Handheld pointer device and pointer positioning method thereof

A pointer positioning method of a handheld pointer device, comprising:

• capturing a first frame containing a reference point when the handheld pointer device updates a first tilt angle presently used to a second tilt angle;
• computing an angle difference between the first and the second tilt angles;
• computing a first pointing coordinate according to the image position of the reference point formed in the first frame and the first tilt angle when the angle difference is larger than a preset angle;
• computing a second pointing coordinate according to the image position of the reference point formed in the first frame and the second tilt angle;
• causing the handheld pointer device to compute a cursor position of a cursor in the subsequent movement of the handheld pointer device on the basis of a first displacement vector between the first and the second pointing coordinates along with the pointing coordinate generated responsive to the movement of the handheld pointer device;
• wherein the step of computing the cursor position comprises:
• a) setting a number of calibrations as N, a compensation vector as C and a calibration coordinate, wherein the calibration coordinate is a third pointing coordinate computed according to the image position of the reference point formed in a second frame and the second tilt angle;
• b) determining whether the first displacement vector is larger than a predetermined threshold;
• c) setting N equal to the first displacement vector divided by C when determines that the first displacement vector is greater than the predetermined threshold, wherein C is a predetermined compensation value;
• setting C equal to the first displacement vector divided by N when determines that the first displacement vector is smaller than the predetermined threshold, wherein N is a predetermined number of calibrations;
• d) computing the sum of the calibration coordinate and C to generate a compensated pointing coordinate;
• e) generating the cursor parameter to correspondingly control the display position of the cursor on the display apparatus according to the compensated pointing coordinate;
• f) executing N−1 and determining whether N is equal to zero;
• and setting a fourth pointing coordinate to be the calibration coordinate and returning to step d) upon determined that N is not equal to zero;
• wherein the forth pointing coordinate is computed according to the image position of the reference point formed in a third frame and the second tilt angle;
• and
• correspondingly generating a cursor parameter for controlling a display position of the cursor on a display apparatus.

A pointer positioning method of a handheld pointer device, comprising:

• causing the handheld pointer device to update a first tilt angle presently used to a second tilt angle at a first time interval;
• causing the handheld pointer device to compute a first pointing coordinate and a second point coordinate according to the image position of the reference point formed in a first frame using the first tilt angle and the second tilt angle in the first time interval, respectively;
• causing the handheld pointer device to compute a third pointing coordinate according to the image position of the reference point formed in a second frame and the second tilt angle at a second time interval, wherein the second time interval occurs after the first time interval;
• and
• computing the cursor position of a cursor according to the first pointing coordinate, the second pointing coordinate, and the third pointing coordinate to correspondingly generate a cursor parameter for controlling a display position of the cursor on a display apparatus;
• and computing the cursor position for controlling the display position of the cursor on the display apparatus according to the third pointing coordinate at the second time interval when a first displacement vector between the first and the second pointing coordinates is computed to be less than a first predetermined threshold;
• wherein the step of computing the cursor position comprises:
• a) setting a number of calibrations as N, a compensation vector as C and a calibration coordinate, wherein the calibration coordinate is set as the third pointing coordinate;
• b) determining whether the first displacement vector is greater than a second predetermined threshold;
• c) setting N equal to the first displacement vector divided by C when determines that the first displacement vector is greater than the second predetermined threshold, wherein C is a predetermined compensation value;
• setting C equal to the first displacement vector divided by N when determines that the first displacement vector is less than the second predetermined threshold, wherein N is a predetermined number of calibrations;
• d) computing the sum of the calibration coordinate and C to generate a compensated pointing coordinate;
• e) generating the cursor parameter to correspondingly control the display position of the cursor on the display apparatus according to the compensated pointing coordinate;
• f) executing N−1 and determining whether N is equal to zero;
• and
• g) setting a fourth pointing coordinate to be the calibration coordinate and returning to step d) upon determined that N is not equal to zero.

A handheld pointer device, comprising:

• an image capturing unit, configured to operatively capture a plurality of images corresponding to the position of a reference point and sequentially generate a plurality of frames;
• an accelerometer unit, configured to detect a plurality of accelerations of the handheld pointer device over multiple axes and generating an acceleration vector;
• and
• a processing unit coupled to the image capturing unit and the accelerometer unit, the processing unit configured to operatively compute a cursor position of a cursor according to the image positions of the reference points in the frames and a first tilt angle;
• wherein when the processing unit updates the first tilt angle presently used in cursor position computation to a second tilt angle according to the plurality of accelerations detected, the processing unit operatively drives the image capturing unit to capture a first frame containing the reference point to respectively compute a first pointing coordinate and a second pointing coordinate using the first and the second tilt angles in coordination with the first frame, drives the image capturing unit to capture a second frame containing the reference point thereafter, computes the cursor position according to the image position of the reference frame in the second frame, the first pointing coordinate, the second pointing coordinate, and generates a cursor parameter for correspondingly controlling a display position of the cursor on a display apparatus;
• wherein the processing unit computes the cursor position according to the image position of the reference point formed in one of the frames and the second tilt angle when the processing unit determines that a first displacement vector between the first and the second pointing coordinates is computed to be less than a first predetermined threshold;
• and the processing unit generates the first displacement vector according to the first and the second pointing coordinates and generates the cursor parameter for correspondingly controlling the display position of the cursor on the display apparatus according to the image position of the reference point formed in the second frame, the first displacement vector, and the second tilt angle;
• wherein the processing unit computes the cursor position by executing the following steps:
• a) setting a number of calibrations as N, a compensation vector as C and a calibration coordinate, wherein the calibration coordinate is a third pointing coordinate computed according the image position of the reference point in the second frame and the second tilt angle;
• b) determining whether the first displacement vector is greater than a second predetermined threshold;
• c) setting N equal to the first displacement vector divided by C when determines that the first displacement vector is greater than the second predetermined threshold, wherein C is a predetermined compensation value;
• setting C equal to the first displacement vector divided by N when determines that the first displacement vector is less than the second predetermined threshold, wherein N is a predetermined number of calibrations;
• d) computing the sum of the calibration coordinate and C to generate a compensated pointing coordinate;
• e) generating the cursor parameter to correspondingly control the display position of the cursor on the display apparatus according to the compensated pointing coordinate;
• f) executing N−1 and determining whether N is equal to zero;
• and
• g) setting a fourth pointing coordinate to be the calibration coordinate and returning to step d) upon determined that N is not equal to zero;
• wherein the forth pointing coordinate is computed according to the image position of the reference point formed in a third frame and the second tilt angle.