JP3014749B2 - Image memory device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention records image data in an external storage device such as an optical disk device, and reads out the image data as necessary to display an image. The present invention relates to an image memory device.

[Conventional technology]

An example of an image file device using an optical disk device as an external storage device is described in JP-A-1-172996.

In such prior art, when image data is recorded on an optical disk, management data including the size of the image to be recorded, the encoding method of the image data, the recording address of the image data on the optical disk, and the like are stored on the optical disk together with the image data. Will be recorded. When reproducing desired image data from the optical disk, first, management data for the image data is reproduced from the optical disk, a recording address of the image data is detected, and based on these, the image data is reproduced from the optical disk. Playback, and further, by determining the image data from the management data,
After decoding, the size of the image is determined from the management data, and the decoded image data is written to the display memory. Thereafter, the image data is read from the display memory, and the image is displayed on the display screen.

[Problems to be solved by the invention]

In the above-mentioned prior art, an image is recorded on an optical disk by compressing the data to reduce the reproduction time and processing time from the optical disk. However, the image of the entire display screen is recorded on the optical disk. Like that.

On the other hand, when the user designates a desired area on the display screen using a mouse or the like, the image data in the designated area (designated area) in the display memory is recorded on the optical disk, and the image of the designated area is recorded. When performing the file, the access unit (data amount at the address) for writing and reading the image data of the display memory may be one pixel, but if it is n pixels (n is an integer of 2 or more), There is such a problem.

That is, the designated area determined by the user on the display screen is set in pixel units. Specifically, for example, what is designated by the mouse when setting the designated area is a pixel serving as the upper left corner and a pixel serving as the lower right corner of the designated area. In other words, two pixels on the display screen are designated by the mouse.
When a point is designated, a rectangular designated area is set with one point in the upper left corner and the other point in the lower right corner. As described above, the pixel indicated on the display screen by the mouse is arbitrary.

On the other hand, assuming that the access unit of the display memory is n pixels, when one address is designated, image data for n pixels is written or read at this address.

Therefore, when an arbitrary designated area is set on the display screen with a mouse, the image data in the designated area must be read out from the display memory and recorded on the optical disk. However, the access unit of the display memory is n pixels. Therefore, the area (extraction area) from which the image data is read from the display memory includes the above-mentioned specified area, but has a size that is an integral multiple of the access unit and is larger than the specified area.

For example, when the specified area has a rectangular shape as described above, the extraction area is an area that protrudes left and right from the specified area.

As described above, since the image data of the extraction area is read from the display memory and recorded on the optical disk, when the image data is reproduced from the optical disk to display the image, the image data is reproduced from the optical disk. The image data of one extraction area is once written in the display memory, read out and sent to the display device.

Therefore, not the image of the designated region set by the user but the image of the extracted region in which this region is extended is displayed on the display screen, which is not what the user desires. In particular, when the image of the designated area desired by the user is inserted into the image originally stored in the display memory and displayed, the image of the extracted area in which the designated area is expanded is originally stored in the display memory. Since the image is displayed by being fitted into the image, even if the image of the designated region set by the user is displayed, the image originally stored in the display memory may have a portion included in the region outside the designated region of the extraction region. You will be lost.

An object of the present invention is to solve the above-described problem, so that an access unit of a display memory is n pixels, but only an image of a designated area set in a pixel unit can be written to the display memory. An image memory device is provided.

[Means for solving the problem]

In order to achieve the above object, the present invention reads out image data of an extraction area corresponding to a specified area from a display memory,
Means for recording in the external storage device together with the management data relating to the designated area and the extraction area; reproducing the image data and the management data of the desired extraction area from the external storage apparatus to generate mask information corresponding to the management data Means for writing the image data reproduced based on the mask information to a display memory.

[Action]

Since the access unit of the display memory is n pixels, the extraction area is generally an extension of the specified area, and the external storage device stores the image data in the specified area outside the specified area in the extracted area. The extended portion of the image data is added and recorded, along with the management data. The reproduction of the image data in the external storage device is performed in units of extraction areas by the management data. In this case, the management data creates mask information for distinguishing the image data within the specified amount area from the other image data in the extraction area, and the display information is written in an access unit in the display memory according to the mask information. Pixel data outside the specified area in the access unit is masked, and writing to the display memory is performed.

