memory, thereby eliminating the need for magnetic heads, drive mechanisms, etc., and reducing size, weight, and power consumption. A camera device is being considered. In particular, in recent years, with the advancement of semiconductor element packaging technology, memory cards with built-in semiconductor memory have come into practical use, and there has been active development of ways to use these memory cards as recording media. It is.

By the way, in the conventional electronic still camera device that uses a semiconductor memory as a recording medium as described above, the image signal converted to digital data is band-compressed and stored in the semiconductor memory. The data length for one image varies depending on the content of the photographed image, the compression rate automatically set on the camera side or specified by the user, and the like. Furthermore, still image data is sequentially written into the semiconductor memory, such as the first image, the second image, etc. in the order in which they were photographed.

[0006] For this reason, if data for, for example, the n-th still image becomes unnecessary and is deleted during shooting, the deleted storage area will contain a still image with a data length greater than or equal to the data length of the n-th still image. This means that 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 erased storage area will not be used at all and will be wasted. , a problem arises in that the storage capacity of the semiconductor memory cannot be used effectively.

Therefore, in an electronic still camera device using a semiconductor memory, the image data storage area of the semiconductor memory is divided into a plurality of unit storage areas (hereinafter referred to as clusters) each having, for example, 64 kbytes. The data for one still image obtained through this process is distributed and recorded in several clusters. In this case, a collection of a plurality of clusters in which one piece of still image data is stored in a distributed manner is called a packet.

[0008] In the semiconductor memory, a MAT (
A memory allocation table (memory allocation table) area is provided, and by sequentially reading the data of a predetermined cluster based on the data of this MAT area during playback,
All the dispersed still image data of one sheet can be read. By distributing and recording still image data for one image into multiple clusters, for example, when the n-th still image data is deleted, the resulting empty clusters can be used to store other still images. It can be used for distributed recording of data, and the storage capacity of the semiconductor memory can be used effectively.

However, in an electronic still camera device using the MAT method as described above, if a plurality of empty clusters are obtained by deleting one packet of still image data, for example, the empty clusters are used as image data in the semiconductor memory. Where in the storage area it is located, please refer to the MAT above.
Since it cannot be found without searching the entire area, when writing new still image data to the empty cluster,
Data transfer between the CPU (Central Processing Unit) installed on the camera side and semiconductor memory becomes complicated, and
A problem arises in that the burden on the PU is heavy.

0010

As described above, in conventional electronic still camera devices, empty clusters generated by erasing still image data recorded in a semiconductor memory are
If you don't search the T area, you won't know its location.
When writing new still image data to the empty cluster, data transfer between the CPU on the camera side and the semiconductor memory becomes complicated, resulting in a problem that the load on the CPU increases.

[0011] Therefore, the present invention has been made in consideration of the above circumstances, and allows the CPU to easily recognize the position of an empty cluster, thereby reducing the processing load on the CPU and substantially reducing the processing execution time. It is an object of the present invention to provide an extremely good electronic still camera device that is shortened in size.

0012

[Means for Solving the Problems] An electronic still camera device according to the present invention converts an optical image of a photographed subject into digitized image data and stores it in a semiconductor memory. The target is a system in which the image data is divided into a plurality of clusters each having a certain storage capacity, and the image data constituting one packet is distributed and stored in the plurality of clusters. Then, one of the image data storage areas of the semiconductor memory is
Information indicating, in units of packets, the empty area at the beginning where a packet's worth of image data is to be recorded is recorded in the semiconductor memory as part of its header data.

[0013]

[Operation] According to the above configuration, the semiconductor memory
Next, information indicating the empty area at the beginning where one packet of image data should be recorded is recorded in units of packets, so the CPU can easily recognize the position of the empty cluster by reading this information. It is possible to reduce the processing load and substantially shorten the processing execution time.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 2 shows the external appearance of the electronic still camera described in this embodiment. That is, this electronic still camera is composed of a camera body 11 and a memory card 12 that is detachable from the camera body 11. The camera body 11 is provided with a lens barrel 13, a finder 14, a shutter 15, etc., as well as an opening 16 into which a memory card 12 is inserted, as in a normal camera.

FIG. 3 shows the internal structure of the camera body 11. That is, 17 in the figure is the lens barrel 1.
This lens 17 guides an optical image of the object to a solid-state image sensor 18, which is made of, for example, a CCD (charge coupled device). The solid-state image sensor 18 outputs an analog electrical image signal depending on the brightness of the optical image guided through the lens 17.

In this way, the image signal output from the solid-state image sensor 18 is supplied to the image processing circuit 19 and subjected to predetermined signal processing, and then converted by the A/D (analog/digital) conversion circuit 20. Converts to digital image data. The image data output from this A/D conversion circuit 20 is compressed by a predetermined amount of data by a band compression circuit 21, and then transferred to a memory interface circuit 22.
The data is written to a semiconductor memory (not shown) in the memory card 12 via the memory card 12.

