JPH11146276A - Image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image processor with which processing can be executed without affecting the read rate of an external storage part when pallet information or gain information can be changed for the unit of a line inside on on- screen display(OSD) area, for example, in order to provide the OSD image of much higher expression. SOLUTION: In OSD image information, the pallet number stream, pallet information and gain information are stored in an external storage part 1. Concerning the pallet information and gain information, on the other hand, a table for read control is provided inside an internal storage part 12 and the read rate of color information and gain information is controlled. Thus, the read rate of the pallet number stream can be secured and the read rate of the external storage part is not affected. Further, the degree of freedom in the number of coloring and blending inside the OSD image is remarkably improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus, and more particularly, to an on-screen display for superimposing control information such as characters and graphics or service information on an image frame of a television or VTR. (Hereinafter referred to as OSD).

[0002]

2. Description of the Related Art In an image processing apparatus having an OSD function for superimposing and displaying an image signal of control information such as characters and graphics or service information (hereinafter abbreviated as service information) on a video frame such as a television signal. Generating an OSD image signal such as service information generally requires color information in which pixels constituting an image are arranged in display scanning order. In order to specify color information to be displayed at a certain pixel position, this color information is used. Instead, a method of using a color information number in which a number is added to the color information to be displayed is known. The method using the color information number has an advantage that when the number of colors of the OSD image is small, the total data amount required for processing can be effectively suppressed.

For example, if 6 bits are used for a luminance signal and 5 bits are used for a blue color difference signal and a red color difference signal as color information, 16 bits are needed for color information for a certain pixel. However, when the total number of colors in an image is limited, for example, when it is limited to 16 colors, a number may be assigned to 16 pieces of color information, and the color information number can be expressed by 4 bits. .

[0004] Hereinafter, the color information given this number is collectively called a palette. The color information will be referred to as pallet information. A pixel in the OSD image is represented by the number of the pallet information (pallet number). The OSD image can be represented as a set of a pallet and a pallet number sequence arranged in the scanning direction from the display start position to the end position of the image. For example, the n-th scan pixel of the OSD image having the palette including the 16 pieces of 16-bit palette information described above is represented by n of the palette number sequence in units of 4 bits.
Just look at the th.

The set of the pallet number sequence and the pallet is O
Since the method of representing the SD image can separate and manage only the palette, it is excellent in image color processing such as instantaneously changing only the color. For these reasons, it is widely used as a standard signal format in the OSD that multiplexes characters, patterns, and the like, such as teletext and traffic information, with television information and the like as additional information.

[0006] Such an OSD image is displayed on a television, V
The simplest method for superimposing and displaying an image frame (hereinafter, referred to as a video image) such as a TR is to replace pixels of the video image with pixels of the OSD image at the display position of the OSD image. At this time, it is known that a more versatile display can be performed by multiplying each of the video pixels and the OSD pixels by a certain coefficient to obtain a sum instead of a simple replacement. In particular, when this calculation is represented by α × (palette information of OSD pixel) + (1−α) × (palette information of video pixel) (where 0 ≦ α ≦ 1), the display result is the OSD image. The video image seems to show through from below. This is called α blending and is known as a special effect in OSD display. However, when such processing is performed, it is necessary to separately add α (hereinafter, referred to as gain information) indicating the blending ratio to the OSD image in addition to the palette.

As a first conventional example for realizing OSD image display, Japanese Patent Application No. 9-10037 filed by the present applicant previously,
There is Japanese Patent Application No. 9-52830. In this example, one OSD image is treated as a set of a pallet, a pallet number sequence, and gain information. In this case, the gain information is O
This is the degree of color decay uniformly applied to the SD image.

FIG. 2 shows the configuration of this image processing apparatus. O
The SD image is usually received from the outside, for example, from a communication line or a storage medium, and stored in a storage device managed by the image processing apparatus. At this time, the pallet and gain information having a relatively small data amount are stored in the internal storage unit 24, and the pallet number sequence having a large data amount is stored in the external storage unit 20. At this time, a plurality of types of OSD images may be stored without exceeding the capacity of the storage device.

