JPH08138040A - Image drawing method and image drawing apparatus - Google Patents

Abstract

(57) [Summary] [Object] To provide an image drawing method capable of drawing a high-quality image with improved processing speed and memory efficiency. [Structure] An inverse affine transformation, which is an inverse transformation to the affine transformation, is obtained (step S21), and further all the bits constituting the deformed image are subjected to the inverse affine transformation to obtain bits on the original image (step S23). ,
The obtained bits on the original image are copied to all the bits of the modified image (step S24).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image drawing method and an image drawing apparatus in an information processing system or the like.

[0002]

2. Description of the Related Art The basic elements that represent the movement of a figure are enlargement, reduction, rotation, inversion and translation, and these operations can be represented mathematically by transformation. Generally, the transformation of a two-dimensional figure is obtained by combining these transformations. This transformation is called a two-dimensional affine transformation.

In order for an information processing system to draw a deformed image using this two-dimensional affine transformation, it is necessary to create drawing data by the following procedure.

(1) The bit coordinates B0 (B0x, B0y) on the original image are subjected to the affine transformation to obtain bit coordinates B1 (B1x, B1y) on the modified image.

(2) Data transfer of bit information corresponding to the coordinate points B0 and B1.

By performing the above (1) and (2) for all bits, the bit information of the modified image is generated from the bit information of the original image.

That is, in order to obtain a deformed image from the original image, the operation of the deformation process is represented by an affine transformation F, and each bit of the original image is copied (transferred) to the position of the transformation F to change the bit string of the transformed image. It is often used to construct and draw it. In addition, the drawing of the deformed image is often performed by preparing a data buffer for each line, and the buffer size is usually set to the width of the rectangle circumscribing the deformed image.

[0008]

However, in the method of realizing a two-dimensional figure by using a two-dimensional affine transformation like the above-mentioned conventional image drawing method, the information processing system draws a deformed image. Therefore, when generating the drawing data necessary for this, there were the following concerns regarding the processing speed and memory efficiency.

(1) Due to a rounding error caused by the conversion process, there arises a defect that a bit is not copied in the bit string of a transformed image without being left blank, or the same bit is duplicated in several places. As a result, , The image may be of low quality. In addition, a method of improving the quality of the deformed image by adding some correction to the bit transferred at the time of conversion is often adopted, but this reduces the processing time and improves the total drawing processing. There is still room for improvement.

(2) The processing speed of the affine transformation F and the inverse affine transformation F'is proportional to the number of bits to be transformed,
When a large-capacity image is transformed, the load becomes large and the processing speed becomes slow.

(3) When the deformed image has a very large inclination, the width of the rectangle circumscribing the deformed image becomes very large with respect to the actually required buffer size, resulting in waste of memory.

In view of the above conventional problems, it is an object of the present invention to provide an image drawing method and an image drawing apparatus which can improve processing speed and memory efficiency and can draw a high quality image.

[0013]

In order to achieve the above-mentioned object, the invention according to claim 1 is 2 in comparison with the original image.
In an image drawing method for performing an image data generation process for generating image data of a deformed image with respect to the original image by applying a deformation represented by a three-dimensional affine transformation, and a drawing process for drawing the image data of the deformed image. The image data generation processing is an inverse affine transformation calculation processing for obtaining an inverse affine transformation that is an inverse transformation to the affine transformation, and the inverse affine transformation is applied to all the bits forming the modified image to obtain an original image. And the bit on the original image is copied to all the bits of the modified image to generate the image data of the modified image.

According to a second aspect of the present invention, in the first aspect of the invention, a mode selection process for selecting one of a processing speed priority mode for giving priority to processing speed and an image quality priority mode for giving priority to image quality; When the image quality priority mode is selected by the mode selection processing, the first data generation processing for generating the image data of the deformed image by the inverse affine transformation calculation processing and the copy processing, and the processing speed priority by the mode selection processing. When the mode is selected,
Image size comparison processing for comparing the sizes of the original image and the modified image, and when the size of the original image is smaller than the modified image in the comparison result of the image size comparison processing, each bit forming the original image is set to The size of the original image is the modified image based on the comparison result of the second data generation process for generating the image data of the modified image by copying to the bit on the modified image subjected to the affine transformation and the image size comparison process. When larger,
A third data generation process for generating image data of the deformed image by the inverse affine transformation calculation process and the copy process is executed.

The invention according to claim 3 is the invention according to claim 1 or 2.
In the invention described in the above, the copy process does not depend on a result of the inverse affine transformation when a bit of a vertex of the original image corresponding to a bit of a vertex of the transformed image is not obtained, and the vertex of the transformed image is obtained. The bits at the vertices of the original image corresponding to the bits are copied unconditionally.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the copy process includes an intersection point calculation process for obtaining an intersection point (Q0, Q1, Q2, Q3) between the deformed image and a circumscribed rectangle. The intersection points Q0 and Q1, which are obtained by the intersection point calculation process.
As equations of straight lines connecting the intersection points Q1 and Q2, the intersection points Q2 and Q3, and the intersection points Q3 and Q0, respectively, y0 = a0 * x0 + b0 (Equation 0) y1 = a1 * x1 + b1 (Equation 1) y2 = a2 * x2 + b2 ... (Equation 2) y3 = a3 * x3 + b3 ... (Equation 3) Equation calculation processing and the value of y corresponding to each line of the deformed image is substituted into Equations 0 to 3 obtained in the equation calculation processing. Then, the copy range calculation process for obtaining the bit copy range on the original image in the line is executed.

