Object recognition device, object recognition method, object recognition program, feature registration device, feature registration method, and feature registration program

An object recognition device for recognition of an object that exists in an image, the device comprising:

• an edge image creator configured to create an edge image from a target image including an object as a target of object recognition;
• a local feature extractor configured to extract a feature of each edge point on an edge image created by the edge image creator, and determine a base point and a support point from edge points in a local area defined for the edge image, the base point being a point to which attention should be paid in the local area, the support point being a point supporting the base point;
• a feature matching unit configured to implement, with reference to a memory, feature matching of a base point and a support point that each have a feature extracted by the local feature extractor to thereby acquire a matching pair, the memory storing therein a base point, a feature of the base point, a support point that supports the base point, a feature of the support point, and a geometric positional relationship between the base point and the support point, the base point being a point to which attention should be paid in a vicinity of a local area defined for an edge image created in advance depending on the object, the base point being determined from edge points in the vicinity of the local area;
• and
• a matching pair determiner configured to determine final matching pairs by employing matching pairs having a highest matching cost among matching pairs obtained by the feature matching unit, wherein an object in a target image is identified based on matching pairs determined by the matching pair determiner;
• wherein the local feature extractor
• extracts a reference axis direction and implements rotation normalization for realization of rotation invariance of an extracted feature, and
• creates a histogram by voting an angle of a direction from a point of interest to a peripheral edge point in a small area centered at the point of interest, and extracts a direction having an angle corresponding to a maximum value in the histogram as the reference axis direction.

An object recognition device for recognition of an object that exists in an image, the device comprising:

• an edge image creator configured to create an edge image from a target image including an object as a target of object recognition;
• a local feature extractor configured to extract a feature of each edge point on an edge image created by the edge image creator, and determine a base point and a support point from edge points in a local area defined for the edge image, the base point being a point to which attention should be paid in the local area, the support point being a point supporting the base point;
• a feature matching unit configured to implement, with reference to a memory, feature matching of a base point and a support point that each have a feature extracted by the local feature extractor to thereby acquire a matching pair, the memory storing therein a base point, a feature of the base point, a support point that supports the base point, a feature of the support point, and a geometric positional relationship between the base point and the support point, the base point being a point to which attention should be paid in a vicinity of a local area defined for an edge image created in advance depending on the object, the base point being determined from edge points in the vicinity of the local area;
• and
• a matching pair determiner configured to determine final matching pairs by employing matching pairs having a highest matching cost among matching pairs obtained by the feature matching unit, wherein an object in a target image is identified based on matching pairs determined by the matching pair determiner,
• wherein
• the local feature extractor determines a reference circle having a proper radius for each of a plurality of multiresolution images that are created by an multiresolution image creator and have different resolutions, and determines the base point and a plurality of the support points from the edge points in a vicinity of the reference circle.

An object recognition method for recognition of an object that exists in an image, the method comprising the steps of:

• (a) creating an edge image from a target image including an object as a target of object recognition;
• (b) extracting a feature of each edge point on an edge image created in the step (a), and determining a base point and a support point from edge points in a local area defined for the edge image, the base point being a point to which attention should be paid in the local area, the support point being a point supporting the base point;
• (c) dividing a circle having a fixed radius along a circumferential direction and a radial direction, and translating into a histogram the number of edge points that exist in each of bins arising from the division to thereby extract a local feature of each of all edge points;
• (d) implementing, with reference to a memory, feature matching of a base point and a support point that each have a feature extracted in the step (b) to thereby acquire a matching pair, the memory storing therein a base point, a feature of the base point, a support point that supports the base point, a feature of the support point, and a geometric positional relationship between the base point and the support point, the base point being a point to which attention should be paid in a vicinity of a local area defined for an edge image created in advance depending on the object, the base point being determined from edge points in the vicinity of the local area;
• and
• (e) determining final matching pairs by employing matching pairs having a highest matching cost among matching pairs obtained in the step (d), wherein an object in a target image is identified based on matching pairs determined in the step (e).

A non-transitory computer-readable medium including instructions, executable by a processor, for performing a method of object recognition for recognition of an object that exists in an image, the method comprising the steps of:

• (a) creating an edge image from a target image including an object as a target of object recognition;
• (b) extracting a feature of each edge point on an edge image created in the step (a), and determining a base point and a support point from edge points in a local area defined for the edge image, the base point being a point to which attention should be paid in the local area, the support point being a point supporting the base point;
• (c) dividing a circle having a fixed radius along a circumferential direction and a radial direction, and translating into a histogram the number of edge points that exist in each of bins arising from the division to thereby extract a local feature of each of all edge points;
• (d) implementing, with reference to a memory, feature matching of a base point and a support point that each have a feature extracted in the step (b) to thereby acquire a matching pair, the memory storing therein a base point, a feature of the base point, a support point that supports the base point, a feature of the support point, and a geometric positional relationship between the base point and the support point, the base point being a point to which attention should be paid in a vicinity of a local area defined for an edge image created in advance depending on the object, the base point being determined from edge points in the vicinity of the local area;
• and
• (e) determining final matching pairs by employing matching pairs having a highest matching cost among matching pairs obtained in the step (d), wherein an object in a target image is identified based on matching pairs determined in the step (e).

