JP3107640B2 - Image data storage method and image data storage device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for storing image data and an apparatus for storing image data.

[0002] In recent years, image data storage devices such as image filing devices and electronic still cameras have been put into practical use.
In such apparatuses, an encoding technique for compressing image data is widely used in order to store image data having a very large data amount in a storage medium having a limited capacity.

In general, the size of image data encoded under the same conditions differs depending on the image, and it is difficult to store the image data. Therefore, the encoded image data (hereinafter, referred to as
There is a demand for the development of an image data storage method and an image data storage device for efficiently storing code data) in a storage medium having a predetermined capacity.

[0004]

2. Description of the Related Art (1) First method As a first method conventionally known, in order to store a predetermined number or more of coded data having different sizes depending on images, the coded data is stored in advance. There is a method of roughly estimating a data amount and determining a compression condition (for example, a quantization step) with a margin.

[0005] As an example, encoding 50 images,
A case where code data needs to be stored in a 5 MByte storage medium will be described. It is assumed that when encoding is performed under the compression condition A, the data amount per code data is known to be 50 KByte to 120 KByte. The average of 50 encoded data is
If it is less than 100 KByte, 50 pieces of code data can be stored, but if the number of images with a large data amount increases as a result of encoding, not all images can be stored. Therefore, the compression condition B (the data amount of the code data rarely exceeds 100 KByte, but the image quality of the restored image is lower than the compression condition A) under the compression condition B where the data amount of the code data is smaller than the compression condition A Encode with a margin. (2) Second Method As a conventionally known second method, there is a method of changing a compression condition for each image to make the amount of code data of each image constant.

For example, a case will be described in which 50 images are encoded and the encoded data needs to be stored in a 5 MByte storage medium. 100KBy data amount per code data
If te, target image data can be stored. Therefore, in an image having a large data amount, encoding is performed under a compression condition in which the data amount is small (the quality of the restored image is low quality), and in an image having a small data amount, the data amount is large (the image quality of the restored image is large). Encoding is performed under adaptive conditions, such as encoding under compression conditions.

[0007]

The above-described conventional method has the following problems. In the first method, the storage capacity of the storage medium is used without waste if there are many images with a large data amount. However, if there are many images with a small data amount, there is a lot of waste in the storage capacity of the storage medium. Occurs.

In the second method, since the compression condition is changed for each image, the data amount is constant. However, the quality of the restored image is greatly varied between high quality and low quality. Also, in order to control the amount of data constant,
Complex processing is required. Furthermore, it is not possible to cope with a case where it is necessary to record an additional image after storing a predetermined number of images first.

The present invention does not cause an increase in the variation in the image quality of the restored image, uses the storage capacity of the storage medium without waste, and adds the image after the storage of the initially specified number of images. It is an object of the present invention to provide an image data storage method and an image data storage device capable of storing an image by using the method.

[0010]

The principle of the present invention will be described with reference to FIGS. FIG. 1 is a flowchart showing the principle of the image data storage method of the present invention, and FIG. 2 is a block diagram showing the principle of the image data storage device of the present invention.

In the image data storing method according to the present invention, as shown in FIG. 1, first, one original image is encoded into a plurality of layers by a hierarchical encoding step (S ₁ ). Such hierarchical coding has been reported in various publications, for example, in the paper "Communication Technology" (August 1989), pp. 56-61, "Progressive Build-up Display Entering the Practical Use Stage". I have. Although it is possible to restore an image from code data of a lower hierarchy of the encoded data obtained by hierarchical encoding, the restored image is a low-quality image. By using code data of a higher hierarchy, a higher-quality image can be restored.

Subsequently, the capacity determination process (S ₂ , S ₃ ,
In S ₄ ), the data amount of the new code data obtained in the above-described hierarchical encoding process and the remaining storage capacity of the code data storage means (storage medium) are calculated, and these are compared to store the code data. It is determined whether or not the capacity for storing new code data is left in the means.

