External 2D Camera as EIH Camera Calibration Workflow

Updated on 2026 / 07 / 23

Examples are valid for:
TMflow Software version: 2.22 or above.
TM Robot Hardware version: All
Other specific requirements: None 
Note that older or newer software versions may have different results.

 

 

Background

 

The built-in TM Robot camera is a zoom camera suitable for most scenarios. If you have specific requirements for resolution, field of view, working distance, or capture speed, you will need an external camera and must complete intrinsic calibration. When the camera moves with the robot arm, hand-eye calibration is also required to convert image coordinates into robot coordinates. 

 


Camera Intrinsic Calibration 

 

Confirm environment and lens parameters → Adjust camera → Capture 15 calibration board images → Compute intrinsics

 

 1. Confirm environment and lens : Verify working distance (D), field of view (FOV), and depth of field(L). Check pixel size (mm) and focal length (f), then estimate the target aperture using (recommended k = 2).

  F = (L × f2) / (2 × k × pixel size × D2)
 
 2. Adjust camera : Use a wide aperture to find focus → stop down to target F → adjust lighting for brightness. Do not change focus or aperture after this step. 
 

Excellent sharpness

Poor sharpness

 
 3. Capture calibration board images : Change the board normal vector orientation (not just in-plane rotation). Start calibration after collecting 15 images with detectable corner points. 
 
 
 
 
Key Reminders 
 
  • When tilting the board, keep the entire surface within the depth of field. Keep the board flat and avoid movement at the moment of capture. 
  • Corner points should cover as much of the image as possible. Use multiple images to complement coverage if one image is insufficient. Only corner points marked in red are included in the calculation. 
 
Common Mistakes Recommended Actions
Changing aperture, focus, or working distance during calibration Lock settings after camera adjustment and keep them unchanged
Rotating the board only within the same orientation Change the normal vector direction to ensure sufficient pose diversity 
Board outside depth of field, bent, or moving during captureConfirm corner points are sharp; reinforce the board and sedure it before capture 
 
 
Complete corner coverage 
Multiple images collectively covering the FOV
FOV do not overlap 
 
 

Camera Hand-Eye Calbiration

 

An external EIH camera is mounted on the robot arm end. After calibration, the TCP is named HandCamera2 (this name cannot be changed).
 
Mount camera → Intrinsic calibration → Import calibration project → Calibrate hand-eye relationship
 
 4. Mount camera : install the camera securely and measure the offset relative to the robot flange. Use Standard Mode if the offset is within X/Y +/-150 mm, Z +200 mm and Rx/Ry +/- 10 degrees; otherwise use Customized Mode (manually teach 15 points). 
 
 
 5. Import Project :  Download Calibration_Project_222_v1.zip from the [Download Center], place Customized_EIH_Calibration.zip on the USB drive at TMROBOT:\TM_Export\RobotID\Projects, then import the porject and TCP via TMflow > Settings > System > Import/Export. 
 
 

 

 

 

 6. Run Calibration : Bind the EIH camera, fix Landmark 2.0 on the actual work plane, set capture points, capture point by point, and confirm that `HandCamera2` is created successfully.

 

Key Reminders 

 

  • Camera mounting position and calibration environment must match the actual application. Aperture, focal length, and working distance must remain the same as in intrinsic calibration.
  • Landmark should be centered and occupy about 1/9 of the image, fully within the field of view and clearly visible during capture.

 

Common Mistakes Recommended Actions
Loose camera mount or position changed after calibration Secure installation and do not move the camera after calibration 
LM out of frame or improper size in image Center it and keep it at about 1/9 of the image for stable detection 
Calibration environment differs from actual application Calibrate at the actual working position and height 
Wrong Standard / Customized Mode selected Choose the mode based on measured installation offset

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