JPH07287774A - Printer - Google Patents

Abstract

PURPOSE:To print out three-dimensional(3D) data by a format appropriate for a recorder by applying 30 geometric transformation to 3D data in accordance with prescribed information, projecting the geometrically transformed 3D data into a two-dimensional(2D) plan, applying interpolation to the projected data, and visually outputting the interpolated data while considering of the color characteristic of the recorder. CONSTITUTION:Three-dimensional(3D) data sent from a computer 1 are stored in an input buffer 2 in a printer 20 and then various geometric data or geometric attribute data are transformed into an internal data format matched with the recorder 9 by an analytical program stored in a command analyzing part 3. A coordinate transforming program 4 executes viewing processing for projecting 3D data to 2D coordinate space, hidden line/hidden face erasing, etc. Then a raster rising part 5 calculates the color density of vertexes of the projected 3D data in accordance with the colors, light source information, etc., of the vertexes, executes color interpolation in accordance with the color characteristic of the printer 20 and writes only a visual part in a page buffer 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus, and more particularly to C
The present invention relates to a printing apparatus for printing three-dimensional information data used in multimedia processing such as AD and CG, and design and color DTP.

[0002]

2. Description of the Related Art In recent years, with the advent of high-performance three-dimensional graphics workstations, it has become possible to easily handle full-color three-dimensional graphics data. As a result, three-dimensional data presentations have been widely used.

In this type of workstation, in order to execute the presentation on the screen using the created graphics data, a plurality of time series images are stored as animation data and presented, or almost all of them are presented. It can be realized by rendering (rendering) in real time.

[0004]

However, in the above-mentioned conventional workstation, in order to print each displayed scene image and make it look like a real thing, at present, the display resolution (about 100 dpi) and the printer Due to the gap between resolutions (400 dpi) and the gap between dynamic and static presentation images,
The following problems occur.

That is, since the screen copy of the rendering result of the image rendered at the screen resolution is output to the printer, the high resolution of the printer is sacrificed, and calculations such as color interpolation are executed in the display space. After that, since it is performed in the printer space, proper color reproduction is not performed. Further, even if high-performance processing such as anti-aliasing is performed on the display, if the image data is sent to the recording device, the image will be blurred this time.

The present invention has been made in view of the above problems, and an object thereof is to provide a printing apparatus capable of printing out three-dimensional data in a form suitable for a recording apparatus.

[0007]

In order to achieve the above-mentioned object, the invention according to claim 1 is a printing apparatus which processes input data and outputs the data visually from a recording apparatus. Means for inputting data, means for performing three-dimensional geometric conversion on the three-dimensional data according to predetermined information, means for projecting the three-dimensional data after the geometric conversion onto a two-dimensional plane, and data after the projection And means for visually outputting the interpolated data in consideration of the color characteristics of the recording device.

With the above arrangement, three-dimensional data can be recorded in a form suitable for the recording device. In the invention according to claim 2, the three-dimensional data includes three-dimensional shape data and three-dimensional attribute data. As a result, the three-dimensional shape data and the three-dimensional attribute data can be expressed in characters instead of binary.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a block diagram showing the basic configuration of a three-dimensional data printing apparatus according to an embodiment of the present invention. In the figure, reference numeral 1 is a workstation WS (computer) that generates three-dimensional data and sends the data to be recorded to the recording device 9.

Here, the predetermined control data flows to the printing device 20 located between the computer 1 and the recording device 9, and the communication form is, for example, a serial form, a network form,
Alternatively, there is no problem in any form such as a bus form, but the description form is a general ASCII representation form. As a result, the above-mentioned data does not have a problem even in a communication path in which 8-bit data cannot be transmitted. However, in terms of the performance of the device, it is desirable that the communication path is a high speed communication path.