Thus, of the image data reproduced from the external storage device, only the image data in the designated area is written to the display memory.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an image memory device according to the present invention, wherein 1 is a display memory, 2 is a cursor display circuit, 3 is a display control circuit, 4 is a synthesis circuit, and 5 is a D / A.
(Digital / analog) conversion circuit, 6 is an area designating circuit, 7 is a mouse, 8 is an area setting circuit, 9 is a write bit mask circuit, 10 is an optical disk device, 11 is an image data recording circuit, and 12 is a management data recording circuit. , 13 is an image data reading circuit, 14 is a management data reading circuit, and 15 is a keyboard.

In the figure, when an image read by an image scanner (not shown) or an image recorded on the optical disk of the optical disk device 10 is displayed on a display device (not shown),
These image data (image data) are stored in the display memory 1. Thereafter, under the control of the display control circuit 3,
The image data is read from the display memory 1, passed through the synthesizing circuit 4, converted into an analog image signal by the D / A conversion circuit 5, supplied to a display device (not shown), and displayed on a display screen.

Here, the correspondence between the bit configuration of the display memory 1 and the pixels on the display screen will be described with reference to FIG.

As shown in FIG. 2 (b), the display screen is composed of 1024 horizontal dots (pixels) and 1024 vertical lines (pixels), and one pixel is composed of 4 bits. Therefore, 16 types of color display are possible. FIG. 2 (b) shows four planes of 1024 dots × 1024 lines, each plane being for a different bit. Therefore, one pixel is composed of a total of four bits, one bit at each corresponding position on each surface.

In the display memory 1, as shown in FIG. 2A, one address consists of 16 bits (one word) and is accessed in units of one word. Accordingly, since one pixel on the display screen has a 4-bit configuration as described above, four pixels are stored in one address of the display memory 1. The four pixels stored at one address have a relationship of being continuously arranged in the horizontal direction on the display screen.

Therefore, at each address in the display memory 1 shown in FIG.
D13,..., D0, and in the display screen shown in FIG. 2 (b), the pixel position at the upper left corner is the origin, and the position of the x-th pixel in the horizontal direction and the y-th pixel in the vertical direction is coordinate ( x, y) (therefore, the origin position is at coordinates (0, 0) and the dot position at the lower right corner is at coordinates (1023, 1023)), and the address in display memory 1 is bit D15-D12 at address 0. 2 (b) is located at the coordinates (0,0). Hereinafter, the pixels consisting of bits D11 to D8, D7 to D4 and D3 to 0 at address 0 in the display memory 1 will be described. Are located at coordinates (1,0), (2,0), (3,0) in FIG. 2 (b), respectively.

Since the number of pixels displayed on one line of the display screen shown in FIG. 2B is 1024, these 1024 pixels are stored in the display memory 1 at 1024/4 = 256 addresses. However, also in this display memory 1, addresses are allocated in 8-bit units, as in a general computer system. Therefore, in practice, one address is added to 16 bits, so that only the even addresses 0, 2, 4, 6,... Are provided as addresses.

Therefore, in the display memory 1, as described above, the pixels for one line on the display screen are recorded at 256 addresses, so that the pixels on the top line of the display screen are 510 pixels from address 0.
The pixel of the next line on the display screen is stored from the address 512 in the display memory 1, as shown in FIGS. 2 (a) and 2 (b).

Next, in FIG. 1, the image data from the image scanner is stored in the display memory 1, and the image data of a desired portion of the display image is transmitted to the optical disc device 10 in a state where the image is displayed on the display screen. The case of recording will be described.

A desired area of the display screen on which the image is displayed is designated by the mouse 7. This area is a designated area and has a square shape (square or rectangular). As described above, the coordinates of the pixel at the upper left corner and the pixel at the lower right corner of the designated area desired by the mouse 7 as described above. Specify two coordinates.

The coordinate data of the two points specified by the mouse 7 is stored in the area specifying circuit 6. Under the control of the display control circuit 3, the area designating circuit 6 causes the cursor display circuit 2 to create cursor data representing a frame-shaped cursor (hereinafter, frame 3 cursor) based on these coordinate data. The cursor data is combined with the image data from the display memory 1 by the combining circuit 4, converted into an analog signal by the D / A conversion circuit 5, and provided to the display device. Accordingly, on the display screen, a desired rectangular specified area of the display image is displayed by being surrounded by the frame cursor. The position can be designated by the mouse 7 in pixel units. Therefore, the size of the designated rectangular area can be arbitrarily designated by the pixel unit pitch.

