JPH04251894A - Disk reproducing device - Google Patents

Abstract

PURPOSE:To display a control panel without spoiling image data on a picture visually by compressing the image data when the image data and control panel are displayed on the display screen of an LCD display. CONSTITUTION:The disk reproducing device which reproduces a disk where image information, etc., is recorded in addition to voice information compresses at least the image data 46b when the image data 46b from the disk and the control panel 46c are displayed on the display screen 46a of the LCD display 13 respectively.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disc reproducing apparatus suitable for application to, for example, a CD-I player for reproducing a CD-I disc on which image information and the like are recorded in addition to audio information.

0002

[Prior Art] In addition to audio data, a CD (compact disc) contains image data (natural images, animation,
A CD that records computer graphics, etc.), text data, program data, etc., and can be operated interactively.
-I (CD Interactive) system has been proposed. Such a CD-I system supports characters,
Since it has the ability to playback images, audio, computer data, etc., it is useful for AV consumer electronics mainly for audio/visuals, electronic publishing mainly for text, database services mainly for information files, and education mainly for dialogue response.・It can be used for entertainment, etc., and is expected to be a new form of media. In the CD-I system, in order to maintain compatibility and make it widely available for home use,
Various specifications have been established. In other words, the CD-I system uses a 68000 series CPU (a 16-bit microprocessor developed by Motorola) and a real-time operating system that handles various files based on the widely used OS9. It will be done. Two trigger buttons and an XY device are used as input devices, and two output systems, audio and video, are provided. Furthermore, the CD-I player is designed to be able to play ordinary compact discs for music. Also,
For example, when playing a CD-I disc, this CD-I
Image data (referred to as a control panel) indicating operation keys such as stop, play/pause, AMS (Auto Music Scan), etc., and other image data are read from the disc and sent to the CD-I player. The information is displayed on an LCD display provided therein.

0003

[Problem to be Solved by the Invention] By the way, when a disc such as the above-mentioned CD-I is played on a CD-I player,
When image data indicating operation keys such as stop, play/pause, AMS (Auto Music Scan), etc. is displayed on the LCD display, part of other image data (for example, pictures) may be hidden. This has the disadvantage of visually damaging the image data. The present invention has been made in view of the above problems, and allows the LCD display to display stop, play/pause, and A.
The present invention attempts to propose a disc playback device capable of displaying image data indicating operation keys such as MS (Auto Music Scan).

0004

[Means for Solving the Problems] The disc reproducing apparatus of the present invention, as shown in FIGS. When displaying the first and second image information 46b and 46c on the display surface 46a of the display unit 13, at least this first image information 4
6b is compressed.

[0005]

[Operation] According to the present invention described above, the first and second image information 46b and 46c from the disk 15 are displayed on the display section 13.
Since at least the first image information 46b is compressed when displayed on the display surface 46a of the display section 13, the first image information 46b displayed on the display surface 46a of the display section 13 can be visually displayed. The second image information 46c can be displayed on the display surface 46a of the display unit 13 without causing any damage.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the disc reproducing apparatus of the present invention will be described in detail below with reference to FIGS. 1 to 3. First, with reference to FIGS. 4 to 11, the appearance etc. of the disc playback device will be explained. In FIG. 4, reference numeral 1 generally indicates a CD-I player for playing the disk of this example. In this example, this CD-I player 1 has an integrated LCD display 13 so that it can be easily carried outside, and is small and lightweight due to the use of integrated circuits and chip components. The goal is to The overall size of this CD-I player 1 is, for example, 140 mm in width.
mm, length 170mm, and height 60mm.

[0007] Inside the case of the player body 2 of the CD-I player 1, there are a disk drive section that rotates the mounted disk 15, a head drive section that moves the optical head in the radial direction of the disk 15, and an optical drive section. A circuit board for processing the reproduction signal from the head is housed. Furthermore,
It houses a computer consisting of a 68000 series CPU.

[0008] On the front side 2a of the player body 2, there are a headphone jack 3, a volume control dial 4, and a power on/off switch.
An off switch 5 is provided. In addition, the player main body 2
An open button 6 is disposed on the front upper edge of the front side surface 2a. On the player body 2 of the CD-I player 1,
The inner lid 7 is rotatably arranged. When the open button 6 is pressed, the inner lid 7 is opened as shown in FIG. When the inner lid 7 is opened, the disc 15 can be loaded/taken out. The inner lid 7 is provided with a window 8. A transparent member is disposed in this window portion 8. Through this window section 8,
The rotational state of the mounted disk 15 can be confirmed.