The three-dimensional data sent from the computer 1 as described above is stored in the input buffer 2 in the printing apparatus 20, and then various geometric data and geometric attributes are calculated by the analysis program in the command analysis unit 3. The data is converted into an internal data format compatible with the recording device 9. Then, the data is transferred to the control by the coordinate conversion program in the coordinate conversion unit 4 in the next stage.

The coordinate conversion program 4 executes a viewing process for projecting three-dimensional data into a two-dimensional coordinate space,
A process for comparing and examining the Z coordinate when projecting the three-dimensional data in the two-dimensional coordinate space with the Z buffer 6 and hidden line hidden surface removal are performed. Here, the Z buffer 6 stores, for each pixel, a Z value (depth) of 16 to 32 bits instead of the grayscale value in the page memory, similarly to a normal page memory. When the depth of the number of bits is increased, the accuracy of hidden line hidden surface removal is improved, but the memory size is increased and the cost of the device is increased.

Next, the rasterizing unit 5 calculates the color density at the vertices according to the color of the vertices of the projected three-dimensional data, the light source information, and the surface attribute, and performs color interpolation within the polygon according to the color characteristics of the printer. Then, only the visible portion in the above Z buffer processing is written in the page buffer 7. Here, the page buffer 7 is composed of four primary colors of CMYK (cyan, magenta, yellow, black) in the subtractive color printer, and has a certain fixed color depth (1 to 8 bits) for each pixel to be printed. It has become a page memory. This color depth depends on the color reproduction capability of the color recording device 9.

When the rasterizing unit 5 finishes drawing the one-page three-dimensional data sent from the computer 1 in the page buffer 7, the data from the page buffer 7 is stored in the hardware of the printer interface 8 and the inside thereof. The interface program sends a video signal according to the horizontal and vertical synchronizing signals from the recording device 9 (the recording device 9 is a color laser beam printer (LB)).
In case of P)).

Alternatively, for every certain scan line, the image data corresponding to the head width of the printer is converted into BitB
After lt, the result is recorded (when the recording device 9 is a color bubble jet printer). Note that BitBlt means a process of performing a logical operation on each bit of bitmap data and writing a character or an image in the frame buffer. Also,
As described above, the recording device 9 is a color recording device that prints three-dimensional data, and may be of any type such as LBP, heat sensitive, inkjet, or the like.

Reference numeral 10 stores a geometrical shape related to a three-dimensional character in order to display the three-dimensional character.
It is a D character font data storage unit. Reference numeral 11 is a management RAM that provides a memory for various programs to use in executing control, and 12 executes various control programs and controls the entire system including printing timing and the like. Central control unit (CPU) for
Is.

Hereinafter, each component of the printing apparatus according to this embodiment will be described in detail. [Explanation of Data Format of Three-Dimensional Data] One implementation example of the data format of various data sent from the computer 1 as a host to the printing apparatus 20 will be shown. The data here is the three-dimensional graphics standard PHIGS (Programmer's Hierarc) which is being discussed by the International Organization for Standardization (ISO).
hical Interactive Graphics System) and CGM (Computer Graphic) that regulates the exchange of graphics information.
s Metafile) takes a format similar to that specified.

A metafile (met that stores three-dimensional data
afile) starts with a begin metafile and ends with an end metafile, as shown in FIG. After this begin metafile, set the default background color set_background_c
Specify in olor. Then, the begin picture command declares that the actual drawing data and drawing attribute designation starts.

The actual three-dimensional drawing data and drawing attributes are as follows. The setlight instruction specifies various light source lighting conditions for rendering. As lighting, for example, ambient light such as sunlight that irradiates in all directions evenly, or parallel light directio that irradiates from a certain direction
Specify the type of nal. Then, use the registered color (white, red, etc.) as the light source color, or use RGB
Specify three default values as the immediate value of.