According to a fifth aspect of the invention, an image generating process for generating a deformed image by applying a deformation represented by a two-dimensional affine transformation to an original image, and an image drawing process for drawing the deformed image. In the image drawing method of performing the separation processing for separating the deformation of the original image by the affine transformation into a pure deformation component and a coordinate movement component by coordinate movement, the pure transformation component causes the bits of the vertices of the original image to change. A moving position calculation process of obtaining a moving coordinate position, a moving distance calculation process of obtaining a moving distance of each bit of a vertex of the original image based on the coordinate position obtained by the moving position calculation process, and a moving distance of each bit. Is executed before the image generation processing and an error determination processing for checking whether or not is within a predetermined range,
In the image generation processing, when the moving distance of any of the bits is larger than the predetermined range, the deformation processing is performed by the pure deformation component and the coordinate movement component to generate the deformed image, When any one of the moving distances is smaller than the predetermined range, the deformed image is generated by performing coordinate movement using only the coordinate movement component on the original image without performing the transformation process. is there.

According to a sixth aspect of the present invention, a deformation image represented by a two-dimensional affine transformation is added to the original image to generate a deformation image for the original image, and the deformation image is converted into data for each line. In an image drawing method of drawing using a buffer, a vertex coordinate calculation process for obtaining the vertex coordinates of a circumscribed rectangle circumscribing the deformed image, a buffer size priority mode for prioritizing the buffer size of the data buffer, and a process for prioritizing the processing procedure. Mode selection processing for selecting one of the procedure priority modes, and when the processing procedure priority mode is selected in the mode selection processing,
When the buffer size priority mode is selected in the first buffer size setting process for setting the buffer size to the width of the circumscribing rectangle, the intersection point of the deformed image and the circumscribing rectangle is obtained. Among the intersections (Q0, Q1, Q2, Q3) obtained by the first intersection calculation processing and the intersection calculation processing, one point (Q0 or Q2) that intersects the vertical line of the circumscribing rectangle, and this point An intersection point (q) at which a line parallel to the horizontal line of the passing circumscribed rectangle intersects the side (Q2-Q3 or Q0-Q1) facing the point.
0 or q2), and a second buffer size setting process for setting the buffer size to | Q0-q0 | or | Q2-q2 |. .

According to a seventh aspect of the present invention, image data generating means for generating the image data of the deformed image for the original image by applying the deformation represented by the two-dimensional affine transformation to the original image, In an image drawing device having drawing means for drawing image data of a deformed image, the image data generating means forms an inverse affine transformation calculating means for obtaining an inverse affine transformation which is an inverse transformation to the affine transformation, and the transformed image. The bits on the original image are obtained by applying the inverse affine transformation to all the bits to be obtained, and the obtained bits on the original image are copied to all the bits of the transformed image to obtain the image of the transformed image. And a copy means for generating data.

According to an eighth aspect of the invention, in the invention of the seventh aspect, mode selecting means for selecting either one of a cutting speed priority mode for giving priority to processing speed and an image quality priority mode for giving priority to image quality, When the image quality priority mode is selected by the mode selecting means, first inverse data generating means for generating image data of the deformed image by the inverse affine transformation calculating means and the copying means, and a processing speed by the mode selecting means. When the priority mode is selected, the image size comparing means for comparing the sizes of the original image and the deformed image, and the comparison result of the image size comparing means, when the size of the original image is smaller than the deformed image, By copying each bit constituting the image to the bit on the transformed image to which the affine transformation has been applied, Second generating image data of an image
When the size of the original image is larger than the deformed image as a result of the comparison between the data generating means and the image size comparing means, the inverse affine transformation calculating means and the copying means generate the image data of the deformed image. And data generating means.

The invention according to claim 9 is the invention according to claim 7 or 8.
In the invention described above, when the bit of the vertex of the original image corresponding to the bit of the vertex of the deformed image is not obtained, the copy unit does not depend on the result of the inverse affine transformation and the vertex of the deformed image. The bits at the vertices of the original image corresponding to the bits are copied unconditionally.