Further, on the front edge of the inner lid 7, a trigger button 10a, a trigger button 10b, and an XY device 11 are arranged. The X-Y device 11 is designed so that the position in the X direction and the Y direction can be specified by pressing the upper, lower, left and right parts from the center. In addition, such X
-Y device 11 includes a trackball, a mouse,
A pointing device such as a joystick can be used. Further above the inner cover 7, an outer cover 12 is rotatably disposed. This outer lid 12 can be opened by hand. This outer lid 12 can be opened to an opening/closing angle of 90 degrees or more, and can be fixed at a predetermined opening/closing angle θ. On the back surface 12a of the outer cover 12, an LCD display 13 of, for example, 4 inches is disposed. When the outer cover 12 is opened, the LCD display 13 is exposed as shown in the figure, and the screen of the LCD display 13 can be viewed.

[0010] Further, on the back surface 12a of the outer cover 12, an LCD is provided.
A drive switch 14 is provided. By operating this LCD drive switch 14, the LCD display 13 is turned on/off.
Can be controlled off. Then, as shown in FIG.
2 toward the front in the figure, it can be used in the same way as a commonly used portable compact disc playback device.

Now, the CD-I player has 15 discs.
To play CD-I discs, CD-I/CD-DA discs (mixed discs of CD-I discs and CD-DA discs), and CD-DA discs (compact discs for normal music playback). Can be done. Here, the data format of CD-I will be explained.

[0012] CD-I records data in a format based on CD-ROM. The data recording unit is a block, similar to a CD-ROM. One block corresponds to 98 frames. The capacity of one block is 6 (
Number of audio data) x 2 (stereo 2 channels) x
98 (number of frames) = 2352 bytes. CD-I
The recording capacity of the entire disc is approximately 640 MB in the case of a disc with a diameter of 12 cm. There are two types of CD-I data structures: Form 1 and Form 2. This corresponds to mode 1 and mode 2 of CD-ROM, respectively. Note that mode 1 in a CD-ROM is one in which an error detection code and an error correction code are added to one block of data to enable powerful error correction. Furthermore, mode 2 in the CD-ROM is such that no error detection code or error correction code is added and a large amount of user data can be taken.

In CD-I, Form 1 and Form 2 can be specified for each block, and Form 1 and Form 2 can be mixed on one disc. CD
The -I format differs from the CD-ROM format in that an 8-byte subheader is provided at the beginning of the user data. In this subheader, blocks in which audio, images, and data are recorded are time-division multiplexed in units of blocks. In order to process these in real time, necessary data is written in duplicate and stored. This subheader consists of four items: file number, channel number, submode, and data type.

That is, FIG. 7A shows the structure of Form 1. In form 1, sync (12 bytes) at the beginning
is provided, followed by a header (4 bytes) and further a subheader (8 bytes). After this, user data (2048 bytes) is provided, which includes an error detection code EDC (4 bytes), P parity (172 bytes) for error correction, and Q parity (1
04 bytes) is added. Form 1 has improved error correction capability, and is suitable for handling data such as character data and program data in which errors cannot be interpolated.

FIG. 7B shows the structure of Form 2. In form 2, a sink (12 bytes) is provided at the beginning, followed by a header (4 bytes), and further a subheader (8 bytes). After this, user data (2324 bytes) and a reserve area (4 bytes) are provided. This form 2 is suitable for handling interpolable data such as audio data and video data. The subheader added to the beginning of user data consists of the file number (2 bytes), channel number (2 bytes), submode (2 bytes), and data type (2 bytes), as shown in Figure 8. configured.

Now, four modes are determined for writing audio data on CD-I. One mode has a sampling frequency of 44.1 kHz and a quantization bit count of 16 bits, which is the same recording method as the current CD-DA. This mode is intended for ultra high-fidelity playback. In one other mode, ADP is used as the recording method.
CM (adaptive differential PCM) is used. The sampling frequency is 37.8 kHz, and the number of quantization bits is 8 bits. In this mode, analog discs, i.e. LP
It can be played with record-like sound quality. Playback time is 2 hours in stereo and 4 hours in monaural. This mode is intended for high-fidelity playback.

