How to measure the offset - PIX4Dcatch RTK – Support

When using the viDoc RTK rover with an Android device or iOS device with a universal mount, the offsets between the antenna and the camera should be set to have precise measurements. Entering these offsets allows PIX4Dcatch to accurately compute the locations received by the viDoc RTK rover with the content captured.

IN THIS ARTICLE

Devices with known offset
Mount the device to the viDoc RTK rover
Measure the x-axis
Measure the y-axis
Measure the z-axis
Enter the axis values

Devices with known offset

There are well tested combination of devices and viDoc RTK rovers, where there is no need to measure the offset. PIX4Dcatch will automatically fill the fields with correct offset values.

Smartphone model of viDoc RTK rover	Tablet model of viDoc RTK rover
iPhone 14 Pro Max iPhone 14 Pro iPhone 13 Pro Max iPhone 13 Pro iPhone 12 Pro Max iPhone 12 Pro iPhone 11 Pro Max iPhone 11 Pro iPhone XR iPad Pro 11	iPad Pro 11

Mount the device to the viDoc RTK rover

PIX4Dcatch Android RTK measure offset axes diagram

Mounted device illustrating the orientation of axes to measure.

Mount the device to the viDoc RTK rover using the appropriate SP-connect case. Phone cases can be purchased separately from the SP-connect website. The SP-connect universal phone mount can be used if the custom model is unavailable. SP-connect cases are also available in most bicycle and motorcycle shops.

Place the device in landscape mode and the display to the front. Notate the orientation of the x, y, and z axes and how they relate to the point of origin on the antenna to measure from. The point of origin resides in the middle of the screw mount at the base of the antenna. It will also be necessary to determine which lens to measure from for devices with multiple camera lenses.

For more information: Mounting a device to the viDoc RTK rover.

Tip: If you don't know which camera lens to measure from. Start PIX4Dcatch and then place something in front of each camera lens. The lens blocked is the appropriate lens to measure from.

Tip: If you use iPad, make sure the device is in landscape mode, and the antenna is pointing upwards. Most probably, the x and y offset values are negative values.

Important: When using the universal mount, the lens and device must be below the antenna when mounting the device to the viDoc.

Measure the x-axis

Measure and notate the value from the antenna base to the center of the lens along the axis for the x-axis offset.

PIX4Dcatch Android RTK measure x offset diagram

Diagram: How to measure the x-axis.

Measure the y-axis

Measure and notate the value from the center of the antenna to the center of the lens along the axis for the y-axis offset.

PIX4Dcatch Android RTK measure y offset diagram

Diagram: How to measure the y-axis.

Measure the z-axis

Measure and notate the depth from the center of the antenna to the center of the lens for the z-axis offset.

PIX4Dcatch Android RTK measure z offset diagram

Diagram: How to measure the z-axis.

Important: Most cases and adaptors are adding extra offset on top of the screen. Make sure, that Z-axis offset is measured to the lens and not the case/adaptor.

Enter the axis values

With the camera offsets properly measured and notated, they can be input into their appropriate Camera Offset Values (Centimeters/Inches) field of the RTK Device Settings dialog. Depending on the region set in the device, centimeters or inches will be the measurement system used for input.

PIX4Dcatch Android RTK device settings dialog

RTK Device Settings dialog for iOS and Android.

Important: Ensure that offset values are entered in the correct units. At Android, the unit setting is not directly available; it is tightened to the language settings. It can be adjusted in the Android global settings under Languages (or App languages). For iOS, units setting is available under the General settings -> Language & Region ->Measurement system.

The camera's offset has been properly set with the populated Camera Offset Values (Centimeters/Inches) field. Continue with the RTK Device Settings dialog to complete the viDoc RTK connection to the device.

For more information: How to use Pix4Dcatch with viDoc RTK rover.