JPS60193079A - Generator of center projected picture - Google Patents

Abstract

PURPOSE:To obtain a center projected output picture easily and effectively by calculating a three-dimensional projected coordinate address through three- dimensional projected conversion by means of data on the height of a coordinate address calculated through two-dimensional reverse-projected conversion. CONSTITUTION:A two-dimensional reverse-projected conversion calculating circuit 4 calculates a coordinate address of an input picture corresponding to that in a altitude of zero of a center-projected picture to be converted and outputted by means of two-dimensional reverse-projected conversion. By utilizing altitude data in the corresponding coordinate address on the input picture, a three-dimensional projected convertion circuit 5 calculates a three-dimensional projected conversion output coordinate address of the center-projected picture by means of three-dimensional projected conversion. An end point address of an output picture memory 3 is specified in a coordinate address of the obtained three-dimensional projected conversion output, and input picture data of an input picture memory 1 is written on the specified address.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention effectively creates a central projection image of a three-dimensional grayscale image from data of a two-dimensional image and data regarding the height at each coordinate position of the image. The present invention relates to a central projection image creation device that can perform central projection images.

[Technical background of the invention and its problems]

In recent years, images taken from flying objects such as artificial satellites and airplanes have been actively used in fields such as resource surveys. In particular, two images taken from different viewpoints are used to stereoscopically view an object to be investigated.

Recently, computer graphics (CG)
It has been considered to create a central projection image by calculating the three-dimensional coordinates of the output image from the three-dimensional coordinates of the input image using the following algorithm. However, in the image processing described above that creates a central projection image from a two-dimensional plane image by image processing, it is necessary to calculate each so-called mesh-like data of Ohma, and each surface of the three-dimensional space must be calculated using image data. There were many problems in the so-called interpolation process for filling the space and in the handling process of data at the rear position hidden by the plane located at the front in the three-dimensional space.

[Purpose of the invention]

The present invention was made in consideration of these circumstances, and its purpose is to change the viewpoint of the 3D image from the input 2D image and the elevation data regarding the height of the image. An object of the present invention is to provide a center projection image creation device that can easily and effectively obtain a center-projected output image (center projection image).

[Summary of the invention]

The present invention provides the input 2 corresponding to the coordinate addresses in the elevation layer of the output center projection image set at different viewpoints with respect to the 3D information formed by the input 2D image and the data regarding the elevation of the image. The coordinate address of the dimensional image is calculated by two-dimensional back projection transformation, and data regarding the height of the image data of each coordinate address of the input planar image is inputted, and the elevation coordinate address of the output center projection image is transformed into three-dimensional projection transformation. The central projection image is obtained in the output image memory by calculating the data of the corresponding coordinate address of the input planar image in the elevation coordinate address of the output image memory.

In other words, each coordinate address of the input image corresponding to the elevation layer of the center projection image is calculated by two-dimensional back projection transformation, and the three-dimensional projection coordinate address of the center projection image is calculated using the data regarding the height of the coordinate address. Calculate by dimensional projection transformation, and write the data of the corresponding coordinate address of the input image from the coordinate address of each elevation layer in the output image memory to the three-dimensional projection coordinate address, to easily and effectively output the center projection. This is to obtain an image.

〔Effect of the invention〕

Thus, according to the present invention, a centrally projected image from any viewpoint can be easily and effectively obtained only by calculating coordinate addresses based on two-dimensional back projection transformation calculation and three-dimensional projection transformation calculation. Furthermore, this process facilitates the interpolation of the image data necessary for the surface of the centrally projected image, and also makes it possible to easily handle image data that is a hidden surface in the centrally projected image. It has great practical effects in image processing.

[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 includes an input image memory 1 that inputs a two-dimensional planar image photographed by a flying object and stores the image data, and an input altitude that stores height data regarding data of each coordinate position of the two-dimensional planar image. A value memory 2, an output image memory 3 that stores center projection image data to be output, a two-dimensional back projection transformation calculation circuit 4, a three-dimensional projection transformation calculation circuit 5, and a control device that controls the projection image transformation process. (CPU)
6. The altitude value data stored in the input altitude value memory 2 is determined from, for example, the altitude value of each point on a map corresponding to the photographed area where the input image was obtained.

The two-dimensional back projection transformation calculation circuit 4 determines coordinate addresses on the input image corresponding to the coordinate addresses in the altitude layer of the center projection image to be converted and output by two-dimensional back projection transformation calculation; The dimensional projection transformation circuit 5 determines the three-dimensional projection transformation output coordinate address of the central projection image by three-dimensional projection transformation calculation using elevation 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 projection transformation output determined by this calculation, and the input image data stored at the corresponding coordinate address of the input image memory 1 is assigned to the specified address. is written. Through this series of processing, the central projection image obtained from the data of the input image and the elevation value data regarding the height of the input image is stored in the output image memory 3.

That is, let f(X, V) be the luminance distribution of the input image, and h(X, V) be the distribution of the height (elevation) of the input image. Then, the Z-axis is defined so that the target coordinate system (x, y) is a right-handed coordinate system as shown in FIG. This coordinate system (
X, V, Z), if a viewpoint is set at point h on the l-axis so that the central projected image is rotated by an angle β with respect to the It is expressed as (x', y', z') in the left-handed system as shown in . Therefore, any point in the target coordinate system (x, y,
The point in the viewpoint coordinate system corresponding to (z) is (x', y',
z'), the homogeneous coordinate system representation is (X', Y').