Reference numeral 23 in FIG. 3 denotes a CPU (Central Processing Unit), which performs overall control of the entire electronic still camera including the memory card 12. For example, C.P.
U23 writes the image data output from the band compression circuit 21 to the memory card 12,
The memory interface circuit 22 is controlled to read data from the memory interface circuit 22. Further, the CPU 23 controls the data amount compression rate of the band compression circuit 21 based on the operation of the operation unit 24 provided in the camera body 11.
It controls the display section 25.

Furthermore, the audio collected by the microphone 26 installed in the camera body 11 is supplied as an analog audio signal to the audio processing circuit 27, where it is converted into digital audio data and processed into a predetermined signal. After signal processing, the signal is stored in the memory card 12 via the memory interface circuit 22.

Next, FIG. 4 shows a memory map of the semiconductor memory built into the memory card 12. first,
Absolute address (hexadecimal) "000000" to "00"
03FF" constitutes a header area 28 in which header data unique to the memory card 12 itself is recorded. This header area 28 is numbered in consideration of future functional improvements. , currently it is “0” in binary
A 1-byte format number recording area 28a in which "0000001" is recorded, and a 1-byte card number recording area 28b in which a card number can be written so that the user can manage a large number of memory cards 12.
and a 14-byte card label recording area 28c for the user to write the title, etc. of the memory card 12.
A 2-byte used packet number recording area 28d indicating the number of recorded packets, a 2-byte remaining cluster number recording area 28e indicating the number of unused clusters, and a 2-byte used cluster number recording area 28e indicating the number of recorded clusters. Area 2
8f and format No. A 1-byte parity check data recording area 28g for detecting bit errors by comparing all data from the recording area 28a to the used cluster number recording area 28f with the addition result, and 1 packet worth of image data should be recorded. Leading unused packet number recording area 28 where the leading free packet number is recorded
h and a 1000-byte option data recording area 28i that can be freely set by the user.

[0020] Also, the absolute address (hexadecimal) is “00
0400” to “0023F7” are each packet 1 to
This is a packet information area 29 in which 2046 types, attributes, connection information, etc. are recorded in 4 bytes each. Furthermore, the absolute address (hexadecimal) is "0023F8" ~
Up to "0033F3" constitutes a directory area 30 in which the number of the cluster where each packet 1 to 2046 starts is recorded in 2 bytes. Also, the absolute address (hexadecimal) is "0033F4" to "004".
3EF" is the MAT area 3 in which the number of the cluster following each cluster is recorded in 2 bytes.
1. Further, the absolute addresses (hexadecimal) from "0043F0" to "FFFFFD" are the packet data area 32 in which actual image and audio data are recorded in packet units. In addition, in the absolute address (hexadecimal), 2 bytes from "FFFFFE" to "FFFFFF" are used as a card area 33 where information specific to semiconductor memory is recorded, and the first byte indicates that the semiconductor memory is EEPROM. In this case, the number of bytes of page writing is recorded, and the type of semiconductor memory, its storage capacity, etc. are recorded in the second byte.

Before explaining the operation which is a characteristic part of the present invention, the basic operation when recording image data on the memory card 12 will be explained with reference to the flowchart shown in FIG. First, start (step S1
), in step S2, the CPU 23 calculates the required number N of clusters from the data length of the image data to be substantially recorded on the memory card 12 after compression processing, and in step S3, the number of clusters N is calculated from the header area 28. The read remaining number of clusters is compared with the calculated required number N of clusters, and in step S4 it is determined whether the remaining number of clusters is less than the required number N. And if it is insufficient (
YES), the CPU 23 causes the display unit 25 to display a warning in step S5, and ends the process (step S6).
) to be done.

Further, if it is determined in step S4 that there is no shortage (NO), the CPU 23 executes step S4.
In step 7, the number of used packets read from the header area 28 is checked, and in step S8, the number of used clusters read from the header area 28 is checked. Based on these check results, in step S9, image data is recorded. A packet number A to be sent and a start cluster number B configuring this packet A are respectively set. Then, in step S10, the CPU 23 reads the contents of the MAT area 31 to check the contents of cluster B, and in step S11, determines whether cluster B is vacant.

Here, if cluster B is empty (YE
S), the CPU 23 performs step S2 in step S12.
"1" is subtracted from the required number N of clusters calculated in step S13 to obtain a new required number N of clusters, and in step S13, it is determined whether or not the required number N of clusters as a result of the subtraction has become "0". Then, if the new required number of clusters N is not "0" (NO), or if it is determined in step S11 that cluster B is not vacant (NO), the CPU 23 sets cluster number B to "0" in step S14. 1'' is added to form a new cluster number B, and the process returns to step S10. By doing this, it is possible to search for vacant cluster numbers by the required number N of clusters.

