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User manual
CNC Camera Assistent
Integrated in USB-CNC
RC 1
CNC Camera Assistent

Table of Contents
1 Introduction ..................................................................................................................................... 3

1.1 Purpose.................................................................................................................................... 3

1.2 Disclaimer ................................................................................................................................ 3

2 Overview.......................................................................................................................................... 4

2.1 Functional Description............................................................................................................. 4

3 Instructions ...................................................................................................................................... 5

3.1 Calibrations.............................................................................................................................. 6

3.1.1 Set Camera Focus ............................................................................................................ 6

3.1.2 Camera Offset Calibrations ............................................................................................. 6

3.1.3 Camera measurement calibration ................................................................................... 7

3.2 Zeroing..................................................................................................................................... 9

3.3 Measurements ...................................................................................................................... 10

4 Compatibility ................................................................................................................................. 11

5 Known Issues ................................................................................................................................. 12

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CNC Camera Assistent

1 Introduction
The CNC Camera Assistent software is used in combination with USB-CNC to provide camera
assisted control of CNC machines. The current software is designed for standard USB
camera’s that can be connected to the machine running the USB-CNC user interface.

Next to control the software offers possibilities for measuring distances.

1.1 Purpose
This document describes how the software can be used for camera assisted zeroing and for
measuring. A typical setup that can be used for the software is given although the hardware
design for camera integration with the CNC machine is out of scope.

The requirements to PC-system and camera are listed in the last part of the document.

1.2 Disclaimer
THE SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. NO WARRANTIES ARE
MADE, EXPRESS OR IMPLIED, THAT THE SOFTWARE IS FREE OF ERROR, OR ARE CONSISTENT WITH
ANY PARTICULAR STANDARD OF MERCHANTABILITY, OR THAT THEY WILL MEET YOUR
REQUIREMENTS FOR ANY PARTICULAR APPLICATION. THEY SHOULD NOT BE RELIED ON FOR SOLVING
A PROBLEM WHOSE INCORRECT SOLUTION COULD RESULT IN INJURY TO A PERSON OR LOSS OF
PROPERTY. IF YOU DO USE THEM IN SUCH A MANNER, IT IS AT YOUR OWN RISK. THE AUTHOR AND
PUBLISHER DISCLAIM ALL LIABILITY FOR DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES TO
PROPERTY , HUMAN INJURIES OR FINANCIAL LOSS RESULTING FROM USE OF THE SOFTWARE.

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CNC Camera Assistent
2 Overview
The software is used in combination with an USB camera. The camera that will be selected hughly
influences the quality of the image and forthcoming the accuracy of zeroing and camera
measurements. The software has been tested with:

1) Standard webcam up to 2.0 Mpixels

2) Microscope webcam up to 1.3 Mpixels

The camera should support following two image formats: 320*240 and 1280*960 24 bits color. The
camera must be connected over USB cable to the computer running USB-CNC. The global setup is
shown below.

Computer running
USB -cable computer to camera
USB-CNC

camera

Figure 1: Camera connection over USB

Mounting of the camera is not further elaborated in this manual. It is expected however that the
camera is mounted to the mill head so that its height changes with the Z-position of the head.

2.1 Functional Description

The camera integration offers two functionalities. One is to enable zeroing in the X and Y plane.
Zeroing is enabled by moving the camera over the point of interest to which the work piece will be
zeroed. After the camera is above the zero reference point the zero buttons for X and Y can be
selected. The software is suited for zeroing on corners, points and circles. Prior to using the zero
functions an offset calibration has to be conducted to determine the offset of the camera center to
the tool tip and to allow for indicating objects in millimeters in the camera image.. This calibration
has to be conducted at a fixed Z-height to allow a clear focus of the camera.

The second function that is offered by the software allows for measuring distances between two
points in a straight line. This function is also dependent on the calibrations as executed for zeroing.

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3 Instructions
The Camera Assistant Software is started by clicking the “camera” icon in the graph menu of USB-
CNC (F2)Once enabled two more buttons will be shown. The Button for calibrating (F4) the software
and the button for measurements (F3).