FIG. 3 shows a designated rectangular area (that is, a designated area).
Is shown as an array of pixels, and black circles represent pixels in the designated area. Here, the coordinates specified by the mouse 7 are (6, 1) and (20, 5).

On the other hand, the area setting circuit 8 determines at which address of the display memory 1 described in FIG. 2 the coordinates specified by the mouse 7 taken into the area specifying circuit 6 are included, and determines a rectangular shape determined by these addresses. Set the region as the extraction region. That is, in FIG. 3, the pixel at the upper left corner of the designated area A consisting of the pixels indicated by the black circles is located at the coordinates (6, 1), and the address of the display memory 1 corresponds to the address 514. The area setting circuit 8 determines the address 514. The pixel at the lower right corner of the designated area A has coordinates (20, 5).
In this case, the address of the display memory 1 corresponds to the address 2570, whereby the area setting circuit 8 determines the address 2570.

Thereafter, as shown in FIG. 3, the area setting circuit 8 divides the display screen into four pixels for each line, and if each division corresponds to each address of the display memory 1, the address 544 becomes the upper left corner. , A rectangular extraction area B such that address 2570 is the lower right corner. When viewed in pixel units, this extraction area B has coordinates (4,1) in the upper left corner and coordinates (23,5) in the lower right corner, and is a pixel represented by a black circle and a pixel represented by a hatched circle. This is a rectangular area consisting of The extracted area B is equal to the specified area A or expanded from the specified area A by a maximum of three pixels in the left-right direction.

On the display screen, the extraction area B is obtained from the designated area A as follows.

That is, referring to FIG. 3, assuming that the coordinate position of the pixel at the left end of the designated area A is (x, y), as shown in FIG. 4A, the binary representation of the x value (b ₉ , b ₈ , b ₇ ,..., b ₁ , b ₀ ) binary representation (b) in which the two lower bits b ₁ , b ₀ are 0 bits.
₉ , b ₈ , b ₇ ,..., B ₃ , 0, 0) represent the x ′ value of the coordinate position (x ′, y ′) of the pixel at the left end of the extraction area B. If the coordinate position of the pixel at the right end of the designated area A is (x, y), the fourth position
As shown in FIG. 6B, the binary representation of the x value (b ₉ , b ₈ , b ₇ ,
..., B ₁ , b ₀ ) are extracted as binary numbers (b ₉ , b ₈ , b ₇ ,..., B ₃ , 1, 1) with one lower bit b ₁ , b ₀ as one bit. Area B
Represents the x 'value of the coordinate position (x', y ') of the pixel at the right end.

Therefore, in FIG. 3, if () ₂ is represented by a binary number, the coordinate position of the leftmost pixel of the designated area A is (6, y).
(Where y = 1, 2,..., 5) and 6 = (110) ₂ , the x coordinate value of the coordinate position of the leftmost pixel of the extraction area B is (100) ₂ = 4 And these coordinate positions are (4,
y). Further, since the coordinate position of the rightmost pixel of the designated area A is (20, y) and 20 = (10100) ₂ , the x coordinate value of the coordinate position of the rightmost pixel of the extraction area B is (1011
1) ₂ = 23, and these coordinate positions are (23, y).

When the user inputs a pixel file number using the keyboard 15, the image data recording circuit 11 converts the image data in the extraction area B set by the area setting circuit 8 from the display memory 1 into 16 bits (4 bits) as an access unit of the display memory 1. Pixel), and record the data on an optical disk of the optical disk device 10. At the same time, the management data recording circuit 12 records, on the optical disk, management data including an image file number input from a keyboard and various parameters necessary for reproducing the image data.

FIG. 5 shows the recording format of this optical disc. As shown in the figure, an optical disk is provided with an image data recording area and a management data recording area, and image data of each image file number is recorded in the image data recording area. In the management data recording area, the management data of each image file number is recorded by being indexed by the image file number.

