JPS6180366A - Forming device of three-dimensional image - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention provides a three-dimensional image that can effectively create a three-dimensional projected image from two-dimensional input image data and data regarding the distance or height of its coordinate address. Regarding the creation device.

[Technical background of the invention and its problems]

Recently, it has been considered to use computer graphics (CG) algorithms to create a three-dimensional projected image, such as a perspective view or a landscape view, from a two-dimensional input image and information regarding its height and the like.

However, conventionally, image processing for creating a three-dimensional projection image from the two-dimensional plane input image generally requires a large amount of calculation and requires a lot of processing time. In addition, interpolation processing to fill each surface of the three-dimensional space with image data, hidden surface processing, etc. are technically extremely difficult and difficult. There is also a problem that the quality of the three-dimensional projection image created in this way is poor.

[Purpose of the invention]

The present invention has been made in consideration of these circumstances, and its purpose is to easily and effectively create three-dimensional projection images such as perspective views and landscape views, and to achieve high quality. An object of the present invention is to provide a three-dimensional image creation device that enables image display.

[Summary of the invention]

The present invention is a further improvement of the special case of three-dimensional image processing previously proposed in Japanese Patent Application No. 59-50010.
The distance of the input image or the coordinate address at zero altitude corresponding to each coordinate address at zero altitude of the dimensional projection output image is calculated by two-dimensional back projection transformation, and the input image data of each of these calculated coordinate addresses is calculated. Calculating the two-dimensional projected coordinate address of the output image by three-dimensional transformation based on distance or altitude information,
Obtain output image data with the two-dimensional projected coordinate address as the end point and the coordinate address at the distance or zero altitude as the start point, and data exceeding the end point address on the near side of the viewpoint of the output image of this output image data is After sequentially writing one line from the near side of the viewpoint to the far side in the line buffer, one line of output image data stored in this line buffer is sequentially transferred to the output image memory one line at a time. Accordingly, a three-dimensional projected image is obtained in the output image memory.

〔Effect of the invention〕

Thus, according to the present invention, three-dimensional projected image information from any viewpoint can be easily obtained by calculating the coordinate addresses.
Moreover, by controlling the writing of output image data to the line buffer, the processing can be performed simply and at high speed. Moreover, at this time, interpolation processing and hidden surface processing can be easily and effectively performed on the output image, and the amount of data input and output can be significantly reduced, which has great practical effects. It can be played.

[Embodiments of the invention]

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

FIG. 1 is a schematic configuration diagram of an embodiment device. This device is 2
An input image memory 1 that inputs a dimensional planar image and stores the image data; an input Z information memory 2 that stores seven pieces of information such as distance and altitude regarding the data of each coordinate position of the two-dimensional planar image; and an output Z information memory 1. A control device for controlling the projection image conversion process, which includes an output image memory 3 for storing 3D display image data, a two-dimensional back projection conversion calculation circuit 4, a three-dimensional conversion calculation circuit 5, a line buffer 6, and a main memory. (CPU) 7.

The Z information data stored in the input Z information memory 2 is obtained from, for example, the elevation value and distance measurement of each coordinate point on a map corresponding to the range from which the input image was obtained.

The two-dimensional back projection transformation calculation circuit 4 calculates coordinate addresses on the input image corresponding to each coordinate address on the seven information zero planes of the three-dimensional projection image to be converted and output by two-dimensional back projection transformation calculation. It is. Further, the three-dimensional conversion circuit 5 calculates the three-dimensional conversion output coordinate address using Z information data at each corresponding coordinate address on the input image. The end point address of the output image memory 3 is specified by the coordinate address of the three-dimensional transformation output obtained by this calculation, and the input image data stored at the corresponding coordinate address of the input image memory 1 is specified at the specified address. written.

Through this series of processing, a three-dimensional parallel projection image obtained from the input image data and Z information data regarding the height and the like of the input image is stored in the output image memory 3.

By the way, the above coordinate address conversion calculation process is performed, for example, as follows. That is, first, the y' coordinate of the output image is kept constant, and the value of the y' coordinate is changed to calculate the image data of the corresponding address of the input image and its coordinate address for one line going from the near side of the viewpoint to the far side of the output image. The input Z information regarding each is accessed. in this case,
Depending on the structure of the image memory, the input image's y′ coordinate and y′
It is also necessary to exchange the coordinates in advance. In this way, one line on the input image to be accessed becomes a diagonal straight line on the input image memory 1. This oblique straight line can be easily converted to 1q as information for one line with respect to a constant y' coordinate of the input image by applying two-dimensional affine transformation, for example. Therefore, it is easily possible to read out one line of image information from the input image memory 1 all at once. Also, reduce the number of accesses,
It becomes possible to efficiently access the input image data and its Z information.

Next, the coordinate address X′ (constant) obtained in this way
Using one line of image information and its Z information data, the three-dimensional conversion calculation circuit 5 calculates a three-dimensional output image on the X' line over one line.

This calculation process is performed in order of the y' coordinates being closest to the viewpoint (y
'o -) y'm), the process is performed in order from y'o to yllm. Note that, depending on the case, the above-mentioned calculation process may be performed in the opposite direction, from zom to ylo.

