JP2001297331A - Device and method for processing image and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To plot a three-dimensional(3D) curve at high speed. SOLUTION: When controlling the action of a human figure model, a controller 1 is operated by a user. On the basis of an entry from the controller 1, a display mode selecting part 2 determines a display mode and controls a data reducing part 4, a line dividing part 5 and a switch 6. A data operating part 3 applies affine transformation to inputted hair data. The data reducing part 4 thins the hair data. The line dividing part 5 determines the number of interpolating points on the 3D curve and operates the coordinate values of the interpolating points. A rendering part 7 executes rendering processing, to which shading is applied. A rendering part 8 executes rendering processing in a single color without applying shading.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus and method, and a recording medium, and more particularly to an image processing apparatus and method and a recording medium suitable for expressing hair by computer graphics.

[0002]

2. Description of the Related Art Computer graphics (hereinafter C)
G) is described in, for example, “Kobayashi, Morishima, and Harashima,“ Simulation Model of Threaded Object Using Motion Model and CG ”, IEICE Technical Report, PRU-90-127, pp. 15-20, 1991 ", the details of which are described. Specifically, it describes a method of expressing one hair by combining a plurality of cubic B-spline curves.

A cubic B-spline curve will be described with reference to FIG. The point P (t) on the cubic B-spline curve is defined by the following equation (1) using the three-dimensional coordinates of the control points Q1 to Q4. _{P (t) = B 1 (} t) Q1 + B 2 (t) Q2 + B 3 (t) Q3 + B 4 (t) Q4 ··· (1)

Here, for the parameter t, 0 ≦ t
≦ 1. B ₁ (t) to B ₄ (t) are defined by the following equation (2). _{B 1 (t) = (1} -t) 3/6 B 2 (t) = (t 3/2) -t 2 + (2/3) B 3 (t) = (t 3/2) + (t ^{2/2) + (t /} 2) + (1/6) B 4 (t) = (t 3/6) ··· (2)

In order to draw a cubic B-spline curve, a large number of interpolation points P (t) are generated using equation (1), and a curve is approximated by connecting these interpolation points with a straight line. are doing. The coordinates of the interpolation point can be calculated by incrementing the parameter t (0 ≦ t ≦ 1) at predetermined intervals.

FIG. 1 shows a cubic B-spline composed of interpolation points P1 to P4 calculated using four control points Q1 to Q4.
The curves are shown. The interpolation point P1 = P (t1) is the starting point of the curve and t1 = 0. Similarly, the interpolation point P2 = P
(t2), the interpolation point P3 = P (t3), and the interpolation point P
4 = P (t4) is the end point of the curve, and t4 = 1.

In the drawing of the hair, at each of the interpolation points P1 to P4, the reflected light is calculated for the light from the light source, the luminance value at the interpolation points P1 to P4 is obtained, and a straight line connecting the interpolation points P1 to P4 is obtained. By interpolating the above luminance values, a smooth luminance value change is realized.

In the example shown in FIG. 2, seven control points Q
The hair C represented by a to Qg is shown. The hair C is composed of four cubic B-spline curves. The interpolation points forming the first cubic B-spline curve are calculated using the control points Qa to Qd. The interpolation points forming the second cubic B-spline curve are calculated using the control points Qb to Qe. The interpolation points forming the third cubic B-spline curve are calculated using the control points Qc to Qf. The fourth tertiary B-
The interpolation points forming the spline curve are calculated using the control points Qd to Qg.

[0009]

The above-described method of approximating the hair with a cubic B-spline curve has no problem in image quality, but has a problem that it takes time to calculate coordinates of interpolation points. Therefore, there is a problem that it is suitable for a still image, but difficult to apply to a moving image.

The present invention has been made in view of such a situation.
The purpose is to be able to describe a dimensional curve.

[0011]

An image processing apparatus according to the present invention comprises a setting means for setting a display mode, a calculating means for calculating coordinates of a predetermined number of interpolation points based on curve data, and a calculating means. Generating means for connecting the coordinates of the calculated predetermined number of interpolation points to approximately generate an image of a curve corresponding to the thread-like object; and generating means for generating an approximate image corresponding to the display mode set by the setting means. And a shade adding means for adding a shade to the image of the generated curve.

The setting means may set the display mode specified by a user.

[0013] The image processing apparatus of the present invention may further include a judging means for judging a display mode based on a user operation, wherein the setting means sets the display mode determined by the judging means. Can be.

