JP2006301925A - Image processing method and image processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow adjustment for improving responsiveness to user's operations, without changing shapes of CG objects even when drawing a CG object having a high drawing load. <P>SOLUTION: In an apparatus which draws CG objects read out from an object storage part 500 by an object drawing part 550, when a drawn object is moved in accordance with input of a user's operation from an operation input part 510, polygons of the object CG are divided into groups of drawing object polygons and drawing non-object polygons by a polygon grouping part 540 on the basis of a reduction rate set by a drawing setting part 530 and only drawing object polygons are drawn, whereby responsiveness is improved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image processing method and an image processing apparatus, and in particular, when drawing a CG object having a high drawing load, the responsiveness to an operation from a user can be improved without changing the shape of the CG object. The present invention relates to an image processing method and an image processing apparatus.

  Conventionally, by using computer graphics (CG) technology, an article (CG object) existing in the same virtual three-dimensional space from a viewpoint (virtual viewpoint) set in the virtual three-dimensional space. There are many image processing apparatuses that generate observed images and present them to users.

  Such an image processing apparatus has a function of generating an image with a desired appearance by changing the position and orientation of the virtual viewpoint and the position and orientation of the CG object by the user operating the operation input device. Yes.

  In order to generate an image with a user's desired appearance, the user operates the operation input device to change the position and orientation of the CG object and the position and orientation of the virtual viewpoint for observing the CG object. Confirm how the CG object looks in the image. In response to the result, it is common to repeat the operation to change the set value.

  For this reason, at least while the user is performing an operation of changing the position and orientation of the CG object or the virtual viewpoint, the operation content must be immediately reflected in the drawing result of the CG object. If there is a delay in the drawing result of the CG object with respect to the user's operation, the position / orientation cannot be changed as intended by the user, and the work efficiency is greatly reduced.

  Even when drawing a CG object with a high drawing load, several efforts have been made in the past in order to prevent a reduction in drawing speed and maintain responsiveness to operations from the user.

  A technique called LOD (Level-of-Detail) prepares a plurality of CG objects with different levels of detail, and displays these CG objects by switching them as necessary, thereby minimizing a reduction in drawing speed. Is. When LOD is used, it is necessary to prepare a plurality of CG objects having different levels of detail in advance, which causes a problem that the burden on the user is heavy.

  Further, since a CG object with a low degree of detail is generated by reducing the number of vertices and the number of polygons from a CG object with a high degree of detail, there is a problem that the shape of the CG object is impaired. In particular, in the case of interference with other CG objects, there is a possibility that the CG object cannot be accurately operated because the shape is damaged.

  As such a prior art, there is JP-A-1-205277 (Patent Document 1). In Patent Document 1, a method of automatically generating an abbreviated model with a low level of detail from a detailed model with a high level of detail and switching between the detailed model and the abbreviated model according to the size of the displayed CG object. It is shown.

There is also JP-A-5-225354 (Patent Document 2). Patent Document 2 discloses a method of drawing a CG object with a wire frame only when the CG object is rotating. When drawing is performed with a wire frame, shading processing is not necessary, so that a certain degree of speedup can be expected.
JP-A-1-205277 JP-A-5-225354

  However, in the case of the method described in Patent Document 1, the problem that the omitted model has to be created in advance is avoided, but the problem that the shape of the omitted model is lost remains.

  In the case of the method described in Patent Document 2, the degree of speed-up depends greatly on the hardware that performs rendering, the number of polygons of the CG object, the shading model used, the number of light sources in the scene, and the like. Depending on the situation, there is a possibility that sufficient response for the user to operate cannot be obtained. Furthermore, since this method cannot adjust the degree of speeding up, there is a problem in that further measures cannot be taken unless sufficient responsiveness is obtained.

  The present invention has been made in view of the above problems, and is intended to improve responsiveness to an operation from a user without changing the shape of a CG object even when drawing a CG object having a high drawing load. An object is to provide an image processing method and an image processing apparatus capable of adjustment.