According to a tenth aspect of the present invention, in the seventh aspect of the invention, the copying means calculates an intersection point (Q0, Q1, Q2, Q3) between the deformed image and the circumscribed rectangle, and Intersection points Q0 and Q obtained by the intersection point calculation means
1, intersections Q1 and Q2, intersections Q2 and Q3, intersections Q3 and Q0
Y0 = a0 * x0 + b0 (Equation 0) y1 = a1 * x1 + b1 (Equation 1) y2 = a2 * x2 + b2 (Equation 2) y3 = a3 * x3 + b3 (Equation 2) 3) and a value of y corresponding to each line of the deformed image are substituted into the equations 0 to 3 obtained by the equation calculation means, and a bit copy on the original image in that line And a copy range calculation means for calculating the range.

According to an eleventh aspect of the present invention, an image generating means for generating a deformed image by applying a deformation represented by a two-dimensional affine transformation to an original image, and an image drawing means for drawing the deformed image. In the image drawing device having, a separation means for separating the deformation of the original image by the affine transformation into a pure deformation component and a coordinate movement component by coordinate movement, and the pure transformation component causes the bits of the vertices of the original image to change. A moving position calculating means for obtaining a moving coordinate position, and a moving distance calculating means for obtaining a moving distance of each bit of a vertex in the original image by the coordinate position obtained by the moving position calculating means,
Error determining means for checking whether or not the moving distance of each bit is within a predetermined range, and the image drawing means, when the moving distance of any of the bits is larger than the predetermined range, While generating the deformed image by performing the deforming means by the pure deformation component and the coordinate movement component,
When the moving distance of any one of the bits is smaller than the predetermined range, the original image is subjected to coordinate movement using only the coordinate movement component without performing the transformation means to generate the transformed image. It was done.

According to a twelfth aspect of the present invention, a modified image represented by a two-dimensional affine transformation is added to the original image to generate a modified image of the original image,
In an image drawing device that draws the modified image using a data buffer for each line, a vertex coordinate calculation unit that obtains the vertex coordinates of a circumscribed rectangle circumscribing the modified image, and a buffer size that gives priority to the buffer size of the data buffer. When the processing procedure priority mode is selected by the mode selection means for selecting one of the processing procedure priority mode for prioritizing the priority mode and the processing procedure, the buffer size is set to the width of the circumscribed rectangle. A first buffer size setting means for setting and a first point for obtaining an intersection of the deformed image and the circumscribed rectangle when the buffer size priority mode is selected by the mode selecting means.
Of the intersection point calculating means and the intersection points (Q0, Q1, Q2, Q3) obtained by the intersection point calculating means, one point (Q0 or Q2) that intersects the vertical line of the circumscribed rectangle, and the circumscribed point passing through this point. Second intersection point calculating means for obtaining an intersection point (q0 or q2) at which a line parallel to the horizontal line of the rectangle intersects with a side (Q2-Q3 or Q0-Q1) directed to the point concerned, and the buffer size | Q0- q0 | or | Q2-q2
And a second buffer size setting means for setting to |.

[0025]

According to the first and seventh aspects of the present invention, with the above configuration, an inverse affine transformation which is an inverse transformation to the affine transformation is obtained, and the inverse affine transformation is performed on all the bits forming the modified image. Then, the bits on the original image are calculated, and the calculated bits on the original image are copied to all the bits of the modified image. As a result, due to the rounding error due to the conversion process, it is possible to solve the problems that the bit is not copied in the bit string of the modified image without being left blank, the same bit is duplicated in several places, and the like.

According to the second and eighth aspects of the invention, when the image quality priority mode is selected, the image data of the deformed image is generated and processed by the method of the invention according to the first or eighth aspect. When the speed priority mode is selected, the sizes of the original image and the deformed image are compared, and when the size of the original image is small, each bit that makes up the original image is converted into a bit on the deformed image that has been affine transformed. The image data of the deformed image is generated by copying, and when the size of the original image is large,
Alternatively, the image data of the deformed image is generated by the method of the present invention. Accordingly, when it is desired to prioritize the processing speed over the image quality, a processing method is selected such that the number of bits for performing the affine transformation and the inverse affine transformation is small.

According to the third and ninth aspects of the invention, when the bits of the vertices of the original image corresponding to the bits of the vertices of the transformed image cannot be obtained, the transformation is performed regardless of the result of the inverse affine transformation. Unconditionally copy the bits of the original image's vertices that correspond to the bits of the image's vertices. As a result, it becomes possible to reliably acquire the bit of the vertex of the original image corresponding to the bit of the vertex of the deformed image.

According to the inventions of claims 4 and 10, the intersection of the deformed image and the circumscribed rectangle is obtained, and the equation of the straight line connecting the intersections is obtained, and the value of y corresponding to each line of the deformed image is calculated. By substituting in Equations 0 to 3, the bit copy range on the original image in that line is obtained. As a result, the start bit of data transfer (copy) is obtained without using the inverse affine transformation, and the number of inverse affine transformation processes can be reduced.

