JPS61255392A - Color image display unit - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a color image display device used in raster scan type computer graphics and the like.

(Prior Art) FIG. 7 is a block diagram showing a conventional color image display device. After the color data from the host computer 1 is received by the receiving mechanism 3 of the color image display device 'a2,
It is stored in the frame memory section 4. The color data read out from the frame memory 4 in synchronization with the video clock signal is applied to the D/A* converter 5 to generate a video signal, which is applied to the display device f7 via the video modulation circuit 6. .

FIG. 8 is a more detailed block diagram around the frame memory. The frame memory section 4 is R (red), G (green),
Three frame memories F1.B (blue) correspond to F1. F2
．． It is composed of F3. In this case, the color data sent from the host computer is divided into three parts, R, G, and B, and provided separately.

(Problems to be Solved by the Invention) When coloring a monochrome image or changing the color of a color image using such a device, calculations for each color of R, G, and B must be performed in the host computer 1. Since this is necessary, the amount of 81i calculation becomes large, and the amount of data to be transferred from the host computer 1 to the color image display bag H2 is also large, resulting in a long data transfer time.

In addition, in the color image display device 2, a frame memory is required for each of R, G, and B, so the memory capacity becomes large. , a memory of 3 Mbytes is required.

The present invention has been made to solve these problems, and provides a color image display device that requires only a small amount of calculations in a host computer, can color or change colors in a short time, and has a small memory capacity. The aim is to realize this.

(Means for Solving the Problems) A color image display device according to the present invention includes a frame memory for inputting a luminance image, a broken line generation circuit for inputting setting parameters and generating a broken line function, and this broken line generation circuit. The present invention is characterized in that it includes a look-up table whose contents are written by the output and outputs color data corresponding to the address specified by the output of the frame memory.

(Function) According to the color image display device having the above configuration, the color of the object light is added to the color of the ambient light below the boundary brightness due to the broken line characteristic of the broken line generation circuit in response to the brightness image data from the frame memory. , above the boundary brightness, by adding the color of the light source, it is possible to generate a naturally colored color image in the w degree image.

(Example) The present invention will be explained in detail below using the drawings.

FIG. 1 shows an example of a color image display device according to the present invention.
FIG. 2 is a configuration block diagram showing an example of Ii. Figures 7 and 8
The same parts as those in the figures are given the same symbols and the explanation will be omitted.

11 is a host computer that generates luminance images (solid models in computer graphics, black and white photographic images, etc.); 12 generates video modulation output of color images based on the image data output of this host computer 11; This is a color image display device. In the color image display device 12, 13 is a receiving mechanism to which the luminance image output from the host computer 11 is sent via the communication line 10; 14 is a frame memory for storing the luminance image data via this receiving mechanism 13; Reference numeral 8 denotes a polygonal line function generation circuit which inputs look-up table setting parameters sent from the host computer 11 via the reception mechanism 13, and LtJ1 to LU3 represent color data set by the output of the polygonal line function generation circuit 8. This is a look up table (hereinafter referred to as LUT) which is addressed by the luminance image output of the frame memory 14 and outputs to the D/A converter.

FIG. 2 is a block diagram showing the detailed configuration of the polygonal function generating circuit 8. As shown in FIG. R1, R3, and R5 are registers in which color parameters ΔRs + ΔGs and ΔaS of the object are set;
R2, R4, R6 are color parameters of the light source ΔRm +Δ
G Tn rΔBm is set in the register, R7 is the register in which the boundary 111 degrees Ip (described later) between the object light and the light source light is set, and R8-R10 are the color parameters S of the ambient light.
A register in which R, So, and Ss are set, A1. A2.
A3 is the register R1, R3, R5 or R2, R4
, R6 as one input, and the registers R8 and R9
81 is an adder whose other input is the output of R10 and whose output is input to the registers R8, R9, and R10. A2. LUT color data output from A3
a counter 82 that generates an address to set to
is the address output of this counter 81 and the register R7
The boundary brightness 1p output from the register R is compared with the boundary brightness 1p output from the register R.
This is a comparator that switches between 1, R3°R5 and R2, R4, Re.