If it is determined that the remaining storage capacity is insufficient, the operator is requested to discard the data, and in the discard data instruction step (S ₅ ), the operator indicates the code data to be discarded. An input is made, and the designated code data is discarded in the data discarding process (S ₆ ) to secure a capacity for storing new code data. In the discard data instruction process by the operator, when instructing the data to be discarded,
For example, it is also possible to display the number of remaining layers for each image, the data amount for each layer, a restored image from code data, and the like so that the operator can refer to them.

Finally, in the data storing step (S ₇ ),
If it is determined in the capacity determination step that the remaining capacity of the code data storage means is sufficient, the new code data is stored in the code data storage means without discarding the code data, while the remaining capacity is insufficient. If it is determined that the new code data exists, the remaining data that has not been discarded among the new code data is stored in the code data storage means.

The above processing is similarly performed for all images (S ₈ , S ₉ ). Note that the order of each process may be such that, after encoding of all layers in one image is completed, the process proceeds to the discard data instruction process. It is also possible to shift to.

Next, as shown in FIG. 2, the image data storage device of the present invention comprises at least a hierarchical coding unit 1, a code data buffer 2, a code data storage unit 3, a judgment unit 4, and a discard instruction input requesting unit 5. And a discard data determination unit 6. The hierarchical encoding unit 1 hierarchically encodes and outputs the original image data, and also outputs the data amount of the obtained encoded data. The code data buffer 2 temporarily stores the new code data obtained by the hierarchical coding unit 1. The code data storage unit 3 stores the code data and outputs the remaining capacity. The determination unit 4 determines the data amount (comparison input a) of the new code data output from the hierarchical coding unit 1,
The remaining capacity (comparison input b) output from the code data storage unit 3 is compared, and if a ≦ b, the code data buffer 2
, The new code data temporarily stored therein is transferred to the code data storage unit 3, and after the transfer, the data in the code data buffer 2 is erased. on the other hand,
If a> b, it instructs the discard instruction input request unit 5 to request the operator to input an instruction for discard data. The destruction instruction input requesting unit 5 requests the operator to input a destruction data instruction when receiving a destruction request instruction from the determination unit 4. The discard data instructing section 6 is a section in which the operator inputs a discard data instruction when the discard instruction is input by the discard instruction input request section 5, and the discard data specified by the operator is stored in the code data storage section 3. The code data storage unit 3 or the code data buffer 2 is instructed to discard the data depending on whether the code data is stored or new code data temporarily stored in the code data buffer 2.

[0017]

According to the present invention, as described above, when there is a shortage of storage capacity for storing the code data obtained by encoding, the code data already stored and the new code data are stored in accordance with the instruction of the operator. A part of the hierarchy in the encoded data obtained by encoding is discarded.

Accordingly, it is not necessary to determine the compression conditions with a margin as in the first conventional method described above.
There is no waste of storage capacity of the storage medium.
Further, since it is not necessary to equalize the data amounts of all the image data as in the second conventional method, complicated processing is not required, and the quality of the restored image can be high or low. Does not increase. Further, even after the storage of the predetermined number of images is completed, additional images can be stored.

Here, in order to clarify the difference between the conventional method and the present invention, FIG. 13 shows images stored in the first conventional method, the second conventional method, and the method of the present invention, respectively. Show data. In the figure, as an example, image 1
5 shows a case where five images of image 5 are stored.

In the first conventional method, as shown in FIG. 13 (a), encoding is performed under a certain condition with a margin, so that the storage capacity is wasted. In the second conventional method, as shown in FIG. 13 (b), since the data amount is fixed for each image, the compression condition is set so that the data amount is reduced for the image 1 and the image 3, so that the decompression is performed. The image quality of the image is low quality, and the image quality of the restored image is excessively high because the compression condition is set so that the data amount of image 2 and image 4 is large.

