Navigation system and navigation method

Abstract

Disclosed are a navigation system and a navigation method, wherein the navigation method comprises the steps of sequentially providing image frames containing navigation information and generating electric signals corresponding to a position of an optical sensor, storing a first image frame into a reference frame memory as a reference frame, storing an input image frame subsequent to the first image frame into an input frame memory as a current input frame, setting a mask window having a predetermined size on the reference frame, obtaining correlation values over all the pixels on the current input frame by a full search comparison method, by moving the mask window on the current input frame pixel by pixel, calculating X-axis and Y-axis displacements of a pixel having the greatest correlation value of all the pixels, and updating the reference frame using the current input frame stored in the input frame memory. The navigation system and the navigation method in accordance with the present invention may change input frame selection period based on movement speed of an optical mouse, so that it is possible to detect movement of an optical mouse without changing sampling speed of an optical sensor even when an optical mouse moves fast. Further, the navigation system and the navigation method in accordance with the present invention may consume low power in comparison with a conventional navigation system and method, and reduce noises existed in an optical mouse.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a navigation system and a navigation method, and more particularly to a navigation system and a navigation method capable of changing input frame selection period based on movement speed of an optical mouse, wherein pixel mapping is performed by comparing all the pixels in a current input frame with all the pixels in a reference frame. [0003] 2. Description of the Related Art [0004] The operation of an optical mouse is will be described below with reference to FIG. 1. Referring to FIG. 1, light beams 7 emitted from an illuminating source 8 are incident onto a worktable and are reflected at the surface 2 of the worktable. The reflected light beams 6 pass through a lens 5 and are incident onto an optical sensor implemented by a semiconductor chip. The optical sensor 3 continuously captures images formed on the surface of the worktable and then the captured images are stored in a memory...

AI Technical Summary

Benefits of technology

The present invention provides a navigation system and method that can accurately detect movement of an optical mouse without increasing sampling speed when the mouse moves fast. The system consumes a small amount of power and has good noise reduction characteristics. The navigation method includes steps of sequentially providing frames containing navigation information and generating electrical signals corresponding to a position of an optical sensor, storing a first frame into a reference frame memory as a reference frame, storing input frames subsequent to the first frame into an input frame memory as a current input frame, setting a mask window on the reference frame, obtaining correlation values over all the pixels on the input frame by a full search comparison method, calculating X-axis and Y-axis displacements of a pixel having the greatest correlation value, updating the reference frame using the current input frame stored in the input frame memory, and detecting displacement values by a displacement detecting circuit. The navigation system includes an optical sensor, A / D converter, input frame memory, reference frame memory, processor, displacement detecting circuit, sample control circuit, and a reference frame memory.

Problems solved by technology

Since such conventional pixel mapping is targeted to detect movement or displacement within one pixel in nine directions, if an optical mouse moves by more than one pixel in one sampling period, the optical mouse cannot trace the movement of the optical mouse and therefore generates an error.

However, there is a limitation to increase electrical speed of an optical sensor.

This conventional method is disadvantageous in additional power consumption and noise increase.

Further, the conventional method is disadvantageous in that the conventional navigation system consumes a great amount of power and causes a big noise because input frame selection period is maintained constant even if movement speed of an optical mouse is changed.

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