[0024] Then, if it is determined in step S13 that the required number of clusters N is "0" (YES), the CP
U23 performs steps S10 to S14 in step S15.
In step S16, image data is distributed and recorded in these clusters. Thereafter, the CPU 23 records the connection information for the N clusters used in the MAT area 31 in step S17, and records the start cluster number B in the area corresponding to packet A of the directory area 30 in step S18. Then, in step S19, the CPU 23 updates the contents of the header area 28, and here the writing of the image data to the memory card 12 is completed (
Step S20) is carried out.

Here, in the basic writing operation of the image data to the memory card 12 as described above, the following is performed.
Distributed recording of new image data in a plurality of empty clusters obtained by erasing one packet of image data will be explained with reference to the flowchart shown in FIG. First, when started (step S21), the CPU 23
In step S22, the contents of the first unused packet number recording area 28h of the header area 28 are read, and in step S23, the contents of the packet information area are checked to detect the number of clusters constituting the read unused packet. Thereafter, in step S24, the CPU 23 compares the number of clusters required for newly recorded image data with the number of detected clusters, and in step S25, determines whether the number of detected clusters is less than the required number of clusters. Determine.

[0026] If it is insufficient (YES), CP
U23 searches for an empty cluster from the contents of the MAT area 31 in step S26, and records new image data in the empty cluster in step S27. Furthermore, if it is determined in step S25 that there is no shortage (NO),
The CPU 23 directly proceeds to the process of step S27. Thereafter, the CPU 23 updates the header data in step S28, and ends the process (step S29). That is, by providing the first unused packet number recording area 28h in the header area 28, the process of searching for empty clusters from the contents of the MAT area 31 is performed in step S2.
6, and that one search process does not need to be performed if it is determined in step S25 that there is no shortage (NO), and the CPU 23 can easily recognize the position of an empty cluster. It is possible to reduce the processing load and substantially shorten the processing execution time.

On the other hand, FIG. 6 shows the operation when the header area 28 of the semiconductor memory is not provided with the first unused packet number recording area 28h. That is, when started (step S30), the CPU 23 specifies the start cluster number for recording new image data in step S31, and in step S32, the CPU 23 specifies the start cluster number for recording new image data.
1, and in step S33, a predetermined number of empty clusters are determined.In step S34, the number of clusters required for newly recorded image data is compared with the determined number of clusters, and in step S35, the determined number of clusters is determined. Determine whether the number of clusters is less than the required number of clusters.

[0028] If it is insufficient (YES), CP
U23 searches the contents of the MAT area 31 again for an empty cluster in step S36, and records new image data in the empty cluster in step S37. Also, if it is determined in step S35 that there is no shortage (NO)
In this case, the CPU 23 directly proceeds to the process of step S37. After that, the CPU 23, in step S38,
The header data is updated and the process ends (step S39). That is, if the header area 28 is not provided with the first unused packet number recording area 28h, the MAT area 31
The process of searching for free clusters from the contents of
32 and S36 are required, which places a burden on the processing of the CPU 23 and increases the processing execution time. It should be noted that the present invention is not limited to the above-mentioned embodiments, and can be implemented with various modifications without departing from the gist thereof.

[0029]

[Effects of the Invention] As detailed above, according to the present invention,
It is possible to provide an extremely good electronic still camera device that allows the CPU to easily recognize the positions of empty clusters, reduces the processing load on the CPU, and substantially shortens the processing execution time.

[Brief explanation of the drawing]

FIG. 1 is a flowchart shown to explain one embodiment of an electronic still camera device according to the present invention.

FIG. 2 is a perspective view showing the external appearance of an electronic still camera described in the same embodiment.

FIG. 3 is a block configuration diagram showing the internal configuration of the electronic still camera.

FIG. 4 is a diagram showing a memory map of the semiconductor memory of the electronic still camera.

FIG. 5 is a flowchart shown to explain the basic operation of the electronic still camera.

FIG. 6 is a flowchart shown to explain the operation of the electronic still camera when the present invention is not used.

[Explanation of symbols]

11...Camera body, 12...Memory card, 13... Lens barrel,
14...finder, 15...shutter, 16...opening, 1
7... Lens, 18... Solid-state imaging device, 19... Imaging processing circuit, 20... A/D conversion circuit, 21... Bandwidth compression circuit, 22...
Memory interface circuit, 23...CPU, 24...Operation unit, 25...Display unit, 26...Microphone, 27...Audio processing circuit, 28...Header area, 29...Packet information area, 30...Directory area, 31...MAT area, 32 ...Packet data area, 33...Card area.

Claims (1)

[Claims] 1. A device that converts an optical image of a photographed object into digitized image data and stores it in a semiconductor memory, and the image data storage area of the semiconductor memory is divided into a plurality of clusters each having a certain storage capacity. In an electronic still camera device in which the image data constituting one packet is distributed and stored in a plurality of clusters, the next one packet of image data is stored in the image data storage area of the semiconductor memory. An electronic still camera device characterized in that information indicating a leading free area to be recorded in units of packets is recorded in the semiconductor memory as part of header data thereof.