In contrast to these conventional methods, the present invention provides:
First, each image is hierarchically encoded into seven layers. Although there is no particular need to have seven layers, a case where hierarchical coding is performed on seven layers will be described as an example. Then, as shown in FIG. 13C, it is assumed that the code data amount exceeds the remaining data amount when the image 5 is stored. In such a case, “No” is determined in the condition determination of S ₄ in FIG. 1, and the process proceeds to S ₅ and S ₆ . The revocation indication process of S _5, the operator may instruct freely image to discard eligible. For example, the operator
The code data of the final hierarchy from image 1 in order to input and instruct the revocation (S _5), discards the instruction data (S _6). Lack of storage capacity simply by discarding the final hierarchy image 1 is not eliminated, the "No" in the condition determination in S _4. While the "No" in the condition determination in S _4, and repeats the processing of S ₅ and S _6. In this example, by discarding the data of the seventh layer of each image from image 1 to image 5, S ₄
Is “Yes” in the condition determination of, and the code data is stored. FIG. 13D shows the state. After this, one more
If it becomes necessary to store one image, additional storage can be performed by the same processing as when several layers of code data are discarded in order to store the image 5.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. (1) First Embodiment FIG. 3 is a block diagram showing a first embodiment of the image data storage device of the present invention, and FIG. 4 is a flowchart showing a part of the operation of the first embodiment.

As shown in FIG. 3, the image data storage device of this embodiment has a hierarchical encoding unit 1, a code data buffer 2,
It comprises a code data storage unit 3, a judgment unit 4, a discard instruction input request unit 5, a discard data instruction unit 6, and a remaining hierarchy storage unit 7. The hierarchical coding unit 1 hierarchically codes the original image data, and outputs the obtained code data, the data amount of the code data, the number of coded images and the number of layers. The code data buffer 2 temporarily stores the new code data obtained by the hierarchical coding unit 1. The code data storage unit 3 stores the code data and calculates and outputs the remaining capacity. The determination unit 4 determines the amount of new code data output from the hierarchical coding unit 1 (comparison input a).
Is compared with the remaining capacity (comparison input b) output from the code data storage unit 3. If a ≦ b, the new code data temporarily stored there is stored in the code data buffer 2. The data is transferred to the code data storage unit 3, and after the transfer, an instruction is made to delete the data in the code data buffer 2. On the other hand, if a> b, it instructs the discard instruction input request unit 5 to request the operator to input an instruction for discard data. The discard instruction input requesting unit 5 requests the operator to input a discard data instruction in accordance with the instruction from the determination unit 4. The remaining hierarchical storage unit 7 stores the number of images encoded by the hierarchical encoding unit 1 and the number of remaining layers for each image. The discard data instruction unit 6
When an image for discarding data is input by the operator in response to the request by the discard instruction input requesting unit 5,
The last layer of the image specified by the operator is referred to as the discard data by referring to the remaining layer storage 7.
Or, it instructs the code data buffer 2.

The image data storage device having the above configuration
The overall operation is performed according to FIG.
The process of discarding the instruction data by the discard data instruction unit 6 (S
₆) Will be specifically described with reference to FIG. First,
S_Five(FIG. 1) and the operator via the discard data indicating unit 6
Indicates the image whose data is to be discarded,
The indicating unit 6 refers to the remaining hierarchy storage unit 7 (S₁₁),Up
The image specified by the operator is a code data buffer.
2 is new code data temporarily stored in
Is determined (S₁₂). If "Yes" here,
With reference to the existing hierarchy storage unit 6 (S₁₃), The above operator
Code data to discard the last layer of the image specified by
To the buffer 2 (S₁₄). On the other hand, if "No"
Then, referring to the remaining hierarchy storage unit 6 again (S₁₅),
Discard the last layer of the image specified by the operator
To the code data storage unit 3 (S₁₆). Soshi
Finally, as the hierarchical code data is discarded, the remaining hierarchical memory is stored.
Update the contents of the part 6 (S ₁₇). Note that the hierarchical encoding unit 1
The number of images and the number of layers encoded by
7 is the hierarchical encoding process (S₁,
S₉).

In the present embodiment, the configuration is such that the remaining hierarchy storage unit 7 is provided, but it is also possible to provide a configuration without this. In this case, the update operation (S ₁₇ ) of the remaining hierarchy storage unit 7 becomes unnecessary in the processing of FIG. 4, but the discard data instruction unit 6 uses the code data storage unit 3 instead of referring to the remaining hierarchy storage unit 7. In addition, it is necessary to check the number of remaining layers by referring to the code data buffer 2. (2) Second Embodiment FIG. 5 is a block diagram showing a second embodiment of the image data storage device of the present invention.

