The calibration methods for image measuring instruments mainly include the following:


1. Image System Calibration:

1. Adjust the focus: use a microscope or other high-precision equipment to observe standard calipers, and adjust the focus of the image measuring instrument to ensure that the image is clear.

2. Calibrate pixel size: Use a standard measuring block of known size to measure its pixel size in the image measuring instrument. Based on the proportional relationship between the actual size and the pixel size, calibrate the pixel size.

3. Color calibration: Adjust the color parameters of the image measuring instrument to ensure that the image colors are true and accurate.

II. Mechanical System Calibration:

1.X-Y axis calibration: Use standard measuring blocks to measure along the X and Y axes, record the measurements and compare them to the standard values. Adjust the device parameters until the error is within the allowable range.

2.Z-axis calibration: Use a height gauge or standard measuring blocks to measure and calibrate the verticality and measurement accuracy of the Z-axis in the Z-axis direction.

III. Software System Calibration:

Software parameter setting: According to the actual usage situation of the image measuring instrument, set appropriate measurement parameters such as measurement speed and sampling rate.

2. Image processing calibration: by adjusting the software's image processing algorithms, optimizing image quality, and improving measurement accuracy.

IV. Comprehensive Correction Methods:

2D calibration: calibrate the X-Y worktable of the image measuring instrument to ensure the accuracy of the X and Y directions.

2. Transmission calibration: calibrate the transmission system (including the objective lens and the reticle plate) using a standard transmission target.

3. Reflective correction: calibrate the reflective system (such as reflective mirrors and collimating mirrors) using standard reflective targets.

4. Camera calibration: calibrate the imaging system of the measuring instrument, including the lens and camera, to eliminate lens distortion and dark current.

5. The optical school is properly aligned: The optical components such as the objective and eyepiece are calibrated using standard optical targets to ensure the performance of the optical system.

6. Mechanical calibration: aligning mechanical systems (including guide rails, screws, etc.) to ensure smooth and precise operation of the mechanical system.

In practice, the calibration of an image measuring instrument is usually carried out by combining the above methods according to the specific model, specifications, and usage environment of the instrument. In addition, the following points should be noted:

1. Calibration Environment: Ensure that the calibration environment is clean, dry, free from vibrations, electromagnetic interference, and maintained at a constant temperature.

2. Calibration tools: Prepare the appropriate calibration tools, such as standard measuring blocks, angle gauges, microscopes, etc.

3.Professional operation: The calibration process should be carried out by personnel with relevant knowledge and skills to avoid damage to the equipment or a decrease in measurement accuracy due to improper operation.

4. Record calibration data: Detailed record the data, adjustment parameters, and calibration results during the calibration process, which can serve as a basis for subsequent equipment maintenance and fault diagnosis.

5. Regular calibration: Based on the frequency of use and working environment of the image measuring instrument, a reasonable calibration cycle should be established to ensure the stable operation of the equipment for a long time.

In summary, the calibration of an image measuring instrument is a complex and delicate process that requires the use of various methods and tools to ensure measurement accuracy and reliability.