Three-dimensional shape measuring apparatus, three-dimensional shape measuring method, three-dimensional shape measuring program, and recording medium

1. A three-dimensional shape measuring apparatus for measuring a three-dimensional shape of a target object by analyzing an optical pattern projected onto the target object, the three-dimensional shape measuring apparatus comprising:

optical pattern projecting means that projects the optical pattern onto a portion of a measurement surface on which the target object is placed, the optical pattern having brightness changing periodically according to a position;

a first line sensor that images an optical pattern-emitted region onto which the optical pattern of the target object is projected;

a second line sensor that images an optical pattern-non-emitted region onto which the optical pattern of the target object is not projected; and

processing means that calculates a phase of the optical pattern at a pixel included in an image obtained by removing background information from images taken by the first and second line sensors based on a brightness value of the pixel and a neighboring pixel in the image, and calculates height information of the target object based on the calculated phase,

wherein the first and second line sensors are arranged at such positions that the first and second line sensors can respectively image the optical pattern-emitted region and the optical pattern-non-emitted region at a time, and

wherein a uniform illumination is emitted to the optical pattern-non-emitted region.

2. The three-dimensional shape measuring apparatus according to claim 1 , comprising:

imaging means that includes a plurality of line sensors,

wherein two of the plurality of line sensors of the imaging means are used as the first line sensor and the second line sensor.

3. The three-dimensional shape measuring apparatus according to claim 2 , comprising:

a pattern generator that includes a transparent section and a shielding section for forming the optical pattern on the optical pattern-emitted region and emitting the uniform illumination on the optical pattern-non-emitted region.

4. The three-dimensional shape measuring apparatus according to claim 2 , further comprising:

uniform illumination projecting means that projects onto the optical pattern-non-emitted region the uniform illumination having the same amount of light as that of the optical pattern projected by the optical pattern projecting means.

5. The three-dimensional shape measuring apparatus according to claim 1 , comprising:

color imaging means that includes a line sensor for detecting brightness of colors of red, green, blue, black and white, wherein

the line sensor for black and white is used as the first line sensor, and

the line sensor for red, green and blue is used as the second line sensor.

6. The three-dimensional shape measuring apparatus according to claim 5 , comprising:

a pattern generator that includes a transparent section and a shielding section for forming the optical pattern on the optical pattern-emitted region and emitting the uniform illumination on the optical pattern-non-emitted region.

7. The three-dimensional shape measuring apparatus according to claim 5 , further comprising:

uniform illumination projecting means that projects onto the optical pattern-non-emitted region the uniform illumination having the same amount of light as that of the optical pattern projected by the optical pattern projecting means.

8. The three-dimensional shape measuring apparatus according to claim 1 , comprising:

color imaging means that includes a line sensor for detecting brightness of colors of red, green, blue, black and white, wherein

a sensor including the line sensor for black and white and a filter for any one of the colors of red, green, and blue is used as the first line sensor, and

a line sensor for one of the colors of red, green, and blue that is the same color as the color of the filter is used as the second line sensor.

9. The three-dimensional shape measuring apparatus according to claim 8 , wherein the first line sensor and the second line sensor image the optical pattern-emitted region and the optical pattern-non-emitted region through an identical lens.

10. The three-dimensional shape measuring apparatus according to claim 8 , comprising:

a pattern generator that includes a transparent section and a shielding section for forming the optical pattern on the optical pattern-emitted region and emitting the uniform illumination on the optical pattern-non-emitted region.

11. The three-dimensional shape measuring apparatus according to claim 8 , further comprising:

uniform illumination projecting means that projects onto the optical pattern-non-emitted region the uniform illumination having the same amount of light as that of the optical pattern projected by the optical pattern projecting means.

12. The three-dimensional shape measuring apparatus according to claim 1 , comprising:

first imaging means that has a first line sensor;

second imaging means that has a second line sensor;

a first mirror that is arranged such that a visual axis of the first line sensor faces the optical pattern-emitted region; and

a second mirror that is arranged such that a visual axis of the second line sensor faces the optical pattern-non-emitted region.

13. The three-dimensional shape measuring apparatus according to claim 12 , comprising:

a pattern generator that includes a transparent section and a shielding section for forming the optical pattern on the optical pattern-emitted region and emitting the uniform illumination on the optical pattern-non-emitted region.

14. The three-dimensional shape measuring apparatus according to claim 12 , further comprising:

uniform illumination projecting means that projects onto the optical pattern-non-emitted region the uniform illumination having the same amount of light as that of the optical pattern projected by the optical pattern projecting means.

15. The three-dimensional shape measuring apparatus according to claim 1 , comprising:

a pattern generator that includes a transparent section and a shielding section for forming the optical pattern on the optical pattern-emitted region and emitting the uniform illumination on the optical pattern-non-emitted region.

16. The three-dimensional shape measuring apparatus according to claim 1 , further comprising:

uniform illumination projecting means that projects onto the optical pattern-non-emitted region the uniform illumination having the same amount of light as that of the optical pattern projected by the optical pattern projecting means.

17. A three-dimensional shape measuring method for a three-dimensional shape measuring apparatus that measures a three-dimensional shape of a target object by analyzing an optical pattern projected onto the target object,

wherein the three-dimensional shape measuring apparatus includes optical pattern projecting means, a first line sensor, and a second line sensor, and

wherein the first and second line sensors are arranged at such positions that the first and second line sensors can respectively image, at a time, an optical pattern-emitted region onto which the optical pattern of the target object is projected and an optical pattern-non-emitted region onto which the optical pattern of the target object is not projected,

wherein a uniform illumination is emitted to the optical pattern-non-emitted region;

the three-dimensional shape measuring method comprising:

an optical pattern projecting step in which the optical pattern projecting means projects the optical pattern onto a portion of a measurement surface on which the target object is placed, the optical pattern having brightness changing periodically according to a position;

an imaging step in which the first line sensor images the optical pattern-emitted region, and the second line sensor images the optical pattern-non-emitted region; and

a calculation step including:

calculating a phase of the optical pattern at a pixel included in an image obtained by removing background information from images taken by the first and second line sensors, based on a brightness value of the pixel and a neighboring pixel in the image; and

calculating height information of the target object based on the calculated phase.

18. A three-dimensional shape measuring program, stored on a non-transitory computer readable medium, for executing a three-dimensional shape measuring method for a three-dimensional shape measuring apparatus that measures a three-dimensional shape of a target object by analyzing an optical pattern projected onto the target object, the three-dimensional shape measuring apparatus comprising:

optical pattern projecting means that projects the optical pattern onto a portion of a measurement surface on which the target object is placed, the optical pattern having brightness changing periodically according to a position;

a first line sensor that images an optical pattern-emitted region onto which the optical pattern of the target object is projected; and

a second line sensor that images an optical pattern-non-emitted region onto which the optical pattern of the target object is not projected,

wherein a uniform illumination is emitted to the optical pattern-non-emitted region,

wherein the first and second line sensors are arranged at such positions that the first and second line sensors can respectively image, at a time, the optical pattern-emitted region and the optical pattern-non-emitted region, and

wherein the three-dimensional shape measuring program causes a computer to execute a calculation step including:

calculating a phase of the optical pattern at a pixel included in an image obtained by removing background information from images taken by the first and second line sensors, based on a brightness value of the pixel and a neighboring pixel in the image; and

calculating height information of the target object based on the calculated phase.