In the rotate command, drawing coordinates (MC)
Each of the axes is rotated about the designated axis by the designated rotation angle, and is mapped to the world coordinate system (WC). The polygon command indicates the geometric shape of the three-dimensional data to be drawn. After indicating the number of vertices, (X,
Three-dimensional coordinate data for the number of vertices (Y, Z) follows. Furthermore, view all_data is specified as an instruction to record three-dimensional data according to the specified geometric data and geometric attributes. And finally, when terminating this metafile,
Issue the corresponding end command to match the level with the various start commands. [Description of Coordinate Conversion Processing] The concept of coordinate conversion in this embodiment will be described with reference to FIGS.

FIG. 3 is a flow chart showing the concept of coordinate conversion of three-dimensional data in this embodiment. In step S301 of the figure, the user of the printing apparatus defines a three-dimensional object in each modeling coordinate system (MC). Each of these objects is defined by a completely unique coordinate system, but in order to collect these objects and construct one scene, the modeling transformation is transformed into the world coordinate system (WC) (step S302).

The conversion here is basically expressed by combining three kinds of conversions. These are rotation (R), scaling (S), translation (T), and their matrix representations are as follows:

[0023]

[Equation 1]

Projection conversion is realized in steps S303 and S304, which are processes for projecting a three-dimensional object defined by three-dimensional world coordinates onto a two-dimensional plane. Specifically, in step S303, coordinate transformation (Vi that determines a new projection coordinate system for performing projection transformation) is performed.
ew Orientation conversion) is executed. Basically, there are two types of three-dimensional projection transformation, parallel projection and perspective projection.
In the present embodiment, for simplification of description, parallel projection will be described below taking a camera model as an example.

FIG. 4 is a diagram showing the principle of three-dimensional projection for parallel projection. In the figure, first, a viewpoint (PRP) position (eye point) 401 for projection is determined. Projection center (VRP) position (center of film surface)
402, and the direction vector U (41
0) and V (409) (tilt of film surface) are also designated.
As a result, the projection plane (VP) 404 is uniquely determined. These designations may be performed by trial and error on the window system of the computer 1 shown in FIG. 1, and the determined camera parameters may be sent to the recording device at the time of printing.

In step 304, an effective area in the three-dimensional space is determined (view mapping conversion). VP (40
4) centered on the front (FP) 403 and back (BP)
By designating 405 by the distance from the VP, the view-volume of the three-dimensional space of interest is determined. As a result, only the objects in the space area surrounded by the broken line in FIG. 4 are displayed and mapped in the normalized space (NPC),
Both (X, Y, Z) are defined in the 0-1 space, and other areas are clipped.

Incidentally, these steps S303 and S304
The mathematical expression expressing the coordinate transformation in (1) is detailed on page 296 of "Computer Graphics" (JD Foley, A VANDAM, translated by Atsumi Imamiya). Here is a brief description of it. That is, these transformations are expressed as one matrix M. M = T * Ry ([theta]) * Rx ([phi]) * Rz ([alpha]) * SHz (a1, b1) * Tpar * Spar (4) Here, each of the above-described expressions (4) is expressed. The coordinate conversion will be briefly described.

1. The VRP (402) is moved in parallel with the origin (corresponding to T in equation (4)). 2. Rotate the normal line N (408) of the VP (404) to the negative Z-axis (Y-axis direction, Ry (θ) · Rx in equation (4)).
(equivalent to (φ)). 3. VUP, that is, the projection of V (409) rotates so as to be on the Y axis (X axis direction, corresponding to Rz (α) in Expression (4)).

4. All planes of the view volume
Distort so that it is orthogonal to the viewing coordinate axis (Equation (4)
Corresponding to SHz (a1, b1)). 5. The view volume is returned to the unit cube by the parallel movement and the scale (corresponding to Tpar × Spar in Expression (4)). In step S305, the coordinate conversion to the physical device, that is, the mapping from the normalized space (NPC) to the recording device to the device coordinate is designated. As a result, the corresponding address of the page buffer 7 of the recording device will be accessed. [Explanation of Rasterization Unit] By the above coordinate conversion, the coordinates of the coordinate values of each vertex of the three-dimensional object mapped on the projection plane VP (404) are calculated. In this rasterization process, polygons are formed. The density value of each internal pixel is calculated by interpolation, and the drawing process is executed. Hereinafter, the rasterization process will be described in detail with reference to the flowchart shown in FIG.