FIG. 6 shows the specific contents of the management data. As shown in the figure, the management data includes the x-coordinate value of the position coordinate (x, y) of the pixel at the upper left corner (see FIG. 3) in the extraction area B, y
Coordinate value, width d expressed by the number of pixels in the horizontal and vertical directions of extraction area B
x, dy, access unit for the extraction area B in the horizontal direction (4 pixels)
In segment lateral pixel number n _L specified area A included in the left end of the segment when the (demarcation dashed line in FIG. 3), also the number of pixels in the rightmost segment n _R, and the pixel data recording area (second 5), the recording addresses of the image data of the corresponding pixel file numbers. In the case of the example shown in FIG. 3, x = 4, y = 1, dx = 20, dy = 5, n _L = 2, n _R = 1.

Next, reproduction of image data from the optical disk device 10 will be described.

In FIG. 1, when an image file number of a desired image to be reproduced is input from the keyboard 15, the management data reading circuit 14 firstly causes the optical disk device 10 to read the management data recording area (FIG. 5) of the optical disk. The management data corresponding to the input image file number is read. Next, the image data reading circuit 13 is controlled by the optical disk device 10 to read the management data reading circuit in the image data recording area of the optical disk.
Recording address in the management data read by 14 (FIG. 6)
The image data is read from the area determined by the formula (1) and sent to the display memory 1 via the write bit mask circuit 9.

In this case, the image data read by the image data reading circuit 13 is the image data in the extraction area B in FIG. 3, but the user wants to reproduce and display from the optical disk in the designated area A in FIG. It is an image of.

Write Bitsutomasuku circuit 9, designated by the image data D _R of the extraction region B outputted from the image data read circuit 13 area A
Extract the image data in. That is, the management data readout circuit 14 includes parameters for the coordinate values x, y, the area width dx, dy, the number of left and right end display pixels n _L , n _{L in} the management data fetched from the optical disk by the optical disk device 10. , A bit mask representing the designated area A is generated, and a pixel selection signal M representing the bit mask is sent to the write bit mask circuit 9. The write bit mask circuit 9 outputs the image data D _R output from the image data read circuit 13 based on the pixel selection signal M.
The part other than the designated area A is masked.

The image data output from the write bit mask circuit 9 is written into the display memory 1, read out as described above, and the image of the designated area A is displayed on the display screen of the display device.

As described above, since the write bit mask circuit 9 performs the masking for each pixel according to the management data, even if the image data is recorded on the optical disk in access units, the image in the designated area A specified in pixel units is obtained. Is surely displayed.

FIG. 7 is a block diagram showing a specific example of the write bit mask circuit 9 in FIG. 1 together with the display memory 1.
1a to 1d are memories constituting the display memory 1, 16 to 19 are NAND gates, and 20 is an inverter.

In the figure, a memory 1a stores the first four bits D15 to D12 of each address shown in FIG.
Hereinafter, the memory 1b stores the next 4 bits D1 to D8, the memory 1c stores the next 4 bits D7 to D4, and the memory 1d stores the last 4 bits.
D3 to D0 are respectively stored. That is, memory 1a ~
1d stores one pixel at a time. These bits D15
Consisting ~D0 reproduced image data D _R, the image data read circuit
13 (FIG. 1) is sent as parallel data.

The address signal AD, the chip select signal ▼, and the read / write signal R / W are sent from the display control circuit 3 (FIG. 1), and the address signal AD and the read / write signal R / W are stored in the memories 1a to 1d, respectively. AD input, R / W input. The chip select signal ▼ is inverted in level by the inverter 20 and supplied to the memories 1a to 1d as ▲ inputs via NAND gates 16 to 19, respectively. These memories 1a ~
In 1d, when both the R / W input and the ▲ ▼ input are “L” (low level), data is written to the address specified by the address signal AD.

Further, a pixel selection signal M is sent from the management data reading circuit 4 (FIG. 1). This pixel selection signal is 4-bit (M ₀ , M ₁ , M ₂ , M ₃ ) parallel data, and the image data D
_Synced to _R. The bit M ₀ NAND gate 16 of the pixel selection signal M, bits M ₁ NAND gate 17, bit M ₂ NAND gate 18, bit M ₃ represents are respectively supplied to a NAND gate 19. The inputs of the memories 1a, 1b, 1c, 1d are such that the chip select signal ▼ is “L” and the bits M ₀ , M ₁ , M ₂ , M ₃ of the pixel select signal M are “H” (high level). Only when it is low.

