An optical mouse is a computer mouse that uses a light source, usually a light-emitting diode (LED), and a light detector, like an array of photodiodes, to detect motion relative to the surface. This is an alternative to a mechanical mouse, which uses moving parts to sense movement.
Earliest optical mice detect motion on the surface of the previously printed mousepad. Whereas modern optical mice work on the most opaque reflective surfaces such as paper, they are usually unable to detect motion on specular reflective surfaces such as polished stone; coherently-lit (laser) mice can function even on such shiny surfaces, but perform poorly on transparent surfaces; dark field illumination allows the mouse to function properly even on the glass. Laser diodes are also used for better resolution and precision. The battery-powered wireless optical mouse blinks LEDs intermittently to conserve power, and only shines firmly when movement is detected.
Video Optical mouse
Mechanical mice
Although not commonly referred to as optical mice, almost all mechanical mice trace motion using LEDs and photodiodes to detect when infrared light rays are performed and not pass through the holes in additional encoder wheel rotation. Thus, the main difference from "optical mice" is not the use of optics, but the lack of moving parts to track the movement of the mouse, instead of using a completely solid state system.
Maps Optical mouse
Initial optical mouse
Early optical mice, first demonstrated by two independent inventors in 1980, come in two different varieties: Some, as found by Steve Kirsch of MIT and Mouse Systems Corporation, use infrared LEDs and quadrant quadrant sensors to detect the grid lines printed with ink absorbing infrared on a special metal surface. The predictive algorithm in the CPU mouse calculates the speed and direction above the grid.
Others, created by Richard F. Lyon of Xerox, use a 16-pixel light-visible image sensor with integrated motion detection on the same chip and track the movement of dots in the dark plane of a printed paper or similar mouse pad. The optical mouse was eventually sold with the Xerox STAR office computer using an inverted reversible chip sensor approach by Lisa M. Williams and Robert S. Cherry from Xerox Microelectronics Center.
The Kirsch and Lyon mice have very different behaviors, because Kirsch mice use the xy coordinate system embedded in the pad, and will not work properly when the pad is rotated, while the Lyon rat uses the xy coordinate system of the mouse body, as mechanical mice do.
Modern optical mouse
Modern independent surface optical mice work by using optoelectronic sensors (essentially, small low resolution video cameras) to take sequential images from the surface where the mouse operates. As computing power becomes cheaper, it becomes possible to embed image processing chips with a particularly strong purpose in the mouse itself. This advancement allows the mouse to detect relative motion on various surfaces, translating mouse movements into the cursor movement and eliminating the need for a special mouse-pad. A surface-independent coherent light optical mouse design was patented by Stephen B. Jackson at Xerox in 1988.
The first commercially available first commercially available optical mouse is Microsoft IntelliMouse with IntelliEye and IntelliMouse Explorer, introduced in 1999 using technology developed by Hewlett-Packard. It works on almost all surfaces, and represents a welcome improvement over mechanical mice, which will pick up dirt, track allegedly, invite rough handling, and need to be separated and cleaned frequently. Other manufacturers soon followed Microsoft's leadership using components produced by HP spin-off Agilent Technologies, and over the next few years mechanical mice became obsolete.
The underlying technology of a modern optical computer mouse is known as the digital image correlation, a technology pioneered by the defense industry to track military targets. A simple binary-image version of the digital image correlation was used in the 1980 Lyon optical mouse. The optical mouse uses image sensors for natural texture images in materials such as wood, fabric, mouse pads and Formica. This surface, when turned on at the grazing angle by the light-emitting diode, produces a different shadow that resembles a hilly field that lights up at sunset. These surface images are captured successively and compared to each other to determine how far the mouse has moved.
To understand how optical flow is used in optical mice, imagine two photographs of the same object except slightly offset with each other. Place the two photos on the light table to make them transparent, and slide one across the other until their image is lined up. The number of edges of one of the other hung photos represents the offset between the images, and in the case of optical distance mouse computer that has been moved.
Optical mice catch a thousand images sequentially or more per second. Depending on how fast the mouse moves, each image will be balanced from the previous by a fraction of pixels or as many as several pixels. The optical mouse mathematically processes these images using cross-correlation to calculate how much each successive image is balanced from the previous one.
Optical mice may use image sensors that have monochromatic pixel pixels 18 Ã- 18 pixels. The sensors will usually share the same ASIC that is used to store and process images. One refinement will speed up the correlation process by using information from previous movements, and other narrowing will prevent deadbands when moving slowly by adding interpolation or jumping.
