JPH11136675A - Image scroll using set top box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system and method by which an Internet page with an optional size or any other image is visualized on a TV screen by using an existing set top box of a digital TV broadcast. SOLUTION: An image is stored in a compressed form in a set top box 107, then only part in matching with a display size of a screen is extracted and fed to a decoder, where the decompression is made, with the result fed to a display device. When a user requests image scrolling, other part is extracted and fed to the decoder and the decoder decompresses the part and the result is displayed on the TV screen.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the display of digital compressed images on a decoding output device, and more particularly to a method of displaying a digital compressed image having a size larger than a display screen. About the system.

[0002]

2. Description of the Related Art As digital television (TV) broadcasting has become widespread, opportunities for attaching a device called a set-top box to a conventional television receiver have been rapidly increasing. The set top box processes digital information received via a communication channel (such as satellite or cable) to display video on a TV screen. These set-top boxes are a type of small PC with limited processing power and memory capacity
It is. In such devices, the controlled memory capacity is usually not a problem because the digital T
This is because the processing capacity required by the V broadcast is extremely limited. Given the potential for set-top boxes to become more widespread in the future, many digital service providers want to increase the processing power of this device.

[0003] Many providers of digital TV broadcasting want to give their customers the ability to access content from other sources, such as the Internet. These contents may be entertainment or business information.

[0004] US Patent Application No. US-A-825326
Discloses an architecture called "Data Carousel" that transmits a series of frames over a broadcast channel. A data carousel consists of a series of image frames that are sent to the user periodically.
Data Carousel also includes an application program that runs on the set top box and allows navigating between frames.
This navigation is performed by linking to a graphic page having information about the position of the hot spot and a page referred to by each hot spot. Each frame has two parts, 1
One is a compressed image, and the other is a navigation information table. An application program running on the set top box stores a specific frame (either a root frame or a user selected frame, depending on the contents of the frame) in the memory of the set top box. . The navigation information table is then separated from the compressed image, and the compressed image is displayed along with the hot spots found by the information obtained from the navigation information table. Each frame corresponds, for example, to an Internet page and is logically associated with another page. The data carousel architecture allows a user to navigate between a series of graphic pages broadcast over a wideband channel. The user can select one of a series of pages and has the illusion of an interactive dialogue.

In an architecture such as the data carousel described above, it is desirable that pages of various sizes can be displayed on a TV screen. The original image (eg, HTML format) needs to be pre-processed in order to be converted and compressed into a format compatible with the set top box decoding device to which the image will be transmitted. This compressed digital image is then sent to the set top box, which decodes the image and displays it on the TV screen.
Generally speaking, the size of the original uncompressed digital bit map may be larger than the size of the TV screen, in which case the image is compressed and "cut in slices" prior to transmission. )"There is a need.

A simple and crude solution to the above problem is:
To cut off the periphery of the final image. In this way, the image is partially lost and in some cases unacceptable.

Another well-known method of splitting an original image is to use uncompressed color bits at multiples of the image's border size if the image does not fit the vertical size of the destination screen. -To split the map. It is necessary to add some kind of graphic cut display to the subpage adjusted in this way. These displays are needed to inform the viewer that there is another logically connected subpage. The major problem with this method is that related, logically connected graphic components located near the boundaries of the screen are cut off, displayed on another page, and the effectiveness of the displayed artifacts is reduced. That can have negative consequences.

The problem is exacerbated when the original image exceeds the screen size in both the vertical and horizontal directions.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a technique for reducing the above-mentioned disadvantages of the prior art.

[0010]

According to the present invention, there is provided a method for displaying a digital image on a receiving device, the receiving device comprising: Receiving means for receiving the data segment over the communication channel; storage means for storing the digital image; processing means; and the receiving device can be connected to display means for displaying the digital image. The size of the image is larger than the size of the display means, and the method includes the following steps. Receiving the image in a compressed form and storing the compressed image in the storage means selecting a first part of the compressed image; Decompressing displaying the decompressed first portion on the display means responding to a user control to generate a second one of the compressed images
Selecting a portion of the image; decompressing a second portion of the image; displaying the decompressed second portion on the display means.