Therefore, when writing to the display memory 1, the read / write signal R / W is set to "L". When the Chitsupuserekuto signal ▲ ▼ becomes "L", the writing of pixel data in memory 1a~1d but it is possible, bits M ₀ of the pixel selection signal M at this timing, M _1, M _2, When M ₃ becomes “H”,
The pixel data at that time is written to the addresses specified by the address signal AD in the memories 1a, 1b, 1c, 1d. Therefore,
Image data D _R as sent come 4 one or more pixels of the image data of the pixels, for example, in order not to store only pixel data by the bits D15~D12 are bits M ₁ of the pixel selection signal M all ~M ₃ and "H", it is sufficient only to "L" bits M _0.

As is clear from FIG. 3, in the region consisting of the four pixels at the left end and the right end in the extraction region B, 1 to 4 pixels of the designated region A are arranged in the horizontal direction. This designated area A
The number of pixels is represented by the number of left end display pixels n _L and the number of right end display pixels n _{R in} the management data shown in FIG. Thus, the image data D _R is at an image data of a region including four pixels left in the extraction region B in FIG. 3 is a bit pattern of the pixel selection signal M, according to the leftmost display pixel number n _L of the management data , Or any of the bit patterns shown in FIG. 8 (a). However, in FIG.
The 0 bit is set to "L" and the 1 bit is set to "H". In the example shown in FIG. 3, since n _L = 2, the pixel selection signal M is M ₀ = M ₁ = 0 bit, M ₂ = M ₃ = 1 bit, and writing is prohibited in the memories 1a and 1b. Memory 1
In c and 1d, the pixels in the designated area A (FIG. 3) are written.

Similarly, when the image data D _R is the image data of a region including four pixels in the right end in the extraction region B in FIG. 3 is a bit pattern of the pixel selection signal M, the rightmost display pixel number n _R of the management data Accordingly, any one of the bit patterns shown in FIG. 8B may be used. In the case of the example shown in FIG. 3, since n _R = 1, the pixel selection signal M is M ₀ = 1 bit, M ₁ = M ₂ = M ₃ = 0 bit, and writing is performed only in the memory 1a. , Memory 1b ~
In 1d, writing of pixels that are included in the extraction area B but not in the specified area A is prohibited.

Note that when the image data D _R is the data of four pixels contained in the specified area A, bit M ₀ ~M ₃ of the pixel selection signal M
Are all 1 bit, and pixel data is written in the memories 1a to 1d. Of course, other than the period in which the pixel data D _R of the extraction area B is supplied, all the bits M ₀ of the pixel selection signal M
~M ₃ is a 0 bit.

In this manner, the writing control to the display memory 1 can be performed on a pixel basis, and only the image data in the specified area by the user is reliably written in the display memory 1 and only the image in the specified area A is displayed on the display screen. Can be displayed.

In FIG. 7, the means for reading image data is omitted.

The address signal AD in FIG. 7 is created based on the coordinate values x, y, the area width dx, dy, etc. in the management data shown in FIG.

Further, in the management data shown in FIG. 6, instead of the left end display pixel number n _L and the right end display pixel number n _R , the designated area B
Data indicating the position and size of (FIG. 3) and the bit pattern of the pixel selection signal M as shown in FIG. 8 may be used. The recording format on the optical disk is not limited to that shown in FIG. 5, and the access unit in the display memory 1 is not limited to only 16 bits.

FIG. 9 is a block diagram showing another embodiment of the image memory device according to the present invention, wherein 21 is a ROM (read only memory), 22 is an address bus, 23 is a data bus, and 24 is a CPU (central processing unit). The same reference numerals are given to the portions corresponding to FIG. 1 and the duplicate description will be omitted.

In FIG. 3, a processing program is stored in a ROM 21. By this processing program, the CPU 24 causes the area designating circuit 6, the area setting circuit 8, the write bit mask circuit 9, the image data recording circuit 11, the management of the image data recording circuit 11 in FIG. Each processing of the data recording circuit 12, the image data reading circuit 13, and the management data reading circuit 14 is performed.

Next, the processing operation of the CPU 24 will be described. In this embodiment, however, as described with reference to FIG. 2, the display memory 1 accesses the four pixels on the display screen in units of 16 bits (one word), and the recording format and management data of the optical disk are It is assumed that they are shown in FIGS. 5 and 6, respectively.

First, the case where the designated area A is set for the image data in the display memory 1 as shown in FIG. 3 and the image data is recorded on the optical disk will be described with reference to FIG.

