US 5,668,894 AGranted

Method for processing three-dimensional shape data

AssigneeMatsushita Electric Industrial Co., Ltd.

InventorsSeiji Hamano, Takashi Ichiyanagi, Tsuyoshi Nomura, Kouhei Hamamura

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Abstract

A method for processing three-dimensional shape data includes steps of obtaining a plurality of point data along a surface of an object having a three-dimensional shape; taking out a point data from the obtained point data to be processed, approximating each specified number of point data in the to-be-processed point data adjacent the taken-out point data by a polynomial and then finding two unit vectors at the taken-out point data; finding an opening angle defined between the two found unit vectors; comparing the found opening angle with a predetermined threshold value of the opening angle, determining whether or not the found opening angle is not larger than the threshold value, and thinning the taken-out point data when the found opening angle is larger than the threshold value and not storing the taken-out point data in a storage unit, and leaving the taken-out point data without the thinning when the found opening angle is not larger than the threshold value and storing the taken-out point data in the storage unit.

Claims6

Dependent claims

A method for processing three-dimensional shape data, comprising:

a first step of obtaining a plurality of data points positionally indicative of respective surface points located along a surface of an object having a three-dimensional shape;
a second step of extracting one of said data points as a to-be-processed data point;
a third step of extracting a predetermined plural number of first data points among said data points which precede said to-be-processed data point, and extracting a predetermined plural number of second data points among said data points which succeed said to-be-processed data point;
a fourth step of subjecting said first data points and said to-be-processed data point to a polynomial approximation to obtain a first approximated line of said first data points and said to-be-processed data point;
a fifth step of subjecting said second data points and said to-be-processed data point to a polynomial approximation to obtain a second approximated line of said second data points and said to-be-processed data point;
a sixth step of obtaining a first unit vector which is tangential said first approximated line and which extends from said to-be-processed data point, and a second unit vector which is tangential said second approximated line and which extends from said to-be-processed data point;
a seventh step of finding an opening angle between said first and second unit vectors;
an eight step of comparing said opening angle with a predetermined threshold opening angle value;
a ninth step of thinning said to-be-processed data point and not storing said to-be-processed data point in a storage unit when said opening angle is larger than said threshold opening angle value, and leaving said to-be-processed data point as is without thinning and storing said to-be-processed data point in the storage unit when said opening angle is not larger than said threshold opening angle value;
and,
a tenth step of repeating said second through ninth steps for each of the remaining data points such that each remaining data point is extracted and processed as said to-be-processed data point.

8 more elements

A method for processing three-dimensional shape data, comprising:

a first step of obtaining a plurality of data points positionally indicative of respective surface points located along a surface of an object having a three-dimensional shape;
a second step of extracting one of said data points as a to-be-processed data point;
a third step of extracting a predetermined plural number of first data points among said data points which precede said to-be-processed data point, and extracting a predetermined plural number of second data points among said data points which succeed said to-be-processed data point;
a fourth step of subjecting said first data points and said to-be-processed data point to a polynomial approximation to obtain a first approximated line of said first data points and said to-be-processed data points;
a fifth step of subjecting said second data points and said to-be-processed data point to a polynomial approximation to obtain a second approximated line of said second data points and said to-be-processed data point;
a sixth step of obtaining a first unit vector which is tangential said first approximated line and which extends from said to-be-processed data point, and a second unit vector which is tangential said second approximated line and which extends from said to-be-processed data point;
a seventh step of finding a distance between ends of said first and second unit vectors;
an eight step of comparing said distance with a predetermined threshold distance value;
a ninth step of thinning said to-be-processed data point and not storing said to-be-processed data point in a storage unit when said distance is larger than said threshold distance value, and leaving said to-be-processed data point as is without thinning and storing said to-be-processed data point in the storage unit when said distance is not larger than said threshold distance value;
and,
a tenth step of repeating said second through ninth steps for each of the remaining data points such that each remaining data point is extracted and processed as said to-be-processed data point.

8 more elements

Dependencies are inferred from the claim text.