  Another object of the present invention is to provide an image processing method and an image processing apparatus that have good responsiveness to user operability without reducing the drawing speed.

In order to achieve the above object, an image processing method according to the present invention comprises the following arrangement. That is,
In an image processing method for generating a two-dimensional image from a three-dimensional CG object, a classification step of classifying polygons constituting the CG object into a first set and a second set, and a drawing step of drawing the polygon The drawing step draws polygons belonging to the first set without drawing polygons belonging to the second set.

  According to another aspect of the present invention, there is provided an image processing apparatus for generating a two-dimensional image from a three-dimensional CG object. The polygons constituting the CG object are divided into a first set and a second set. Classifying means for classifying into a set and drawing means for drawing the polygon are provided, and the drawing means draws the polygon belonging to the first set without drawing the polygon belonging to the second set.

  The present invention can enhance the responsiveness without changing the shape of the CG object even when drawing a CG object with a high drawing load.

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

[First Embodiment]
FIG. 1 is a block diagram showing a hardware configuration in a first embodiment of an image processing apparatus (hereinafter abbreviated as this apparatus) according to the present invention.

  In FIG. 1, the apparatus includes a computer 100, an operation device 200, and a display device 300. The computer 100 further includes a CPU 10, a RAM 20, a disk device 30, an operation input device 40, and an image drawing device 50.

  CPU10 transfers the program code currently hold | maintained at the disk apparatus 30 to RAM20, and performs a process based on the command. The CPU 10 is connected to the system bus 60, and can communicate with the RAM 20, the disk device 30, the operation input device 40, and the image drawing device 50 to control them.

  The RAM 20 is realized by a main storage device such as a memory. The RAM 20 temporarily stores various data such as program code for executing information processing, control information of the program, vertex coordinates of the three-dimensional CG object (hereinafter simply referred to as CG object) and surface configuration information via the system bus 60. Hold.

  The disk device 30 is realized by an auxiliary storage device such as a hard disk. The disk device 30 holds the program code of the program that implements the image processing apparatus of the present embodiment, control information of the program, vertex information of the CG object, surface configuration information, and the like.

  The operation input device 40 is realized by various interface devices. A signal from the operation device 200 connected to the outside of the computer 100 is input as data, and the data is stored in the RAM 20 via the system bus 60.

  The image drawing device 50 is realized by a device such as a graphics card. In the present embodiment, the image output device 50 receives a command from the CPU 10, performs CG drawing processing, generates an image as a drawing result, converts the image into an appropriate image signal, and sends the image to the display device 300.

  The system bus 60 is a communication path through which the devices constituting the computer 100 are connected and the devices communicate with each other.

  The operation device 200 is realized by a device such as a mouse, a keyboard, and various switches, and is used for giving a command to the apparatus when the user operates the operation device 200. When receiving an input from the user, the operation device 200 sends a control signal to the operation input device 40.

  The display device 300 is realized by a display device such as a CRT or a liquid crystal display device. The display device 300 displays the image signal sent from the image drawing device 50 and presents the processing result to the user.

  FIG. 2 is a block diagram showing a schematic functional configuration in the first embodiment of the image processing apparatus according to the present invention.

  2, the object storage unit 500 includes the disk device 30 illustrated in FIG. 1, and holds CG object data that is information regarding the shape of the CG object to be displayed. More specifically, it holds the vertex coordinates of the polygons that make up the CG object and the IDs of the coordinates that make up the surface. Alternatively, an ID indicating the type of free-form surface and the coordinates of control points constituting the free-form surface are held. In the present embodiment, the CG object data is composed only of information relating to the shape of the CG object. However, other parameters necessary for drawing the CG object, such as color, material, and texture, are included in the CG object data. In addition, the object storage unit 500 may hold them.