Designated on the display screen, the mouse 7, the coordinate position (x _L, y _T) of the upper left corner of the specified area A Specifies the (step 100), similarly the coordinate position where the lower right corner (x _R, y _B) (Step 1
01) Then, the CPU 24 fetches these coordinate position data from the mouse 7 and sets them in the cursor display circuit 2 to display a frame cursor representing the designated area A on the display screen as in the embodiment shown in FIG. Let (step 10
2). When the frame cursor does not indicate the desired designated area A (step 103), the processing operation of steps 100 to 102 is performed by using the mouse 7 again, so that the designated area A can be corrected.

Further, CPU 24 first receives the coordinate position data from the mouse 7, in order to set the extraction area B that match the access unit of the display memory 1, the left end coordinates of the extracted area B from x _L value of the coordinate position data Find the x value of the position (step
104), also calculates the x values of the rightmost coordinate position of the extracted region B from x _R value (step 105). These x values are obtained by the operation described in FIG. 4. The x value x _L ′ at the left end is represented by the hexadecimal number of the x value (FFFC) ₁₆ (where 16 represents a hexadecimal number). The rightmost x value x _R 'is obtained by ORing (0003) ₁₆ with the hexadecimal number of the x value.

Next, the optical disk device 10 is operated to search for an empty area in the management data recording area (FIG. 5) of the optical disk (step 106), read the image file number of the empty area, and notify the user (step 107). ). And
The position (x _L ′, y _T ) of the upper left corner of the extraction area B set as an access unit of the display memory 1 and the area width dx (= x _R ′ −x
_{L '+1), dy (=} y B -y T +1), left display pixel number n _L (=
4- (x _L −x _L ′)), right end display pixel number n _R (= x _R ′ −x _R +
1) is recorded as management data in the area from which the image file number in the management data of the optical disk has been read. (Steps 108-112).

When the recording of the management data is completed in this manner, next, an empty area in the image data recording area (FIG. 5) of the optical disk is searched (step 113), and the address of the leading end of the empty area is entered into the management data recording area. In the area where the above-mentioned management data is recorded, it is recorded as an addition of the management data (step 114).

After the above operation is performed, the operation shifts to an operation of recording the image data in the extraction area B in the display memory 1 in the searched empty area in the image data recording area of the optical disk.

For this purpose, first, the extraction area B in the display memory 1
4 pixels in the upper left corner of ((4,1), (5,1),
An address at which (pixels at the coordinate positions of (6, 1) and (7, 1)) are stored (step 115), and image data for an access unit (one word) at the specified address is read (step 115). 116) Recording is performed at the head address of the empty area in the image data recording area of the optical disk (step 117). Then, the designated address of the display memory 1 is incremented by +2 to set the next designated address (step 118). Whether the designated address is within the extraction area B based on the area width dx obtained in step 109 It is determined whether or not it is (step 119). In the case of the example shown in FIG.
There are four addresses read out for the line, and the line is outside the extraction area B by the four increments in step 118. When the designated address is within the extraction area B, the process returns to step 116, and the image data of the access unit at the new designated address in the display memory 1 is read out.
Record on an optical disk. This operation is repeated until the designated address obtained in step 118 is outside the extraction area B, and the image data in the extraction area B in one line on the display screen is sequentially recorded on the optical disk.

The designated address determined in step 118 is the extraction area B
If it is outside (step 119), all the image data in the extraction area B in one line (for example, the line whose y coordinate value is 1 in FIG. 3) is recorded on the optical disk. The address of the display memory 1 in which the leftmost four pixels that fall into the extraction area B in the line is stored (step 120), and it is determined whether or not this line is within the extraction area B (step 121). As long as the line determined in step 120 is within the extraction area B, step 11
The series of operations from 6 to 121 are repeated, and all the image data in the extraction area B is recorded on the optical disk.

Next, the operation of reading the image data recorded on the optical disk as described above will be described with reference to FIG.

The ROM 21 (FIG. 9) stores mask data corresponding to the left and right end display pixel numbers n _R and n _L. Other image data is stored in the memory 1 and is read out from the optical disk in an area corresponding to the designated area A determined by the management data of the memory 1 without erasing the other image data outside this area. The following operation is performed so as to store the image data of the designated area A in the extracted area B. In this way, the image data from the optical disk is displayed on the display memory without erasing the other image data. To write "1", the mask data shown in FIG. 12 is used.

