Molecular Devices QPix 420, User Manual

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Chapter 9: Regional Picking Processes
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To select the colonies for regional picking:
1. From the list in the upper-right, select the barcode or identifier of the receptacle to view.
2. Refine the colony Selection criteria.
Compactness sets the level of irregularity for picking colonies. The value is a ratio of
the perimeter divided by the area of the colony, so that irregular shaped colonies are
closer to 0 and colonies that are more of a perfect circle are closer to 1. The system
default value is that a colony equal to or less than 0.65 and is not picked.
Axis Ratio measures how oval the colony is. The value is a ratio of the longest diameter
divided by the shortest diameter, so oval shaped colonies are closer to 0 and round
colonies are closer to 1. The system default value is that a colony equal to or less than
0.65 is not picked.
Min Diameter (mm) sets the minimum diameter of colonies for picking. A colony equal
to or smaller than the value in this field is not picked.
Note: The Min Diameter (mm) cannot be lower than the Diameter value set in the
Debris Discard section of the test image.
Max Diameter (mm) sets the maximum diameter of colonies for picking. A colony equal
to or greater than the value in this field is not picked.
Min Proximity (mm) sets the distance between colonies to be picked, so that when
picking one colony, a different adjacent colony is not picked. The system default value
is 0.45 mm.
3. For a fluorescent image, adjust the Intensity Measure as shown in the histogram. This
option is available only for instruments with a fluorescence imaging module.
Mean Intensity is the average fluorescence of the detected colony (the fluorescence of
all the pixels within the colony perimeter divided by the number of pixels within the
colony perimeter).
Median Intensity is the middle fluorescence value of all the pixels within the detected
colony perimeter.
Geometric Intensity is the geometric intensity of the detect colony or the fluorescence
of all the pixels within the colony perimeter.
Centre Mean Intensity is the average fluorescence value of the middle 9 pixels within
the detected colony perimeter.
Select Greater than, Less than, or Between and then enter a value to define the
fluorescence intensity threshold. For Between, enter two values to define the range.
4. Change the pickable property of individual objects.
To define an object as pickable, right click the object and select Pick Item to display the
object in green.
To define an object as unpickable, right click the object and select Discard Item to
display the object in blue.