Apparatus and method for measuring 3d shapes of objects using event based camera

A three-dimensional measurement method, comprising steps of

• projecting a line-shaped light pattern onto an object being measured, such that the object is scanned by the line-shaped light pattern;
• two-dimensionally imaging the object, pixel by pixel, at irregular intervals while the line-shaped light pattern is projected to the object;
• and
• measuring a three-dimensional shape of the object based on image data of the object imaged by an imaging unit by applying a light-section method to the image data, wherein the imaging unit is provided with an imaging element configured to have previously set two-dimensional coordinate positions and output event data, the event data being generated from pixels subjected to changes in luminance of the light reflected from the object, the event data being associated with two-dimensional coordinate positions among the previously set two-dimensional coordinate positions, the event data being positive-polarity event data when the luminance changes to be brighter,
• wherein the measurement step is configured to measure a three-dimensional shape of the object in accordance with the light-sectioning method, based on selected positive-polarity event data, wherein the selected positive-polarity event data are provided, pixel by pixel, by removing, among the plurality of positive-polarity event data at each of the pixels of the imaging element, first positive-polarity event data immediately followed by second positive-polarity event data with a time difference between the first and second positive-polarity event data, the time difference being less than or equal to a predetermined threshold.

A three-dimensional measurement apparatus, comprising:

• a light projection device configured to project a line-shaped light pattern onto an object being measured, such that the object is scanned by the line-shaped light pattern;
• an imaging unit configured to two-dimensionally image the object, pixel by pixel, at irregular intervals while the line-shaped light pattern is projected to the object;
• and
• a measurement unit configured to measure a three-dimensional shape of the object based on image data of the object imaged by the imaging unit by applying a light-section method to the image data,
• wherein
• the imaging unit is provided with an imaging element configured to have previously set two-dimensional coordinate positions and output event data, the event data being generated at pixels subjected to changes in luminance of the light reflected from the object by being projected by the light projection device, the event data being associated with two-dimensional coordinate positions among the previously set two-dimensional coordinate positions, the event data being positive-polarity event data when the luminance changes to be brighter;
• and
• the measurement unit comprises
• a signal processing circuit that produces selected positive-polarity event data which are provided, pixel by pixel, by removing, among the plurality of positive-polarity event data at each of the pixels of the imaging element, first positive-polarity event data immediately followed by second positive-polarity event data with a time difference between the first and second positive-polarity event data, the time difference being less than or equal to a predetermined threshold;
• and
• a measuring circuit that measures a three-dimensional shape of the object in accordance with the light-sectioning method, based on the selected positive-polarity event data.