Optical navigation device and locus smoothing method thereof

Abstract

There is provided an optical navigation device including an image sensor, a processing unit, a storage unit and an output unit. The image sensor is configured to successively capture images. The processing unit is configured to calculate a current displacement according to the images and to compare the current displacement or an accumulated displacement with a threshold so as to determine an outputted displacement. The storage unit is configured to save the accumulated displacement. The output unit is configured to output the outputted displacement with a report rate.

What is claimed is: 
     
         1 . An optical navigation device, comprising:
 an image sensor configured to successively capture images;   a processing unit configured to calculate a current displacement according to the images and to compare the current displacement or an accumulated displacement with a threshold so as to determine an outputted displacement; and   an output unit configured to output the outputted displacement with a report rate.   
     
     
         2 . The optical navigation device as claimed in  claim 1 , wherein the output unit outputs the current displacement when the current displacement is larger than or equal to the threshold; and the current displacement is accumulated when the current displacement is smaller then the threshold. 
     
     
         3 . The optical navigation device as claimed in  claim 1 , wherein the output unit outputs a zero displacement when the current displacement is smaller then the threshold. 
     
     
         4 . The optical navigation device as claimed in  claim 2 , further comprising a counting unit configured to count an accumulated parameter. 
     
     
         5 . The optical navigation device as claimed in  claim 4 , wherein the processing unit further calculates an average displacement of the accumulated displacement when the accumulated displacement is larger than or equal to the threshold or the accumulated parameter is larger than or equal to a predetermined accumulation value. 
     
     
         6 . The optical navigation device as claimed in  claim 5 , wherein the output unit outputs the average displacement for several times. 
     
     
         7 . The optical navigation device as claimed in  claim 6 , wherein an output time of the output unit outputting the average displacement is determined according to the accumulated parameter. 
     
     
         8 . The optical navigation device as claimed in  claim 4 , wherein the output unit outputs a zero displacement when the accumulated displacement is smaller than the threshold and the accumulated parameter is smaller then a predetermined accumulation value. 
     
     
         9 . The optical navigation device as claimed in  claim 4 , wherein the output unit outputs the accumulated displacement when the accumulated displacement is larger than or equal to the threshold or the accumulated parameter is larger than or equal to a predetermined accumulation value. 
     
     
         10 . The optical navigation device as claimed in  claim 1 , wherein the processing unit directly accumulates a next current displacement to the accumulated displacement when the current displacement is smaller than the threshold. 
     
     
         11 . A locus smoothing method of an optical navigation device, comprising:
 successively capturing images with an image sensor;   calculating, using a processing unit, a current displacement according to the images; and   comparing, using the processing unit, the current displacement with a threshold thereby determining the current displacement is outputted or accumulated.   
     
     
         12 . The locus smoothing method as claimed in  claim 11 , wherein when the current displacement is smaller than the threshold, the locus smoothing method further comprises:
 calculating, using the processing unit, a next current displacement;   directly accumulating the next current displacement to the accumulated displacement;   comparing, using the processing unit, the accumulated displacement with the threshold; and   outputting the accumulated displacement when the accumulated displacement is larger than or equal to the threshold.   
     
     
         13 . The locus smoothing method as claimed in  claim 12 , further comprising:
 outputting a zero displacement when the accumulated displacement is smaller than the threshold.   
     
     
         14 . The locus smoothing method as claimed in  claim 11 , wherein when the current displacement is smaller than the threshold, the locus smoothing method further comprises:
 counting an accumulated parameter with a counting unit; and   outputting the accumulated displacement or an average displacement of the accumulated displacement when the accumulated parameter is larger than or equal to a predetermined accumulation value.   
     
     
         15 . The locus smoothing method as claimed in  claim 14 , wherein the processing unit outputs the average displacement for several times according to the accumulated parameter. 
     
     
         16 . A locus smoothing method of an optical navigation device, comprising:
 successively capturing images with an image sensor;   calculating, using a processing unit, a current displacement according to the images;   comparing, using the processing unit, the current displacement with a threshold;   outputting the current displacement when the current displacement is larger than or equal to the threshold; and   accumulating the current displacement to an accumulated displacement and outputting a zero displacement when the current displacement is smaller than the threshold.   
     
     
         17 . The locus smoothing method as claimed in  claim 16 , wherein when the current displacement is smaller than the threshold, the locus smoothing method further comprises:
 calculating, using the processing unit, a next current displacement;   directly accumulating the next current displacement to the accumulated displacement;   comparing, using the processing unit, the accumulated displacement with the threshold; and   outputting the accumulated displacement for one time or outputting an average displacement of the accumulated displacement for several times when the accumulated displacement is larger than or equal to the threshold.   
     
     
         18 . The locus smoothing method as claimed in  claim 17 , further comprising:
 outputting a zero displacement when the accumulated displacement is smaller than the threshold.   
     
     
         19 . The locus smoothing method as claimed in  claim 16 , wherein when the current displacement is smaller than the threshold, the locus smoothing method further comprises:
 counting an accumulated parameter with a counting unit; and   outputting the accumulated displacement for one time or outputting an average displacement of the accumulated displacement for several times when the accumulated parameter is larger than or equal to a predetermined accumulation value.   
     
     
         20 . The locus smoothing method as claimed in  claim 19 , wherein an output time of outputting the average displacement is determined according to the accumulated parameter.