Method and system for laser intensity calibration in a three-dimensional multi-color laser scanning system

A method for color calibration in a three-dimensional multi-color laser scanning system, comprising:

• creating a field of view (FOV) calibration look up table file, wherein a laser power drift compensation is applied to a first set of output laser intensity values from color laser heads of the scanning system;
• creating a laser intensity-color reflectance calibration profile, wherein a laser power drift compensation is applied to a second set of output laser intensity values from color laser heads of the scanning system, and a FOV compensation is applied to the second set of output laser intensity values using the FOV calibration look up table file;
• creating a laser intensity-surface normal calibration profile, wherein a laser power drift compensation is applied to a third set of output laser intensity values from color laser heads of the scanning system, and a FOV compensation is applied to the third set of output laser intensity values using the FOV calibration look up table file;
• and
• calculating intrinsic color values from a fourth set of output laser intensity values, wherein a laser power drift compensation is applied to the fourth set of output laser intensity values from color laser heads of the scanning system, a FOV compensation is applied to the fourth set of output laser intensity values using the FOV calibration look up table file, and a surface normal compensation is applied to the fourth set of output laser intensity values using the laser intensity-surface normal calibration profile.

A method for color calibration in a three-dimensional multi-color laser scanning system, comprising

• scanning an object with the scanning system, wherein the scanning system scans the object with color laser heads;
• receiving laser intensities from the scanned object, wherein the received laser intensities correspond to laser intensity values;
• calibrating the laser intensity values to compensate for at least one of:
• laser power drift fluctuations affecting the received laser intensities,
• FOV scanning position changes affecting the received laser intensities, and
• surface normal directions affecting the received laser intensities;
• and
• calculating one or more color values of the scanned object using the calibrated laser intensity values;
• wherein the step of calibrating laser intensity values to compensate for laser power drift fluctuations, comprises applying a laser power drift compensation to the laser intensity values, wherein the laser power drift compensation is achieved by using a linear regression fit analysis;
• and
• wherein the step of calibrating the laser intensity values to compensate for FOV scanning position changes, comprises applying a FOV compensation to the laser intensity values, further comprising the steps of:
• obtaining laser intensity values from a FOV calibration lookup table for given scanning positions;
• obtaining a linear regression fit equation by using the laser intensity values from the FOV calibration lookup table and the highest average intensity value from the FOV calibration target;
• and
• determining FOV compensated laser intensity values by applying the linear regression fit equation to the laser intensity values.

A computer readable medium encoded with a plurality of processor-executable instructions for implementing a computerized method for color calibration in a three-dimensional multi-color laser scanning system, the instructions comprising the steps of:

• scanning an object with the scanning system, wherein the scanning system scans the object with color laser heads;
• receiving laser intensities from the scanned object, wherein the received laser intensities correspond to laser intensity values;
• calibrating the laser intensity values to compensate for at least one of:
• laser power drift fluctuations affecting the received laser intensities,
• FOV scanning position changes affecting the received laser intensities, and
• surface normal directions affecting the received laser intensities;
• and
• calculating one or more color values of the scanned object using the calibrated laser intensity values;
• wherein the step of calibrating laser intensity values to compensate for laser power drift fluctuations, comprises applying a laser power drift compensation to the laser intensity values, wherein the laser power drift compensation is achieved by using a linear regression fit analysis;
• wherein the step of calibrating the laser intensity values to compensate for FOV scanning position changes, comprises applying a FOV compensation to the laser intensity values, further comprising the steps of:
• obtaining laser intensity values from a FOV calibration lookup table for given scanning positions;
• obtaining a linear regression fit equation by using the laser intensity values from the FOV calibration lookup table and the highest average intensity value from the FOV calibration target;
• and
• determining FOV compensated laser intensity values by applying the linear regression fit equation to the laser intensity values.

A system for color calibration in a three-dimensional multi-color laser scanning system, comprising:

• a scanning system;
• and
• a computer system, in communication with the scanning system, programmed to implement a method for color calibration in the scanning system, comprising:
• a memory for storing instructions;
• and
• a processor in communication with the memory, the processor operative to utilize the instructions stored in the memory for executing the method, comprised of the steps:
• scanning an object with the scanning system, wherein the scanning system scans the object with color laser heads;
• receiving laser intensities from the scanned object, wherein the received laser intensities correspond to laser intensity values;
• calibrating the laser intensity values to compensate for at least one of:
• laser power drift fluctuations affecting the received laser intensities,
• FOV scanning position changes affecting the received laser intensities, and
• surface normal directions affecting the received laser intensities;
• and
• calculating one or more color values of the scanned object using the calibrated laser intensity values;
• wherein the step of calibrating laser intensity values to compensate for laser power drift fluctuations, comprises applying a laser power drift compensation to the laser intensity values, wherein the laser power drift compensation is achieved by using a linear regression fit analysis;
• wherein the step of calibrating the laser intensity values to compensate for FOV scanning position changes, comprises applying a FOV compensation to the laser intensity values, further comprising the steps of:
• obtaining laser intensity values from a FOV calibration lookup table for given scanning positions;
• obtaining a linear regression fit equation by using the laser intensity values from the FOV calibration lookup table and the highest average intensity value from the FOV calibration target;
• and
• determining FOV compensated laser intensity values by applying the linear regression fit equation to the laser intensity values.