According to the fifth and eleventh aspects of the invention, the deformation of the original image by the affine transformation is separated into a pure deformation component and a coordinate movement component by coordinate movement,
The pure deformation component is used to find the coordinate position where the bit of the vertex of the original image moves, and the moving distance of each bit of the vertex in the original image is obtained from the obtained coordinate position, and the moving distance of each bit is obtained. Is within a predetermined range, and when any one of the moving distances of the respective bits is larger than the predetermined range, the deformation image is obtained by performing a deformation process by the pure deformation component and the coordinate movement component. When the moving distance of any one of the bits is smaller than the predetermined range, the transformed image is generated by performing coordinate movement using only the coordinate movement component without performing the transformation process on the original image. To generate. As a result, for example, it becomes possible to ignore a deformation that cannot be visually recognized.

According to the sixth and twelfth aspects of the present invention, the vertex coordinates of the circumscribed rectangle with which the deformed image is circumscribed are obtained, and when the processing procedure priority mode is selected in the mode selection processing, the buffer size is set to the circumscribed rectangle. When the buffer size priority mode is selected, the intersection of the deformed image and the circumscribed rectangle is calculated, and one of the intersections that intersects the vertical line of the circumscribed rectangle and this point are passed. Find the intersection point where the line parallel to the horizontal line of the circumscribed rectangle intersects the side toward the point, and set the buffer size to | Q0-q0 | or | Q.
2-q2 | As a result, only the buffer size actually required is acquired.

[0031]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of an information processing system to which an image drawing method and an image drawing apparatus according to the first embodiment of the present invention are applied.

This information processing system includes a central processing unit 1 for controlling the operation of the entire system, a storage unit 2 provided with a ROM for storing control programs and the like, a buffer for storing bit information and the like, and various types of storage units. An input device 3 for inputting input information and a graphic display device 4 having a bit map memory constitute a main part.

An image drawing method (operation of the image drawing apparatus) of this embodiment, which is executed by the information processing system having the above-described structure, will be described below with reference to the flowchart of FIG. 2 (claims 1 and 7). Corresponding to the invention described).

It is assumed that the above information processing system is required to transform a two-dimensional image represented by the conversion formula F = (M0, M1, M2, M3).

The central processing unit 1 uses the inverse transformation F '(F' = (M0 ', M1', M2 ', M3'):
Inverse affine transformation) is obtained (step S21).

Next, it is determined whether or not all the bits forming the original image I1 have been processed (step S22), and the answer is negative (NO) at first, so the process proceeds to step S23.

If the inverse transformation F'obtained in step S21 is used, the bit on the original image is B0 (B0x, B0
y), B1 (B1x, B1
y), the relationship between B0 and B1 is as follows.

B0x = B1x * M3 ′ + B1y * M2 ′ (1) B0y = B1x * M1 ′ + B1y * M0 ′ (2) (1) and (2) From both equations, the central processing unit 1 is B0 (B0x, B0y) corresponding to the bit before conversion of the transformed bit B1 (B1x, B1y) is obtained (step S2).
3).

Subsequently, B1 (B1x, B1) of the buffer for storing the prepared bit information in the storage device 2 is stored.
The bit information of B0 obtained in step S23 is copied to the data area for y) (step S24).

The procedure of these steps S23 and S24 is
Bit data transfer (copying) for transformation is realized by repeating all the bits on the transformed image I1. Then, when the data transfer of all bits of the original image I0 is completed, drawing is performed with the bit string.

According to the present embodiment, due to the rounding error due to the conversion process, there is a problem that the bit is not copied in the bit string of the modified image without being left blank, or the same bit is duplicated in several places. As a result, it is possible to draw a high-quality image.

When the image drawing method of this embodiment is applied to an information processing system that draws the deformed image I1 line by line, a rectangle in which the deformed image is circumscribed is obtained and the circumscribed rectangle of the circumscribed rectangle is determined. The reverse conversion F ′ is applied in order from the left end, and the position where the conversion result is first judged to be within the original image I0 is obtained as a transfer start bit, and the conversion result is first judged to be outside the original image. All data up to the previous bit will be transferred.

FIG. 3 is a flowchart showing an image drawing method according to the second embodiment of the present invention (corresponding to the invention described in claims 2 and 8).

For the information processing system shown in FIG.
It is assumed that the transformation of a two-dimensional image represented by the conversion formula F = (M0, M1, M2, M3) is requested.

The central processing unit 1 determines whether to give priority to increasing the display speed of the deformed image (processing speed priority mode) or improving the image quality of the generated deformed image (image quality priority mode). (Step S31).

When it is determined in step S31 that priority is given to increasing the display speed of the transformed image, the central processing unit 1 compares the size of the original image with the size of the transformed image (step S32). That is, the purpose is to switch between the affine transformation and the inverse affine transformation by a method with a small number of bits to be transformed.

If it is determined in step S32 that the size of the original image is smaller than the image size after the transformation, the bit on the original image is set to B0 (B0x, B
0y), the bit on the image after transformation is B1 (B1x, B1
y), the relationship between B0 and B1 is as follows.

B1x = B0x * M3 + B0y * M2 (3) B1y = B0x * M1 + B0y * M0 (4) Therefore, the above (3),
(4) The bit data transfer for transformation is realized by a method of obtaining the transformed bits from the pre-conversion bits for all the bits on the transformed image using both equations (step S33).