[0014] The image processing apparatus of the present invention can further include thinning means for thinning out the curve data in accordance with the display mode set by the setting means.

[0015] The image processing apparatus of the present invention may further include a reducing means for reducing the number of interpolation points calculated by the calculating means in accordance with the display mode set by the setting means.

The generation means connects the coordinates of a predetermined number of interpolation points calculated by the calculation means in accordance with the display mode set by the setting means, and approximates a monochromatic image of a curve corresponding to the thread-like object. It can be made to generate automatically.

According to the image processing method of the present invention, there are provided a setting step of setting a display mode, a calculating step of calculating coordinates of a predetermined number of interpolation points based on curve data, and a predetermined step calculated in the processing of the calculating step. In the generation step, the coordinates of the interpolation points are connected to generate a curve image corresponding to the thread-like object approximately, and in the display mode set in the setting step, A shadow adding step of adding a shadow to the image of the curve generated approximately.

The program of the recording medium according to the present invention is calculated by a setting step of setting a display mode, a calculating step of calculating coordinates of a predetermined number of interpolation points based on curve data, and a calculating step. A generating step of connecting the coordinates of a predetermined number of interpolation points to approximately generate an image of a curve corresponding to the thread-like object, and a processing of the generating step corresponding to the display mode set in the processing of the setting step And adding a shadow to the image of the curve approximately generated in step (a).

In the image processing apparatus and method according to the present invention, a display mode is set, coordinates of a predetermined number of interpolation points are calculated based on the curve data, and the calculated predetermined coordinates are calculated. The coordinates of the number of interpolation points are concatenated to approximately generate an image of a curve corresponding to the thread-like object. Furthermore, a shade is added to the image of the curve generated approximately in accordance with the set display mode.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A configuration example of a hair drawing apparatus to which the present invention is applied will be described with reference to FIG. This hair drawing apparatus is based on input hair data (consisting of the number of control points and three-dimensional coordinate values of each control point), such as a cubic B-spline curve approximating one hair. Is generated and the image data is output to the display device 9.

The controller 1 of the head drawing apparatus is operated by the user when controlling the movement (movement, rotation, etc.) of the human model on which the head is drawn using the head drawing apparatus. The controller 1 outputs the input operation information for controlling the movement of the human model to the display mode selection unit 2 and the data operation unit 3.

The display mode selection unit 2 determines a display mode based on operation information for controlling the movement of the human model input from the controller 1, and according to the determined display mode, a data reduction unit 4 and a line division unit 5. , And the switch 6. Details of the display mode will be described later with reference to FIG.

Note that the user can directly select a display mode using the controller 1. In that case, the display mode selection unit 2 controls the data reduction unit 4, the line division unit 5, and the switch 6 according to the display mode selected by the user.

The data operation unit 3 stores the three-dimensional coordinate values of the control points constituting the input hair data into the controller 1.
Affine conversion is performed on the basis of the information on the operation of controlling the movement of the human model input from, and the result is output to the data reduction unit 4.

The data reduction unit 4 thins out the hair data input from the data operation unit 3 (thin the number of hairs to be drawn) based on the control from the display mode selection unit 2 and sends the data to the line division unit 5. Output.

The line division unit 5 determines the number of interpolation points of the three-dimensional curve corresponding to one hair and calculates the coordinate values of the interpolation points based on the control from the display mode selection unit 2. Then, the data is output to the switch 6 as interpolation point data.

The switch 6 outputs the interpolation point data input from the line division unit 5 to the lettering unit 7 or the lettering unit 8 based on the control from the display mode selection unit 2.

The rendering unit 7 executes a rendering process in which data from the switch 6 is subjected to shading (shading), and outputs image data as a processing result to the display device 9. The rendering unit 8 performs rendering processing on the hair data from the switch 6 in a single color without shading (without shading), and outputs image data as a processing result to the display device 9.

Here, the rendering processing with shading is performed by performing lighting calculation in consideration of reflection of light from a light source at each connection point (division point) of a plurality of connected straight lines approximating a three-dimensional curve. In addition, rendering is performed after interpolating between the connection points using the value of the lighting calculation at the connection points.

On the other hand, the rendering processing of a single color without shading is to render a plurality of connected straight lines approximating a three-dimensional curve in a single color without considering the existence of a light source.