In another mode, A is used as the recording method.
DPCM is used. The sampling frequency is 37.8
kHz, and the number of quantization bits is 4 bits. In this mode, you can play back with sound quality comparable to FM broadcasting. Playback time is 4 hours in stereo and 8 hours in monaural. This mode is intended for long-term high-fidelity playback.

In another mode, A is used as the recording method.
DPCM is used. The sampling frequency is 18.9
kHz, and the number of quantization bits is 4 bits. Playback time is 8 hours in stereo and 16 hours in monaural. This mode is intended for speech reproduction.

Next, image data will be explained. Image data is processed as follows depending on the type of image data. In the case of a natural image, the sampling frequency of the luminance signal Y is 7.6 MHz, the sampling frequency of the color difference signals U and V is 3.8 MHz, and they are sampled at a ratio of 4:2:2. Then, each bit is compressed to 4 bits and recorded, and when reproduced, it is made into 8 bits. In the case of graphics, a CLUT (color lookup table) is used. CLUT graphics are 256 colors (8 bits), 128 colors (7 bits), 1
There are 3 modes with 6 colors (4 bits), and you can select and use the color you need from 16 million colors.

[0020] In the case of animation, run-length codes are used. This compresses image data using color information and the length between pixels. You can use this code to create full-screen animations. Next, to explain about the disk, C
For D-I disks, mechanical dimensions such as outer diameter dimensions, center hole dimensions, and thickness; optical parameters such as refractive index and reflectance; recording parameters such as disk rotation direction, recording linear velocity, track shape, and track pitch; The usage environment and other conditions are all similar to those of a normal compact disc for music (CD-DA).

[0021] Then, whether or not it is a CD-I disc is determined by checking the TOC (Table
Of Contents). That is, CD-I disc or CD-
In the I/CD-DA disc, PSEC is set to "10" when (POINT=A0). On the other hand, in other disks, PSEC is set to "00" when (POINT=A0). Therefore, (POINT=A0)
From PSEC at the time of CD-I disc or CD-I
/You can determine whether the disc is a CD-DA disc or another disc. Then, on the CD-I disc (POINT=A0, A1
, A2) is set to (01×0). CD-I/CD-DA disc (POINT
=A0) control field is always (01×0
), and other control fields are (00x0)
It is said that Therefore, from the control field, CD
-I disk or CD-I/CD-DA disk can be determined.

Now, since CD-I includes audio data and requires high-speed processing in real time, processing is performed using machine language. The CPU for this purpose is the 68-bit CPU developed by Motorola.
000 series is specified. Furthermore, the CD-RTOS (real-time operating system) that handles various files is based on OS9, and its programs are incorporated into the system using ROM. As input devices, at least two trigger buttons and an XY device are prepared. There are also two output systems: audio and video. The CD-I player is designed to play music CD-DA.

FIG. 9 shows a CD-I for playing back this example disc.
This shows the internal configuration of the player. In FIG. 9, the disk 15 is rotated by a spindle motor 21.
It is rotated at V (constant linear velocity). The rotation of the spindle motor 21 is controlled by a spindle servo circuit 22.
It is controlled based on the clock reproduced by the reproduction circuit 28. Further, the output of the system controller 20 is supplied to the spindle servo circuit 22 . The recorded signal on the disk 15 is reproduced by the optical head 23. Optical head 23 is supported by a two-axis device. The output of the focus/tracking servo circuit 25 is supplied to this two-axis device. Focus/tracking servo circuit 25
is supplied with the output of the system controller 20. A focus/tracking servo circuit 25 applies servo to the optical head 23 in two axes, the focusing direction and the tracking direction, based on the output of the photodetector. The optical head 23 also moves the disk 15 by a slide feeding mechanism 24 using, for example, a linear motor.
is movable in the radial direction. This slide feed mechanism 2
4 is controlled by a thread servo circuit 26. The output of the system controller 20 is supplied to the thread servo circuit 26 . With this slide feeding mechanism 24,
The optical head 23 can be accessed to a desired track position.