When it is determined in step S31 that the image quality of the deformed image generated is improved, or when it is determined in step S32 that the size of the original image is larger than the image size after deformation, Bit data transfer for transformation is realized by the image drawing method shown in FIG. 2 of the first embodiment (step S34). And
When the data transfer of all bits of the original image I0 is completed, drawing is performed with the bit string.

According to the present embodiment, when it is desired to prioritize the processing speed over the image quality, a processing method that reduces the number of bits for performing affine transformation and inverse affine transformation is selected. Is improved.

FIG. 4 is a flowchart showing an image drawing method according to the third embodiment of the present invention (corresponding to the invention described in claims 3 and 9), and FIG. 5 is a term (symbol) relating to the present embodiment.
It is a conceptual diagram for explaining.

As shown in FIG. 5, it is assumed that the vertices (four corners) of the rectangle forming the original image are (O0, O1, O2, O3), and when the original image is transformed, the previous vertices (O0 , O1, O2, O3) is assumed to be (P0, P1, P2, P3).

In the method using the inverse transform as described in the first embodiment, (O0, O1, O corresponding to (P0, P1, P2, P3))
2, O3) is obtained from the above two equations (Equations (1) and (2)). From the rounding error that occurs during the processing of these two equations, (O0, O1, O2, O3) is Coordinates (O0 ', O1', O2 ',
O3 '). This (O0 ', O1', O2 ', O
3 ') is determined to be outside the original image, it is obtained by the above equations (1) and (2) (O0', O1 ', O2', O
3 ') instead of the regular (O0, O1, O2, O as shown in FIG.
Data is transferred as 3) as bits corresponding to (P0, P1, P2, P3).

According to the present embodiment, the vertices (P0, P
It is possible to reliably acquire the bits of the vertices (O0, O1, O2, O3) of the original image that correspond to the bits of (1, P2, P3), and the important information for recognizing the size and inclination of the rectangular image can be obtained. You can always draw without missing.

FIG. 6 is a flowchart showing an image drawing method according to the fourth embodiment of the present invention (corresponding to the invention described in claims 5 and 11), and FIG. 7 is an explanation of terms (symbols) relating to the present embodiment. It is a conceptual diagram for doing.

For the information processing system shown in FIG.
It is assumed that the transformation of the image as represented by the conversion formula F = (M0, M1, M2, M3) is requested.

First, the central processing unit 1 separates the deformation of the image by the conversion formula F into the pure deformation component F1 and the coordinate movement component F2 (step S51). Further, the figure conversion by the conversion formula F is used to determine where the coordinates of the four vertices forming the original image move (step S52).

It is assumed that the vertices (O0, O1, O2, O3) of the rectangle of the original image are moved to (P0, P1, P2, P3) as shown in FIG. 7 in step S52. At this time, the moving distances Δ0 (| P0-O0 |) and Δ1 (| P1-O1
|), Δ2 (| P2-O2 |), Δ3 (| P3-O3
|) Is calculated (step S53).

Further, assuming that the error to the extent that the deformation cannot be visually detected is expressed as Δ, it is checked whether Δ0, Δ1, Δ2 and Δ3 obtained in step S53 are within the range of the error Δ (step). S54).

At step S54, Δ0, Δ1, Δ2, Δ3
If any of the above is judged to be larger than the error Δ, the processing for the requested deformation is continuously executed and the deformed image is drawn (step S55). On the other hand, in step S54, Δ0,
If it is determined that any one of Δ1, Δ2, and Δ3 is smaller than the error Δ, the drawing process is finished only by performing coordinate movement using the conversion formula 2 on the original image (step S55).

According to the present embodiment, the deformation that cannot be visually recognized can be ignored, so that the image drawing process can be reduced.

FIG. 8 is a flow chart showing an image drawing method according to the fifth embodiment of the present invention (corresponding to the inventions of claims 6 and 12), and FIG. 9 is an explanation of terms (symbols) relating to the present embodiment. It is a conceptual diagram for doing.

For the information processing system shown in FIG.
It is assumed that the transformation of the image as represented by the conversion formula F = (M0, M1, M2, M3) is requested. The rectangle Q of the deformed image at this time is indicated by a rectangle surrounded by a solid line in FIG. 9, and the circumscribed rectangle P for the deformed image is indicated by a rectangle enclosed by a dotted line in FIG. 9.

The central processing unit 1 firstly coordinates the four vertices (P0, P1, P) forming the circumscribed rectangle P with respect to the deformed image.
2, P3) is calculated (step S61), and then it is determined whether the buffer size should be prioritized (buffer size priority mode) or whether the processing procedure should be reduced (processing procedure priority mode) (step S62).

If it is determined in step S62 that the reduction of the processing procedure is prioritized, the buffer size S for one line required for drawing the deformed image is set to the width of the circumscribing rectangle P (| P0-P1 | or | P2-P3 |) (step S63).