Enable Camera Camera Camera

Assistant Measurements Calibration

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CNC Camera Assistent

3.1 Calibrations

3.1.1 Set Camera Focus

First thing to do is to set the camera focus. To do this the Z-height must be calibrated. Put the Z-
height in a fixed position that is convenient for you. Not to close so the camera will not collide with
the work piece but also not too far away to still use enough resolution. The advise it to mount the
camera between 50 to 100 mm from the surface of a work piece. After the Z-height has been set
select “calibrate camera(F4)” in the graph menu. The following screen will be shown.

Tooltip Camera Height

Select “storeHeightOffset” (left top button). Now the Z height is stored. Next step is to focus the
camera at this Z-position. This must be done manually and varies per camera. The camera image is
visible In the main screen which allows for visual focusing.

3.1.2 Camera Offset Calibrations

The camera offset in X,Y must be performed once. The calibration data is stored in the cnc.ini file. A
recalibration must be performed in case this file is refreshed (reinstall USB-CNC) or the position of
the camera is altered. To calibrate the camera position to the tool tip the tool tip must first be
moved to a reference point. Do this by first moving the Z-position to the Z position that is stored in

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CNC Camera Assistent
the previous calibration. Now move the tool tip above the reference point (manually). Then click the
button “Tooltip” in the calibration menu. Now move the camera image above the reference point
(red cross) and click he button “Camera”. The image can be zoomed (Zoom button/F8).

Click when tool tip Click when camera

above reference cross is above
point reference point

Use zoom keys to enlarge the

image to be able to better
calibrate the offset

3.1.3 Camera measurement calibration

Next step in calibrations is to calibrate the dimensions of the camera view, Therefore again, the
camera has to be at the previously calibrated Z-position. A ruler should be placed under the camera.
Then enable the measurement calibration by clicking the calibration button (midde left). Two
crosses will be shown: one blue, one green. Move the Green cross to one reference point by clicking
the left button. Then move the blue cross to the second reference point and click the right mouse
button. Now enter the distance, that is read from the ruler between the two points, in the textbox
next to the “Calibrate measurement button”. Then click the save button and as last step click again
on the “Calibrate measurement button”. Clicking this button stores the calibration data. You will
now return to measurement modus.

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 CNC Camera Assistent

Blue cross, reference 2. Calibrate measure

button to start
calibration and Click save button to
conclude calibration. store the calibration
value.
Concluding the
calibration actually
Green cross, reference 1.
saves the calibration
data

Fill in dimension [mm] as

read on ruler between green
and blue cross

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3.2 Zeroing
After calibrations the software can be used for zeroing based on the camera position above a
reference point. To do this move the camera above a reference point with the cross and press Zero X
and Zero Y in the USB-CNC main window. In case a circle (hole) is used to zero on, the software
supports changing the circle size that is drawn in the cross. To do this go to the calibration window
(F4) and fill in the Diameter in millimeters of the circle size. 3a-Middle of camera image
3b-Middle of camera image aligned with zeroing point
aligned with zeroing point

2-Middle of camera image

aligned with reference
point

1-Fill in circle size diameter

for easy positioning of the
middle of the camera above
the marker hole.
To move the tooltip above the refence point move the mill to X=0,Y=0.

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3.3 Measurements
The camera software can also be used to measure the distance between 2 points. Therefore the
measurement mode must be activated. This is done through the “Measure” button (F3). A green and
blue cross appear. The green cross can be paced by left clicking the mouse and the blue cross by right
clicking. The distance between both points is shown in the screen behind the text “Distance”.

Point 1

Point 2

Distance between both points (1-2) in

[mm]

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4 Compatibility
The software is compatible with most standard USB camera’s. To use the camera’s the accompanying
driver software must be installed first. The camera must support at least to resolutions: 320x240
pixels and 1280*960 pixels . The color depth must be 24 bit rgb. With this specification almost all
camera’s fulfill. However to get optimal image quality a microscope usb cam is best suited because of
their optics. Dependent on the application and use a cam with a led ring to light the workpiece is
ideal.

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CNC Camera Assistent
5 Known Issues
 After calibrations the ini-file of USBCNC is overwritten. This requires the mill to be homed
again.

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