Optical touch system, apparatus and method for calculating the position of an object
First Claim
1. An apparatus for calculating the position of an object, the apparatus being suitable for an optical touch system and being provided for determining a representative position of the object in a sensed image, the apparatus comprising:
- an image sensor; and
a processing circuit electrically coupled to the image sensor, the processing circuit acquiring a sensed image containing an image of the object through the image sensor, and the processing circuit obtaining brightness value of at least one pixel in each pixel column of the sensed image to obtain a first brightness distribution profile, the processing circuit comparing the first brightness distribution profile with a second brightness distribution profile obtained from a background image, so as to select a plurality of column pixel brightness values in the first brightness distribution profile as an imaging range of the object, the processing circuit selecting column pixel brightness value corresponding to at least one dot from a curve segment of the imaging range in the second brightness distribution profile and acquiring the column pixel brightness value corresponding to the lowest dot of the at least one dot, so as to regard the acquired column pixel brightness value corresponding to the lowest dot as a brightness reference value, the processing circuit further calculating the brightness difference between the brightness reference value and the column pixel brightness value corresponding to each dot of the curve segment of the imaging range in the first brightness distribution profile, so as to calculate a gravity of the imaging range and to regard the gravity as a representative position of the object in the sensed image.
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Accused Products
Abstract
An optical touch system, an apparatus and a method for calculating the position of an object are provided. The apparatus includes an image sensor and a processing circuit. The processing circuit selects at least one dot from a curve segment of a brightness distribution profile obtained from a background image, wherein the curve segment corresponds to an imaging range of an object. And the processing circuit regards the column pixel brightness value corresponding to the dot as a brightness reference value. Afterwards, the processing circuit calculates brightness difference between the brightness reference value and the column pixel brightness values corresponding to the dots of a curve segment of a brightness distribution profile obtained from a sensed image, so as to further calculate a gravity of the imaging range. After that, the processing circuit regards the gravity as a representative position of the object in the sensed image.
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Citations
12 Claims
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1. An apparatus for calculating the position of an object, the apparatus being suitable for an optical touch system and being provided for determining a representative position of the object in a sensed image, the apparatus comprising:
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an image sensor; and a processing circuit electrically coupled to the image sensor, the processing circuit acquiring a sensed image containing an image of the object through the image sensor, and the processing circuit obtaining brightness value of at least one pixel in each pixel column of the sensed image to obtain a first brightness distribution profile, the processing circuit comparing the first brightness distribution profile with a second brightness distribution profile obtained from a background image, so as to select a plurality of column pixel brightness values in the first brightness distribution profile as an imaging range of the object, the processing circuit selecting column pixel brightness value corresponding to at least one dot from a curve segment of the imaging range in the second brightness distribution profile and acquiring the column pixel brightness value corresponding to the lowest dot of the at least one dot, so as to regard the acquired column pixel brightness value corresponding to the lowest dot as a brightness reference value, the processing circuit further calculating the brightness difference between the brightness reference value and the column pixel brightness value corresponding to each dot of the curve segment of the imaging range in the first brightness distribution profile, so as to calculate a gravity of the imaging range and to regard the gravity as a representative position of the object in the sensed image. - View Dependent Claims (2, 3, 4, 5)
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6. A method for calculating the position of an object, the method being used for an optical touch system and being provided for determining a representative position of the object in an sensed image, the method comprising the steps of:
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acquiring a brightness value of at least a pixel in each pixel column of the sensed image containing an image of the object to obtain a first brightness distribution profile; comparing the first brightness distribution profile with a second brightness distribution profile obtained from a background image, so as to select a plurality of column pixel brightness values in the first brightness distribution profile as an imaging range of the object; selecting a column pixel brightness value corresponding to at least one dot from a curve segment of the imaging range in the second brightness distribution profile and acquiring the column pixel brightness value corresponding to the lowest dot of the at least one dot, so as to regard the acquired column pixel brightness value corresponding to the lowest dot as a brightness reference value; and calculating the brightness difference between the brightness reference value and the column pixel brightness value corresponding to each dot of the curve segment of the imaging range in the first brightness distribution profile, so as to calculate a gravity of the imaging range and to regard the gravity as a representative position of the object in the sensed image. - View Dependent Claims (7, 8, 9)
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10. An apparatus for calculating the position of an object, the apparatus being suitable for an optical touch system and being provided for determining a representative position of the object in a sensed image, the apparatus comprising:
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an image sensor; and a processing circuit electrically coupled to the image sensor, the processing circuit acquiring a sensed image containing an image of the object through the image sensor, and the processing circuit obtaining brightness value of at least one pixel in each pixel column of the sensed image to obtain a first brightness distribution profile, the processing circuit comparing the first brightness distribution profile with a second brightness distribution profile obtained from a background image, so as to select a plurality of column pixel brightness values in the first brightness distribution profile as an imaging range of the object, the processing circuit selecting one column pixel brightness value corresponding to at least one dot from a curve segment of the imaging range in the second brightness distribution profile as a brightness reference value, the processing circuit further calculating the brightness difference between the brightness reference value and the column pixel brightness value corresponding to each dot of the curve segment of the imaging range in the first brightness distribution profile, so as to calculate a gravity of the imaging range and to regard the gravity as a representative position of the object in the sensed image. - View Dependent Claims (11, 12)
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Specification