  The operation input unit 510 inputs an instruction operation performed by the user on the operation device 200 connected to the apparatus to the apparatus, and sends the contents of the instruction operation to the control unit 520. In the case of the present embodiment, the operations performed by the user on the apparatus include activation and termination of the apparatus, reading of CG object data, change of the virtual viewpoint position and orientation, change of the CG object position and orientation, and change of the drawing polygon reduction rate. However, operations other than these may be accepted.

  Upon receiving an input from the operation input unit 510, the control unit 520 issues a predetermined operation command according to the user's operation content, and sends the operation command to the drawing setting unit 530 and the polygon grouping unit 540. Control the operation of each part.

  In the present embodiment, commands issued by the control unit 520 include a CG object data read command, a CG object position / posture setting command, a virtual viewpoint position / posture setting command, a polygon grouping command, a polygon reduction rate setting command, and the like.

  For example, when the operation input unit 510 inputs an operation of changing the virtual viewpoint position / orientation from the user, the control unit 520 issues a virtual viewpoint position / orientation setting command to the drawing setting unit 530 and a polygon to the polygon grouping unit 540. A grouping command is issued and each is sent out.

  The drawing setting unit 530 reads CG object data, sets the position and orientation of the CG object, and sets the position and orientation of the virtual viewpoint for observing the CG object. These operations are determined according to an operation command sent from the control unit 520.

  Regarding the setting of the position and orientation of the CG object and the setting of the position and orientation of the virtual viewpoint, when a corresponding operation command is not input, a value already held by the drawing setting unit 530 or a predetermined default value is set. Used, no value update is performed. In addition, when the CG object held by the object storage unit 500 is composed of a free-form surface, the drawing setting unit 530 divides the free-form surface into polygons by performing tessellation, and apexes constituting the polygons The coordinates and the IDs of the coordinates constituting the surface are generated.

  Based on a command from the control unit 520, the polygon grouping unit 540 classifies and groups the polygons to be drawn and the polygons that are not to be drawn for each polygon constituting the CG object.

  Here, the processing of the polygon grouping unit 540 will be described in more detail.

  For example, it is assumed that the object storage unit 500 holds data relating to polygons constituting the object as shown in FIG. The data in FIG. 3 is composed of a total of 20 polygons, and IDs from 1 to 20 are assigned to each polygon. Although one object will be described, in order to display a plurality of objects in actual display, the following processing is performed for each object.

  Polygon grouping unit 540 receives a polygon grouping command and a polygon reduction rate setting command from control unit 520. The polygon grouping command is a command issued when the user performs an operation for changing the position and orientation of the virtual viewpoint or the CG object on the operation device 200. When a polygon grouping command is input to the polygon grouping unit 540, the following polygon grouping process is performed.

  When a polygon drawing reduction rate setting command is input from the control unit 520, the polygon grouping unit 540 sets a polygon reduction rate r (positive real number) at the same time. When the polygon drawing reduction rate setting command is not input, a value previously used and held by the polygon grouping unit 540 or a predetermined default value is set as the polygon reduction rate r. Will not be updated.

  The polygon grouping unit 540 classifies each polygon into either a drawing target polygon group (hereinafter referred to as P) or a drawing non-target polygon group (hereinafter referred to as Q). At this time, classification is performed so that the ratio of the number of constituent polygons of P and Q is 1-r: r. As the value of r is larger, the number of polygons of Q, that is, the number of polygons that are not drawn increases, and drawing is speeded up. At the time of drawing the CG object, drawing is not performed for the polygon belonging to Q. Therefore, the drawing result is such that a part of the CG object is missing, and the detail is lost in that part. However, unlike the conventional method, since the shape of the CG object itself is unchanged, there is little influence on the user grasping the shape of the CG object.

  For example, when r = 0.5 is designated by the control unit 520, the polygon grouping unit 540 determines that the ratio of the number of polygons belonging to P is 0.5 (ie, the ratio of the number of polygons between P and Q) with respect to all polygons. Is grouped so as to be 1: 1).