The display device 9 is an LCD (Liquid Crystal Displ.).
ay) or a CRT (Cathode Ray Tube), and displays an image corresponding to image data as a result of rendering processing input from the rendering unit 7 or the rendering unit 8.

Next, the operation of the hair drawing apparatus will be described with reference to FIG.
This will be described with reference to a flowchart. In step S <b> 1, the display mode selection unit 2 determines a display mode based on information on an operation for controlling the movement of the human model input from the controller 1.

As a display mode, as shown in FIG.
Five types of high-quality mode, normal mode, high-speed drawing mode 1, high-speed drawing mode 2, and high-speed drawing mode 3 are prepared. The display mode is determined, for example, as shown in FIG. 5, when a still human model is rendered, the high image quality mode is selected, and when the displacement amount of the human model is small (when it is smaller than the predetermined threshold th1), When the normal mode is selected and the displacement of the human model is large (when it is larger than the predetermined threshold th1), the high-speed drawing mode 1 is selected, and when the displacement of the human model is very large (the predetermined threshold th2 ( > When the threshold value is larger than the threshold value th1), the high-speed drawing mode 2 is selected.
When checking the volume of the hair of the human model, the high-speed drawing mode 3 is selected.

FIG. 5 is merely an example of the criterion, and the display mode may be determined according to a different criterion. In step S1, the user may directly select the display mode.

In step S2, the data operation unit 3
, Hair data including coordinates of control points of a three-dimensional curve such as a B-spline curve is input. In step S3, the data operation unit 3 performs affine transformation on the three-dimensional coordinate values of the control points constituting the input hair data based on the operation information for controlling the movement of the human model input from the controller 1. , To the data reduction unit 4. When the operation of controlling the movement of the human model is not performed on the controller 1, the affine transformation is not performed, and the hair data is output to the data reduction unit 4 as it is.

In step S4, the display mode selection unit 2 determines whether to reduce the number of hairs (whether to thin out) based on the display mode determined in step S1. This criterion is determined, for example, according to FIG. That is, when the display mode is the high-speed rendering mode 1 or the high-speed rendering mode 2, it is determined that the number of hairs is reduced. When the display mode is the high-quality mode, the normal mode, or the high-speed rendering mode 3, the number of hairs is reduced. Is determined not to be reduced.

If it is determined in step S4 that the number of hairs is to be reduced, the process proceeds to step S5. In step S5, the data reduction unit 2 sets the display mode selection unit 2
According to the control from, the hair data input from the data operation unit 3 is reduced (thinned out) at a predetermined ratio and output to the line dividing unit 5.

In step S6, the display mode selector 2 determines whether to reduce the number of line divisions based on the display mode determined in step S1. This criterion is determined, for example, according to FIG. That is,
Display mode is Normal mode or High-speed drawing mode 2
Is determined to reduce the number of line divisions, and when the display mode is the high image quality mode, the high-speed rendering mode 1 or the high-speed rendering mode 3, it is determined not to reduce the number of line divisions.

If it is determined in step S6 that the number of line divisions is to be reduced, the process proceeds to step S7. In step S7, the line dividing unit 5 determines the number of interpolation points for which the coordinate values are calculated in step S8 to be smaller than usual (for example, the number of interpolation points which is usually 7 points is
5 points). In step S <b> 8, the line dividing unit 5 calculates the coordinate values of the interpolation points by using the equation (1) by the number of the determined interpolation points, and outputs the calculated values to the switch 6 as interpolation point data.

In step S9, the display mode selection unit 2 determines whether to perform shading based on the display mode determined in step S1. This criterion is determined, for example, according to FIG. That is, when the display mode is the high-quality mode, the normal mode, the high-speed drawing mode 1, or the high-speed drawing mode 2, it is determined that shading is to be performed. When the display mode is the high-speed drawing 3, it is determined that shading is not to be performed. You. If shading is not performed, it is determined that single-color drawing is performed.

If it is determined in step S9 that shading is to be performed, the process proceeds to step S10. In step S10, the switch 6 sets the display mode selection unit 2
, The interpolation point data from the line dividing unit 5 is output to the rendering unit 7. Using the interpolation point data input from the switch 6, the rendering unit 7 performs a rendering process in which shading is performed in consideration of the light source as shown in FIG. 7, and displays image data as a processing result on the display device 9. Output.

In step S11, the display device 9
Displays the input image data.