If it is shown by z', w'>, then it becomes. Therefore, the calculation result is X' = x Y' = ycosβ-z sinβ Z' = -y sinβ-z cosβW' = -y
sinβ/h−zcosβ/h+1. Therefore, its normal coordinates are X' = X'/W' -x b / (-y sinβ-z cosβ+h
)V'-Y'/W'-(y cosβ-z sinβ)11÷(-y31
11β-Z CO3β+h )Z'-Z'/W' -(-ysinβ-z cosβ) he(-ysin
β-z cos β+h). Here, since the above Z' is not related to the two-dimensional display of the centrally projected image,
Ignore that ingredient. In addition, especially considering a zero-elevation plane (z' = 0), x' = x l+ / (-V Sinβ 1) y'
The following relationship is obtained: = y cos β h/ (-V sin β + h). These (X', V') indicate the coordinates obtained by perspectively projecting the input image of the target coordinate system (x, y, z).

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. It is excellent in terms of processing and movement rate. Based on this viewpoint, the two-dimensional back projection conversion calculation circuit 4 uses the coordinate address (x', y') at zero altitude of the output center projection image as known data,
The above coordinate address (x', y') corresponds to the coordinate address (x, y) on the input image as X = X' CO3β h/ (h cosβ+y'
sin β) V = V' h / (b cos β + y
'sin β) by a two-dimensional back projection transformation calculation. The three-dimensional projection conversion calculation circuit 5 uses the elevation data h at the coordinate addresses (X, V) calculated as described above to calculate the elevation coordinate addresses (x", y", Z") in the output center projection image. ) is determined by the three-dimensional projection transformation calculation.The address data calculated by the three-dimensional projection transformation calculation circuit 5 specifies the address of the output image memory 3, and the address of the input image memory 1 is specified at that address. The image data stored at the corresponding address (x, y), that is, the density f(x, y) of the input image
is written.

In the coordinate address calculation described above, the coordinate address (x' : y') at the zero altitude of the output image can be given as an integer value as the sample point, but from this coordinate address (x', y') A coordinate address (x, y) calculated by the two-dimensional back projection transformation, and a coordinate address (xlT, yH) calculated from this coordinate address (x, y) by the three-dimensional projection 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. In other words, if mesh data of the input image (image data given as an integer value address) is used to interpolate the data of the coordinate address (x, y) calculated by the above two-dimensional backprojection transformation, good.

Figure 3 shows the concept of the projection image conversion process using the coordinate address calculation described above. ) shows the address space (X, V) of the input image, and (C) shows the address space (x/l, y#) of the centrally projected image on the output image memory 3, respectively. Further, FIG. 4 shows an example of a processing algorithm for calculating the coordinate address in this apparatus.

Then, a center projection image obtained by performing two-dimensional projection transformation from the input image stored in the input image memory 1 and the height-related data of the input image stored in the input elevation value memory 2 is stored on the output image memory 3. When considering a perspective, first
0,0,h ) and the range of two-dimensional projection transformation is determined.

As a result, the zero-elevation coordinate space (x', y') of the output image (two-dimensional projection image) is determined as shown in FIG. 3(a). After that, the coordinate space (x'
.
Select the upper scan points X' in order. Address calculation processing is then performed for each of the scan addresses (x', y') that are sequentially selected in this manner.

This address calculation is first performed in the two-dimensional backprojection conversion calculation circuit 4 between the zero-elevation address space of the output image shown in FIG. 3(a) and the address space of the input image shown in FIG. 3(b). , scan address (x', y')
The address (X, V ) of the input image corresponding to is calculated by two-dimensional back projection transformation, and the elevation data Z z = h (x, y ). After that, the address (
The three-dimensional projection transformation calculation circuit 5 calculates the projection transformation data (x", y", z") for three-dimensional data (x, y, z) consisting of the elevation value data Z
) by three-dimensional projection transformation calculation, and from this projection transformation data (xl/ , y″, z′/ ), the projection address (xll , yJL ) on the output image is determined as shown in FIG.
). In this way, the address (x', y')
and the calculated address data (xl/ , ylJ
) to specify the address of the output image memory 3,
At that address, at the corresponding address (X, Y) of the input image memory 1, the image data is stored with the (X', V') as the starting point and the (xll, ylJ) as the ending point.
Write r(x,y).

This series of address calculations and writing of image data to the output image memory 3 are performed in sequence for each scan point described above.

In this way, according to this device, the data of the center projection image is obtained in order from the position farthest from the viewpoint, so while effectively processing hidden points, which has been a problem in the past, the data of the center projection image without omissions can be stored in the output image memory. You can get above 3. Therefore, a center projection image can be obtained easily and efficiently, and the image processing efficiency is very high, which is a great practical effect.

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 rotation in the X-axis direction with respect to central projection is handled, but rotation in the y-axis direction can also be handled in the same way. The water-saturated 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 (G) 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... Memory for input elevation value, 3... Memory for output image, 4... 2-dimensional back projection conversion calculation circuit, 5... 3-dimensional projection conversion calculation circuit. ,6・
...Control unit (CPU). Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] Means for calculating the coordinate addresses of the input image corresponding to the coordinate addresses at zero altitude of the output image by two-dimensional back projection transformation; means for calculating a two-dimensional projected coordinate address of an image by three-dimensional projection transformation; and a means for calculating the corresponding coordinate address of the input image such that the zero-elevation coordinate address of the output image memory is the starting point and the two-dimensional projected coordinate address is the ending point. 1. A central projection image creation device, comprising means for writing data.