JP3554073B2 - Encoding method and apparatus - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to an encoding method and apparatus capable of encoding an image at high speed using hierarchical encoding, in particular.
[0002]
[Prior art]
First, the concept of ordinary hierarchical coding will be described with reference to FIG. In the figure, reference numeral 501 denotes an original image read by an image scanner or the like or artificially created by various software. Numerals 502 to 504 denote reduced images created by reducing 501, respectively. Reference numerals 505 to 507 denote encoders each of which inputs an image between two layers and performs encoding. Reference numeral 508 denotes an encoder that performs encoding using only the reduced image 504 because the image has the lowest resolution.
[0003]
In actual applications, 505 to 508 often use the same physical encoder, but are shown separately for convenience of explanation.
[0004]
The code data encoded by the encoders 505 to 508 are all collected into one data by a code data collection unit 509 and stored in a storage medium such as a magnetic disk 510, for example.
[0005]
FIG. 6 is a diagram illustrating an example of hierarchized code data. In the figure, L3 is code data of an original picture (highest resolution) layer, and L0 is code data of the lowest resolution. Further, n3 to n0 are code data lengths in each layer. EOL (End Of Layer) is a marker code indicating the end of the code in each layer.
[0006]
In the above-described configuration, at the time of encoding, since the image is sequentially reduced from the original image, the image is output in order from the code on the high resolution side (L3 → L0). On the other hand, at the time of decoding, images must be reproduced in order from the smallest image.
[0007]
Therefore, in order to read the code data of L0, it is necessary to skip L3 to L1. For this purpose, EOL in each layer must be detected and counted, or n3 to n0 must be separately calculated and stored separately at the time of encoding, and then skipped by that value.
[0008]
Next, FIG. 7 shows a configuration example of a system using the above-described hierarchical coding. In FIG. 7, all devices and blocks are conveniently connected by a common bus, but need not necessarily be on a common bus.
[0009]
In the figure, reference numeral 701 denotes an image scanner. Note that there is no particular mention as to whether the image read by the image scanner 701 is color or black and white. 702 is a printer. An MPU 703 controls the entire system. An image reduction unit 705 generates a reduced image from an original image input by the scanner 701 or a smaller reduced image from the reduced image.
[0010]
Note that the image reduction unit 705 includes an image memory as needed, and the image reduction method is not particularly described.
[0011]
The image data reduced and hierarchized by the above-described image reduction unit 705 is sent to an encoder / decoder 706 and encoded. Generally, the image reduction unit 705 and the encoder / decoder 706 are often common blocks, but are shown separately for convenience. The code data output from the code / decoder 706 is stored in the recording medium 708.
[0012]
[Problems to be solved by the invention]
However, the above-described hierarchical coding has the following disadvantages.
[0013]
First, the hierarchized code data is output in the order of high-resolution to low-resolution by the normal encoder, so on the decoder side to display from the low-resolution side, there is a problem in the access method to the code data, and until the display. However, there is a disadvantage that the speed is slow.
[0014]
Further, in order to improve the accessibility of the code data, it is necessary to separately store code data management information and the like in addition to the code data.
[0015]
When code data is to be recorded on a recording medium for direct storage having a relatively low access speed (such as a magneto-optical disk), there is a disadvantage that a plurality of images cannot be stored at high speed due to a problem of access speed.
[0016]
The present invention has been made to solve the above-mentioned problem, and temporarily stores hierarchically encoded data, rearranges the hierarchical order by sorting , and deletes the code length information of each layer. It is an object of the present invention to provide an encoding method and apparatus capable of performing hierarchical encoding and decoding at high speed by accumulating .
[0017]
[Means for Solving the Problems]
In order to achieve the above object, the encoding method of the present invention has the following steps.
[0018]
An image reduction step of reducing the original image to a size smaller than the original image size at least once, a hierarchical encoding step of hierarchically encoding the original image and the image reduced by the image reduction step, and the hierarchical encoding A first accumulation step of accumulating code data of each layer encoded by the step, a sorting step of reversing the order of the code data accumulated in the first accumulation step, and a sorting step of sorting by the sorting step. and have a second storage step of storing the code data, the second storage step, hierarchical order is replaced by the sorting step, accumulates encoded data code length information of each layer has been removed.