According to the present invention, there is further provided a receiving device connectable to a display means for displaying a digital image, wherein the size of the image is larger than the screen size of the display means. Including. Means for receiving a digital image in compressed form over a communication channel; storage means for storing the digital image in compressed form; first means for selecting a first part of the compressed image.
Processing means for decompressing a first part of the image and transmitting the decompressed first part of the image to the display means; and in response to user control, the compression Second of the rendered image
Third processing means for selecting a part of the image; fourth processing means for decompressing a second part of the image and transmitting the decompressed second part of the image to the display means

[0012]

FIG. 1 shows an overview of the structure of a digital video display system that can incorporate the present invention. System 100 includes a providing device 101 from which images to be displayed are transmitted and a transmitting device 103 for transmitting the compressed digital image to a plurality of receiving devices over a communication channel. According to a preferred embodiment of the present invention, these images are transmitted using a satellite communication system, but by any other means (such as wireless or cable).
Can also be used to transmit a data packet to multiple receiving devices. Each receiving device includes a TV receiver 105 and a set top box 107, which processes the images received over the communication channel closely and converts these images to the TV receiver 105.
Convert to a format that conforms to. Both the TV set 105 and the set top box 107 are controlled by the user. Such control can be performed using the remote control 109, for example.

The image of a complete digital bit map is too heavy to process as it is, given the storage space occupation and transmission time. So the size of the bit map "compresses" the image before transmission.
(compress) ". According to the preferred embodiment, the international standard MPEG-II was used as the compression format, but other standards (such as JPEG or GIF) can be used as well.

FIG. 2 outlines the structure of a set top box that can be used to implement a preferred embodiment of the present invention. The demultiplexer 201 receives as input a transfer stream including an application data stream and a video and audio stream. A transport stream is a means by which information is sent by the sending device 103 to a plurality of receiving devices over a communication channel. The demultiplexer 201 extracts an application data stream and a video and audio stream from the transfer stream. The video and audio streams, such as a movie, are then sent directly to the MPEG decoder 203, where the MPE
The G decoder decompresses the image and displays it on the screen of the TV set 105.

On the other hand, the application data stream is stored in the memory 205. application·
The data stream consists of instructions and data carousel
It may include a static image, such as an I-frame of the architecture. The instructions are interpreted and executed by the set top box CPU 207 in accordance with the operating system stored in the memory 205.

In the preferred embodiment of the present invention, the operating system "OpenTV" was used.

As mentioned above, one potential source of images that a set top box user may be interested in is the Internet. data·
The carousel architecture can be used to enable a series of interlinked pages, giving the user limited interactivity. The size of these pages may be larger than the screen of the TV receiver.

The problem of displaying images larger than the screen size is a well-known problem in computer science.
According to current state-of-the-art methods, images received over a communication channel can be decompressed and stored as a bit map in main storage, and then a picture of the scrollable image can be displayed in a graphics window. Unfortunately, as noted above, this type of device usually has only a limited amount of memory for economy, while
Storing maps requires a large memory area. In addition, the graphics processing capabilities required to process images in the form of bit maps are usually not as powerful in set-top boxes.

According to a preferred embodiment of the present invention, the received image is in a compressed format (MPEG-II format).
Is stored in the memory of the set top box. Some rectangles of the entire image are retrieved from memory, decompressed and displayed. When the user requests scrolling of the image using the remote control 109, another sub-rectangle is retrieved from memory and
Uncompressed and displayed. In this way, memory occupancy is substantially reduced. The reason is that the compressed image is much smaller than the fully uncompressed image. From the compressed and stored image, the location of a well-defined relatively small rectangular section can be determined as part of the original uncompressed image, so that the exact decompressed and displayed This approach is only possible if a large sub-rectangle can be identified on the compressed image. The format of the MPEG-II standard meets that requirement. That is, the image is
Editable (editabl
e) ”.

