Correlation
Angle
The Correlation Angle tool allow the user to train Automation Manager
to find a specific piece of an image at any angle by comparing it to a predefined
image (what we will call the model) that has been captured at multiple angles.
Using the Correlation Angle Tool
The Correlation Angle tool needs to be trained before it can be run.
Training the Model
Select the Correlation Angle tool in the sequence by clicking it. A blue ROI
will appear on the Viewer Window. Arrange the blue ROI over the
part of the image to train. Right-click the tool and choose
"Train".
Next, look on the tool's Models page. Use the
right and left arrows to view the model you have trained at different
angles.
The dropdown menu has three options:
Model
is the actual
image of the model you have trained.
Model-Low
Resolution
shows how the model looks in low resolution
mode.
Result Image
shows an image
result of the correlation. Points of
correlation are shown as
light spots.
The Angle page sets the angles and incriments at which the model will be trained. These settings are set in degrees.
Angle Start sets the initial angle.
Angle Incriment
sets how many degrees the ROI will rotate between grabs. If the
Angle Incriment is set to 10 then the tool will grab a new picture of
the model every10 degrees.
Number of Angles sets the number of images that will be trained of the model.
If
the Number of Angles is set to 5, and the Angle Incriment is set to 10,
and the Angle Start is set to 30 then a picture of the model will be
grabbed at 30, 40, 50, 60 and 70 degrees.
Running the Correlation
Once
the tool is trained the green ROI needs to be positioned on the Viewer
Window so that the target of correllation will always be in view as
subsequent pictures are taken. When the tool is run it will but a
mark at the center of the greatest area of correllation and put record
results in the tool's parameters page.
Score is the level of correlation. 1 is a perfect match.
Angle_Radians and Degrees reports the angle at which the model had the highest level of correllation to the grabbed image.
Point is the point at the center of the greatest correllation. This point can be passed to other tools.
More Settings
On the tool's parameters page check the UseAngleHint box to suggest an angle for the tool to consider first. Set that angle in the AngleHint
box. When the AngleHint is set the tool will check the defined
angle for correlation first. This setting can be used to speed
the tool if the angle of correlation is typically known.
On the
tool's inputs page the TrainROI can be deleted. In this case the
green SearchROI can be used for training and searching.
The Correlation page sets how the tool runs. The correlation tool works by doing a low resolution
pass search for
the model (i.e. what you have trained). After this low pass
search is done over the entire image there may be several canidates
that could possibly be the right match. Next, a high
resolution
scan is done on each of the possible canidates. The
caniditate
with the highest percentage of similarity will be selected from the
image.
The Minimum Accpet Score is a percentage based on similarity (of
shape, not brightness or contrast) to the trained model. If
the
score is below the Minimum Accept Score,
nothing will be
selected from that image and it fails the part.
Sub Sample X
Sub Sample Y
The correlation does a low resolution pass search of the entire image
for the model. This
low pass search is
done to select possible regions that may correlate to the model you
have trained. Based on the possible regions found in the low
resolution pass a high resolution pass is done to select the sector
that is most similar to the trained model. The low pass
search
speeds up
the execution time
to find the model.
The subsample factors define how to render the
image for the low
pass search. For example, if the subsample is 3 then only every thrid
pixel
is used in the
low resolution pass. Note: the higher these factors the faster the
search, but if the sub sample factors are too high, then the model may
not
be found. To check
that the factors are not too high, view the "Model-Low" resolution
model and hit "Re-Train". This
low resolution model should be recognizable.




The Re-Train button will retrain the Low Pass model only.
It
will resample the model with a lower resollution for the first pass
(see above - Sub Sample). When the "Sub Sample" X and/or Y
have
been adjusted the "Re-Train" button must be hit in order for the change
to be made. You can see how the change has affected the model
be
selecting "Model-Low Resolution" from the dropdown menu.
"Re-Train" will only resample the model that has already been trained,
it will not genetrate a completely new model.