When it is determined in step S62 that the buffer size has priority, the buffer size S is set according to the following procedure.

First, the intersection (Q0, Q1, Q2, Q3) of the rectangle Q of the deformed image and the circumscribed rectangle P for the deformed image is calculated (step S64), and then the intersection (Q0, Q1, Q2, Q3). Of the vertical lines of the circumscribed rectangle P (| P0-P3 | or | P1
-P2 |) intersects with a point (Q0 or Q2) and a line parallel to the horizontal line (| P0-P1 | or | P2-P3 |) of the circumscribed rectangle P passing through this point (Q0 or Q2). , The side facing the point (Q2-Q3 or Q0-Q1)
Find the intersection (q0 or q2) that intersects with (step S
65).

The buffer size S is set to | Q0-q0 | or | Q2-q2 | from the intersection (q0 or q2) obtained in step S65 (step S66).

According to this embodiment, it is possible to acquire only the buffer size that is actually required, and the memory can be effectively used.

FIG. 10 is a flow chart showing an image drawing method according to the sixth embodiment of the present invention (corresponding to the invention described in claims 4 and 10), and FIG. 11 is an explanation of terms (symbols) relating to the present embodiment. It is a conceptual diagram for doing.

For the information processing system shown in FIG.
It is assumed that the transformation of the image as represented by the conversion formula F = (M0, M1, M2, M3) is requested. The rectangle Q of the deformed image at this time is indicated by a rectangle surrounded by a solid line in FIG. 11, and the circumscribed rectangle P for the deformed image is indicated by a rectangle surrounded by a dotted line in FIG.

The central processing unit 1 firstly coordinates the four vertices (P0, P1, P) forming the circumscribed rectangle P for the deformed image.
2, P3) is calculated (step S71), and then the intersection (Q0, Q0 of the rectangle Q of the deformed image and the circumscribed rectangle P for the deformed image) is calculated.
Q1, Q2, Q3) are calculated (step S72).

Then, the intersection point (Q0,
From Q1, Q2, Q3), the outline of the deformed image (Q0 and Q1, Q1
And Q2, Q2 and Q3, and a straight line connecting Q3 and Q0), equations (5) to (8) are obtained (step S73).

Y0 = a0 * x0 + b0 (5) y1 = a1 * x1 + b1 (6) y2 = a2 * x2 + b2 (7) y3 = a3 * x3 + b3 (8) For example, surrounded by dots in FIG. If the image data of the selected line is to be generated, the value of y corresponding to this line is set in step S7.
By substituting the equations (5) to (8) for the four straight lines obtained in step 3, the transfer range of the data on this line (start point d
s, end point de) coordinate point (ds = (dsx, dsy),
de = (dex, dey), where dsy = dey = y)
Is calculated (step S74).

As in the first embodiment, the processing time of the inverse transformation F'is long and it is useless to apply transformation to all the bits in order from the left end of the circumscribed rectangle of the transformed image. On the other hand, in the present embodiment, since the bit ds is obtained through the data transfer without using the inverse transform F ′, the number of times the inverse transform F ′ is processed can be reduced, and the image drawing processing speed is improved. .

[0077]

As described in detail above, according to the first and seventh aspects of the present invention, due to the rounding error due to the conversion process, the bits are not copied in the bit string of the deformed image while being left blank. The problem that the same bit is duplicated in several places is solved, and a high-quality image can be drawn.

According to the second and eighth aspects of the invention, when it is desired to prioritize the processing speed over the image quality, a processing method is selected such that the number of bits for performing the affine transformation and the inverse affine transformation is small. Therefore, the processing speed of image drawing is improved.

According to the third and ninth aspects of the present invention, it becomes possible to reliably acquire the bit of the vertex of the original image corresponding to the vertex bit of the deformed image, and recognize the size and inclination of the rectangular image. It is possible to always draw important information at a time without missing.

According to the fourth and tenth aspects of the present invention, the number of times of inverse affine transformation processing can be reduced, so that the processing speed of image drawing is improved.

According to the fifth and eleventh aspects of the present invention, the deformation that cannot be visually recognized can be ignored, so that the image drawing process can be reduced.

According to the sixth and twelfth aspects of the present invention, it is possible to acquire only the buffer size that is actually required, and the memory can be effectively used.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an information processing system to which an image drawing method and an image drawing apparatus according to a first embodiment of the present invention are applied.

FIG. 2 is a flowchart showing an image drawing method of the first embodiment.

FIG. 3 is a flowchart showing an image drawing method according to a second embodiment of the present invention.

FIG. 4 is a flowchart showing an image drawing method according to a third embodiment of the present invention.

FIG. 5 is a conceptual diagram for explaining terms (symbols) relating to the third embodiment.

FIG. 6 is a flowchart showing an image drawing method according to a fourth embodiment of the present invention.

FIG. 7 is a conceptual diagram for explaining terms (symbols) related to the fourth example.