Prior to the OSD image display start timing, the memory control unit 21 reads a pallet number sequence from the external storage unit 20. The read pallet number string is written into the pallet number string buffer 22. When the display start timing of the OSD image comes, the pallet reference unit 23 reads the pallet number from the pallet number string buffer 22,
The read pallet number is sent to the pallet register of the internal storage unit 24. Thus, the palette register of the internal storage unit 24 outputs the palette information corresponding to the number to the multiplier 25. When performing the blending, the gain information α stored in the gain register of the internal storage unit 24
Is sent to the multiplier 25, and 1−α is sent to the multiplier 26. The result of the multiplication by the multiplier 25 and the result of the multiplication of the video image and the 1-α by the multiplier 26 are added by the adder 27, whereby a blending output of the OSD image and the video image is obtained. It should be noted that a pallet register and a gain register in the internal storage unit 24 have external CPUs 28 respectively.
The pallet and the gain information are transferred and written in advance through the interface 29 from the same.

Conventional example 2 for realizing OSD image display
OSD using LSI Logic's L4002
Application Note (LSI LOGIC Co., App
lication Note, "Using the L64002 on-screen display
feature ") data sheet, where one O
The SD image is handled as a set of a pallet, a pallet number sequence, and gain information. The gain information in this case is OSD
This is the degree of color attenuation applied uniformly to an image.

The O which is handled by the image processing apparatus of the conventional example 2
The SD image has a format in which gain information, a pallet, a pallet number string, and the like are sequentially connected to form a block of data string with a control header. This OSD
The image is received from outside, for example, from a communication line or an information storage medium, and stored in an external storage unit managed by the image processing apparatus.
The data is read from the external storage unit and reproduced / displayed in accordance with the required display timing. A plurality of types of OSD images can be stored without exceeding the capacity of the external storage unit.

In the conventional example 1, the pallet and the gain information of the OSD image information are stored internally, and the external reading is performed only with the pallet number sequence. In the second conventional example, the pallet number sequence and all the pallet and gain information are read out.
It is necessary to increase the read rate as compared with.

In the first conventional example, information constituting one OSD image is separately stored in an external storage unit and an internal storage unit.
The internal storage unit reads and writes faster than the external storage unit, but has a smaller capacity. Therefore, OSD that can be displayed simultaneously
The number of images is determined by the capacity of the internal storage unit. On the other hand, in the image processing apparatus described in the second conventional example, all the information necessary for displaying the OSD image is continuously stored in the same storage device. Is determined by the capacity of Generally, the capacity of the external storage unit can be larger than that of the internal storage unit. Therefore, the configuration of Conventional Example 2 can simultaneously display more OSD images.

[0014]

The conventional OSD described above.
In the image, the amount of pallet and gain information was smaller than the pallet number sequence, and the dominant data amount was the pallet number sequence. On the other hand, in order to realize an OSD image with higher expressive power, it is conceivable to extend the palette and gain information.

For example, in both the prior art examples 1 and 2, the gain information uniformly covers the entire OSD screen. However, the gain information can be set for each palette information (each color information). By using a set of gain information similar to the above (hereinafter, referred to as a gain), the degree of freedom of blending is significantly increased.

In both of the conventional examples, one OSD
The palette and gain information was fixed for the image.
On the other hand, pallet and gain information are stored in one OSD.
If it is possible to change the scan line unit in the image,
Both the number of colors in the SD image and the degree of freedom in blending are significantly increased.

However, in such an extension, it is necessary to prepare a pallet and a gain for each scanning line (hereinafter, simply referred to as a line), and the total data amount increases by a considerable amount as compared with the pallet number sequence. Therefore, when such an extension is made, it is difficult to store the increased pallet and gain in an internal storage device having a small capacity in the above-described conventional example 1.

In order to update the pallet and the gain for each line, a method of transferring the pallet and the gain into the image processing apparatus by using the interrupt function of the external CPU can be considered. Since the data transfer is frequently performed, the processing load on the CPU is significantly increased. Therefore, the display performance depends on the processing performance of the CPU and the performance of the transfer bus, and it is difficult to bring out a constant display performance.

Therefore, when the update information such as the pallet and the gain is stored in the same external storage device as the pallet number string and read out, as in the second conventional example, a constant display capability is obtained regardless of the processing performance of the CPU. be able to.

However, in both of Conventional Examples 1 and 2, when the increased pallets and gains are to be stored in the external storage unit, if the readout rate of the external storage unit is constant, the pallet number sequence is read based on such information. Rate is squeezed. As a result, the display of the OSD image is restricted.

However, depending on the OSD image to be displayed,
It may not be necessary to update the pallet and gain every line. For example, there is a case where updating of the pallet and the gain in units of two lines is sufficient. If the update of the pallet and the gain can be controlled on a line-by-line basis, the pallet and gain reading rate can be reduced by half compared to the case of performing the update on a line-by-line basis. Therefore, the reading rate of the pallet number sequence can be ensured accordingly. However, if these control tables are provided externally, the reading rate of the pallet number sequence will be reduced.