In step S501 of FIG. 5, the reflection color of each vertex forming a polygon is formulated and calculated using the following algorithm (light source reflection calculation model) according to the characteristics of the light source and the surface characteristics of the object. . Here, the density value depends on the type of light source for each color component (RGB),
The equations (5), (6), and (7) are applied, and each component is added by the equation (8). When the calculation result exceeds 1, it is considered to be saturated, and the value is set to 1.

[0031]

[Equation 2]

[0032]

[Equation 3]

FIG. 6 is a diagram showing a relationship between a three-dimensional object arrangement and a light source as an environment of light reflection calculation. This calculation is
Should be implemented in the WC coordinate system. The reason is that if the perspective projection model is applied in the subsequent Viewing transformation or the like, accurate calculation of the light reflection calculation cannot be performed. In the figure, the unit vector Vl from the object to the light source
(704) and the unit reflection vector Vr from the object
(706) is the normal vector Vn from the object
It has a symmetric relationship with (705).

In step S502, the above step S5
In accordance with the vertex reflection color calculated in 01, processing for interpolating the density value inside the polygon and color shading are performed. In this embodiment, an application example of glow shading is shown. In the glow shading, if the grayscale value by light source calculation of each vertex of the polygon is known, the grayscale value at an arbitrary point inside the polygon is obtained by linear interpolation. This algorithm will be described with reference to FIG.

In FIG. 7, assuming that the density values at the vertices ABC of the triangle are IA (801), IB (802), IC (803), IQ (804)
The density value at is linearly interpolated as follows. IQ = uIA + (1-u) IB (9) where 0 ≦ u ≦ 1 and u = AQ / AB. Similarly, the density value IR (805) at the point R between ACs is also linearly interpolated as follows.

IR = vIA + (1-v) IC (10) Here, 0 ≦ v ≦ 1 and v = AR / AC. Finally, in the same way, the density value between Q and R is interpolated, and the density value at point P
IP (806) is calculated according to equation (11). Ip = wIQ + (1-w) IR (11) where 0 ≦ w ≦ 1 and w = QP / QR.

The above linear interpolation of colors is applied to each of the (R, G, B) color spaces. However,
Since the above method is a simple linear interpolation of the density, the density value at the same point P is not always constant due to the rotation. Therefore, ideally, an interpolation algorithm based on area distribution as described below is required.

[0038]

[Equation 4]

In step S503, the color density calculated according to the performance of the color recording apparatus is mapped to the color in the device space. Here, if the mapping is simply performed linearly, pseudo contours and moire may occur. Therefore, color conversion is performed to preserve the density. However, if the color depth of the recording device is 8 bits or more and sufficient color resolution is possible, the density conversion processing is not necessary.

The error diffusion method is used as an example of density preservation. This is performed by inputting R, G, B color information for each scan line and executing the following algorithm as shown in FIG. It outputs R, G, B color information according to the color depth of the recording device. 1. An optimum digital output density value is calculated using the current input density value 901 of the target pixel (this has been calculated in the processing up to step S502) and the accumulated error density E. For example, in a color recording device having an 8-bit depth frame buffer, mapping to discrete values of R, G, and B colors 0 to 5 is performed.

2. Error between input density value and output density value (E)
To calculate. 3. As shown in FIG. 8, regarding this error E, 7/16, 3/1
The error components of 6,5 / 16 and 1/16 are added to each neighboring pixel. In step S504, conversion processing from the RGB color space for display to the YMCK color space for printer is performed. Although this color conversion algorithm is known, a rough block processing example will be described here with reference to the flowchart shown in FIG.