Referring now to FIG. 3, the pre-processing of the image before transmission is shown. The head end (providing device) 101 is a transmission source of an image to be displayed (FIG. 1). The image may be, for example, that carried by a page on the Internet, which the head end 101 will handle in detail. Also, any digital image of any size can be transmitted. According to a preferred embodiment of the present invention, the input data representing the digital image is:
A bit map of pixels having color information associated with each pixel. The color of each pixel is, for example, three RGB components (or YUV components)
Can be expressed using the saturation value for each of

According to a preferred embodiment of the present invention, the compressed image is carefully processed by the head end 101 before transmission. A table that represents the position of certain "syntactical elements", such as parts of an image or macroblock, with respect to the compressed image as offset values from a given reference point. Created. This information is very useful for increasing the processing speed when the user requests scrolling. In the absence of this table, these "parts arranged together" must be sought during processing, and under limited hardware capabilities, this operation can have a significant effect on the final result. Could give. As described above, according to a preferred embodiment of the present invention, the MPE
The standard for G-II compression was used. This format allows for "editing" the image without decompression. For editing operations,
It must be possible to reconstruct from the coded data of the partial rectangle of the original image.

In the embodiment described herein, only vertical scrolling of the image was considered. The reason is that vertical scrolling is more common.
However, a horizontal scrolling table can be created using the same pre-processing as described for vertical scrolling. In this case, another level of coding structure is analyzed,
The reason is that in the case of the MPEG-II standard, it is necessary to access the macro block component of the image.

The server at the head end 101 packetizes the image, or series of images, and the frames of the packetized image are then MPEG-II
Wrapped in the transfer stream. This operation is performed using the required MPEG-II header around the data packet.
This is done by enclosing the data and transport stream header structure. The MPEG-II transport stream is then multiplexed by the transmitting device 103 and sent over a communication channel as a digital video broadcast. The digital video broadcast data stream is identical to the transport stream transmitting the video content except for its size and content,
Treated similarly. The compressed image is then transmitted over a channel (such as a satellite or cable) to a plurality of set-top boxes to which the broadcast is sent.

The application program is transmitted with the image or sequence of images. This application program is executed by the CPU 207 of the set top box and allows the user to interact with the displayed image or series of images. For example, in the data carousel described in US-A-825326, the application program contains all the information to select the required frame and navigate between related pages. There are two types of data packets, one is a compressed image and related information (eg, the location table,
And data carocell navigation data tables).
Another is an application data packet that contains all the information needed by the set top box to display and process the image. According to the preferred embodiment, the application program is sent with the image or sequence of images, but this is not the only way to make the application program available to the set top box CPU. For example, the application program can be permanently stored in the memory 205 of the set top box. Transmitting an application program with an image or sequence of images has the obvious advantage of requiring no changes to the existing structure and each receiving set top box.

FIG. 4 shows an overview of a data packet containing an image when the present invention is implemented with data carocell transmission.

Next, reference is made to FIG. When the set top box 107 receives the stream, the demultiplexer 201 stores in the memory 205 all data that is not a video and audio stream. Next, the CPU 20
7 executes the application program. If the image to be displayed is larger than the size of the TV screen, the defaulted base part of the image is retrieved,
First appears on the screen. It is common to select the upper left of the image, but it is equally possible to select any sub-rectangle. The retrieved part is in a compressed form at that time and is then sent to the MPEG decoder 203, which simply decompresses the image and displays it on the TV screen. It is also possible to present the image to the viewer with one or more "hot spots", which display information about operations that can be performed using the remote control 109. For example, in the case of a data carousel, a hot spot visually indicates a link that the user can select. Image scrolling can be associated with one of these hot spots and can be visually selected and easily controlled on the screen using the appropriate commands on the remote control. When scrolling is requested, the application program finds the appropriate sub-rectangle from the compressed image stored in memory 205 and sends it to decoder 203. The decoder repeats the decompression operation and sends the image to the TV screen. As mentioned above, one of the advantages of the present invention is that no changes are required to existing set top boxes.
Set top boxes only perform their normal operations. For example, from the perspective of a decoder, there is no difference whether the compressed image is a still image (such as an MPEG I-frame) or a single video of a movie.
The set top box keeps refreshing the image on the TV screen until a new image is received.
This operation is exactly the same as what a set top box would normally do when transmitting a movie on a TV set.

In summary, the following matters are disclosed regarding the configuration of the present invention.