Therefore, an object of the present invention is to minimize the limitation on the display of OSD images by ensuring the maximum reading rate of the pallet number sequence even when the reading rate of the external storage unit cannot be increased. It is to provide a possible image processing device.

[0023]

In order to solve the above-mentioned problems, an image processing apparatus according to the present invention comprises a television, a VT
An image processing apparatus having an on-screen display (OSD) function for superimposing and displaying control information or service information such as characters and graphics on an image frame such as R and having an external storage unit for managing at least outside the apparatus. A color information number sequence, color information, and gain information of the OSD image information are stored in an external storage unit, and a color information control table and a gain information control table for reading out the color information and the gain information are stored inside the apparatus. It is characterized by having at least an internal storage unit for storing a table (that is, a pallet update table and a gain update table in FIG. 1).

In this case, it is preferable that the external storage unit is configured so that the gain information storage area is divided in units of four scanning lines, and the gain information is stored in the external storage unit in the upper part.

It is preferable to further provide a color information register and a gain information register for storing the color information and the gain information read from the control tables for the color information and the gain information, respectively.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of an image processing apparatus according to the present invention has an external storage unit for storing a pallet number sequence, a pallet, and a gain among image information constituting an OSD image. And a pallet update table and a gain update table for storing respective update information of pallets and gains stored externally are provided in the image processing apparatus, and pallet information and gain information read in internally by these update tables. Are respectively provided inside the pallet register and the gain register.

With this configuration, it is possible to control the read rate of the pallet information and the gain information and to secure the read rate of the pallet number sequence. Further, since the update table for reading control of the pallet information and the gain information is arranged inside, the reading rate of the external storage unit is not affected.

[0028]

Next, a more specific embodiment of the image processing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing one embodiment of an image processing apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes an external storage unit (external memory). The external memory 1 stores a pallet number sequence, a pallet, and a gain among image information constituting an OSD image. The pallet update information for controlling the pallet update and the gain update information for controlling the gain update are stored in an external CP.
The information is stored in the pallet update table and the gain update table of the internal storage unit (internal memory) 12 from the U10 or the like via the interface 11.

The memory control unit 2 operates to read out the required number of pallet number strings, pallets, and gains from the external memory 1 in time for display. First, the memory control unit 2 sets the time before the display start timing comes.
The pallet and gain for the first line are read from the external memory 1 in advance. The memory control unit 2 sends a pallet write signal to the pallet buffer 4 to perform pallet writing. Further, the memory control unit 2 sends a gain write signal to the gain buffer 5 and performs gain writing. In FIG. 1, a broken line indicates a flow of a control signal, and a solid line indicates a flow of information, data, and the like.

Next, the memory control unit 2 reads the pallet number sequence from the external memory 1 before the display start timing. This data is temporarily stored in the pallet number string buffer 3 for adjustment with the read rate of the external memory 1.

Next, the memory control unit 2 sends a palette write signal to the palette register 7 before the display start timing, and transfers the palette stored in the palette buffer 4 to the palette register 7. Similarly, the memory control unit 2 sends a gain write signal to the gain register 8 before the display start timing, and transfers the gain stored in the gain buffer 5 to the gain register 8.

The pallet reference section 6 reads the pallet number from the pallet number string buffer 3 at the display start timing, and sends out the address where the pallet information corresponding to the pallet number is stored to the pallet register 7. Similarly, an address at which gain information corresponding to the pallet number is stored is sent to the gain register 8. The pallet register 7 and the gain register 8 output pallet information and gain information to be displayed, respectively, and these values are multiplied by the arithmetic unit 9, and the multiplication result is output from the image processing apparatus 100.

Next, during the display period of the first line of the OSD image, the memory control unit 2 refers to the pallet update table and the gain update table of the internal memory 12. When updating the pallet or gain in the next line, control is performed so that the pallet and gain to be used in the next line are read. The read pallet and gain are stored in the pallet buffer 4 and the gain buffer 5, respectively. After the display of the first line of the OSD image is completed, the memory control unit 2 stores the stored palette and gain in the palette register 7 before the start of the display of the next line.
And transfer to the gain register 8.

The memory control unit 2 reads the pallet number sequence from the external memory 1 within a range where the pallet number sequence buffer 3 in which the pallet numbers are stored does not underflow or overflows.
Continue to transfer to.

The image processing apparatus 100 performs the above operation on an OS
Repeat until the display end line of the D image. Here, the memory control unit 2 reads the pallet number sequence from the external memory 1 so as to be sufficiently in time for the display timing, stores the pallet number sequence in the pallet number sequence buffer 3, and reads the pallet and the gain to be updated in line units from the external memory 1 at the same time. Need to be stored in the pallet buffer 4 and the gain buffer 5.