  FIG. 4 shows the result of grouping when r = 0.5. In FIG. 4, polygons with an odd ID are classified as P (polygons shown in gray in FIG. 4), and polygons with an even ID are classified as Q. That is, in the example of FIG. 4, only the polygons indicated in gray are drawn by the object drawing unit 550. As a method of classifying each polygon into P and Q, it is possible to classify by other means such as a random number as well as an even number and an odd number.

  FIG. 5 shows the result of grouping when r = 0.2. Similar to the example of FIG. 4, polygons shown in gray are drawn by the object drawing unit 550. In the example of FIG. 5, since the polygon reduction rate is specified as r = 0.2, the ratio of the number of polygons of P and Q is 4: 1. In this case, since more polygons are classified into P than in the example of FIG. 4, the drawing speed is lower than in the example of FIG. 4, but the loss of detail in the CG object is reduced.

  The polygon grouping unit 540 may refer to the classification result in the previous frame when performing grouping. For example, when determining the polygon belonging to P, the polygon grouping unit 540 preferentially assigns the polygon belonging to Q in the previous frame to P. By classifying P and Q in this way, the configuration of the drawing target polygon group changes every frame, so that all polygons are drawn within a certain period of time. The probability that each polygon is drawn becomes uniform, and the loss of details of the CG object can be minimized.

  In this embodiment, classification is performed such that the ratio of the number of polygons of P and Q is 1-r: r, but this ratio is not limited to the number of polygons. For example, classification may be performed so that the ratio of the total area of polygons is 1-r: r between P and Q.

  If no polygon grouping command is input from the control unit 520, all polygons belong to P.

  The object drawing unit 550 draws only the polygons to be drawn (that is, polygons belonging to P) among the polygons grouped by the polygon grouping unit 540.

  In addition to the polygon belonging to P, the object drawing unit 550 may simultaneously draw the outline for the entire CG object.

  In addition, the user inputs the polygon reduction rate r through the operation input unit 510, or a predetermined value is used as the polygon reduction rate r, but depending on the processing speed of the object drawing unit 550, the control unit 520 may automatically determine r. In this case, the control unit 520 holds the value of the target frame rate f. f is a value indicating how many frames per second the object drawing unit 550 can perform, and the value of f may be input by the user through the operation input unit 510 or a predetermined value (for example, * F = 30) may be used. The control unit 520 sets r = 0 as an initial value, and measures the number of frames f ′ that the object drawing unit 550 has actually drawn in one second in a state where r = 0. If f ′ <f, the control unit 520 sets a value r = 0.1 that is newly increased by 0.1 to r. In this way, the control unit 520 increases r so that f ′> f (up to 0.9). In this way, it is possible to automatically adjust the polygon reduction rate r based on the frame rate, which is a value that is more easily understood by the user.

  The control of the present embodiment having the above configuration will be described below. FIG. 6 is a flowchart of processing performed by the information processing apparatus of this embodiment. The program code according to the flowchart is stored in a storage device such as the disk device 30 or the RAM 20 in the device of the present embodiment, and is read out and executed by the CPU 10.

  First, when the image processing apparatus of the present embodiment is activated, the CPU 10 reads out the data of the CG object stored in the disk device 30 constituting the object storage unit 500 and holds it in the RAM 20 in step S1010. The

  Next, in step S1020, the operation input unit 510 inputs an operation performed by the user on the operation device 200 to the apparatus. The operation information input by the operation input unit 510 is sent to the control unit 520. In the control unit 520, an appropriate command is issued according to the user's operation content, and is sent to the drawing setting unit 530 and the polygon grouping unit 540.

  In step S1030, the drawing setting unit 530 sets the position and orientation of the CG object and the position and orientation of the virtual viewpoint for observing the CG object.

  In step S1040, the polygon grouping unit 540 performs polygon grouping processing.

  In step S1050, the object drawing unit 550 performs a polygon drawing process of the CG object.

  In step S1060, if an operation corresponding to termination of the apparatus is input from the user in step S1020, the process of the apparatus is terminated. Otherwise, the process returns to step S1020.

