1. What is calibration?
Calibration is essential for the DermoPico Hair APP to function. Since our CMA Hair devices are used with various types of cellphones and distinct models of cellphone possess different camera modules, selecting the exact region-of-interest (ROI) from the images taken by different cellphones is key to accurate hair diagnosis. Our DermoPico Hair calibration procedure is designed just to achieve this.
With calibration we obtain a key parameter “size-factor“. By storing this size-factor in APP, each time when a hair image is captured we are able to get from the image the exact ROI for diagnosis.
To perform calibration, make sure you have the CMA Hair device correctly attached to your cellphone allowing ideal alignment of the camera lens and the CMA Hair device peephole. We begin calibration by capturing an image of the calibration paper. Do ensure you are using the high-quality calibration paper that comes with the CMA Hair device. Using any self-printed calibration paper will affect the calibration and diagnoses results.
Figure 1. Calibration paper for DermoPico Hair application
2. Calibration for DermoPico Hair
We begin calibration by capturing an image of the calibration paper. The only requirement when taking the image is to make sure the middle red dot is at the center of the field-of-view (FoV), or say at the center of the peephole of the CMA Hair device. Well captured DermoPico Hair calibration images are as follows.
Figure 2. Well captured DermoPico Hair calibration images
To ensure calibrations are done correctly, we can check the result images given by our calibration algorithm. The following images demonstrate examples of nicely done hair calibrations from which we can see a green circle well fits the peephole while staying reasonably away from the edge of the device.
Figure 3. Example results of correctly done DermoPico Hair calibrations
The following table shows example Hair ROI images after calibration with different mobile devices.
| Cellphone Model | Original Image | ROI Image |
|---|---|---|
| Galaxy S9 |  |  |
| iPad Mini 6 |  |  |
| iPhone 6s |  |  |
| iPhone 12 |  |  |
3. When calibration is necessary
The table below summarizes the criteria when calibration is necessary in the DermoPico Hair APP:
- Initial use of the DermoPico Hair APP and the CMA Hair device
- Upon removal and reinstallation of the DermoPico Hair APP
- Upon full detachment and reattachment of the CMA Hair device and the holder
- When you notice diagnoses result images come out with parts of the CMA Hair device in it. This could happen if after previous successful calibration, the CMA Hair device holder has shifted position