Therefore, the processing for displaying the 3D image is calculated using the scale factor C of the Z information from each y/s point (starting point) on the 7 information zero plane obtained by the above 2D projection inverse transformation processing. This is performed by sequentially writing output image data to addresses on the buffer memory 6 up to the three-dimensional parallel projection point ye (end point) ye = MS +C-Z (X, V). The writing process of this output image data to the buffer memory 6 is performed sequentially from ylo to y/m of each starting point on the Z information zero plane as follows. That is, at this time, when writing the image data regarding the starting point to the buffer memory 6, the buffer memory 6 is written immediately before writing the image data regarding the starting point.
Remember the end point y/6 of the image data written to
Of the output image data, only the image data at addresses beyond the end point yle of the immediately preceding image data are written into the buffer memory 6.

By this control, hidden surface processing is automatically performed on the output image, and at the same time, the number of times image data is written to the buffer memory 6 is also significantly reduced. This effect is particularly noticeable when creating a three-dimensional projected image when the altitude of the viewpoint is low, such as a landscape map. Each time one line of output image data is written into the buffer memory 6 in this manner, that one line of image data is transferred to the output image memory 3 and written therein. Through this series of processing, a three-dimensional parallel projection image obtained from the input image data and the seven information data of the input image is obtained on the output image memory 3.

That is, now, the distribution of brightness of the input image is f (x, y), and the distribution of seven information such as distance and altitude of the input image is h (X, V).
shall be. And its target coordinate system (X.

Two axes are defined so that y) is a right-handed coordinate as shown in FIG. With respect to this coordinate system (x, y, z), if a viewpoint is set at point h on the Z axis so that the parallel projected image is rotated by an angle β around the X axis and seen through, the viewpoint coordinate system is For example, as shown in Figure 2, the left-handed system (x', y'
, z'). Therefore, any point (x, y) in the target coordinate system.

(x', y', z' of the viewpoint coordinate system corresponding to
), then the homogeneous coordinate system representation is (X'
, Y', Z', W'). Therefore, the calculation result is
nβ/h-Z(i0sβ/h+1. Therefore, its normal coordinates are y'-X'/W' =xh/ (-y sinβ-z cosβ10h)y'
=Y'/W' =(ycosβ-z sinβ)h ÷(-ysinβ-2cosβ+h) z'=Z'/W'=<-ysinβ-z cosβ)h÷(-ysin
β-z cos β0h). Here, the above component 2' is ignored because it is not related to the two-dimensional display of the projected image. Also, especially considering the Z information plane which becomes (z'-0), x' -xh/ (-y sinβ 10h) y' -y
The relationship cosβh/(=ysinβ+h) is obtained. This (z',,y') is the target coordinate system (x, y)
It shows the coordinates of perspective projection of the input image.

By the way, in general, in image processing, even in the case of three-dimensional display, as in the case of two-dimensional image processing, the output image address is specified and the address of the input image corresponding to this output image address is calculated. This is superior in terms of processing efficiency. Based on this point of view, the two-dimensional back projection transformation calculation circuit 4 uses the coordinate address (x', y') at 7 information zero of the output projection image as known data, and calculates the coordinate address (x', y') as known data. The coordinate address (x, y) on the corresponding input image is X=XCO8βh/(hcosβ+y sinβ)y=
'yh/(h cosβ±ysinβ), which is obtained by two-dimensional back projection transformation calculation. The three-dimensional transformation calculation circuit 5 uses the distance 1h between the viewpoint and the image center at the coordinate address (x, y) calculated as described above to calculate the coordinate address (x'
, y'e) are determined by the three-dimensional transformation calculation described above. In this calculation process, if the value of y' is kept constant, the input image data for one line and its Z information data can be processed at high speed by sequentially changing the value of y' from ylo to zom. As mentioned above, calculation processing can be executed by accessing the .

The address data calculated by the three-dimensional conversion calculation circuit 5 specifies the address of the line buffer 6, and the image data stored at the corresponding address (x, y) of the input image memory 1 is stored at that address, that is, The input density f (x,y) is written.

In addition, in the coordinate address calculation described above, the Z information of the output image is zero (coordinate address (y').

y') can be given as an integer value as the sampling point, and from this coordinate address (x', y') the above two
The coordinate address (x,
y), and this coordinate address (X.

The coordinate address (x', y'e) calculated from y) by the three-dimensional transformation is generally not an integer value.

Therefore, in this case, interpolation processing may be performed on the coordinate address (x, y) in the same way as normal image processing. That is, the coordinate address (x, y
) data may be interpolated.

FIG. 3 shows the concept of the projection image conversion process using the coordinate address calculation described above. FIG.
The figure (b) shows the address space (x, y) of the input image, and the figure (C) shows the address space (x', y'e) of the projected image on the output image memory 3. . Further, FIG. 4(d) shows the concept of writing output image data to the line buffer 6. FIG. 4 shows an example of the processing algorithm for calculating the coordinate address in this apparatus.