The operation of the color image display device having such a configuration will be explained in detail. First, the host computer 11 sends the LUT setting parameters ΔRs + ΔGs + ΔB5 · ΔRm,
60m, ΔBm, I p , SR, SO.

Ss is sent to the polygonal line function generation circuit 8 via the receiving mechanism 13 of the color image display device [12]. Register R8, R9,
Ambient light color parameters SR, So set in RIO
, Ss are adders A1. This is the initial value of the A2゜A3 output, and in the range where the output of the counter 81 is smaller than the boundary brightness Ip, the registers R1, R3, and R5 are selected by the output of the comparator 82, and the color parameters ΔRs and ΔG5 of the object are selected in synchronization with the counter output. ．． ΔBs is added by adder A1. A.2. A3
is added to one input of When the output of the counter 81 increases and becomes larger than the boundary brightness rp, the registers R2, R4, and R6 are selected by the output of the comparator 82, and the color parameters ΔRm and ΔGT11 of the light source are synchronized with the counter output.
．． ΔBT11 is the adder A1. It is added to one input of A2 and A3. Adder Al.

A2. The output of A3 is sequentially applied to registers R8, R9, R10 and becomes the next summation input at the other input of the paralyzer. The LUT data OR, Do outputted from the polygonal function generating circuit 8 in this manner.

According to Da, the polygonal line functions shown in FIGS.
．． LLJ2. Written to LU3. In the figure, the brightness III on the horizontal axis corresponds to the address input of LLJT, and the boundary brightness r
p is a turning point.

The luminance image generated by host computer 11 is then sent to frame memory 14 via communication line 10 and receiving mechanism 13. Look up table L addressed by luminance output from frame memory 14
U1. LU2. The color data of LU3 is output to the D/Δ converter 5.

RGB signals are output from the D/A converter 5 and displayed on a color CRT via a video amplifier 6.

The basic principle of the broken line function written to the LUT will be explained next. The most famous model of light reflection from objects in the natural world is the phonQ reflection model expressed by equation (1).

1-C5-CO3θs+cm(cosθm)r110s・Ss...(1) However, H-(Rr, Gr, 8z): Reflection color vector C5=(R
s, Gs, Sg): Color vector of object Cm= (Rm,
Gm, Bm): Color vector of light source Sg: Ambient light intensity θg: Diffuse reflection angle θm: One-plane reflection angle Nm: Specular reflection index In the model of the above equation, reflected light is composed of diffuse reflection, specular reflection, and ambient light. ing. Figure 4 shows the change in brightness with respect to the position of an object that is hit by light, and when compared with phong's reflection model, the diffuse reflection C
5 expresses the color of the object, and its intensity ICgl is distributed gently over the entire surface that is illuminated by the light (A), specular reflection Cr
n is the color of the light source and its intensity ICm1 is locally distributed (B), so the total reflected light III
III is 111=ICsl+l εml'' (2), and its distribution is such that the specular reflection component is added to the diffuse reflection component (C). Also, under natural lighting, the peaks of diffuse reflection and specular reflection are Therefore, as shown in (C), an appropriate boundary brightness 1p is set from the brightness data of the black and white image, and the color of the object is expressed at n1 degrees lower than p, and the light source is expressed at a brightness higher than Ip. By expressing the color of the object, it is possible to realize the color of the object that is close to natural.

Figure 5 shows the color vector I of the reflected light from the object as the color vector (R
GB) is shown in space. 1mln is component SR
, SO, Sa indicate an ambient light color vector whose luminance (length from the origin of the color vector in RGB space) is Imtn.