The output of the optical head 23 is supplied to a CD reproducing circuit 28 via an RF amplifier 27. The CD reproducing circuit 28 is composed of a bit clock reproducing circuit and the like. In the CD playback circuit 28, the output of the optical head 23 is EFM demodulated and subjected to error correction processing. This CD playback circuit 28
is controlled by the system controller 20. CD
The output of the reproducing circuit 28 is supplied to a CD-ROM reproducing circuit 29. The CD-ROM playback circuit 29 includes a sync detection circuit, a descrambling circuit, an error correction circuit, and the like. A sync is detected by the CD reproducing circuit 28, and the scrambler is released. Then, the header address is checked and the target block is accessed. In the case of Form 1, error correction processing is further performed. This CD-ROM playback circuit 29 is controlled by a system controller 20.

The system controller 20 receives input from an input device 30 . The input device 30 consists of two trigger buttons 10a and 10b and an XY device 11. 31 is a CP for controlling the CD-I system
It is U. As the CPU 31, a 68000 series CPU is used. The CPU 31 includes a master controller 3.
2 is connected. Further, the CPU 31 and the system controller 20 are bidirectionally connected. A bus 33 is derived from the CPU 31. Note that the CPU 31 and the master controller 32 may be integrated into one chip. The data reproduced by the CD-ROM reproduction circuit is sent to the bus 33. The bus 33 includes a video controller 3.
RAMs 35a and 35b are connected via 4a and 34b, respectively. The bus 33 also includes a system ROM 36.
, a backup non-volatile RAM 37 are bidirectionally connected. The bus 33 also includes an audio decoder 38.
is connected.

Image data of the data reproduced by the CD-ROM reproduction circuit 29 is processed under the control of the CPU 31.
It is supplied to video controllers 34a and 34b. Video controllers 34a and 34b form a video signal based on this image data. This video signal is supplied to a video synthesizer 39. This video synthesizer 39 synthesizes the video signal from the video controller 34a and the video signal from the video controller 34b. The output of this video synthesizer 39 is supplied to the LCD display 13 via the LCD circuit 40. The LCD display 13 is driven by the LCD
It can be turned on/off by the drive switch 14.

Audio data of the data reproduced by the CD-ROM reproduction circuit 29 is supplied to an audio decoder 38 under the control of the CPU 31. If the audio data is ADPCM, the audio decoder 38 decodes the ADPCM. The decoded audio data is supplied to the DA converter 41 and converted into an analog signal. Then, the headphone output terminal 3 is connected via a low-pass filter 42 and an amplifier 43.
is output from. The audio signal level output from the headphone output terminal 3 can be set using the volume adjustment dial 4.

Next, the operation when the disc 15 is loaded into the CD-I player 1 and played back will be described. FIG. 3 shows the operation when the LCD display 13 is turned on. First, in step 51, when the power is turned on using the power on/off switch 5 (see FIG. 4), it is determined whether the calendar and internal clock are set, and if "YES", the process moves to step 52.
If "NO", the process moves to step 53. Step 5
2, the X-Y device, trigger button 10a and 1
0b is operated to set the calendar and internal clock. Then, the process moves to step 53. In step 53, it is determined whether or not the disk 15 has been installed, and "YE
If the answer is "S", the process moves to step 56; if the answer is "NO", the process moves to step 54. In step 54, when the disk 15 is not installed, the LCD is displayed as shown in FIG. 10A.
A display area 45 of the display 13 displays a message indicating that a disc is not loaded, and a display area 46 displays a calendar and time. Then, the process moves to step 55.

In step 55, it is determined whether or not the disk 15 is mounted. If ``YES'', the process moves to step 56. In step 56, the TOC on the innermost circumference of the disk 15 is accessed. and step 57
to move to. In step 57, first, from the TOC data, a CD-I/CD-DA disc or a CD-
It is determined whether the disc is an I disc or a CD-DA disc. That is, for a CD-I disc or a CD-I/CD-DA disc, PSEC when (POINT=A0) is “
10”, and for other discs, (POINT=A0
), PSEC is set to “00”, so (P
From PSEC when OINT=A0), CD-I disc, CD-I/CD-DA disc, or CD-D
It is determined whether it is the A disk.