The development of a modern optical mouse at Hewlett-Packard Co. supported by a series of related projects during the 1990s at HP Laboratories. In 1992 William Holland was awarded US Patent 5,089,712 and John Ertel, William William, Kent Vincent, Rueiming Jamp, and Richard Baldwin were awarded US Pat. No. 5,149,980 to measure the progress of linear paper in printers by linking paper fiber images. Ross R. Allen, David Beard, Mark T. Smith, and Barclay J. Tullis were awarded US Patents 5,578,813 (1996) and 5,644,139 (1997) for two-dimensional optical navigation dimensions (ie position measurement) based on microscopic detection and correlation, features attached to the surface where the navigation sensor is traveling, and uses position measurement from each end of the linear image sensor (document) to reconstruct the document image. This is a free-handed scanning concept used on HP CapShare 920 handheld scanners. By illustrating the optical means that explicitly overcome the limitations of wheels, balls, and rollers used in contemporary computer mice, optical mouse is anticipated. These patents form the basis for US Pat. No. 5,729,008 (1998) granted to Travis N. Blalock, Richard A. Baumgartner, Thomas Hornak, Mark T. Smith, and Barclay J. Tullis, in which surface-sensing feature imagery, processing images, and image correlations are realized by integrated circuits to produce position measurements. Improved accuracy of 2D optical navigation, required for optical navigation applications to advanced 2D measurements of advanced (paper) media in large HP DesignJet format printers, further refined in US Pat. 6,195,475 awarded in 2001 to Raymond G. Beausoleil, Jr., and Ross R. Allen.
While image reconstruction in a document scanning application (Allen et al.) Requires resolution by optical navigators in the order of 1/600 of an inch, the implementation of optical position measurements on a computer mouse not only benefits from an inherent cost reduction. in navigating at lower resolutions, but also enjoy the advantages of visual feedback to the user cursor position on the computer screen. In 2002, Gary Gordon, Derek Knee, Rajeev Badyal and Jason Hartlove were awarded US Pat. No. 6,433,780 for an optical computer mouse that measures position using image correlations.
Light source
Mouse LED
Optical mice often use a light-emitting diode (LED) for illumination when first popularized. Color LED optical mouse can vary, but red is the most common, because red diodes are not expensive and silicon photodetector is very sensitive to red light. Other colors are sometimes used, as the blue LEDs of the V-Mouse VM-101 are illustrated on the right.
Laser mouse
The laser mouse uses an infrared laser diode as a substitute for LEDs to illuminate surfaces under their sensors. In early 1998, Sun Microsystems provided a laser mouse with their Sun SPARCstation servers and workstations. However, the laser mice did not enter the mainstream market until 2004, when Paul Machin at Logitech, in partnership with Agilent Technologies introduced the laser mouse MX 1000 . This mouse uses a small infrared laser instead of the LED and has significantly improved image resolution captured by the mouse. Laser illumination allows superior surface tracking compared to LED-illuminated optical mice.
Laser Glass (or glaser ) mice have the same capabilities as a laser mouse but can also be used on mirror or transparent glass much better. In 2008, Avago Technologies introduced a laser navigation sensor emiternya integrated into the IC using VCSEL technology.
In August 2009, Logitech introduced mice with two lasers, to track on a better glass and glossy surface; they dub them as "Darkfield" laser sensors.
Power
Manufacturers often engineer their optical mice - especially battery-powered wireless models - to save power whenever possible. To do this, the mouse dims or flashes the laser or LED while in idle mode (each mouse has a different standby time). The typical implementation (by Logitech) has four power states, where the sensor pulsates at different rates per second:
- 11500: active, for accurate response on the move, the lighting is bright.
- 1100: active condition backwards when not moving, lighting looks boring.
- 110: standby
- 12: sleep state
Movements can be detected in these countries; some mice change the sensor completely in the state of sleep, need a click button to wake up.
Optical mice using infrared (LED or laser) elements offer substantial improvements in battery life over visible spectrum illumination. Some mice, such as the Logitech V450 848m laser mouse, are capable of functioning on two AA batteries for a full year, due to the low power requirements of the infrared laser.
Mice designed to be used where low latency and high response are important, as in playing a video game, can ignore power saving features and require cable connections to improve performance. Examples of rats that sacrifice power savings in performance support are Logitech G5 and Razer Copperhead.
Optical versus mechanical mouse
Unlike mechanical rats, whose tracking mechanisms can be clogged with fiber, optical mice have no moving parts (other than buttons and scroll wheels); Therefore, they require no maintenance other than from disposing of debris that may collect under the light emitter. However, they are generally unable to track glossy and transparent surfaces, including multiple mouse-pads, causing the cursor to float unexpectedly during operation. Mice with fewer image processing strengths also have rapid motion tracking issues, whereas some high quality mice can track faster than 2 m/s.
Some models of the laser mouse can track on a glossy and transparent surface, and have a much higher sensitivity.
In 2006 mechanical mice had lower average power requirements than their optical counterparts; the power used by mice is relatively small, and only important consideration when power comes from the battery, with limited capacity.
Optical models outperform mechanical mice on uneven, slippery, soft, sticky, or loose surfaces, and generally in less mobile situations with mouse pads. Because the optical mouse creates motion based on images that LED (or infrared diodes) are on, being used with colorful mouse pads can produce unreliable performance; However, laser mice do not suffer from this problem and will track on such surfaces.
References
Source of the article : Wikipedia
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