(1) (A) receiving means for receiving a data segment on a communication channel, (B) storage means for storing a digital image, and (C) processing means, A method for displaying an image in a receiving device connectable to display means for displaying the image, wherein the size of the image is larger than the size of the display means, and (D) compressing the image. Receiving the compressed image in the stored format and storing the compressed image in the storage means; and (E) selecting a first portion of the compressed image;
(F) decompressing a first portion of the image; (G) displaying the decompressed first portion on the display means; (H) responding to user control;
Selecting a second portion of the compressed image; (I) decompressing the second portion of the image; and (J) displaying the decompressed second portion on the display means. Displaying. (2) The method according to (1), wherein the image to be compressed is compressed according to the MPEG-II standard. (3) The method according to any one of the preceding claims, wherein the receiving device is also capable of receiving television (TV) video and audio streams. (4) The method according to any one of the preceding claims, wherein the display means is a television receiver. (5) A receiving device connectable to the display means for displaying a digital image having a size larger than the size of the display means, and (A) for receiving a digital image in a compressed format on a communication channel. Receiving means,
(B) storage means for storing the compressed (format) image; and (C) a first of the compressed image.
First processing means for selecting a portion of the image; and (D) decompressing a first portion of the image and transmitting the decompressed first portion of the image to the display means. (E) third processing means for selecting a second portion of the compressed image in response to user control; and (F) compressing a second portion of the image. Fourth processing means for decompressing and transmitting the decompressed second portion of the image to the display device. (6) the receiving device is a set top box capable of receiving a video and audio stream of a TV;
The receiving device according to (5). (7) the receiving device is a television receiver;
The receiving device according to (6). (8) The receiving device according to (6) or (7), wherein the receiving device conforms to the MPEG-II standard.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a transmission system incorporating the present invention.

FIG. 2 is a schematic diagram of a set top box.

FIG. 3 is a schematic diagram illustrating a process of image compression according to a preferred embodiment of the present invention.

FIG. 4 illustrates a data packet used for image transmission according to a preferred embodiment of the present invention.

FIG. 5 illustrates a scroll scroll according to a preferred embodiment of the present invention.
It is a schematic diagram showing a process.

[Explanation of symbols]

 100 transmission system 101 providing device (head-end)

Continued on the front page (72) Inventor Marcello Vitaletti 1-14, Italy, Rome, Via Gia Stantino 41

Claims (8)

[Claims] 1. An apparatus comprising: (A) receiving means for receiving a data segment on a communication channel; (B) storage means for storing a digital image; and (C) processing means. A method for displaying an image in a receiving device connectable to display means for displaying the image, the method comprising: (D) compressing the image; Receiving the compressed image in the storage means and storing the compressed image in the storage means; (E) selecting a first portion of the compressed image; and (F) a first portion of the image. Decompressing the
(G) displaying the decompressed first portion on the display means; and (H) selecting a second portion of the compressed image in response to user control;
A method comprising: (I) decompressing a second portion of said image; and (J) displaying said decompressed second portion on said display means. 2. The image to be compressed is MPEG-II.
The method of claim 1, wherein the method is compressed according to a standard. 3. The method according to claim 1, wherein the receiving device is also capable of receiving television (TV) video and audio streams. 4. The method according to claim 1, wherein said display means is a television receiver. 5. A receiving device connectable to a display means for displaying a digital image having a size larger than the size of the display means, wherein (A) receiving a digital image in a compressed form on a communication channel. (B) storage means for storing the compressed (format) image; and (C) first processing for selecting a first portion of the compressed image. Means,
(D) second processing means for decompressing a first portion of the image and transmitting the decompressed first portion of the image to the display means; and (E) responsive to user control. And third processing means for selecting a second portion of the compressed image; and (F) a second portion of the image.
And a fourth processing means for transmitting the uncompressed second portion of the image to the display device. 6. The receiving apparatus according to claim 5, wherein said receiving apparatus is a set top box capable of receiving a video and audio stream of a TV. 7. The receiving device according to claim 6, wherein said receiving device is a television receiver. 8. The receiving device according to claim 6, wherein said receiving device conforms to the MPEG-II standard.