A feature registration device that registers a feature used in object recognition processing for recognition of an object that exists in an image, the device comprising:

• an edge image creator configured to create an edge image of a model of an object in advance;
• and
• a model feature extractor configured to extract a feature of each edge point on an edge image created by the edge image creator, and determine a base point and a support point from edge points in a local area defined for the edge image, the model feature extractor storing in a memory the base point, a feature of the base point, the support point, a feature of the support point, and a geometric positional relationship between the base point and the support point, the base point being a point to which attention should be paid in the local area, the support point being a point supporting the base point,
• wherein the model feature extractor divides a circle having a fixed radius along a circumferential direction and a radial direction, and translates into a histogram the number of edge points that exist in each of bins arising from the division to thereby extract a local feature of each of all edge points.

A feature registration device that registers a feature used in object recognition processing for recognition of an object that exists in an image, the device comprising:

• an edge image creator configured to create an edge image of a model of an object in advance;
• and
• a model feature extractor configured to extract a feature of each edge point on an edge image created by the edge image creator, and determine a base point and a support point from edge points in a local area defined for the edge image, the model feature extractor storing in a memory the base point, a feature of the base point, the support point, a feature of the support point, and a geometric positional relationship between the base point and the support point, the base point being a point to which attention should be paid in the local area, the support point being a point supporting the base point,
• wherein the model feature extractor determines a reference circle having any optional radius and determines a base point and a plurality of support points from the edge points in a vicinity of the reference circle, and the model feature extractor calculates a relative positional relationship between each support point and the base point, and
• wherein the model feature extractor divides the reference circle into a plurality of regions along a circumferential direction and defines a sampling area in each region to thereby define a point closest to the reference circle in each sampling area as a sampling point, and the model feature extractor refers to a history of positions of already-determined base points to thereby select from a sampling point group a point other than a point near a pixel corresponding to the already-defined base point so that the selected base point is defined as a newly-determined base point and other sampling points are defined as support points.

A feature registration device that registers a feature used in object recognition processing for recognition of an object that exists in an image, the device comprising:

• an edge image creator configured to create an edge image of a model of an object in advance;
• and
• a model feature extractor configured to extract a feature of each edge point on an edge image created by the edge image creator, and determine a base point and a support point from edge points in a local area defined for the edge image, the model feature extractor storing in a memory the base point, a feature of the base point, the support point, a feature of the support point, and a geometric positional relationship between the base point and the support point, the base point being a point to which attention should be paid in the local area, the support point being a point supporting the base point,
• wherein the model feature extractor:
• determines a reference circle having any optional radius by using a feature of each edge point on an edge image created by the edge image creator and determines a base point and a plurality of support points from the edge points in a vicinity of the reference circle,
• calculates a relative positional relationship between each support point and the base point,
• extracts an area that offers a large distance between local features of edge points on the area to thereby determine the reference circle,
• divides a predetermined reference circle depending on a radius of a local feature and extracts a local feature for each region arising from the division,
• calculates a distance between features to create a map of a distance between features, and
• determines the reference circle by using the map.

A feature registration device that registers a feature used in object recognition processing for recognition of an object that exists in an image, the device comprising:

• an edge image creator configured to create an edge image of a model of an object in advance;
• and
• a model feature extractor configured to extract a feature of each edge point on an edge image created by the edge image creator, and determine a base point and a support point from edge points in a local area defined for the edge image, the model feature extractor storing in a memory the base point, a feature of the base point, the support point, a feature of the support point, and a geometric positional relationship between the base point and the support point, the base point being a point to which attention should be paid in the local area, the support point being a point supporting the base point,
• wherein
• the model feature extractor determines a reference circle having a proper radius for each of a plurality of multiresolution images that are created by an multiresolution image creator and have different resolutions, and determines the base point and a plurality of the support points from the edge points in a vicinity of the reference circle.

A feature registration method for registration of a feature used in object recognition processing for recognition of an object that exists in an image, the method comprising the steps of:

• (a) creating an edge image of a model of an object in advance;
• (b) extracting a feature of each edge point on an edge image created in the step (a), determining a base point and a support point from edge points in a local area defined for the edge image, and storing in a memory the base point, a feature of the base point, the support point, a feature of the support point, and a geometric positional relationship between the base point and the support point, the base point being a point to which attention should be paid in the local area, the support point being a point supporting the base point;
• and
• (c) dividing a circle having a fixed radius along a circumferential direction and a radial direction, and translating into a histogram the number of edge points that exist in each of bins arising from the division to thereby extract a local feature of each of all edge points.

A non-transitory computer-readable medium including instructions, executable by a processor, for performing a method of feature registration that registers a feature used in object recognition processing for recognition of an object that exists in an image, the method comprising the steps of:

• (a) creating an edge image of a model of an object in advance;
• (b) extracting a feature of each edge point on an edge image created in the step (a), determining a base point and a support point from edge points in a local area defined for the edge image, and storing in a memory the base point, a feature of the base point, the support point, a feature of the support point, and a geometric positional relationship between the base point and the support point, the base point being a point to which attention should be paid in the local area, the support point being a point supporting the base point;
• and
• (c) dividing a circle having a fixed radius along a circumferential direction and a radial direction, and translating into a histogram the number of edge points that exist in each of bins arising from the division to thereby extract a local feature of each of all edge points.