Three dimensional shape measurement apparatus, control method therefor, and storage medium

A three dimensional shape measurement apparatus comprising:

• a projection unit configured to project a stripe pattern including a light portion and a dark portion to a measurement area;
• a photographing unit configured to photograph a target object in the measurement area while the stripe pattern is projected by the projection unit, wherein the photographing unit has single image sensing element and single focus position;
• a detection unit configured to detect an edge position representing a boundary between a light portion and a dark portion based on an image photographed by the photographing unit;
• and
• a measurement unit configured to measure a three dimensional shape of the target object based on the edge position detected by the detection unit,
• wherein a focus position of the photographing unit is set farther than a position which is determined by an axis going through a center of a projection range of the projection unit and an axis going through a center of a photographing range of the photographing unit, when observed from the photographing unit,
• wherein the focus position of the photographing unit is not set nearer than the determined position which is determined by the axis going through the center of the projection range of the projection unit and the axis going through the center of the photographing range of the photographing unit, when observed from the photographing unit.

A three dimensional shape measurement apparatus comprising:

• a projection unit configured to project a pattern including a light part region and a dark part region to a target object;
• a photographing unit configured to photograph the target object to which the pattern is projected;
• a detection unit configured to detect an edge position representing a boundary between the light part region and the dark part region based on an image photographed by the photographing unit;
• and
• a measurement unit configured to measure a three dimensional shape of the target object based on the edge position detected by the detection unit,
• wherein a focus position of the photographing unit is, in a measurement area that is within a predetermined range of region from a measurement reference plane including a position which is determined by an axis going through a center of a projection range of the projection unit and an axis going through a center of a photographing range of the photographing unit, set farther than the measurement reference plane when observed from the photographing unit,
• wherein a contrast value between the light part region and the dark part region in the image photographed by the photographing unit has a maximum value in an area farther than the position, when observed from the photographing unit.

A three dimensional shape measurement apparatus comprising:

• a projection unit configured to project a pattern including a light portion and a dark portion to a target object;
• a photographing unit configured to photograph the target object onto which the pattern is projected;
• a detection unit configured to detect an edge position representing a boundary between the light portion and the dark portion based on an image photographed by the photographing unit;
• and
• a measurement unit configured to measure a three dimensional shape of the target object based on the edge position detected by the detection unit,
• wherein a focus position of the photographing unit is set farther than a position which is determined by an axis going through a center of a projection range of the projection unit and an axis going through a center of a photographing range of the photographing unit, when observed from the photographing unit, such that a measurement error of the edge position determined based on a brightness of a photographed image and a contrast value of the photographed image in a first measurement plane that is a measurement plane nearest to the photographing unit becomes substantially equal to a measurement error of the edge position in a second measurement plane that is the farthest from the photographing unit, of measurement planes in a measurement area that is an area within a predetermined range from a measurement reference plane including the position which is determined by the axis going through the center of the projection range of the projection unit and the axis going through the center of the photographing range of the photographing unit.

A control method for a three dimensional shape measurement apparatus including a projection unit, a photographing unit, and a measurement unit, the method comprising:

• a projection step of causing the projection unit configured to project a stripe pattern including a light portion and a dark portion to a measurement area;
• a photographing step of causing the photographing unit configured to photograph a target object in the measurement area while the stripe pattern is projected by the projection unit, wherein the photographing unit has single image sensing element and single focus position;
• a detection step of detecting an edge position representing a boundary between a light portion and a dark portion based on an image photographed by the photographing unit;
• and
• a measurement step of causing the measurement unit configured to measure a three dimensional shape of the target object based on the edge position detected by the detection unit,
• wherein a focus position of the photographing unit is set farther than a position which is determined by an axis going through a center of a projection range of the projection unit and an axis going through a center of a photographing range of the photographing unit, when observed from the photographing unit,
• wherein the focus position of the photographing unit is not set nearer than the position which is determined by the axis going through the center of the projection range of the projection unit and the axis going through the center of the photographing range of the photographing unit, when observed from the photographing unit.

A control method for a three dimensional shape measurement apparatus including a projection unit, a photographing unit, and a measurement unit, the method comprising:

• a projection step of causing the projection unit configured to project a pattern including a light part region and a dark part region to a target object;
• a photographing step of causing the photographing unit configured to photograph the target object to which the pattern is projected;
• a detection step of detecting an edge position representing a boundary between the light part region and the dark part region based on an image photographed by the photographing unit;
• and
• a measurement step of causing the measurement unit configured to measure a three dimensional shape of the target object based on the edge position detected by the detection unit,
• wherein a focus position of the photographing unit is, in a measurement area that is within a predetermined range of region from a measurement reference plane including a position which is determined by an axis going through a center of a projection range of the projection unit and an axis going through a center of a photographing range of the photographing unit, set farther than the measurement reference plane when observed from the photographing unit,
• wherein a contrast value between the light part region and the dark part region in the image photographed by the photographing unit has a maximum value in an area farther than the position, when observed from the photographing unit.