In the first embodiment, when the operator instructs the image to be discarded, the operator does not have a means for knowing information to be used for reference. However, in this embodiment, FIG.
In addition to the above configuration, a remaining layer display section 8 for displaying the number of remaining layers of each image is newly provided. By doing so, the operator can instruct, for example, an image having many remaining layers as discarded data with reference to the displayed number of remaining layers.

The overall operation of this embodiment is performed in accordance with FIG. 1 in the same manner as in the first embodiment, but when the discard data instruction is input (S ₅ ), the remaining hierarchy storage unit 7 The number of remaining layers of each image stored in the
To be displayed. (3) Third Embodiment FIG. 6 is a block diagram showing a third embodiment of the image data storage device of the present invention.

As shown in the figure, in this embodiment, in addition to the configuration of FIG. 3, a data amount display section 9 for storing and displaying the data amount of each layer output from the layer coding section 1 is provided. It is newly provided so that an operator can designate discard data with reference to the displayed information. For example, by giving priority to an image having a large data amount as discarded data, it is possible to minimize the number of images in which image quality is degraded due to data discarding.

The overall operation of this embodiment is performed in accordance with FIG. 1 in the same manner as in the previous embodiment, but when inputting the discard data instruction (S ₅ ), each image has its own layer. The data amount is displayed on the data amount display section 9. (4) Fourth Embodiment FIG. 7 is a block diagram showing a fourth embodiment of the image data storage device of the present invention.

As shown in the figure, in the present embodiment, in addition to the configuration of FIG. 3, the image quality (for example, the S / N ratio with the original image) of the image restored from the code data of each image up to each layer. , And an image quality display unit 11 for storing and displaying the calculation result. The operator can instruct discarded data based on the image quality displayed on the image quality display unit 11, and can preferentially instruct, for example, images with higher image quality as discarded data.

The overall operation of the present embodiment is performed in accordance with FIG. 1 in the same manner as in the previous embodiment. In the hierarchical coding (S ₁ , S ₉ ) therein, the codes up to each layer are encoded. The image quality of the image restored from the data is calculated by the image quality calculation unit 10, and the image quality calculated by the image quality calculation unit 10 is displayed on the image quality display unit 11 at the time of inputting the discard data instruction (S ₅ ). I do. (5) Fifth Embodiment FIG. 8 is a block diagram showing a fifth embodiment of the image data storage device of the present invention, and FIG. 9 is a flowchart showing a part of the operation of the fifth embodiment.

As shown in FIG. 8, in this embodiment, in addition to the configuration of FIG. 3, an image is restored from the code data of each image stored in the code data buffer 2 and the code data storage unit 3 and displayed. And a display image instructing unit 13 for instructing an image to be displayed by an operator. With such a configuration, the operator designates a desired image by the display image instructing unit 13 so that the designated image can be restored / reconstructed.
Since the displayed image is displayed on the display unit 12, it is possible to instruct the discard data based on the displayed image. For example, by confirming the restored image, the discard data can be given priority from the image of lower importance. Will be able to be instructed.

The overall operation of the present embodiment is performed in accordance with FIG. 1. In particular, the processing (S ₅ ) for inputting the discard data instruction will be specifically described with reference to FIG. First, it is determined whether or not the operator needs to display an image on the image restoration / display unit 12 (S ₂₁ ). If not, the operator gives an instruction of discard data as it is (S ₂₁ ).
₂₂ ). On the other hand, if the operator requires a display image, first the operator directs the desired image by the display image indicating section 13 (S _23), followed by image restoration and display unit 12 the designated image is restored and displayed (S _24). Then, when the operator looks at the displayed image and also needs to display another new image, S
Appropriately repeating the process of ₂₃ and S _24, when it no longer needs the image display, and instructs discard data (S _22). (6) Sixth Embodiment This embodiment has a configuration in which not only the image to be restored but also the number of layers can be specified by replacing the display image specifying unit 13 in FIG. 8 with a display image / layer specifying unit. In this way, when the operator designates the number of layers of a desired image by the display image / layer designation unit, the image restored from the code data up to the designated layer is displayed on the image restoration / display unit 12. The operator will be
It is possible to check the image quality when data is discarded and to specify discarded data.

