Computer graphics processing and selective visual display system – Computer graphic processing system – Plural graphics processors
Reexamination Certificate
2000-11-07
2004-08-24
Bella, Matthew C. (Department: 2676)
Computer graphics processing and selective visual display system
Computer graphic processing system
Plural graphics processors
C345S475000, C345S606000, C345S560000, C382S300000, C382S304000
Reexamination Certificate
active
06781586
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to an interpolation processing apparatus, an interpolation processing method and an image display apparatus, and more particularly to an interpolation processing apparatus, an interpolation processing method and an image display apparatus suitably applied to format conversion of image data in which, for example, a programmable video DSP (Digital Signal Processor) is used.
Conventionally, various apparatus such as an image display apparatus execute a process for format conversion by converting the number of pixels of image data by an interpolation arithmetic operation process. In such a process for format conversion as just mentioned, a device for exclusive use in the form of an ASIC (Application Specific IC) is used popularly.
In particular, various formats are available for image data. For example, in the VGA (Video Graphics Array), a screen is composed of 640×480 pixels or dots. Meanwhile, in the SVGA (Super VGA), a screen is composed of 800×600 pixels or dots; in the XGA (extended Graphics Array), a screen is composed of 1,024×768 pixels or dots; and in the UXGA (Ultra XGA), a screen is composed of 1,600×1,200 pixels or dots.
The VGA and so forth mentioned above are formats applied to computer equipments. However, for image data, various formats which are different in the number of pixels, scanning number of lines and so forth also depending upon the system of television broadcasting are available in addition to the formats applied to computer equipments.
Meanwhile, as display apparatus for displaying image data, fixed pixel displaying devices such as a liquid crystal display (LCD) device and a digital micromirror device (DMD) are available. Each of such fixed pixel displaying devices can display a fixed number of pixels and has a unique resolution based on the number of pixels.
If a display apparatus having a unique resolution is connected so that image data of a format which does not comply with the resolution are inputted thereto, then a process of format conversion for converting the number of pixels is required. This format conversion process is executed using an interpolation arithmetic operation process. More particularly, if it is intended to display a television broadcast on a liquid crystal display apparatus, then a process of format conversion is required because of difference between the format used by the liquid crystal display apparatus and the format of the television broadcast. An interpolation arithmetic operation process for such conversion of the number of pixels is applied not only to such format conversion of image data as described above but also to partial enlargement or contraction of an image.
Such an interpolation arithmetic operation process as described above is executed by successive weighted addition of image data with weighting coefficients produced using an interpolation function. In order to allow format conversion, enlargement of an image or reduction of an image with a high picture quality, various functions are selectively used as the interpolation function.
FIG. 18
is a characteristic diagram illustrating an interpolation function f(x) according to a bilinear approximate function which is one of such interpolation functions as just described. The interpolation function f(x) illustrated in
FIG. 18
can be expressed in accordance with the following expressions using a phase x normalized with a pixel interval:
f
(
x
)=1
−|x
|(|
x
|≦1)
f
(
x
)=0 (|
x
|>1) (1)
Meanwhile,
FIG. 19
is a diagram illustrating a relationship of pixels in a horizontal direction or a vertical direction between VGA image data and SVGA image data. The number of pixels of the VGA is 640×480 dots while the number of pixels of the SVGA is 800×600 dots, and the ratio in number of pixels between the VGA and the SVGA is 4:5. Consequently, the relationship of pixels illustrated in
FIG. 19
repetitively appears in a horizontal direction and a vertical direction. It is to be noted that the values 5 and 4 between pixels in
FIG. 19
denote numerical values representative of pixel intervals in image data of the VGA and image data of the SVGA, respectively.
The pixel of the SVGA denoted by reference character a in
FIG. 19
overlaps with the pixel of the VGA denoted by reference character A and has a phase x equal to the value 0 with respect to the pixel A. Meanwhile, the phase x of the pixel a has the different value 1 with respect to the pixel B next to the pixel A and has values greater than 1 individually with respect to the pixels denoted by reference characters C to E. Consequently, when the interpolation function of the expressions (1) is used to perform format conversion of image data of the VGA into image data of the SVGA, with regard to the pixel a, a weighting coefficient of the value 1 is produced for the pixel A, and another weighting coefficient of the value 0 is produced for the other pixels B to E.
The pixel of the SVGA denoted by reference character b has the phase x of the value −⅘ with respect to the pixel A. Meanwhile, the phase x of the pixel b has the value ⅕ with respect to the pixel B next to the pixel A and has values greater than 1 individually with respect to the pixels C to E. Consequently, when format conversion of image data of the VGA into image data of the SVGA is to be performed, with regard to the pixel b, weighting coefficients of the values ⅕ and ⅘ are produced for the pixels A and B, respectively, and another weighting coefficient of the value 0 is produced for the other pixels C to E similarly.
The pixel of the SVGA denoted by reference character c has the phase x of the value −⅗ with respect to the pixel B. Meanwhile, the phase x of the pixel c has the value ⅖ with respect to the pixel C next to the pixel B and has values greater than 1 individually with respect to the other pixels A, D and E. Consequently, when format conversion of the image data is to be formed, with regard to the pixel c, weighting coeffecients of the values ⅖ and ⅗ are produced for the pixels B and C, respectively, and another weighting coeffecient of the value 0 is produced for the other pixels A, D and E similarly.
Further, when format conversion of image data is to be performed, with regard to the pixel of the SVGA denoted by reference character d, weighting coefficients of the values ⅗ and ⅖ are produced for the pixels C and D, respectively, and with regard to the pixel of the SVGA denoted by reference character e, weighting coeffecients of the values ⅘ and ⅕ are produced for the pixels D and E, respectively.
Consequently, when the bilinear approximate function is used to perform format conversion of image data of the VGA into image data of the SVGA, a weighted addition process represented by the following expressions is repeated to produce image data of the SVGA:
a
=1
×A
b
=⅕
×A
+⅘
×B
c
=⅖
×B
+⅗
×C
d
=⅗
×C
+⅘
×D
e
=⅘
×D
+⅕
×E
f
=1
×E
(2)
A device for exclusive use which employs an ASIC includes, in order for the arithmetic operation process given by the expressions (2) above to be executed at a high speed, a coefficient generation circuit for holding and successively outputting weighting coefficients, a multiplication circuit for multiplying input image data by the weighting coefficients to weight the input data, and an addition circuit for adding results of the weighting by the multiplication circuit. The device can thus process an image on the real time basis and display also moving pictures without giving an unfamiliar feeling to a viewer.
While such a device for exclusive use employing an ASIC is used, in the field of image processing, various image processes are executed using a device for universa
Bella Matthew C.
Frommer William S.
Frommer & Lawrence & Haug LLP
Nguyen Hau
Smid Dennis M.
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