Wednesday, November 25, 2015

How-To: do measurements using camera and common objects of known W/H ratio and length in "Partometer3D - camera measure"

Presentation about Partometer3D.

measure pencil accurately using square wooden tile and credit card.

How to measure:

I use square wooden tile to define the measurement plane. I don't know its dimensions, but I know that it's SQUARE:

- I go to Preferences and select Measurement Plane as Custom Plane.
- Then in How plane is defined I select Only W/H Ratio.
- Then in Custom Plane W/H Ratio I enter 1.0 (square shape).

Now with this settings I can define measurement plane using the wooden tile. I need to set the scale for the measurement plane in selected units (mm). To do this I place a credit card on the plane and use its LONG side as a reference (ROL). 

Then I set ROL size in Preferences:
  1. Using ROL is selected automatically.
  2. Touch Reference Object Length and select Credit card (Long Side) from the list.

Now I am ready to measure:
- bound the wooden tile with reference box on the screen.
- use blue ruler (ROL) to mark the credit card length
- measure the pencil with white ruler!

Please note, in this example if I use a wooden tile of known size I don't need ROL for measurements - the tile would define the plane and scale automatically as soon as we select corresponding option in Preferences and enter its dimensions.


1. Use option menu button to open Preferences in the menu. On some devices it appears as a "..." (three dots) button as you can see on the screenshots in the upper right corner. You might have a problem with this button on Samsung devices, in this case please check our post:

2."ROL" and " W / H" boxes in the lower left corner are touchable and you can do SHORT or LONG touches as a shortcut for plane and ROL settings.

3. Measurement accuracy depends on how accurate you mark your references. Please select bigger reference objects to get better result. In this presentation sheet of paper is a good choice for measurements of small objects (screws, rings, etc) on it.

Partometer3D Android app on Google Play

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