Optical navigation device and lift detection method thereof
AssigneePixart Imaging Inc.
InventorTzu-Yu CHEN
Life of this patent
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Abstract
An optical navigation device includes a light source, an image sensor, a navigation unit and a lift detection unit. The light source is configured to illuminate a work surface. The image sensor receives reflected light from the work surface to output an image frame. The navigation unit is configured to filter the image frame and output a filtered image frame. The lift detection unit is configured to calculate a maximum difference of intensities between two adjacent pixels in the image frame, calculate a pixel number of pixels of interest in the filtered image frame, and identify a lift event by comparing the maximum difference with a difference threshold and/or comparing the pixel number with an operating threshold.
Claims20
An optical navigation device, adapted to be operated on a work surface, the optical navigation device comprising:
- a light source configured to illuminate the work surface;
- an image sensor configured to receive reflected light from the work surface to output an image frame;
- a navigation unit configured to filter the image frame and output a filtered image frame;
- and
- a lift detection unit configured to calculate a maximum difference of intensities between two adjacent pixels in the image frame, calculate a pixel number of at least one pixel of interest in the filtered image frame and identify a lift event according to at least one of (i) when the maximum difference is lower than a difference threshold and (ii) when the pixel number is lower than an operating threshold.
An optical navigation device, adapted to be operated on a work surface, the optical navigation device comprising:
- a light source configured to illuminate the work surface;
- an image sensor configured to receive reflected light from the work surface to output an image frame;
- an image processing unit configured to pre-process the image frame to increase an image contrast of the image frame and output a pre-processed image frame;
- a navigation unit configured to filter the pre-processed image and output a pre-processed and filtered image frame;
- and
- a lift detection unit configured to calculate a maximum difference of intensities between two adjacent pixels in the pre-processed image frame, calculate a pixel number of at least one pixel of interest in the pre-processed and filtered image frame and identify a lift event according to at least one of (i) when the maximum difference is lower than a difference threshold and (ii) when the pixel number is lower than an operating threshold.
A lift detection method of an optical navigation device, the optical navigation device comprising an image sensor, a navigation unit and a lift detection unit, the lift detection method comprising:
- capturing, using the image sensor, an image frame of a work surface;
- filtering, using the navigation unit, the image frame to output a filtered image frame;
- and
- calculating, using the lift detection unit, a maximum difference of intensities between two adjacent pixels in the image frame, calculating a pixel number of at least one pixel of interest in the filtered image frame and identifying a lift event according to at least one of (i) comparing the maximum difference with a difference threshold and (ii) comparing the pixel number with an operating threshold.
Dependencies are inferred from the claim text.