That is, in step S1001 of FIG. 9, the LOG conversion is performed to convert the CM from the RGB color space to the CM.
Convert to Y color space. Here, if the obtained CMY color is used as it is, a grayish color is obtained, so the minimum value of the YMC density values is K (black).
Then, the k value is subtracted from each density of CMY (black generation in step S1002).

In step S1003, since the RGB values do not have an ideal frequency separation characteristic, a process for applying a matrix for changing each value of CMYK, that is, a masking process is executed. After the black processing in step S1004, step S1005
Then, a gamma process for correcting the information changed in step S1004 is performed. Finally, this gamma correction is performed, and the YMCK value is stored as the recording density in the page buffer 7 which is the frame buffer.

As the final processing of the three-dimensional rasterizing, in step S505, hidden line hidden surface removal is performed so that hidden objects are not displayed when viewed from a certain viewpoint, and color density information is written in the page buffer 7. .
This algorithm is shown below in the form of pseudo coding. 1101. Each pixel of the page buffer 7 (Y, M, C, K) is set to the background color.

1102. Set all Z buffers 6 of the recorder to the minimum Z value. 1103. Scan convert individual polygons (coordinate conversion). 1104. Dept corresponding to pixel (x, y) in a polygon
Calculate hz (x, y). (Steps S301 to S30 of FIG. 3
4) 1105. The depth value of z (x, y) and the Z buffer (x, y) 6 stored in the z buffer are compared.

1106. if z (x, y)> z buffer (x, y) 6 Write the gray value of the polygon in the page buffer 7 (see FIG. 5).
Step S504), the Z buffer (x, y) 6 is set to z.
Replace with (x, y). It should be noted that the above steps S1103 to S1106 all perform calculations for polygons. Since this algorithm is simple, it can be speeded up by hardware. [Description of Recording Device] FIG. 10 shows a color inkjet printer device (IJ) to which the printing device according to the present embodiment can be applied.
It is a general view of RA). The appearance of the color recording device 9 shown in FIG. 1 is the same as that shown in FIG.

In FIG. 10, the spiral groove 50 of the lead screw 5005 that rotates via the driving force transmission gears 5011 and 5009 in association with the forward and reverse rotations of the drive motor 5013.
The carriage HC engaging with 04 has a pin (not shown) and is reciprocated in the directions of arrows a and b in the figure. An inkjet cartridge IJC is mounted on the carriage HC.

The paper pressing plate 5002 presses the paper P against the platen 5000 along the moving direction of the carriage HC. The photocouplers 5007 and 5008 are the carriage H.
This is a home position detecting means for confirming the existence of the lever 50006 of C in this area and switching the rotation direction of the motor 5013. Reference numeral 5016 is a member that indicates a cap member 5022 that caps the front surface of the recording head, and reference numeral 5015 is a means for sucking the inside of the cap, which performs suction recovery of the recording head through the opening 5023 in the cap. Also, the cleaning blade 5017
Can be moved in the front-back direction by the member 5019. These are supported by the main body support plate 5018.

Needless to say, a well-known cleaning blade can be applied to the blade instead of the illustrated form. Reference numeral 5012 is a lever for starting suction for suction recovery, and a cam 502 that engages with the carriage HC.
The drive force from the drive motor 5013 is controlled by a known clutch switching transmission means. The capping, cleaning, and suction recovery are configured such that when the carriage HC comes to the area on the home position side, desired processing can be performed at the corresponding positions by the action of the lead screw 5005. However, these may be activated at timings other than the above.

As described above, according to this embodiment,
By converting 3D data such as geometric data and geometric attribute data into an internal data format that is compatible with the recording device, and then performing coordinate conversion, the rendering of the 3D data is adapted to the color space and characteristics of the recording device. It can be carried out in the form and the capacity of the recording device can be maximized. <Modification> A modification of the above embodiment will be described.