If it is determined in step S9 that shading is not to be performed, the process proceeds to step S12. In step S12, the switch 6 outputs the interpolation point data from the line division unit 5 to the rendering unit 8 based on the control of the display mode selection unit 2. Using the interpolation point data input from the switch 6, the rendering unit 8 executes a single-color rendering process (single-color rendering process) without shading without considering a light source, as shown in FIG. Is output to the display device 9. In this case, since the shading is not performed as compared with the execution of the processing in step S10, the image quality is inferior, but the processing speed is improved.

If it is determined in step S4 that the number of hairs is not reduced, the processing in step S5 is skipped. If the process of step S5 is skipped, all the hair is drawn as shown in FIG. Conversely, when the process of step S5 is performed, the hair is drawn out as shown in FIG. As is apparent from a comparison of FIGS. 9 and 10, the image (FIG. 10) in which the processing in step S5 is executed has a lower image quality than the image (FIG. 9) in which the processing in step S5 is skipped. Will be inferior. However, because the amount of hair data to be processed is reduced, the processing speed is increased.

If it is determined in step S6 that the number of line divisions is not to be reduced, the processing in step S7 is skipped. Therefore, the number of interpolation points constituting the three-dimensional curve is a normal number (for example, seven points).

When the process in step S7 is skipped, as shown in FIG. 11, the three-dimensional curve representing the hair is approximated by a line connecting the normal seven interpolation points P1 to P7. On the other hand, when the process of step S7 is executed, as shown in FIG.
It is approximated by a line connecting 5.

As is apparent from a comparison between FIG. 11 and FIG. 12, the image obtained when the processing in step S7 is executed (FIG. 12) is the image obtained when the processing in step S7 is skipped (FIG. 11). ), The image quality is inferior. However, since the number of interpolation points is small, it is not necessary to calculate the coordinate values of the interpolation points. Therefore, the processing speed is improved.

According to the processing of the hair drawing apparatus as described above,
For example, when the human model is moved quickly, the drawing processing speed can be prioritized over the image quality of the image. Conversely, when the human model is not moved quickly, the image quality can be prioritized over the speed of the drawing process.

In this embodiment, five types of display modes (high-quality mode, normal mode, high-speed drawing mode 1, high-speed drawing mode 2, and high-speed drawing mode 3) are set as display modes. By combining the presence / absence of the processing of the section 4 (reduction in the number of lines in FIG. 6), the presence / absence of the processing of the line division section 5 (reduction of the number of divisions in FIG. 6), and the presence / absence of the shading processing, 8 (= 2
³ ) Different display modes can be set.

The display mode is selected by the display mode selection unit 2.
It is also possible for the user to arbitrarily determine, instead of just determining.

In the present embodiment, the hair is
Although the approximation is performed using a dimensional curve, a two-dimensional curve may be used.

Further, the present invention can be applied to a case where a thread-like object other than the hair is represented by CG.

By the way, the above-described series of processes of the hair drawing apparatus can be executed by hardware, but can also be executed by software. When a series of processing is executed by software, a program constituting the software can execute various functions by installing a computer built into dedicated hardware or installing various programs. It is installed from a recording medium into a possible general-purpose personal computer or the like.

FIG. 13 shows an example of the configuration of a personal computer for realizing a hair drawing device. This personal computer has a CPU (Central Processing Unit) 21
Built-in. An input / output interface 25 is connected to the CPU 21 via a bus 24. The input / output interface 25 includes an input unit 26 including an input device such as a keyboard and a mouse corresponding to the controller 1, an image output unit 27 that outputs image data of the hair as a processing result to the display device 9, and a program and various data. A storage unit 28 including a hard disk drive for storing data, a communication unit 29 for communicating data via the Internet or the like, and a drive 30 for reading / writing data from / to a recording medium such as a magnetic disk 31 to a semiconductor memory 34 are connected. I have. The bus 34 has a ROM (Read Only Memory) 3
2 and a RAM (Random Access Memory) 33 are connected.

The program for causing the personal computer to execute the operation as the hair drawing device is supplied to the personal computer in a state where it is stored in the magnetic disk 31 to the semiconductor memory 34, read out by the drive 30, and stored in the storage unit 28. Installed on the internal hard disk drive. The program installed in the storage unit 28 is loaded from the storage unit 28 to the RAM 23 and executed by a command from the CPU 21 corresponding to a command from the user input to the input unit 26.