At step 58, a message is displayed on the LCD display 13 indicating that a CD-DA disc is loaded. That is, when a CD-DA disc is loaded, as shown in FIG. 10B, a display indicating that the disc is loaded is displayed in the display area 45 of the LCD display 13, and a PL for operating the CD-DA is displayed in the display area 46.
Operation keys such as AY, AMS, and STOP are displayed. Then, the process moves to step 59. Step 59
Then, the user (operator) selects the LCD display 1.
When the operation keys displayed in the display area 46 of No. 3 are operated via the XY device 11 and the trigger buttons 10a and 10b, the CD-DA disc is played back in accordance with this operation. If it is determined in step 57 that the disc is not a CD-DA disc, the process moves to step 60. In step 60, it is determined whether the disc is a CD-I disc or a CD-I/CD-DA disc. That is, (POINT=A0, A1,
The control field of A2) is (01x0), and the (POINT=A0) of the CD-I/CD-DA disc
) control field is always set to (01x0), and other control fields are set to (00x0), so it can be determined from this control field whether it is a CD-I disc or a CD-I/CD-DA disc. be done. Then, the process moves to step 61.

At step 61, a message indicating that a CD-I disc is loaded is displayed on the LCD display 13. That is, when a CD-I disc is loaded, a display indicating that the disc is loaded is displayed in the display area 45 of the LCD display 13, and the title of the application software is displayed in the display area 47, as shown in FIG. 11C. . Then, the process moves to step 62. In step 62, when the user operates the XY device 11 and the trigger buttons 10a and 10b according to the support of the application software, the CD-I disc is played back in response to this operation. At this point, the process moves to subroutine S1 to perform compression processing, etc., which will be described later. Now, when it is determined in step 60 that the disc is not a CD-I disc, the mounted disc 15
is determined to be a CD-I/CD-DA disc, and the process moves to step 63.
/ When a CD-DA disc is installed, Figure 1
As shown in 1D, the display area 45 of the LCD display 13 displays a display indicating that the disc is loaded, and the display area 46 displays PLAY, AMS,
Operation keys such as STOP are displayed, and the title of the application software is displayed in the display area 47. Then, the process moves to step 64.

In step 64, the user operates the XY device 11 and the trigger buttons 10a and 10b, and selects playback according to this operation. and step 65
to move to. In step 65, it is determined whether or not CD-DA playback has been selected. If "YES", the process moves to step 66; if "NO", the process moves to step 67. In step 66, when the operation keys displayed in the display area 46 are operated by the user via the X-Y device and the trigger buttons 10a and 10b, only a portion of the CD-DA area is played according to this operation. . In step 67, when the user operates the XY device 11 and the trigger buttons 10a and 10b according to instructions from the application software, the CD-I/CD-DA is played back in response to this operation.

[0033] In this way, in the case of a CD-I/CD-DA disc, only the CD-DA area can be played back, and thereby only the sound of the application software can be enjoyed.

By the way, when playing back a CD-DA disc, only audio playback is performed, so there is no need to display any information on the LCD display 13 disposed on the back surface 12a of the outer cover 12. Further, even when only audio reproduction is performed on a CD-I/CD-DA disc, the display on the LCD display 13 is unnecessary. If the LCD display 13 is driven when there is no need for screen display in this way, power consumption will be wasted. Therefore, in this example, C
In the D-I player 1, the LCD drive switch 14 turns the LCD display 13 on when screen display is not necessary.
can be turned off to reduce power consumption.

However, when the LCD display 13 is turned off, operations cannot be performed while viewing the display on the LCD display 13. In addition to the trigger button 10a, the trigger button 10b, and the X-Y device 11, a dedicated key for audio playback may be provided, but this increases the number of keys and leads to an increase in the size of the device. . Therefore, in this example, when the mounted disc is a CD-DA disc and the drive of the LCD display 13 is turned off, or when the mounted disc is a CD-DA disc and audio playback is performed and the LCD display 13
When the drive of the trigger button 10 is turned off,
a, the trigger button 10b and the XY device 11 are made to function as dedicated keys for audio reproduction. That is, for example, if the trigger button 10a is
"LAY/PAUSE key", trigger button 10b is "
The left and right directions of the XY device 11 function as the "AMS key". As a result, L
Even when the drive of the CD display 13 is stopped, various audio playback operations can be performed freely. In addition, CD-D
Since video playback is not performed on A disc, CD-
When the DA disk is installed, the LCD display 13
The trigger button 10a, the trigger button 10b, and the XY device 11 may be made to function not only as on/off keys but also as dedicated keys for audio reproduction. Further, regardless of the type of disc, if the LCD display 13 is turned off, the trigger button 10a, trigger button 10b, and XY device 11 may function as dedicated keys for audio reproduction.