The reading rate of this pallet number sequence,
If the sum of the pallet reading rate and the gain reading rate exceeds the reading rate of the external memory 1, O
Failure to display SD images. Therefore, in such a case, it is necessary to prevent the display of the OSD image from being broken by adding some restrictions. Therefore, in the image processing apparatus of the present embodiment, the external CPU 10 or the like sets pallet update information and gain update information in the pallet update table and the gain update table of the internal memory 12 according to the display amount of the pallet number sequence, By controlling the update and non-update of the pallet and the gain, the reading rate of the pallet number sequence is ensured.

FIG. 3 shows an example of the configuration of the pallet update table and the gain update table in the internal memory 12. As shown in FIG. 7A, the pallet update table is the OSD
Each image display line has a 1-bit palette flag. Here, the maximum number of displayable lines is n, and the palette update table has a storage capacity of n [bits]. The pallet flag, when its value is 1, indicates that the line is updated to a new pallet. If the value is 0, it indicates that the palette is not updated on that line.

As shown in FIG. 3B, the gain update table has a 1-bit gain flag for each display line of the OSD image. Here, the maximum displayable line is n, and the gain update table has a storage capacity of n [bits]. When the value of the gain flag is 1, it indicates that the line is updated to a new gain. If the value is 0, it indicates that the gain is not updated for that line.

The pallet update table and the gain update table can be set independently of each other.

FIG. 4 is an explanatory diagram (configuration example 1) showing the correspondence between the palette update table and the gain update table stored in the internal memory 12 and the palette and the gain stored in the external memory 1. Here, assuming the case of field display of an NTSC image, the maximum displayable line number n is set to n = 240.

As shown in FIG. 3C, the total number of pallet information in the pallet required for one update is 16 when the pallet number is 4 [bits] and represents one pixel.
It is made into pieces. The pallet updated in line units is 1
Assuming that one piece of pallet information is 2 [bytes], pallet numbers are composed of 16 pieces of pallet information from 0 to 15, and the total information amount is 2 × 16 = 32 [bytes].

On the other hand, the total number of pieces of gain information within the gain required for one update is set to 16 in the case where the pallet number is 4 [bits] and represents one pixel. Assuming that one piece of gain information is 1 [byte], the gain updated on a line basis is composed of 16 pieces of gain information from pallet numbers 0 to 15, and the total information amount is 1 × 1.
6 = 16 [bytes].

In the first configuration example, if the flag of the pallet update table is 1, an update pallet is prepared, and if the flag of the pallet update table is 0, no update pallet is prepared. For example, as shown in FIG. 4A, the update timing of the pallet is set to line 0, line 2, line 2
In the case of 39, the pallet of line 0, the pallet of line 2, and the pallet of line 239 are successively stored in the external memory 1 as shown in FIG. Then, the memory control unit 2 refers to the pallet update table of the internal memory 12 at the time of updating the line, and if the flag is 1, reads the pallet from the external memory 1 and operates to advance the next read address by 32 [bytes].

In the configuration example 1, if the flag of the gain update table is 1, an update gain is prepared. For example, as shown in FIG. 4B, the update timings of the gains are set to line 0, line 2, line 5, line 7, line 2
36, line 237, and line 239, the external memory 1 stores line 0, line 2, line 5, line 7, line 236, and line 23 as shown in FIG.
7. The gain of the line 239 is stored continuously. Then, the memory control unit 2 sets the internal memory 12
With reference to the gain update table described above, if the flag is 1, the gain data is read from the external memory 1 and the next read address is advanced by 16 [bytes].

As described above, in the case of the configuration example 1, the total amount of the pallets and gains stored in the external memory 1 is the minimum, but when a new pallet or gain is added to a certain line, the line located after that It is necessary to rewrite all the pallets and gain information.

FIG. 5 is an explanatory diagram (configuration example 2) showing the correspondence between the palette update table and the gain update table stored in the internal memory 12 and the palette and the gain stored in the external memory 1. In this case, the internal memory 1
Regardless of the value of the flag of the pallet update table or the gain update table of No. 2, the pallet storage area and the gain storage area for the maximum number of displayable lines are secured in the external memory 1.
The total amount of pallets and gains to be secured in the external memory 1 is the maximum, but new pallets and gains can be easily added and deleted.