The overall operation of the present embodiment is performed in accordance with FIG. 1. In the processing of inputting the discard data instruction (S ₅ ), the display image instruction processing (S ₂₃ ) of FIG. 9 is displayed. This is replaced with the processing of the image / layer instruction. (7) Seventh Embodiment FIG. 10 is a flowchart showing the operation of the image data storage device according to the seventh embodiment of the present invention.

In the first to sixth embodiments, the hierarchy of one image
After encoding is completed, the process proceeds to the capacity determination process.
Therefore, the code data buffer 2 stores the code data of one image.
It needed enough space to store it. So, the real
In the embodiment, as shown in FIG. 10, one-layer encoding (S₁,
S₃₃, S₃₄) Is completed every time the storage capacity is determined.
And processing of the instruction of the discarded data (S_Two~ S₇To do)
It was made. In this way, the code
Data buffer 2 can store one layer of code data
Small capacity. Note that S_FourCoding hierarchy in
The data volume is S ₆If the new coding layer is discarded at
Becomes 0.

The components for realizing the above operation may be the same as those in the first to sixth embodiments. Detailed processing such as discard data instruction can be performed in the same manner as in the first to sixth embodiments. (8) Eighth Embodiment FIG. 11 is a block diagram showing an eighth embodiment of the image data storage device of the present invention, and FIG. 12 is a flowchart showing the operation of the eighth embodiment.

In the first to sixth embodiments, the instruction data is discarded every time after the discard data instruction step.
If the discard data instruction is issued a plurality of times in order to secure a capacity enough to store the code data of one image, the instruction data is also discarded a plurality of times. Therefore, in the present embodiment, as shown in FIG. 11, a data amount storage unit 14 for storing the data amount of each layer newly encoded by the layer encoding unit 1, a data amount storage unit 14 for storing the data amount and a remaining layer storage unit 7 and a remaining capacity calculation unit 15 for calculating the remaining capacity of the code data storage unit 3 based on the number of remaining layers stored in the storage unit 7.

The operation of the present embodiment (FIG. 12) is different from that of FIG. 1 in that the instruction data discarding process (S ₆ ) in FIG.
A point which is performed when it is determined "Yes" in the condition judgment of S _4, the processing of the data amount calculating code data (S _2), and that stores the calculated data amount of the data amount storage unit 14, The remaining data amount calculation process (S ₃ ) is performed in the code data storage unit 3 in the same manner as in the above embodiment, but the remaining data amount calculation process (S ₄₁ ) newly added after S ₅ is performed in the remaining capacity calculation unit. Reference numeral 15 denotes the remaining hierarchy storage unit 7 and the data amount storage unit 1.
4 with reference to FIG. Note that S ₃
Also in the calculation of the remaining data amount may be executed by the remaining capacity calculation unit 15 similarly to S _41, such a case, the function code data storage unit 3 calculates the remaining capacity is not needed .

According to this embodiment, even if the discard data instruction (S ₅ ) is issued a plurality of times in order to secure a capacity enough to store the code data of one image, only one instruction data is issued. It can be completed by discarding (S ₆ ).

[0040]

According to the present invention, the variation in the image quality of the restored image is not increased, the storage capacity of the storage medium is used without waste, and the initially specified number of images have been stored. It is possible to store additional images later.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating the principle of an image data storage method according to the present invention.

FIG. 2 is a block diagram showing the principle of the image data storage device of the present invention.

FIG. 3 is a block diagram showing a first embodiment of the image data storage device of the present invention.

FIG. 4 is a flowchart showing a part of the operation of the first embodiment.

FIG. 5 is a block diagram showing a second embodiment of the image data storage device of the present invention.