Then, from the input image stored in the input image memory 1 and the data related to the two pieces of information of the input image stored in the input Z information memory 2, a two-dimensional projection transformed projection image is obtained on the output image memory 3. In the case, first the viewpoint (
0, O, h) is determined. As a result, the coordinate space (X', V') of seven information zeros of the output image (two-dimensional projection image) is determined as shown in FIG. 3(a). After that, the above coordinate space of zero altitude (y'.

y') to be subjected to address calculation processing, and points y' on the line X' are selected in order from a position closer to the viewpoint (a position closer to the front on the projected image). Then, the addresses (x', y'
), address calculation processing is performed on the input image and Z information, respectively.

This address calculation is first performed in the two-dimensional backprojection calculation circuit 4 by converting the address space of the output image with 7 information zero shown in FIG. 3(a) and the address space of the input image shown in FIG. 3(b). In between, the address (x, y) of the input image corresponding to the address (X', V') is calculated by two-dimensional back projection transformation and stored from the input Z information memory 2 to the above address (X, V). This is done by reading out the Z information data Z Z = (X, y). After that, the address (
The three-dimensional conversion calculation circuit 5 converts the three-dimensional data (x, y, z) consisting of the three-dimensional data (x, y, z) and the seven information data 2 into the converted data (y').

ye) is obtained by three-dimensional projection transformation calculation. This conversion data (x', ye) becomes the conversion address (x', ye) on the output image as shown in FIG. 3(c). Address calculated in this way (X', ye)
and the address (x', ys
) specifies the address of the line buffer 6,
To that address, to the corresponding address (x, y) of the input image memory 1, to the starting point (X', 'l/S), to the corresponding address (y').

The image data f(x, y) with ye) as the end point.

Write.

At this time, as shown in FIG. 3(d), the line buffer 6
The end point address ye of the image data written immediately before is memorized, and only for the part where the address of the image data calculated in the next step exceeds the end point address ye,
The image data f (X, V) is controlled to be written to that address. In other words, when the image data for each coordinate point of one line is obtained as fo, fl, f2 to fn, the above f1. f
Control is performed to sequentially write data 2 to fn.

As a result, only the output image data that can be seen from the viewpoint is sequentially written into the line buffer 6, which significantly reduces the amount of image data written into the line buffer 6, and at the same time performs processing on hidden surfaces. It can be achieved. Then, in this way, 1 is added to line buffer y6.
When image data for a line is stored, the image data for one line is transferred to the output image memory 3 and written in the corresponding line.

In this way, according to this device, the data of the 3D display image is obtained in order from the position closer to the viewpoint, so while effectively processing hidden points, which has been a problem in the past, it is possible to create a 3D display image without omissions for the output image. It can be obtained on memory 3. Therefore, a three-dimensional display image can be easily and efficiently obtained, and great practical effects such as very high image processing efficiency can be achieved. Also, using line buffer 6, 1
Since the image conversion process is performed line by line and the image data is transferred all at once and written to the output image memory 3, the access process to the image memory 3 can be greatly simplified, and no time is wasted in controlling the access. Since the amount of time spent is reduced, the overall processing speed can be increased.

Note that the present invention is not limited to the embodiments described above. For example, in the embodiment, elevation data was used as the third axis of the image, but other distribution data h' (x.

It is also possible to use y). Further, in the embodiment, only the rotation in the X-axis direction is treated with respect to image conversion, but rotation in the y-axis and z-axis directions can also be handled in the same way, and simultaneous rotation in each of these directions can be handled in the same way. In addition, the present invention can be implemented with various modifications without departing from the gist thereof.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an apparatus according to an embodiment of the present invention, FIG. 2 is a diagram showing a coordinate space of a projected image, and FIGS. 3(a) to 3(d) illustrate the processing concept of address calculation according to the present invention. The figure shown in FIG. 4 is a diagram showing the flow of address calculation processing of the embodiment device. 1... Memory for input image, 2... Memo 1c for input Z information, 3... Memo 1c for output image, 4- 2-dimensional back projection conversion calculation circuit, 5... 3-dimensional conversion calculation circuit, 6...
Line buffer, 7...control unit (CUP).

Claims (3)

[Claims] (1) Means for calculating the distance of the input image or the coordinate address at zero altitude corresponding to each coordinate address at zero altitude of the output image by two-dimensional back projection transformation, and the input of each of these calculated coordinate addresses means for calculating a two-dimensional projected coordinate address of the output image by three-dimensional transformation based on distance or altitude information regarding image data; and a means for calculating the two-dimensional projected coordinate address of the output image by three-dimensional transformation, and the distance or altitude with the two-dimensional projected coordinate address calculated by this three-dimensional transformation as an end point. Means for sequentially writing data exceeding the end point address on the near side of the viewpoint of the output image of the output image data starting from the coordinate address at zero into a line buffer, and output image data for one line stored in the line buffer. A three-dimensional image creation device, comprising means for transferring and writing the image to an output image memory. (2) The three-dimensional image creation device according to claim 1, wherein the line buffer stores output image data for one line extending from the near side of the viewpoint of the output image to the far side. (3) The three-dimensional image creation device according to claim 1, wherein the output image data is written to the line buffer in order from the output image data on the near side of the viewpoint of one line of the output image.