[0019]
In order to achieve the above object, an encoding device according to the present invention has the following configuration.
[0020]
Image reducing means for reducing the original image to a size smaller than the original image size at least once, hierarchical coding means for hierarchically coding the original image and the image reduced by the image reducing means, First storage means for storing the code data of each layer encoded by the means, sorting means for reversely sorting the order of the code data stored in the first storage means, and sorting by the sorting means. and a second storing means for storing the code data, said second storage means, hierarchical order is replaced by the sorting means, you accumulate encoded data code length information of each layer has been removed.
[0022]
【Example】
Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the drawings.
[0023]
FIG. 1 is a block diagram illustrating a configuration of a system using hierarchical coding in the present embodiment. In the figure, 101 to 103, 105, 106, 108, and 109 are equivalent to 701 to 703, 705, 706, 708, and 709 in FIG.
[0024]
The difference from FIG. 7 is that the encoded data is temporarily stored in a primary storage medium (for example, a magnetic disk or the like) 107 having a relatively high access speed and transmitted to a sorter (SORT) 104 as necessary. The point is that the order of the code data is changed.
[0025]
Here, the operation of hierarchical encoding in the present embodiment will be described below with reference to FIGS.
[0026]
FIG. 2 is a diagram showing a flow of image data at the time of image scanning.
[0027]
First, the image data read by the scanner 201 is transmitted to the image reduction unit 205 and reduced at least once to form a hierarchical image. The original image data before reduction and the image data after reduction are each encoded by the hierarchical encoder 206, and the encoded data of each resolution is stored in the primary storage device 207 according to the format shown in FIG. The primary storage device 207 uses a relatively high-speed recording medium such as a magnetic disk in order to correspond to a high-speed image reading speed in real time.
[0028]
As shown in FIG. 6, the code length (n3 to n0) of each layer is added to the code data (L3 to L0: note that the highest resolution code data L3 precedes) of each layer, and the primary storage is performed. It is stored in the device 207.
[0029]
Next, FIG. 3 is a diagram showing a flow of image data at the time of code sorting.
[0030]
In FIG. 3, code data stored in the primary storage device 307 is transmitted to the sorter 304 as necessary. Of course, after the scan, if it is determined that the scan is not performed normally or that the original does not need to be stored, the original can be discarded without being transmitted to the sorter 304.
[0031]
The sorter 304 sorts the code data of each layer in the order shown in FIG. 6 at high speed by referring to the code length (n3 to n0) of each layer, and changes the code from the lowest resolution code to the highest resolution code. Then, it is converted to the reverse order of the encoding. After the sorting process, the code data of each layer (L0 to L3: note that the lowest resolution code data L0 precedes) is transmitted to the secondary storage device 308.
[0032]
Since the sorted code data is already sorted in order from low resolution (layer 0) to high resolution (layer 3), it is not necessary to rearrange the code data at the time of decoding. There is no need to store the length separately.
[0033]
Since the medium constituting the secondary storage device 308 is stored for a long period of time and has a large amount of storage, there is no need to access the medium at high speed. Therefore, a removable magneto-optical disk is generally used.
[0034]
Next, FIG. 4 is a diagram showing a flow of each data at the time of decoding, displaying, or printing the code data stored in the secondary storage device 408.
[0035]
The code data (L0 to L3) read from the secondary storage device 408 is transferred to the decoding device 406 in order from the one with the lowest resolution to the one with the highest resolution. It is sent to the display 409 or the printer 402 for printing.
[0036]
As described above, by providing a two-stage storage device, that is, a configuration in which a storage device capable of high-speed access is provided separately from a large-capacity storage device for long-term storage, hierarchical encoding corresponding to high-speed reading by a scanner becomes possible. In addition, the code data is sorted, the order is changed to one suitable for the decoding process, and the data is stored in the secondary storage device, so that quick decoding can be performed during display or printing.