Here, FIG. 12 (a) shows the mask data (MASK) _L in the region of the leftmost 4 pixels of the extraction region B, and FIG. 12 (b) shows the mask data (MASK) _R in the region of the rightmost 4 pixels. 0 and F are hexadecimal numbers, each of which is a 16-bit unit serving as an access unit of the display memory 1. 0 indicates a pixel that does not fall within the designated area A, and F indicates a pixel that falls within the designated area A. Each is represented.

In FIG. 11, when the image file number of the image data to be read is input from the keyboard 15 (FIG. 9) (step 200), the management data recording area (FIG. 5) of the optical disk is checked (step 201). Then, it is determined whether there is management data for the input image file number (step 202).

When the management data exists, the management data is reproduced from the optical disk (step 203), and the mask data (MAS) corresponding to the left and right end display pixel numbers n _L and n _R of the management data is reproduced.
K) _L , (MASK) _R is read from the ROM 21 (FIG. 9) and set (step 204).

Next, from the management data reproduced in step 203, the address where the image data of the upper left corner 4 pixels (access unit) in the extraction area B is to be written is obtained as the leading address (step 205), and the image data recording of the optical disk is performed. The image data of these four pixels is reproduced from the area (FIG. 5) (step 206). In addition, the display memory 1
The image data of four pixels already stored is read out from the leading end address of step (step 207), and the image data from the optical disk and the mask data (MASK) _L are AND-processed.
Image data and mask data (MASK) from display memory 1
Inversion mask data of _L (▲) A synthesis process including AND processing with _L and OR processing of data obtained as a result of these AND processing is performed (step 208). The data obtained by the synthesizing process is written to the head address of the display memory 1 (step 209).

Here, in the synthesizing process, the former AND process is a process of extracting image data of a pixel entering the designated area A from the image data from the optical disk, and the latter AND process is a process of extracting the image data from the display memory 1. This is a process of extracting image data of pixels outside the designated area A from the data, and the OR process is a process of combining these extracted image data to create image data in access units. That is, the image data from the optical disk is now
(X ₁ , X ₂ , X ₃ , X ₄ ), and similarly, the image data from the display memory 1 is (Y ₁ , Y ₂ , Y ₃ , Y ₄ ), and n in FIG.
Assuming the use of _L = 1 of the mask data _{(MASK) L, (X 1} , X 2, X 3, X 4) (000F) (Y 1, Y 2, Y 3, Y 4) (F000) = (Y ₁ , Y ₂ , Y ₃ , Y ₄ ) are obtained.

When such image data is written to the head address of the display memory 1, the image data from the optical disk in the designated area A is stored at the head address, and the image data originally written to the display memory 1 is stored outside the specified area A. Will be remembered.

That is, even if writing is performed in access units,
Writing can be performed in one address in one address.

Next, the leading address of the display memory 1 is incremented by +2 to obtain a new designated address (step 21).
0), the image data of the next four pixels is reproduced from the optical disk (step 211), and written to this designated address in the display memory 1 (step 212). A series of operations in steps 210 to 212 are repeated.

The designated address of the display memory 1 designates one of the four right-most areas of the extraction area B based on the area width dx of the management data, and when writing of pixel data in this area is completed (step 213). In the case of the example shown in FIG. 3, after the specified address is set twice in step 210), the specified address of the display memory 1 is incremented by +2 to be a new specified address (step 214). Then, the image data of the next four pixels is read from the optical disk (step 21).
At the same time, the image data originally stored is read out from the designated address in the display memory 1 (step 21).
6), using the mask data (MASK) _R of FIG. 12 (b) corresponding to the right end display pixel number n _R , the image data is subjected to the same synthesizing processing as in step 208 described above (step 217). ), And writes to the designated address obtained in step 214 of the display memory 1.

Thus, the writing of the image data of the designated area A for one line is completed, the start address of the next line extraction area B in the display memory 1 is set (step 219), and the next width is obtained from the management data area width dy. It is determined whether or not the line is within the extraction area B (step 220), and the operation from step 206 is performed on this line.

When the image data thus written in the display memory 1 is displayed, the image read from the optical disk is displayed in the designated area A in the example of FIG. The image originally stored in the memory 1 is displayed.

