Computer graphics processing and selective visual display system – Computer graphics processing – Graphic manipulation
Reexamination Certificate
1999-03-23
2001-12-11
Brier, Jeffery (Department: 2672)
Computer graphics processing and selective visual display system
Computer graphics processing
Graphic manipulation
C345S634000
Reexamination Certificate
active
06330002
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an image color blending processor which in particular implements semitransparent display such that two images are superimposed and the back image is able to be seen through the front image, and implements a color blending process of interpolating pixels when upscaling the display of the images.
DESCRIPTION OF THE RELATED ART
To achieve the semitransparent display of images, the color blending process called a blending has been well known. The &agr; blending is a method to make a composite image of two images, and a method which creates the appearance of the background image being seen through the superimposing image when one image is a superimposing image and the other image is a background image. When one pixel data of a color image is composed of each digital element of R, G, B indicating the luminance of the pixel, the a blending processes, S [R, G, B]=&agr; F [R, G, B]+(1−&agr;)H [R, G, B].
In this, &agr;is a numerical value representing the degree of the transparency and is called an alpha value. F [R, G, B] is the data of each color of one pixel of the superimposing image, H [R, G, B] is the data of each color of one pixel of the background image existing at the same place as the pixel of the superimposing image and S [R, G, B] is the data of each color of the composite pixel. &agr;=0 means perfect transparency and &agr;=1 means perfect opacity; therefore, 0<&agr;<1.
FIG. 1
is a block diagram showing the construction of the process of the &agr; blending. In
FIG. 1
, a background image
11
and a superimposing image
12
are together expressed as the image data stored in a memory
1
. A frame memory
21
is in a data processor
2
and stores one frame of the background image which is read from the background image
11
in sequence and a frame memory
22
is in the data processor
2
and stores one frame of the superimposing image which is read from the superimposing image
12
in sequence.
Reading from the frame memory
21
and the frame memory
22
and writing to a frame memory for display
23
are implemented by a common address signal.
A superimposing pixel value read from the frame memory
22
is multiplied by the value a at a multiplier
66
and a background pixel value read from the frame memory
21
is multiplied by the value (1−&agr;) at a multiplier
65
and the outputs from the multipliers
65
and
66
are added at an adder
67
and are inputted to the frame memory for display
23
, and the data from the frame memory for display
23
is read and shown on a display
3
.
As mentioned above, in the a blending process, an arbitrary value can be selected for the value a showing the degree of transparency. However, there is a problem in that a large quantity of calculation is needed when the multipliers
65
and
66
are obtained using software, because this process is implemented at the time of data transfer to the frame memory, and the display speed of the image is influenced by the throughput of the display. Thus, the problem is that a fully smooth color blending process cannot be implemented when a real time process such as regenerating animation is needed.
The Japanese Patent Application Laid-Open No. SHO 61-159690 discloses a method in which the &agr; blending is not applied for the pixel values of the superimposing image and background image, and the pixels of the superimposing image are thinned out at a certain ratio and superimposed on the background image, and the semitransparent display is implemented artificially. However, by thinning out the pixels of the superimposing image simply, for example, along a line having with a width of one pixel in the image, there is a problem in that portions of the line either does not appear or appears as a coarse dotted line even though the line is actually being displayed.
This kind of color blending process is applied for not only the semitransparent display of the superimposing image but also the up scaling of images. As an example, the case in which an image is up scaled twice in the vertical direction is explained. In this case, the same data is displayed in two lines, but the natural appearance of the image is lost. Therefore, an interpolating process is implemented.
FIG. 2
is a diagram showing a part of a frame memory for the image data to be up scaled in the vertical direction. In
FIGS. 2
, A, B, C and D are each shown as one line of memory.
FIG. 3
is a flowchart showing the scale up process of the conventional type. For example, in the case that a line AB is interpolated between a line A and a line B (the “yes” response at step
90
), the data of one pixel of one line (for example line A) of the image to be up scaled is taken out (step
91
). The data of one pixel of the next line (for example line B) is taken out, wherein this pixel is at the same horizontal position as the pixel taken out from the line A (step
92
). Then, an average value of the two pixels taken out is calculated (step
93
). That is, the a blending is implemented as &agr;=½. This average value is inserted in between lines as a pixel value of the line AB and the interpolation is implemented. This interpolation process is implemented in every two lines and the up scaled image in the vertical direction is obtained (step
90
and steps
96
to
100
).
In this case, a color blending calculation is also needed (step
93
) in the above mentioned example in which the average value is interpolated every two lines and the 200% up scale in the vertical direction is implemented. However, in the case of a 300% up scale, a blending using a suitable a value is needed in order to implement a smooth interpolating process, which creates a problem in that a big burden is loaded to the process.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an image color blending processor in which an a blending process does not place a big burden on the processor and which is able to filly implement a color blending in high quality and in real time even in a processor of small throughput.
In order to solve the above mentioned problems, the present invention provides an image color blending processor which utilizes the characteristic of the sense of sight and is able to implement a semitransparent display and an up scale display in a simple processor.
According to a first aspect of the present invention, for achieving the above mentioned objects, an image color blending processor, which displays a second original image superimposed semitransparently on a first original image, provides a display pixel selecting section which divides a display image into plural small regions constituted of a definite number of pixels adjacent to each other, and refers to the timing and display address of a display frame for the respective small regions in each display frame of said display image, and selects in sequence a pixel data of small regions of said first original image and a pixel data of said small regions of said second original image at a defined rate, by making the selecting rate of each pixel uniform in time and space, and a display processing section which generates a display image signal based on the pixel data selected at said display pixel selecting section.
According to the second aspect of the present invention, in the first aspect, said small region is constituted of at least
4
adjacent pixels.
According to a third aspect of the present invention, in the first aspect, an image color blending processor provides a first frame memory for developing said first original image, a second frame memory for developing said second original image and a timing counter for incrementing in a cycle a counting value of from 0 to 3 while synchronizing a vertical synchronizing signal of said display image.
According to a fourth aspect of the present invention, in the first aspect, said display pixel selecting section selects a pixel data corresponding to either the disp
Brier Jeffery
Good-Johnson Motilewa
NEC Corporation
Ostrolenk Faber Gerb & Soffen, LLP
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