When character information is used as three-dimensional information,
It can also be used as a three-dimensional DTP presentation material creation tool. To define a three-dimensional character font, two pieces of information are defined as actual character patterns. That is, considering the thickness of characters (a)
It is contour outline information and (b) filling data inside the character. And when displaying characters three-dimensionally,
The above (a) is the peripheral three-dimensional portion (side surface) having the thickness of the three-dimensional character, and (b) is the front three-dimensional portion.

When the outline of a character is taken into consideration, such as the letters "C" and "n" of the alphabet, the outline outline information and the fill data are common for the character that can be drawn with one stroke. However, data that cannot be drawn with one stroke, such as "o" and "a", have different data. this,
An explanation will be given using the character pattern of "a".

FIG. 11 shows the control points of the outline of the three-dimensional font, which are divided into two loops, the outer circumference (solid line) and the inner circumference (dotted line). On the other hand, FIG. 12 shows the filling information, which is divided into three loop components: a right half loop (diagonal hatching portion), a left half upper loop (vertical hatching portion), and a lower loop (horizontal hatching portion). .

As described above, the character data can basically be composed of a straight line and a curve passing through the control points. That is, although internally having such a data structure, it becomes possible for the user to rotate the character "a" by 30 degrees around the x-axis and render it with ambient light. The present invention may be applied to a system including a plurality of devices or an apparatus including a single device. Further, it goes without saying that the present invention can be applied to the case where it is achieved by supplying a program to a system or an apparatus.

[0055]

As described above, according to the first aspect of the invention, the rendering of the three-dimensional data is performed by the color of the recording device without increasing the load on the host computer which is the output source of the three-dimensional data. It can be executed in a form suitable for space and various characteristics. According to the second aspect of the invention, the three-dimensional shape data and the three-dimensional attribute data can be expressed in characters instead of binary.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a three-dimensional data printing apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of a command for recording three-dimensional data according to an embodiment.

FIG. 3 is a flowchart showing the concept of coordinate conversion of three-dimensional data.

FIG. 4 is a diagram showing the principle of three-dimensional projection.

FIG. 5 is a flowchart showing rasterizing of three-dimensional data according to an embodiment.

FIG. 6 is a diagram showing a relationship between a three-dimensional object arrangement and a light source as an environment for light reflection calculation.

FIG. 7 is a diagram showing an algorithm of color shading.

FIG. 8 is a diagram showing an error diffusion method.

FIG. 9 is a flowchart showing a color conversion process according to the embodiment.

FIG. 10 is a schematic view of a color recording apparatus according to an embodiment.

FIG. 11 is a diagram showing a method of creating a three-dimensional font according to an embodiment.

FIG. 12 is a diagram showing a method of creating a three-dimensional font according to an embodiment.

[Explanation of symbols]

 1 computer 2 input buffer 3 command analysis unit 4 three-dimensional coordinate conversion unit 5 three-dimensional rasterization unit 6 Z buffer 7 page buffer 8 printer interface 9 recording device 10 3D character font data storage unit 11 management RAM 12 CPU

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location H04N 9/79 H04N 5/91 H 9/79 H

Claims (5)

[Claims] 1. A printing apparatus for processing input data and visually outputting it from a recording apparatus, comprising: means for inputting predetermined three-dimensional data; and three-dimensional geometry for the three-dimensional data according to predetermined information. A means for performing transformation, a means for projecting the three-dimensional data after the geometric transformation onto a two-dimensional plane, a means for interpolating the data after the projection, and a color characteristic of the recording device in consideration. A printing device for visually outputting the interpolated data. 2. The printing apparatus according to claim 1, wherein the three-dimensional data includes three-dimensional shape data and three-dimensional attribute data. 3. The printing apparatus according to claim 1, wherein the interpolation interpolation is color shading, and vertex color sky blue interpolation is performed. 4. The printing apparatus according to claim 1, further comprising means for controlling whether the interpolation is performed in an RGB additive color space or a subtractive color space. 5. The printing apparatus according to claim 1, wherein a character font can be used as the three-dimensional data.