In this embodiment, when the relationship between the bits of the display memory 1 and the pixels on the display screen is different from the case of FIG. 2, it goes without saying that the mask data is also different from that of FIG.

Also, using a well-known direct memory access control device that directly transfers data between memories by hardware,
Needless to say, the direct memory access control device can perform a series of processes in steps 116 to 119 in FIG. 10 and a series of processes in steps 210 to 213 in FIG. 11 instead of the CPU 24. In this case, for such processing, setting of the transfer source address, setting of the transfer destination address, setting of the transfer word number, setting of the transfer mode, transfer start instruction, transfer end monitoring to the direct memory access control device, etc. It goes without saying that well-known software processing is required when using a direct memory access control device.

〔The invention's effect〕

As described above, according to the present invention, even for a display memory using a plurality of pixels of a display screen as an access unit,
The writing control of the image eta on a pixel basis becomes possible, and even if a designated area having an arbitrary size and shape is set, an image in the designated area can be displayed.

When writing image data in a specified area of the image data set in the access unit of the display memory to the display memory, the image data in the specified area other than the left and right end areas of the specified area is stored in the display memory. Since writing can be directly performed on the display memory in access units, the time for writing to the display memory can be shortened, and the display speed of an image can be increased.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of an image memory device according to the present invention, FIG. 2 is a diagram showing a correspondence relationship between a bit configuration in a display memory and pixels on a display screen in FIG. 1, and FIG. Is a diagram showing the relationship between the designated region and the extraction region on the display screen, FIG. 4 is a diagram showing the coordinate positional relationship between the end of the designated region and the end of the extraction region in FIG. 3, and FIG. FIG. 6 is a diagram showing a recording format of an optical disk in the optical disk device in FIG. 6, FIG. 6 is a diagram showing the contents of management data recorded together with image data on this optical disk, and FIG. 7 is a diagram of the write bit mask circuit in FIG. FIG. 8 is a block diagram showing a specific example together with a display memory, FIG. 8 is a bit pattern diagram of a pixel selection signal in FIG. 7, FIG. 9 is a block diagram showing another embodiment of the image memory device according to the present invention, and FIG. Is the optical data of the image data of this embodiment. Flow chart showing the recording operation to the disk, FIG. 11 also shows the reproduction operation of image data from the optical disc the flow chart, FIG. 12 is a diagram showing mask data used during this reproduction operation. 1 ... display memory, 6 ... area designation circuit, 7 ... mouse, 8 ... area setting circuit, 9 ... write bit mask circuit, 10 ... optical disk device, 11 ... image data recording circuit, 12 ... ... Management data recording circuit, 13 ... Image data reading circuit, 14 ... Management data reading circuit, 21 ... ROM, 24 ... C
PU.

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G09G 5/00 G06T 1/60 G06T 11/00

Claims (3)

(57) [Claims] 1. A display memory in which pixels of one screen are stored as image data, and image data of n pixels (where n is an integer of 2 or more) is used as an access unit, and image data read from the display memory is used. Display means for displaying an image,
An image memory device including an external storage device for recording and reproducing image data read from the display memory in the access unit, wherein first means for setting an arbitrary area on a display screen of the display means as a designated area; A second means for setting an extraction area including the designated area and formed in access units of the display memory, reading image data in the extraction area from the display memory, and recording the image data in the external storage device; Third means for generating management data relating to the designated area and the extraction area and recording the management data in the external storage device; image data of the extraction area desired from the external storage device;
Fourth means for reproducing the management data in response thereto, fifth means for generating mask information for defining the designated area in the extraction area based on the management data, And determining the image data in the designated area of the reproduced image data, and writing the image data obtained by the discrimination to an area of the display memory corresponding to the designated area. An image memory device characterized in that: 2. The method according to claim 1, wherein the mask information is created for an area corresponding to the access unit at the left and right ends on the display screen of the extraction area, and in the area included in the specified area, An image memory device wherein reproduced image data is directly written into the display memory. 3. The apparatus according to claim 2, wherein said sixth means reads image data from an area of said display memory corresponding to said mask information, and reads said read image data and said reproduced image data from said external storage device. Is processed based on the mask information, and a portion not included in the designated area in the left and right end access unit areas of the extraction area is replaced with the read image data, and the extraction area in the display memory is replaced. An image memory device for writing to an address corresponding to an area of an access unit at the left and right ends of the image memory.