Page 13
How to Measure Leaf Area by Conveyor
1.
In
Settings, Video, Advanced Video Config
... set the video camera shutter
speed to about 10ms. If the shutter speed is too
slow the image blurs and
accuracy is lost. If too fast the illumination beats with the mains frequency.
2.
In
Settings, Video,
Advanced Camera Config...
optimise lens aperture and
camera settings.
3.
It may be necessary to repeat steps 1& 2 to optimise the image.
4. To save the camera settings see
on page 6.
5.
Grab
an image of a stationary ruler and
Calibrate
as described above.
6.
Grab
an image of a stationary leaf and pick healthy and diseased areas.
7. Enable
Conveyor
in the
Area
Control Window
8. Select live
Video.
9. Turn on the Conveyor via its own Control Box.
Note it can go forwards and backwards. When running correctly, each leaf is
grabbed once, only when fully in the field of view (or
Area of Interest
, if defined).
10. Feed leaves in and check they are being fully thresholded.
If necessary, adjust the colour picking thresholds until you are satisfied.
11. Clear any unwanted results using the delete button
12. Enable
Log data
in the
Area
Control Window, and name a results file in the
Save
As
dialog.
13. Feed leaves carefully into the conveyor, one at a time.
See also the
online Help
and
WinDIAS User Manual.
How to Measure Long Leaves
Use this for leaves which are too long to be grabbed all at once.
The Long Leaf mode requires a reference leaf of known area for calibration.
Instead of grabbing each whole leaf once, the conveyor constantly measures a narrow
vertical strip in the field of view, as the leaf continuously enters, producing a
cumulative total proportional to the whole area. This is then scaled according to the
known area of the reference leaf, which you have to determine independently.
1. Cut a short section from your long leaf, feed into the centre of the conveyor, stop
the conveyor unit, grab and measure the area, having calibrated using a ruler.
2. Enable both
Conveyor
and
Long Leaf
modes, and turn the conveyor unit on.
3. Feed through your reference leaf again, and enter its known area when asked.
4. The long leaf mode is now calibrated.
5. Feed leaves carefully into the conveyor, one at a time
.
