Wobulation is the known variation ("wobble") in a characteristic. For example, wobulation of advanced radar waveform modulations – where the repetition rate or center frequency of a signal is changed in a repetitive fashion to reduce the probability of interception.
In
large-screen television technology
Large-screen television technology (colloquially big-screen TV) developed rapidly in the late 1990s and 2000s. Prior to the development of thin-screen technologies, rear-projection television was standard for larger displays, and jumbotron, a n ...
, wobulation is
Hewlett-Packard's term for a form of
interlacing designed for use with
fixed pixel display
Fixed pixel displays are display technologies such as LCD and plasma that use an unfluctuating matrix of pixels with a set number of pixels in each row and column. With such displays, adjusting ( scaling) to different aspect ratios because of di ...
s. The term is loosely derived from the word 'wobble' and was inspired by HP's work with the overlap of printing ink. Wobulation reduces the cost and complexity of components required for the creation of high resolution
TVs.
Wobulation works by overlapping
pixel
In digital imaging, a pixel (abbreviated px), pel, or picture element is the smallest addressable element in a raster image, or the smallest point in an all points addressable display device.
In most digital display devices, pixels are the ...
s. It does so by generating multiple sub-frames of data while an optical image shifting mechanism (e.g. the mirror of a
digital micromirror device
The digital micromirror device, or DMD, is the microoptoelectromechanical system (MOEMS) that is the core of the trademarked DLP projection technology from Texas Instruments (TI). Texas Instrument's DMD was created by solid-state physicist and ...
) then displaces the projected image of each sub-frame by a fraction of a pixel (e.g. one-half or one-third). The sub-frames are then projected in rapid succession, and appear to the human eye as if they are being projected simultaneously and superimposed. For example, a high-resolution HDTV video frame is divided into two sub-frames, A and B. Sub-frame A is projected, and then the miniature mirror on a digital micromirror device switches and displaces sub-frame B one half pixel length as it is projected. When projected in rapid succession, the sub-frames superimpose, and create to the human eye a complete and seamless image. If the video sub-frames are aligned so that the corners of the pixels in the second sub-frame are projected at the centers of the first, the illusion of double the resolution is achieved, like in an interlaced
CRT display. Thus a lower resolution fixed pixel device using wobulation can emulate the picture of a higher resolution fixed device, at a reduced cost.
, wobulation is used only to double the horizontal resolution of a display, unlike CRT interlacing that doubles the vertical resolution. However, it is capable of doubling the vertical and horizontal resolution of an image (2× wobulation).
While wobulation can in theory be used in many types of display devices, it is currently primarily used in displays using
Digital Light Processing
Digital Light Processing (DLP) is a set of chipsets based on optical micro-electro-mechanical technology that uses a digital micromirror device. It was originally developed in 1987 by Larry Hornbeck of Texas Instruments. While the DLP imagin ...
(DLP). DLP is a
Texas Instruments
Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globa ...
(TI) technology which relies on a Digital Micromirror Device (DMD) chip. TI calls its implementation of wobulation 'SmoothPicture'. Horizontal wobulation used in current TI products allows a DMD chip with a 960×1080 mirror array to produce a 1920×1080 pixel picture; most recent designs employed in
3D DLP sets use "offset-diamond pixel layout", where the mirrors form a "
checkerboard pattern" array.
DLP products
Texas Instruments Also, the image overlap inherent in the use of wobulation eliminates the 'screen door' effect common on other fixed pixel displays such as plasma and LCD, but may in some implementations also create some reduction in sharpness. Wobulation was used by a number of TV manufacturers, including Hewlett-Packard, Mitsubishi, RCA
The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent trust owned by General Electric (GE), Westinghouse, AT&T Corporation and United Fruit Comp ...
, Samsung
The Samsung Group (or simply Samsung) ( ko, 삼성 ) is a South Korean multinational manufacturing conglomerate headquartered in Samsung Town, Seoul, South Korea. It comprises numerous affiliated businesses, most of them united under the ...
, and Toshiba
, commonly known as Toshiba and stylized as TOSHIBA, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan. Its diversified products and services include power, industrial and social infrastructure systems, ...
.
References
*
*
* {{US patent reference
, number = 7034811
, inventor = William Allen
, y = 2006, m = 04, d = 25
, title = Image display system and method
External links
Hewlett-Packard Wobulation
Explanation
at Popular Science
Printing