A control method for a three dimensional shape measurement apparatus including a projection unit, a photographing unit, and a measurement unit, the method comprising:

• a projection step of causing the projection unit configured to project a pattern including a light portion and a dark portion to a target object;
• a photographing step of causing the photographing unit configured to photograph the target object onto which the pattern is projected;
• a detection step of detecting an edge position representing a boundary between the light portion and the dark portion based on an image photographed by the photographing unit;
• and
• a measurement step of causing the measurement unit configured to measure a three dimensional shape of the target object based on the edge position detected by the detection unit,
• wherein a focus position of the photographing unit is set farther than a position which is determined by an axis going through a center of a projection range of the projection unit and an axis going through a center of a photographing range of the photographing unit, when observed from the photographing unit, such that a measurement error of the edge position determined based on a brightness of the photographed image and a contrast value of the photographed image in a first measurement plane that is a measurement plane nearest to the photographing unit becomes substantially equal to a measurement error of the edge position in a second measurement plane that is the farthest from the photographing unit, of measurement planes in a measurement area that is an area within a predetermined range from a measurement reference plane including the position which is determined by an axis going through the center of the projection range of the projection unit and the axis going through the center of the photographing range of the photographing unit.

A non-transitory computer-readable storage medium storing a computer program for causing a computer to execute each step in a control method for a three dimensional shape measurement apparatus, the method comprising:

• a projection step of causing the projection unit configured to project a stripe pattern including a light portion and a dark portion to a measurement area;
• a photographing step of causing the photographing unit configured to photograph a target object in the measurement area while the stripe pattern is projected by the projection unit, wherein the photographing unit has single image sensing element and single focus position;
• a detection step of detecting an edge position representing a boundary between a light portion and a dark portion based on an image photographed by the photographing unit;
• and
• a measurement step of causing the measurement unit configured to measure a three dimensional shape of the target object based on the edge position detected by the detection unit,
• wherein a focus position of the photographing unit is set farther than a position which is determined by an axis going through a center of a projection range of the projection unit and an axis going through a center of a photographing range of the photographing unit, when observed from the photographing unit,
• wherein the focus position of the photographing unit is not set nearer than the position which is determined by the axis going through the center of the projection range of the projection unit and the axis going through the center of the photographing range of the photographing unit, when observed from the photographing unit.

A non-transitory computer-readable storage medium storing a computer program for causing a computer to execute each step in a control method for a three dimensional shape measurement apparatus, the method comprising:

• a projection step of causing the projection unit configured to project a pattern including a light part region and a dark part region to a target object;
• a photographing step of causing the photographing unit configured to photograph the target object to which the pattern is projected;
• a detection step of detecting an edge position representing a boundary between the light part region and the dark part region based on an image photographed by the photographing unit;
• and
• a measurement step of causing the measurement unit configured to measure a three dimensional shape of the target object based on the edge position detected by the detection unit,
• wherein a focus position of the photographing unit is, in a measurement area that is within a predetermined range of region from a measurement reference plane including a position which is determined by an axis going through a center of a projection range of the projection unit and an axis going through a center of a photographing range of the photographing unit, set farther than the measurement reference plane when observed from the photographing unit,
• wherein a contrast value between the light part region and the dark part region in the image photographed by the photographing unit has a maximum value in an area farther than the position, when observed from the photographing unit.

A non-transitory computer-readable storage medium storing a computer program for causing a computer to execute each step in a control method for a three dimensional shape measurement apparatus, the method comprising:

• a projection step of causing the projection unit configured to project a pattern including a light portion and a dark portion to a target object;
• a photographing step of causing the photographing unit configured to photograph the target object onto which the pattern is projected;
• a detection step of detecting an edge position representing a boundary between the light portion and the dark portion based on an image photographed by the photographing unit;
• and
• a measurement step of causing the measurement unit configured to measure a three dimensional shape of the target object based on the edge position detected by the detection unit,
• wherein a focus position of the photographing unit is set farther than a position which is determined by an axis going through a center of a projection range of the projection unit and an axis going through a center of a photographing range of the photographing unit, when observed from the photographing unit, such that a measurement error of the edge position determined based on a brightness of a photographed image and a contrast value of the photographed image in a first measurement plane that is a measurement plane nearest to the photographing unit becomes substantially equal to a measurement error of the edge position in a second measurement plane that is the farthest from the photographing unit, of measurement planes in a measurement area that is an area within a predetermined range from a measurement reference plane including the position which is determined by an axis going through the center of the projection range of the projection unit and the axis going through the center of the photographing range of the photographing unit.