In the correspondence relationship between the gain update table stored in the internal memory 12 and the gain stored in the external memory 1 of the configuration example 2, when the read data amount does not match the read unit of the external memory 1, useless reading is performed. May occur. For example, it is assumed that the gain required for updating one line is 16 [bytes], but the read unit of the external memory 1 is 32 [bytes]. In this case, the gain for two lines is read from the external memory 1 by one access. If the value of the gain update table for the two lines in the internal memory 12 is “10” or “01”, the read data is read. Of the pallet number sequence, which is not effective.

FIG. 6 is an explanatory diagram (configuration example 3) showing the correspondence between the gain update table indicated by the reference numeral 61 and the gain stored in the external memory 1. FIG. 6 also shows the gain of Configuration Example 2 to which reference numeral 60 is assigned. This is an example showing that waste occurs when the read unit of the external memory 1 is 32 [bytes] in the configuration example 2. As described above, with the gain 60 stored in the external memory 1 of the configuration example 2, when the value of the gain update table of the internal memory 12 is “10” or “01” for each access unit,
Since half of the read data is not used, waste occurs.

On the other hand, in the gain 61 stored in the external memory 1 of the configuration example 3, the gain storage area is divided in units of four lines, and the gain is stored in the gain storage area upward. For example, as shown in the gain update table of FIG. 6, the gain flag for lines 0 to 3 is “1010”. That is, since the lines 0 and 2 are valid, the gains of the lines 0 and 2 are stored in the gain storage area for the lines 0 to 3 secured in the external memory 1 from the top. The gain flag in the next lines 4 to 7 is “0101”
Therefore, the gains of the line 5 and the line 7 are stored in the gain storage area for the lines 4 to 7 secured in the external memory 1 from the top. When the data is stored as described above and the access is controlled so as not to be accessed when the gain flag is “00”, useless reading of the gain can be suppressed as compared with the configuration example 2.

The preferred embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and various design changes can be made without departing from the spirit of the present invention. It is.

[0052]

As is clear from the above-described embodiment, according to the present invention, among the image information constituting the OSD image,
The pallet number sequence, the pallet, and the gain are stored in the external memory, and the pallet update information for controlling the pallet update and the gain update information for controlling the gain update are stored in the pallet update table and the internal memory. By storing the data in the gain update table, even if the read rate of the external memory cannot be increased, the read rate of the pallet number sequence can be maximized and the limitation on the OSD image display can be suppressed. it can.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an image processing apparatus according to the present invention.

FIG. 2 is a block diagram illustrating a conventional example of an image processing apparatus.

FIG. 3 is an explanatory diagram showing a configuration example of a pallet and a gain update table for controlling reading of a pallet and a gain in the image processing apparatus according to the present invention.

FIG. 4 is an explanatory diagram showing a configuration example 1 of a pallet update table and a gain update table in the image processing apparatus according to the present invention, and pallets and gains stored in an external memory;

FIG. 5 is an explanatory diagram showing a configuration example 2 of a pallet update table and a gain update table in the image processing apparatus according to the present invention, and pallets and gains stored in an external memory.

FIG. 6 is an explanatory diagram showing a configuration example 3 of a gain update table and a gain stored in an external memory in the image processing apparatus according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... External storage part (external memory), 2 ... Memory control part, 3
... Pallet number string buffer, 4 ... Palette buffer, 5
... Gain buffer, 6 ... Palette reference section, 7 ... Pallet register, 8 ... Gain register, 9 ... Calculation section, 10 ... C
PU, 11 interface, 12 internal memory, 20
... External storage unit, 21 ... Memory control unit, 22 ... Palette number string buffer, 23 ... Palette reference unit, 24 ... Internal storage unit, 25, 26 ... Multiplier, 27 ... Adder, 28 ... CP
U, 29: Interface, 100: Image processing device, α
... Gain information.

Claims (3)

[Claims] An external storage unit having an on-screen display (OSD) function for superimposing and displaying control information such as characters and graphics or service information on an image frame of a television, a VTR, or the like, and managing at least outside the apparatus. In the image processing apparatus provided, the color information number sequence, the color information, and the gain information of the OSD image information are stored in the external storage unit, and the color information for reading the color information and the gain information respectively is stored in the apparatus. An image processing apparatus comprising at least an internal storage unit for storing a control table and a gain information control table. 2. The image processing apparatus according to claim 1, wherein said external storage section is configured to divide a gain information storage area in units of four scanning lines, and to store the gain information in the storage area. 3. A color information register and a gain information register for respectively storing color information and gain information read based on the control tables for the color information and gain information, respectively. The image processing apparatus according to any one of the preceding claims.