[0037]
Further, since there is no need to separately save a code data management file or the like for changing the order of the code data at the time of decoding, the complexity of file management can be eliminated, and the data capacity can be reduced. is there.
[0038]
Further, in this embodiment, a magnetic disk is assumed as a temporary storage device. However, when higher-speed reading / storing is required, it goes without saying that the use of a semiconductor memory such as a RAM is effective. No.
[0039]
Furthermore, in this embodiment, a sorter dedicated to rearrangement of the code data is provided separately from the MPU for controlling the whole, but it goes without saying that the sorting function can be realized by software on the MPU.
[0040]
The present invention may be applied to a system including a plurality of devices or to an apparatus including a single device.
[0041]
Needless to say, the present invention can be applied to a case where the present invention is achieved by supplying a program to a system or an apparatus.
[0042]
【The invention's effect】
As described above, according to the present invention, it is possible to temporarily accumulate hierarchically encoded data, change the order of layers by sorting, and accumulate code data in which the code length information of each layer is deleted. , It is possible to provide an encoding method and apparatus capable of performing hierarchical encoding and decoding at high speed.
[0043]
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a system configuration according to an embodiment.
FIG. 2 is a diagram showing a flow of code data at the time of scanning an image.
FIG. 3 is a diagram showing a flow of code data at the time of sorting.
FIG. 4 is a diagram showing a data flow at the time of decoding, display, or printing.
FIG. 5 is a diagram illustrating the concept of ordinary hierarchical coding.
FIG. 6 is a diagram showing a configuration of hierarchized code data.
FIG. 7 is a diagram showing a configuration of a system using ordinary hierarchical coding.
[Explanation of symbols]
101 image scanner 102 printer 103 MPU
104 Sorter 105 Image reduction unit 106 Encoding / decoding unit 107 Magnetic disk 108 Magneto-optical disk 109 Display 201 Image scanner 202 Printer 203 MPU
204 Sorter 205 Image reduction unit 206 Encoding / decoding unit 207 Magnetic disk 208 Magneto-optical disk 209 Display 301 Image scanner 302 Printer 303 MPU
304 Sorter 305 Image reduction unit 306 Encoding / decoding unit 307 Magnetic disk 308 Magneto-optical disk 309 Display 401 Image scanner 402 Printer 403 MPU
404 Sorter 405 Image reduction unit 406 Encoding / decoding unit 407 Magnetic disk 408 Magneto-optical disk 409 Display 501 Original image 502 Reduced image 503 Reduced image 504 Reduced image (lowest resolution image)
505 Hierarchical encoder 506 Hierarchical encoder 507 Hierarchical encoder 508 Encoder 509 for lowest resolution image Code data collection unit 510 for each layer 510 Magnetic disk 701 Image scanner 702 Printer 703 MPU
705 Image reduction unit 706 Encoding / decoding unit 708 Code data storage recording medium 709 Display

Claims (4)

Image reducing means for reducing the original image to a size smaller than the original image size at least once;
Hierarchical encoding means for hierarchically encoding the original image and the image reduced by the image reducing means,
First storage means for storing code data of each layer encoded by the layer encoding means;
Sorting means for sorting the order of the code data stored in the first storage means in reverse order;
A second storage unit for storing the code data sorted by the sorting unit ,
Said second storage means, the hierarchical order is replaced by sorting means, the encoding apparatus characterized that you accumulated code data code length information of each layer has been removed. 2. The encoding apparatus according to claim 1, wherein the sorting unit is performed as needed. An image reduction step of reducing the original image at least once to a size smaller than the original image size;
A hierarchical encoding step of hierarchically encoding the original image and the image reduced by the image reduction step,
A first accumulation step of accumulating code data of each layer encoded by the layer encoding step;
A sorting step of reversing the order of the code data accumulated in the first accumulation step;
Have a second storage step of storing the sorted code data by the sorting step,
The encoding method according to claim 2, wherein the second storing step stores code data in which the order of the layers is changed by the sorting step and the code length information of each layer is deleted . The encoding method according to claim 3 , wherein the sorting step is performed as needed.

Images