Advanced camera calibration

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Saito Ryosuke

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Nov 27, 2021, 12:51:24 PM11/27/21
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Hi

I am trying Advanced camera calibration, which is new in version "2021-11-26_01-10-41.f48f194".
It is still running.

After completing the calibration of the top camera, the homing operation will be performed automatically.
However, on my machine, it was not appropriate to perform the homing operation with the top camera looking at the secondary fiducial. (The head collided with an object on the stage.... :-(

If possible, I would like to be able to skip the Z axis in the homing operation that occurs in the sequence when a job is run for camera calibration.
(I can avoid breaking head parts....

Oh, now TopCamera's Advanced Calibration has given me my desired result. Excellent!

thanks,
Ryosuke

tonyl...@gmail.com

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Nov 27, 2021, 3:01:44 PM11/27/21
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Hi Ryosuke,

> it was not appropriate to perform the homing operation with the top camera looking at the secondary fiducial.
I don't understand what you are saying? Did it try to home on the secondary fiducial?  The homing operation performed should be exactly as if you clicked the Home button on the Machine Control panel.  Does your machine have some special restrictions as to where the head can be before you click the Home button?

mark maker

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Nov 27, 2021, 3:45:21 PM11/27/21
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> If possible, I would like to be able to skip the Z axis in the homing operation that occurs in the sequence when a job is run for camera calibration.
> (I can avoid breaking head parts....

I don't understand what you mean. Please elaborate.

_Mark

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Saito Ryosuke

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Nov 27, 2021, 9:31:49 PM11/27/21
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Hi tony

sorry for the confusion.
I need to pay attention to the output when using automatic translation...

1. The advanced calibration of the top camera is performed for the primary and secondary fiducials.
2. The advanced calibration performs a homing operation at the end of the process. (This is where I see the problem.)

There was a problem with the placement of the objects on my stage, and I didn't anticipate that the nozzles would move when the camera was looking at the secondary fiducials.
The nozzle moved in the Z direction at that location, causing the nozzle to clash with an object on the stage.

In this case, for all fiducials, the solution should be to place the object in such a way that it avoids crashing into the nozzle when the camera is looking at it.

Automatic homing always carries with it the risk of crash.
If the calibration process does not require a homing operation, I would like to be able to choose not to return to the home position.

thanks,
Ryosuke

2021年11月28日(日) 5:01 tonyl...@gmail.com <tonyl...@gmail.com>:
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mark maker

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Nov 28, 2021, 3:53:29 AM11/28/21
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Hi Saito,

To better understand: what do you mean by "stage"?

> The nozzle moved in the Z direction at that location, causing the nozzle to clash with an object on the stage.

This should not happen. Can you be more specific? When exactly was this the case? What is your Safe Z?

> In this case, for all fiducials, the solution should be to place the object in such a way that it avoids crashing into the nozzle when the camera is looking at it.

Yes, see the Wiki here:

The camera must be free to move in a wide area (250mm × 250mm) centered around the fiducial so that the camera can perform some fast moves for various calibration purposes. Do not place the fiducial at the edge of the machine motion range.

https://github.com/openpnp/openpnp/wiki/Vision-Solutions#calibration-primary-fiducial

This large range is needed for backlash-calibration.

> Automatic homing always carries with it the risk of crash.

Ideally, it should not. The assumption is that Z homes to the maximum (single nozzle) or to the mid-point (dual nozzle) first, only then it moves in X, Y. When your nozzle is at the homed Z, it should be above all obstacles over the whole soft-limit range (i.e. where it can be after OpenPnP operation) and moving from anywhere there towards the homing end-switches.

But I agree, that we cannot take this for granted. There are machines that are manually homed, and some that need manual positioning of the head and/or nozzle safely, before homing is allowed. So full homing should not be performed implicitly.

On the other hand, Visual Homing is an option. In fact, when you do the Advanced Camera Calibration through Issues & Solutions, that's what it does (only for method ResetToFiducialLocation though).

_Mark

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