FIG. 8 is a flowchart showing an image drawing method according to a fifth embodiment of the present invention.

FIG. 9 is a conceptual diagram for explaining terms (symbols) related to the fifth example.

FIG. 10 is a flowchart showing an image drawing method according to a sixth embodiment of the present invention.

FIG. 11 is a conceptual diagram for explaining terms (symbols) relating to the sixth embodiment.

[Explanation of symbols]

 1 Central Processing Unit 2 Storage Device 3 Input Device 4 Display Device

Claims (12)

[Claims] 1. An image data generating process for generating image data of a deformed image for the original image by applying a deformation represented by a two-dimensional affine transformation to the original image, and image data of the deformed image. In an image drawing method for performing drawing processing for drawing, the image data generation processing is an inverse affine transformation calculation processing for obtaining an inverse affine transformation that is an inverse transformation to the affine transformation, and for all bits that make up the deformed image. A copy process in which the inverse affine transformation is performed to obtain bits on the original image, and the obtained bits on the original image are copied to all bits of the modified image to generate image data of the modified image. An image drawing method comprising: 2. A mode selection process for selecting one of a processing speed priority mode for giving priority to processing speed and an image quality priority mode for giving priority to image quality; and when the image quality priority mode is selected by the mode selection process, A first data generation process for generating image data of the deformed image by the inverse affine transformation calculation process and the copy process; and the original image and the deformed image when a processing speed priority mode is selected by the mode selection process. Image size comparison processing for comparing image sizes, and when the size of the original image is smaller than the transformed image in the comparison result of the image size comparison processing, each bit forming the original image is transformed by applying the affine transformation. A second data generation process for generating image data of the deformed image by copying to a bit on the image; If the size of the original image is larger than the modified image in the comparison result of the image size comparison process, a third data generation process for generating image data of the modified image by the inverse affine transformation calculation process and the copy process is performed. The image drawing method according to claim 1, wherein the image drawing method is executed. 3. The copy process, when the bit of the vertex of the original image corresponding to the bit of the vertex of the deformed image is not obtained, the vertex of the deformed image does not depend on the result of the inverse affine transformation. 3. The image drawing method according to claim 1, wherein the bits at the vertices of the original image corresponding to the bits are copied unconditionally. 4. The copy processing is performed at intersections (Q0, Q1, Q2) of the deformed image and a circumscribed rectangle.
As an equation of a straight line connecting the intersection point calculation processing for obtaining Q3) and the intersection points Q0 and Q1, the intersection points Q1 and Q2, the intersection points Q2 and Q3, and the intersection points Q3 and Q0, y0 = a0 * x0 + b0. (Equation 0) y1 = a1 * x1 + b1 (Equation 1) y2 = a2 * x2 + b2 (Equation 2) y3 = a3 * x3 + b3 (Equation 3) Equation calculation processing and each line of the modified image And a copy range calculation process for calculating a bit copy range on the original image in the line by substituting the value of y corresponding to the formulas 0 to 3 calculated in the formula calculation process. The image drawing method according to claim 1. 5. An image drawing method for performing an image generation process for generating a deformed image by applying a deformation represented by a two-dimensional affine transformation to an original image, and an image drawing process for drawing the deformed image. In the above, a separation process for separating the deformation of the original image by the affine transformation into a pure deformation component and a coordinate movement component by coordinate movement, and a coordinate position where the bit of the vertex of the original image moves is obtained by the pure transformation component. Moving position calculation processing, moving distance calculation processing for obtaining a moving distance of each bit of the vertex of the original image by the coordinate position obtained by the moving position calculation processing, and moving distance of each bit within a predetermined range. An error determination process for checking whether or not there is any is executed before the image generation process, and the image generation process is When the shift distance is larger than the predetermined range, the deformation process is performed by the pure deformation component and the coordinate movement component to generate the deformed image, and the movement distance of any one of the bits is in the predetermined range. When it is smaller than the original image, the transformed image is generated by performing coordinate movement using only the coordinate movement component without performing the transformation process on the original image. 6. A deformed image for the original image is generated by applying a deformation represented by a two-dimensional affine transformation to the original image, and the deformed image is drawn using a data buffer for each line. In the image drawing method, one of vertex coordinate calculation processing for obtaining vertex coordinates of a circumscribing rectangle circumscribing the deformed image, buffer size priority mode for giving priority to the buffer size of the data buffer, and processing procedure priority mode for giving priority to processing procedure. A mode selection process of selecting one, a first buffer size setting process of setting the buffer size to a width of the circumscribing rectangle when a processing procedure priority mode is selected in the mode selection process, and the mode selection process When the buffer size priority mode is selected in, the intersection of the deformed image and the circumscribed rectangle A first intersection point calculation process Mel, intersection determined by the intersection calculation process (Q0, Q1,
