Optical mouse technology in the car Application

Optical mice Set modern imaging technology and high-resolution digital image processing technology, and it is important invention of the mouse technology, with its unique technology and price advantage rapidly becoming the standard computer configuration. Optical mice by the imaging system IAS, signal processing DSP system, the three major systems SPI interface system components. IAS system by which light source, optical lenses and optical devices CMOS sensor consists of three parts. The mouse work through internal light source (a light-emitting diode), illuminate the mouse at the bottom, the bottom part of the surface reflectance of light through optical lens spread CMOS photosensitive chip, CMOS chip by the photosensitive hundreds of optoelectronic devices composed of matrix, in the CMOS image for the Matrix signal conversion, Chuan losers DSP systems to signal processing, DSP and storage this image signal sampling period of the last images were compared, if a sampling point has two images in the position of a mobile, on the issue of vertical and horizontal displacement signal to the two direction SPI Interface System, otherwise continue with the next sampling cycle. SPI Interface System of the DSP processing to the signal output. Optical mouse has two main technical parameters, is a resolution, units are dpi (pixels / inch), for example, a 1600 dpi mouse can tell the smallest spacing of 25.4 mm/1600 = 0.015875mm; Another is the sampling frequency, sampling of the per second CMOS shooting Image frame count and DSP chip can process images per second of the frame count. For example, Microsoft IE4 optical mice sampling frequency is 9000 / sec, can provide 1409.7 mm / s tracking speed. Optical mouse technology in the field of application of the feasibility of car Optical mice measure changes in the displacement, and a real physical displacement between the optical lens resulting in physical and the ratio between transform imaging. Computer configuration of the optical mouse is part of a high-optical-optical lens rate is close imaging, desktop users in smaller mobile, computer cursor on the screen in a greater response. By changing the optical lens-k-rate, increasing physical distance between lens and can trace its speed into k-fold increase. Of course, due to changes in the mouse close-up imaging for long-distance imaging, the resolution of the mouse itself has changed, but this change does not affect the application in the car. Microsoft IE4 photosensitive chip CMOS optical mouse as an example, suppose the greatest speed of 200 km / h, the optical lens factor k = 200 × 1000/3600/1.4097 = 39.4, then a resolution of 0.015875 × 39.4 = 0.625mm . From this we can see that when the optical lens factor k = 39.4, tracking speed can reach its maximum 200 km / h, resolution of less than 1 mm, and its measurement accuracy still high, to meet the speed measurement requirements. For example, in optical mice at the bottom directly in the camera zoom lens experiment on the road, set a mouse output value of the same results showed that the farther the road from the mouse, the greater the scope of sampling, the movement of the mouse itself needs greater distance; Mice without the lens from the close road mobile smallest. Take distance imaging, in poor light when necessary auxiliary lighting. In this experiment using ordinary flashlight can meet the requirements. Optical mice are close-up imaging, a small sampling of the small sampling plane sometimes lack of feature points, causing For more homogeneous surface such as the mirror, and other adaptive differential. Vehicles traveling relatively coarse dry pavement much every aspect of the characteristics of other points with a clear distinction, but also because it is remote imaging, surface sampling, feature points more, there is no adaptability problem, a large number of experiments have proved this point. Optical mice in the image processing technology without mechanical movement, all semiconductor circuits, high science and technology content, only two 300 g weight, small size, its application to automobiles field is very convenient. Because, from image acquisition, processing the data output entirely off-the-shelf optical mouse technology, related only to its output data can be used to develop applications in particular simple. In ABS, ESP on the Application Anti-lock Braking System ABS is to be Locking wheels when braking force to reduce, but will not Locking wheels when braking force when the increase, repeated moves to reach safety brake. Automotive Brake process, the ground between the wheel and slip phenomenon that slip ratio δ = (Vt - Va) / Vt × 100% (where: δ --- slip ratio; Vt --- car wheel line speed; Vehicle speed Va --- .) Experiments show that, in order to achieve the best braking effect, should be controlled slip rate of 15% to 20% range. Clearly, control slip rate must know that speed. Due to the accurate measurement of the speed sensor (such as Doppler velocimetry) very expensive, most vehicles only measuring wheel speed, wheel speed estimated speed according to the ABS, dual parameters (speed, wheel speed) into single simplified measurement parameters (wheel speed) measurements, a lack of essential parameters, to a large extent affect the ABS results. The optical mice image sensor technology applied to the ABS speed measurement system, to be installed in a vehicle image sensor, and the sampling of the road, according to installation height adjustment coefficients k optical lens, making it a long-distance imaging, and then output the data into a displacement speed. Applied to the ESP system, the body needs in the vertical or horizontal straight line on the two locations (such as the two mirrors bearings) were installed image sensor, measuring the two longitudinal, transverse acceleration changes in both directions, that is to say when the body above two points in the longitudinal direction and the lateral acceleration basically the same no displacement, the body for straight forward movement; When the two measured lateral acceleration, a lateral sliding body; When the two vertical acceleration of a difference, accompanied by a horizontal rotating body, numerical side of the lateral in the rotation, according to the two horizontal displacement of poor and the body width computable Rotation angle. As in reverse after the application As in reverse after the application is the use of body image sensor location and orientation measurement positioning methods. After depending on the existing reversing devices through car camera, the car displayed on the screen environment; Some of the screen also showed that direction and lane track body to help pilots determine body position and the external environment relations. These devices are characterized by the actual body position and see on the screen is isolated environment, in the screen and the driver could not see the whole body and the environment on the other. With these different devices using optical mouse technology is the first use of body image sensor location and direction tracking positioning, the animated simulation of the actual vehicle reversing process and the environment photographs superimposed with the outside world. As previously stated in its approach to the two mirrors on the image sensor bearings were installed under the car's body began to assume a vertical and horizontal direction of the earth coordinate system, and one set of coordinates of the origin Image Sensor (coordinates calculation method required under the arbitrary assumptions). When first started to take photographs after the car, and then calculate the coordinates of the camera; At the same time according to reversing the course of two image sensors, the displacement of change, the calculated body coordinates, the two coordinate points can be determined at the same time auto body position and direction. According to the model of a vehicle location coordinates and auto body reversing the direction of the process simulation and photos superimposed and the environment. Thus, the actual vehicle on the ground movement, body model in the photos on the ensuing campaign, in the screen to see is a photo of the environment movement in the body of a model, as if the driver outside the vehicle, overlooking the entire body surroundings, reversing the process transparent. Reversing camera in the photo, when the vehicle movement at the edge of the current photographs, according to vehicle location coordinates corresponding photo call. It should be stated that, in the body model and photos superimposed in the simulation of motor sport body should be a three-dimensional model, and the virtual camera tracking model and the actual car photo camera angle, height, etc. to the same parameters of the lens, so that baby and the environment Integration, a simulation of the entire the process can be accurate and realistic. At the same time, as far as possible, suppress baby height, so as not to block the car environment. Summing up As the core technology for optical mice - the development of image processing is continuing. It is reported that the Shenzhen company has successfully developed a third generation of optical mice, the largest mobile speed of an order of magnitude, up to 100,000 dpi resolution. Image sensors small size, low price, high precision measurement, in the car lot of space. In this paper, only a brief account of the image sensors in the gun, the application of positioning, more applications can be logged in the State Intellectual Property Office website, View image measurement method patent literature.