FIG. 6 is a block diagram showing a third embodiment of the image data storage device of the present invention.

FIG. 7 is a block diagram showing a fourth embodiment of the image data storage device of the present invention.

FIG. 8 is a block diagram showing a fifth embodiment of the image data storage device of the present invention.

FIG. 9 is a flowchart showing a part of the operation of the fifth embodiment.

FIG. 10 is a flowchart illustrating an operation of the image data storage device according to the seventh embodiment of the present invention.

FIG. 11 is a block diagram showing an eighth embodiment of the image data storage device of the present invention.

FIG. 12 is a flowchart showing the operation of the eighth embodiment.

FIG. 13 is a diagram schematically illustrating image data stored in the conventional method and the image data stored in the method of the present invention, respectively.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hierarchical encoding part 2 Code data buffer 3 Code data storage part 4 Judgment part 5 Discard instruction input request part 6 Discard data instruction part 7 Remaining layer storage part 8 Remaining layer display part 9 Data amount display part 10 Image quality calculation part 11 Image quality display Unit 12 image restoration / display unit 13 display image instruction unit 14 data amount storage unit 15 remaining capacity calculation unit

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-4-117065 (JP, A) JP-A-3-136570 (JP, A) JP-A-2-54671 (JP, A) JP-A-2- 55487 (JP, A) Patent 3085777 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 1/41-1/419 G06T 9/00 H04N 5/92 H04N 7/24

Claims (10)

(57) [Claims] 1. A layer encoding process for encoding an original image by dividing it into two or more layers, and the code data having a capacity sufficient to store new layer code data obtained in the layer encoding process. It is determined whether or not the data remains in the storage means. If the data is not left, the data should be discarded in accordance with a capacity judging process of requesting the operator to discard the hierarchical code data and a request for discarding the data in the capacity judging process. A discard data instructing step of inputting and instructing code data by an operator, a data discarding step of discarding hierarchical code data to be discarded specified in the discard data instructing step, and Storing the remaining data in the code data storage means. 2. The apparatus according to claim 1, further comprising a remaining layer storage step of storing the number of remaining layers for each image, wherein the instruction is given by referring to the remaining layer stored in the remaining layer storage step. 2. The image data storage method according to claim 1, wherein: 3. A remaining layer display step of displaying the number of remaining layers for each image, wherein the operator refers to the remaining layer displayed in the remaining layer display step and gives an instruction in the discard data instruction step. 2. The image data storage method according to claim 1, wherein: 4. A data amount storing step of storing a data amount for each hierarchy, wherein an instruction in the discard data instruction step is performed by referring to the data amount stored in the data amount storing step. The image data storage method according to claim 1. 5. A data amount display step of displaying a data amount for each hierarchy, wherein an operator refers to the data amount displayed in the data amount display step and issues an instruction in the discard data instruction step. The image data storage method according to claim 1, wherein: 6. An image quality display step of displaying an image quality of a restored image restored from code data up to each layer obtained in the layer encoding step, wherein an operator refers to the image quality displayed in the image quality display step. 2. The image data storage method according to claim 1, wherein an instruction is issued in the discard data instruction step. 7. An image restoring / displaying step of restoring and displaying an image from code data, wherein an operator refers to the restored image displayed in the image restoring / displaying step to give an instruction in the discard data instruction step. 2. The image data storage method according to claim 1, wherein the method is performed. 8. The image data storing method according to claim 7, further comprising a number-of-layers instructing step in which an operator designates the number of layers of the image to be restored in said image restoring / displaying step. 9. The image data storing method according to claim 1, wherein said capacity determining step is executed each time one layer is encoded in said layer encoding step. 10. A layer coding unit for coding an original image by dividing it into two or more layers, a code data storage unit for storing layer code data obtained in the layer coding process, and a layer coding unit. It is determined whether or not a sufficient capacity for storing the new hierarchical code data obtained in the process remains in the code data storage means. If not, the operator is asked to discard the hierarchical code data. An image data storage device, comprising: a determination unit for making a request; and a discard data instruction unit for designating code data to be discarded by an operator in response to a request for data destruction by the determination unit.