  In this embodiment, a series of processing from step S1020 to step S1060 is performed in a short time, and the time required to complete these processing once is usually about several milliseconds to several hundred milliseconds. Is within.

  In the present invention, a storage medium recording software program codes for realizing the functions of the above-described embodiments is supplied to a system or apparatus, and the computer (or CPU or MPU) of the system or apparatus stores the storage medium in the storage medium. Needless to say, this can also be achieved by reading and executing the programmed program code.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.

  Examples of the storage medium for supplying the program code include a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, CD-R, DVD-ROM, DVD-R, magnetic tape, nonvolatile memory card, A ROM or the like can be used.

  Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) operating on the computer based on the instruction of the program code. It goes without saying that a case where the function of the above-described embodiment is realized by performing part or all of the actual processing and the processing is included.

  Further, after the program code read from the storage medium is written into a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

  As described above, according to the embodiment of the present invention, even when drawing a CG object having a high drawing load, it is possible to improve the responsiveness to the operation from the user without changing the shape of the CG object. It becomes.

  Moreover, according to the embodiment of the present invention, it is not necessary to have separate objects in order to improve responsiveness.

  Furthermore, according to the embodiment of the present invention, since the reduction rate of the CG object is changed according to the frame rate, an appropriate reduction rate can be set according to the complexity of the CG object and the capability of the apparatus.

It is a block diagram which shows the hardware constitutions in 1st Embodiment of the image processing apparatus by this invention. 1 is a block diagram showing a schematic configuration in a first embodiment of an image processing apparatus according to the present invention. It is a figure which shows the example of the polygon data in 1st Embodiment of the image processing apparatus by this invention. In the first embodiment of the image processing apparatus according to the present invention, it is a diagram showing an example of a drawing result when r = 0.5. In the first embodiment of the image processing apparatus according to the present invention, it is a diagram showing an example of a drawing result when r = 0.2. It is a flowchart which shows the process sequence in 1st Embodiment of the image processing apparatus by this invention.

Explanation of symbols

500 Object Storage Unit 510 Operation Input Unit 520 Control Unit 530 Drawing Setting Unit 540 Polygon Grouping Unit 550 Object Drawing Unit

Claims (10)

In an image processing method for generating a two-dimensional image from a three-dimensional CG object,
A classification step of classifying the polygons constituting the CG object into a first set and a second set;
A drawing step of drawing a polygon constituting the CG object,
The image processing method characterized in that the drawing step draws the first polygon without drawing the polygon of the second set. A position and orientation setting step of setting the position and orientation of the CG object and the position and orientation of the virtual viewpoint;
The classifying step classifies the polygons constituting the CG object into the first set when neither the position / posture of the CG object or the position / posture of the virtual viewpoint is changed by the position / posture setting step. The image processing method according to claim 1, wherein: A classification parameter setting step for inputting classification parameters;
The image processing method according to claim 1, wherein the classification step classifies the polygons based on the classification parameters.   4. The classification step according to claim 3, wherein the number of polygons belonging to the first set and the number of polygons belonging to the second set are classified so that the ratio is determined by the classification parameter. The image processing method as described.   The classifying step classifies the total area of polygons belonging to the first set and the total area of polygons belonging to the second set so as to be a ratio determined by the classification parameter. The image processing method according to claim 3.   6. The image processing method according to claim 1, wherein the drawing step draws a contour line of a CG object.   7. The classification step according to claim 1, wherein a part or all of polygons belonging to the second set in a past frame are classified so as to belong to the first set. Image processing method. In an image processing apparatus that generates a two-dimensional image from a three-dimensional CG object,
Classification means for classifying the polygons constituting the CG object into a first set and a second set;
Drawing means for drawing the polygon,
The image processing apparatus, wherein the drawing means draws polygons belonging to the first set without drawing the polygons of the second set.   A program for causing a computer to implement the image processing method according to claim 1.   A storage medium storing a program for causing a computer to implement the image processing method according to claim 1.

Images