Corresponding to the increase in the brightness of the black and white image, the color vector [mLn of this ambient light has the same component ratio (RG
A minute color vector (ΔR5, ΔG g +68g>) whose vector direction is the same in B space is added, and when the brightness reaches the boundary brightness 1p, a minute color vector with the same component ratio as the color vector Cm of the light source is added. (ΔRm, ΔGm,
ΔBm> is added. [maX is the maximum brightness Im
This is the color vector of the reflected light from the object when it reaches ax. The color vector 1 of the reflected light from the object is [from mzn to ip, the color expression of the displayed object is gradually strengthened to express diffuse reflection, and ip
From [max], the color expression of the light source illuminating the display object is gradually strengthened to express specular reflection. The relationship between the color vector of the reflected light of the object and the luminance in Figure 5 is expressed for each RGB component by the broken line function in Figure 3, and rmt
The luminance values up to Im@X are set in the LUT by dividing them by the number of elements in the LUT. In this broken line function, the smoothness of the displayed object is expressed as the ratio of the size of Cs and CT11. That is, as shown in FIG. 3, the more the Ip is set to '151w degrees, the rougher the surface of the display object, such as paper,
The quality is closer to that of a brick surface, and the lower the brightness is set, the more
Clean surfaces, e.g. plastic.

The quality is close to that of metal.

According to the device having such a configuration, since it has a built-in broken line function generator, it is possible to convert a luminance signal of a monochrome image into a color signal having natural colors and textures.

Further, since only one frame memory is required for the luminance image, the memory capacity can be small.

For example, in the case of a 1024x1024 pixel display, 2M bytes of memory can be saved significantly compared to conventional devices (FIGS. 7 and 8). Furthermore, the ability to realistically represent displayed objects is as good as conventional ones.

Furthermore, since calculations for each RGB color are not required and only brightness calculations are required, the amount of calculation in the host computer is reduced when coloring or changing colors. Furthermore, since the data sent through the communication line is only the luminance data and LLJT setting parameters, the transfer time is reduced to about 1/3 compared to the conventional device.

Furthermore, by selecting the value of the boundary brightness 1p, the texture of the object can be changed freely.

FIG. 6 is a block diagram showing a second embodiment of the present invention. In addition to increasing the number of pits in the frame memory and storing luminance data in the frame memory 142,
By storing the object number in the object number memory 141, it is possible to display a plurality of objects having different colors and textures at the same time. In this case, the LUT 9 also has a large capacity and stores a number of broken line functions corresponding to the number of objects.

Due to the various effects described above, the color image display device according to the present invention can be effectively applied to a wide range of fields such as CAD.

(Effects of the Invention) As described above, according to the present invention, a color image display device that requires a small amount of calculation in a host computer, can color or change colors in a short time, and requires a small memory capacity. can be realized with a simple configuration. Furthermore, by selecting the value of the boundary brightness Ip, the texture of the object can be changed freely.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of a color image display device according to the present invention, FIG.
The figure is a characteristic curve diagram for explaining the contents written in the LUT of the apparatus shown in Figure 1, Figure 4 is a characteristic curve diagram showing the basic principle of the apparatus shown in Figure 1, Figure 5 is a vector diagram of the same color, and Figure 6 is a bookmark diagram. A block diagram showing a second embodiment of the invention, FIG. 7 is a block diagram showing a conventional example of a color image display device, and FIG.
FIG. 2 is a block diagram showing a part of the device. 14... Frame memory, 8... Broken line generation circuit,
LtJl, LU2. LLI3, 9... Look up table, 12... Color image display device, ΔRs
+ΔG! +ΔB S +ΔRm, ΔGm, ΔBm +
I p +SR, So, Sa...setting parameters.

Claims (2)

[Claims] (1) A frame memory into which a luminance image is input, a broken line generation circuit which inputs setting parameters and generates a broken line function, and whose contents are written by the output of this broken line generation circuit, and which is written by the brightness image output of the frame memory. 1. A color image display device, comprising: a look-up table that outputs color data corresponding to a specified address, and generating a color image in which a luminance image is colored. (2) When the broken line of the broken line generation circuit is below the boundary brightness, the color vector of the object light with a size corresponding to the brightness of the brightness image is added to the color vector of the ambient light, and when the brightness is above the boundary brightness, it is added to the reflected color vector at the boundary brightness. 2. The color image display device according to claim 1, wherein the color image display device is configured to calculate a reflected color vector by adding color vectors of light sources having a size corresponding to the brightness of the brightness image.