In this specification, the steps for describing the program recorded on the recording medium are not limited to the processing performed in chronological order according to the described order. Alternatively, it also includes individually executed processing.

In this specification, the system is
It represents the entire device composed of a plurality of devices.

[0058]

As described above, according to the image processing apparatus and method of the present invention and the program of the recording medium, the display mode is set, and the image of the curve approximately generated corresponding to the set display mode is set. Since a shadow is added to the image, it is possible to draw a three-dimensional curve at high speed.

[Brief description of the drawings]

FIG. 1 is a diagram for describing a B-spline curve representing hair.

FIG. 2 is a diagram for explaining a B-spline curve representing hair.

FIG. 3 is a block diagram illustrating a configuration example of a hair drawing device to which the present invention has been applied.

FIG. 4 is a flowchart illustrating an operation of the hair drawing device.

FIG. 5 is a diagram showing selection criteria for a display mode.

FIG. 6 is a diagram showing the presence or absence of each process in each display mode.

FIG. 7 is a diagram illustrating an example of hair displayed as a processing result of the hair drawing device.

FIG. 8 is a diagram illustrating an example of hair displayed as a processing result of the hair drawing device.

FIG. 9 is a diagram illustrating an example of hair displayed as a processing result of the hair drawing device.

FIG. 10 is a diagram illustrating an example of hair displayed as a processing result of the hair drawing device.

FIG. 11 is a diagram illustrating an example of hair displayed as a processing result of the hair drawing device.

FIG. 12 is a diagram illustrating an example of hair displayed as a processing result of the hair drawing device.

FIG. 13 is a diagram illustrating a configuration example of a personal computer that realizes a hair drawing device.

[Explanation of symbols]

1 controller, 2 display mode selection unit, 3 data operation unit, 4 data reduction unit, 5 line division unit, 6 switch, 7, 8 rendering unit, 9
Display device, 31 magnetic disk, 32 optical disk, 33 magneto-optical disk, 34 semiconductor memory

Claims (8)

[Claims] 1. An image processing apparatus for generating an image of a thread-like object based on curve data composed of a plurality of control point coordinates, wherein: a setting means for setting a display mode; Calculating means for calculating the coordinates of the number of interpolation points; generating the image of the curve corresponding to the thread-like object approximately by linking the coordinates of the predetermined number of the interpolation points calculated by the calculating means; An image processing apparatus, comprising: a shading unit that adds a shading to the image of the curve approximately generated by the generating unit in accordance with the display mode set by the setting unit. 2. The image processing apparatus according to claim 1, wherein the setting unit sets the display mode specified by a user. 3. The apparatus according to claim 1, further comprising a determination unit configured to determine the display mode based on a user operation, wherein the setting unit sets the display mode determined by the determination unit. Image processing device. 4. The image processing apparatus according to claim 1, further comprising a thinning unit that thins out the curve data in accordance with the display mode set by the setting unit. 5. The apparatus according to claim 1, further comprising a reducing unit configured to reduce the number of the interpolation points to be calculated by the calculating unit in accordance with the display mode set by the setting unit. Image processing device. 6. The method according to claim 1, wherein the generating unit connects the coordinates of the predetermined number of the interpolation points calculated by the calculating unit in accordance with the display mode set by the setting unit, and corresponds to the thread-like object. The image processing apparatus according to claim 1, wherein a monochrome image of a curved curve is approximately generated. 7. An image processing method of an image processing apparatus for generating an image of a thread-like object based on curve data composed of a plurality of control point coordinates, wherein: a setting step of setting a display mode; A calculation step of calculating coordinates of a predetermined number of interpolation points; and connecting the coordinates of the predetermined number of the interpolation points calculated in the processing of the calculation step to form an image of a curve corresponding to the thread-like object. Generating the image, and adding a shadow to the image of the curve approximately generated in the processing of the generating step in accordance with the display mode set in the processing of the setting step. And an image processing method. 8. An image processing program for generating an image of a thread-like object based on curve data composed of a plurality of control point coordinates, comprising: a setting step of setting a display mode; A calculation step of calculating coordinates of a predetermined number of interpolation points; and connecting the coordinates of the predetermined number of the interpolation points calculated in the processing of the calculation step to form an image of a curve corresponding to the thread-like object. Generating the image, and adding a shadow to the image of the curve approximately generated in the processing of the generating step in accordance with the display mode set in the processing of the setting step. And a recording medium storing a computer-readable program.