Line segment and arc detection apparatus

A detection apparatus for detecting an arc in a specified image, comprising:

• a feature quantity calculating part configured to determine a feature quantity of each point in the specified image;
• a Hough transform part configured to convert an arc that passes through an arbitrary point in the specified image to a value set of coordinates (a,b,r) in a Hough space by defining orthogonal coordinates with respect to a reference point in the specified image and representing an arbitrary arc in the specified image using a value set of coordinates (a, b) of its center in an orthogonal coordinate system and a radius r;
• a counting part configured to add a value weighted by a feature quantity of a point in the specified image in a storage entry corresponding to a value set of coordinates (a,b,r) in the Hough space to which the point in the specified image is converted by the Hough transform part;
• and
• a detection part configured to detect the arc in the specified image by identifying a value set of coordinates (a,b,r) for which the count exceeds a first threshold.

A detection method for detecting a line segment in a specified image, comprising:

• a feature quantity calculating step to determine a feature quantity of each point in the specified image;
• a Hough transform step to convert a straight line that passes through an arbitrary point in the specified image to a value set of coordinates (θ,ρ) in a Hough space by representing an arbitrary straight line in the specified image using a length ρ of a perpendicular extending from a reference point of the specified image to the arbitrary straight line in the specified image and an angle θ formed by the perpendicular with a reference axis that passes through the reference point;
• a counting step to add a value weighted by a feature quantity of a point in the specified image in a storage entry corresponding to a value set of coordinates (θ,ρ) in the Hough space to which the point in the specified image is converted by the Hough transform part;
• and
• a detection step to detect the straight line in the specified image by identifying a value set of coordinates (θ,ρ) for which the count exceeds a first threshold.

A detection method for detecting an arc in a specified image, comprising:

• a feature quantity calculating step to determine a feature quantity of each point in the specified image;
• a Hough transform step to convert an arc that passes through an arbitrary point in the specified image to a value set of coordinates (a,b,r) in a Hough space by defining orthogonal coordinates with respect to a reference point in the specified image and representing an arbitrary arc in the specified image using a value set of coordinates (a, b) of its center in an orthogonal coordinate system and a radius r;
• a counting step to add a value weighted by a feature quantity of a point in the specified image in a storage entry corresponding to a value set of coordinates (a,b,r) in the Hough space to which the point in the specified image is converted by the Hough transform part;
• and
• a detection step to detect the arc in the specified image by identifying a value set of coordinates (a,b,r) for which the count exceeds a first threshold.

A detection apparatus for detecting a line segment in a specified image in a color space, comprising:

• a generating part configured to generate from the specified image a plurality of component images in the color space;
• a feature quantity calculating part configured to determine a feature quantity of each point in each component image;
• a Hough transform part configured to convert a straight line that passes through an arbitrary point in each component image to a value set of coordinates (θ,ρ) in a Hough space by representing an arbitrary straight line in each component image using a length ρ of a perpendicular extending from a reference point of the specified image to the arbitrary straight line in each component image and an angle θ formed by the perpendicular with a reference axis that passes through the reference point;
• a counting part configured to add a value weighted by a feature quantity of a point in each component image in a storage entry corresponding to a value set of coordinates (θ,ρ) in the Hough space to which the point in each component image is converted by the Hough transform part;
• a comprehensive counting part configured to comprehensively evaluate the counts for all component images to determine a comprehensive count;
• and
• a detection part configured to detect the straight line in the specified image by identifying a value set of coordinates (θ,ρ) for which the comprehensive count exceeds a first threshold.

A detection apparatus for detecting an arc in a specified image in a color space, comprising:

• a generating part configured to generate from the specified image a plurality of component image images in the color space;
• a feature quantity calculating part configured to determine a feature quantity of each point in each component image;
• a Hough transform part configured to convert an arc that passes through an arbitrary point in each component image to a value set of coordinates (a,b,r) in a Hough space by defining orthogonal coordinates with respect to a reference point in each component image and representing an arbitrary arc in each component image using a value set of coordinates (a, b) of its center in an orthogonal coordinate system and a radius r;
• a counting part configured to sum a value weighted by a feature quantity of a point in each component image in a storage entry corresponding to a value set of coordinates (a,b,r) in the Hough space to which the point in each component image is converted by the Hough transform part;
• a comprehensive counting part configured to comprehensively evaluate the counts for all component images to determine a comprehensive count;
• and
• a detection part configured to detect the arc in the specified image by identifying a value set of coordinates (a,b,r) for which the comprehensive count exceeds a first threshold.

A detection method for detecting a line segment in a specified image in a color space, comprising:

• a generating step to generate from the specified image a plurality of component images in the color space;
• a feature quantity calculating step to determine a feature quantity of each point in each component image;
• a Hough transform step to convert a straight line that passes through an arbitrary point in each component image to a value set of coordinates (θ,ρ) in a Hough space by representing an arbitrary straight line in each component image using a length ρ of a perpendicular extending from a reference point of the component image to the arbitrary straight line in each component image and an angle θ formed by the perpendicular with a reference axis that passes through the reference point;
• a counting step to add a value weighted by a feature quantity of a point in each component image in a storage entry corresponding to a value set of coordinates (θ,ρ) in the Hough space to which the point in each component image is converted by the Hough transform part;
• a comprehensive counting step to comprehensively evaluate the counts for all component images to determine a comprehensive count;
• and
• a detection step to detect the straight line in the specified image by identifying a value set of coordinates (θ,ρ) for which the comprehensive count exceeds a first threshold.

A detection method for detecting an arc in a specified image in a color space, comprising:

• a generating step to generate from the specified image a plurality of component images in the color space;
• a feature quantity calculating step to determine a feature quantity of each point in each component image;
• a Hough transform step to convert an arc that passes through an arbitrary point in each component image to a value set of coordinates (a,b,r) in a Hough space by defining orthogonal coordinates with respect to a reference point in each component image and representing an arbitrary arc in each component image using a value set of coordinates (a, b) of its center in an orthogonal coordinate system and a radius r;
• a counting step to add a value weighted by a feature quantity of a point in each component image in a storage entry corresponding to a value set of coordinates (a,b,r) in the Hough space to which the point in each component image is converted by the Hough transform part;
• a comprehensive counting step to comprehensively evaluate the counts for all component images to determine a comprehensive count;
• and
• a detection step to detect the arc in the specified image by identifying a value set of coordinates (a,b,r) for which the comprehensive count exceeds a first threshold.