Of Q2 and Q3, one point (Q0 or Q2) that intersects the vertical line of the circumscribing rectangle and the side (Q2-Q) that is parallel to the horizontal line of the circumscribing rectangle that passes through this point.
3 or Q0-Q1) intersecting point (q0 or q2)
And a second intersection calculation process for obtaining the buffer size | Q0-q0 | or | Q2-q
An image drawing method characterized by executing a second buffer size setting process for setting 2 | 7. An image data generating unit for generating image data of a deformed image for the original image by applying a deformation represented by a two-dimensional affine transformation to the original image, and image data of the deformed image. In an image drawing device having a drawing unit for drawing, the image data generation unit is an inverse affine transformation calculation unit that obtains an inverse affine transformation that is an inverse transformation to the affine transformation, and for all bits that configure the deformed image. Means for performing the inverse affine transformation to obtain bits on the original image, and copying the obtained bits on the original image to all the bits of the deformed image to generate image data of the deformed image. An image drawing device comprising: 8. A mode selection means for selecting one of a processing speed priority mode for giving priority to processing speed and an image quality priority mode for giving priority to image quality, and, when the image quality priority mode is selected by the mode selection means, A first data generating unit that generates image data of the deformed image by the inverse affine transformation calculating unit and the copying unit; and the original image and the deformed image when the processing speed priority mode is selected by the mode selecting unit. Image size comparing means for comparing image sizes, and when the size of the original image is smaller than the deformed image in the comparison result of the image size comparing means, each bit forming the original image is transformed by applying the affine transformation. Second data generating means for generating image data of the deformed image by copying to a bit on the image When the size of the original image is larger than the deformed image as a result of the comparison by the image size comparing unit, a third data generating unit that generates the image data of the deformed image by the inverse affine transformation calculating unit and the copying unit is provided. The image drawing apparatus according to claim 7, further comprising: 9. The copy means, when the bit of the vertex of the original image corresponding to the bit of the vertex of the deformed image is not obtained, the vertex of the deformed image does not depend on the result of the inverse affine transformation. 9. The image drawing apparatus according to claim 7, wherein the bits of the vertices of the original image corresponding to the above bits are unconditionally copied. 10. The copy means is configured such that intersections (Q0, Q1, Q2) between the deformed image and a circumscribed rectangle are included.
As an equation of a straight line connecting the intersection point calculating means for obtaining Q3) and the intersection points Q0 and Q1, the intersection points Q1 and Q2, the intersection points Q2 and Q3, and the intersection points Q3 and Q0, y0 = a0 * x0 + b0. (Equation 0) y1 = a1 * x1 + b1 (Equation 1) y2 = a2 * x2 + b2 (Equation 2) y3 = a3 * x3 + b3 .. And a copy range calculation means for calculating the bit copy range on the original image in the line by substituting the value of y corresponding to the above into the formulas 0 to 3 calculated by the formula calculation means. The image drawing device according to claim 7. 11. An image drawing apparatus having an image generating means for generating a deformed image by applying a deformation represented by a two-dimensional affine transformation to an original image, and an image drawing means for drawing the deformed image. In the above, a separation means for separating the deformation of the original image by the affine transformation into a pure deformation component and a coordinate movement component by coordinate movement, and a coordinate position where a bit of a vertex of the original image moves is obtained by the pure transformation component. A moving position calculating means, a moving distance calculating means for calculating a moving distance of each bit of a vertex of the original image by the coordinate position obtained by the moving position calculating means, and a moving distance of each bit within a predetermined range. Error determining means for checking whether or not there is a predetermined distance, and When it is larger than the predetermined range, the deforming means is performed by the pure deformation component and the coordinate movement component to generate the deformed image, and when the movement distance of any of the bits is smaller than the predetermined range, An image drawing apparatus, wherein the original image is subjected to coordinate movement using only the coordinate movement component without performing the transformation means to generate the transformed image. 12. A deformed image for the original image is generated by applying a deformation represented by a two-dimensional affine transformation to the original image, and the deformed image is drawn using a data buffer for each line. In the image drawing device, one of a vertex coordinate calculation unit that obtains vertex coordinates of a circumscribed rectangle that circumscribes the deformed image, a buffer size priority mode that gives priority to the buffer size of the data buffer, and a processing procedure priority mode that gives priority to a processing procedure. A mode selecting means for selecting one, a first buffer size setting means for setting the buffer size to a lateral width of the circumscribing rectangle when the processing procedure priority mode is selected by the mode selecting means, and the mode selecting means When the buffer size priority mode is selected in, the intersection of the deformed image and the circumscribed rectangle First intersection point calculating means, the intersection point of intersection obtained by the calculating means (Q0, Q1 seeking,
Of Q2 and Q3, one point (Q0 or Q2) that intersects the vertical line of the circumscribing rectangle and the side (Q2-Q) that is parallel to the horizontal line of the circumscribing rectangle that passes through this point.
3 or Q0-Q1) intersecting point (q0 or q2)
And a buffer size of | Q0-q0 | or | Q2-q.
An image drawing apparatus comprising: a second buffer size setting unit for setting 2 |