Now, the above subroutine S1 will be explained with reference to FIG. 1. In this example, when displaying image data such as a picture from the disk 15 on the LCD display 13, stop and play /pause, A
Image data indicating operation keys such as MS (Auto Music Scan), that is, control panel 46c (
(see FIG. 2B) can be displayed without hiding image data such as pictures (see FIG. 2A).

That is, in this subroutine S1, first, in step 70, it is determined whether or not, for example, the trigger button 10a and the trigger button 10b are pressed together.If "YES", the process moves to step 71, and "
If "NO", this subroutine S1 is exited. In step 71, for example, a status bit for controlling image data is set to "1". Then, the process moves to step 72. In step 72, it is determined whether the status bit is "1" or not. If "YES", the process moves to step 73; if "NO", this subroutine S
Exit 1.

In step 73, the LCD display 1
When the image data 46b is displayed over the entire display surface 46a as shown in FIG. 2A, for example, the RAM 35a or
Pixels of the image data 46b written in the image data 46b (see FIG. 9) are thinned out in the vertical and horizontal directions. Then, the process moves to step 74. In step 74, step 73
R in which the image data 46b compressed in
In the AM 35a or 35b, a control panel 46c as shown in FIG. 2B, that is, image data is written to a predetermined position (address). In this way, the image data 46b and control panel 46c written in the RAM 35a or 35b are read out, processed by the video synthesizer 39 and the LCD circuit 40, and displayed on the display surface 46a of the LCD display 13. At this time, as shown in FIG. 2C, on the display surface 46a of the LCD display 13, image data 46b' obtained by reducing the image data 46b shown in FIG. 2A is displayed, and the image data 46b' shown in FIG. A control panel 46c is displayed.

Therefore, the control panel 46c can be displayed without impairing the visual state of the image data 46, that is, without hiding part of the image data 46b. In this way, the user can obtain the image data 4 by reducing the image data 46b.
6b' can be fully viewed, and operations can be performed while viewing the control panel 46c.

It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0041]

According to the present invention described above, when displaying the first and second image information from the disk on the display surface of the display unit, at least the first image information is compressed. Therefore, there is an advantage that the second image information can be displayed on the display surface of the display section without visually impairing the first image information displayed on the display surface of the display section.

[Brief explanation of the drawing]

FIG. 1 is a flowchart for explaining an example of a disc playback device of the present invention.

FIG. 2 is a diagram showing image compression for explaining an example of the disc playback device of the present invention.

FIG. 3 is a flowchart for explaining an example of the disc playback device of the present invention.

FIG. 4 is a perspective view showing an example of the disc playback device of the present invention.

FIG. 5 is a perspective view showing an example of a disc playback device of the present invention.

FIG. 6 is a perspective view showing an example of the disc playback device of the present invention.

FIG. 7 is a diagram showing a form for explaining an example of the disc playback device of the present invention.

FIG. 8 is a diagram showing a subheader for explaining an example of the disc playback device of the present invention.

FIG. 9 is a block diagram showing the inside of an example of the disc playback device of the present invention.

FIG. 10 is a diagram showing a display state when a disc is not inserted and when a CD-DA disc is inserted, for explaining an example of the disc reproducing apparatus of the present invention.

FIG. 11 is a diagram illustrating a display state when a CD-I disc and a CD-I/CD-DA disc are inserted to explain an example of the disc reproducing apparatus of the present invention.

[Explanation of symbols]

1 CD-I player 13 LCD display 15 Disc 46a Display surface 46b Image data 46c Control panel

Claims (1)

[Claims] Claim 1: In a disc playback device that plays back a disc on which image information and the like are recorded in addition to audio information, when first and second image information from the disc are respectively displayed on a display surface of a display unit. A disc playback device characterized in that: at least the first image information is compressed.