Leica POWER MOSAIC, LAS POWER MOSAIC User Manual

LAS Power Mosaic

Get the Big Picture

LAS Power Mosaic is designed to bring a whole
new dimension to microscopy, providing you
with a unique understanding of the relationship
between microscopic features and the overall
structure of the specimen.

LAS Power Mosaic provides the ultimate in
high-resolution specimen visualisation. Scan
the entire specimen or select a specifi c region
of interest and it’s scanned at high speed. The
captured images are immediately combined to
form a seamless mosaic image.

Once the scan is complete you can relocate
effortlessly to areas of interest with a single
mouse click and can view the live microscope
image that corresponds to a chosen location.
Additionally you can zoom and pan around the
entire digitised mosaic image using easy and
intuitive “browsing” tools.

The acquired images, including the entire
mosaic can be saved for subsequent review,
discussion with colleagues or publication.

LAS Power Mosaic is ideal for both routine and
research applications and provides modes of
scanning to suit all forms of optical microscopy.
It’s specifi cally developed to be both versatile
and easy to use. This powerful LAS option
provides the microscopist with a high
performance mosaic imaging solution while
retaining conventional use of the microscope.

Z-Stack Mosaic

In addition to the standard scanning and review
capabilities, the Power Mosaic Plus module
further extends the capability using “Z-Stack”
acquisition to provide 3-D mosaic imaging and
visualisation, ideally suited to specimens with a
wide focal range.

Key benefits include:

�

Scanning and acquisition at camera frame
rates to ensure high speed and rapid
throughput

�

Tile edge merging provides highest possible
image quality

�

No restrictions on objective or imaging
method

�

Fast and accurate relocation with easy and
intuitive review tools

�

Intelligent memory management supports
mosaic sizes limited only by available disk
space

�

Fully automated focus control and tracking

�

User control of image size to ensure
suitability for publication and archiving.

�

One click calibration for easy camera
alignment

�

Optional advanced functions, including
powerful 3-D Z-Stack mosaic acquisition for
powerful focus visualisation

Features at a Glance

Power Mosaic Scanning

�

Uses triggered image capture for fast

continuous scan and acquire

�

Standard scan available using step and

acquire for low light applications

�

Image streaming for mosaic sizes only

limited by disk space

�

Additional scans can be easily added to

extend an initial scan

Scan Patterns

�

Rectangle, Circular, Annular, Cross (+ and x),

or Random

�

Overlap of tiles allows joins to be merged

smoothly

�

Camera rotation is automatically corrected

�

Create a scan pattern interactively or by

entering the exact details

Microscope Automation

�

An Oasis XY stage and Z focus control drive

board is used

�

A software joystick or Leica smart move can

be used for stage and focus movement

�

Fully compatible with Leica Microsystems

LAS confi gured microscopes handling focus,
turret, condenser and lamp controls as
available

Leica DFC Camera

�

Exposure, saturation, gain and gamma

control from LAS controls

�

Triggered acquisition from progressive scan

and DFC FX cameras for fastest scans

�

Automatic and manual white balance

�

Color or monochrome acquisition (8 or 16-bit)

�

Shading correction for smooth mosaic

results

How it Works

When the system is initially configured a simple,
single click calibration procedure is performed
for each objective lens on the microscope. This
informs the system of the exact correlation
between a stage movement and the associated
spatial value in microns for the objective. This
calibration information enables the system
to maintain precise and accurate positional
information for each image acquired. In
particular, this also compensates for camera
rotation and stage orientation.

In addition to the spatial calibration of the system,
“shading correction” is set-up to eliminate any
uneven illumination in the acquired images.
Finally you can optionally, employ a number of
different automatic focussing techniques as
appropriate for the scanning method and the
nature of the specimen.

Once the scan area has been defined the system
automatically calculates the number of images
that need to be acquired to form a complete full
resolution mosaic of the chosen area. You simply
select the type of scan required. The exact nature
of the scan performed is fully controllable and
depends on the microscopy method employed
(eg : brightfield or fluorescence) and the format
of mosaic required. Everything else is handled
automatically by the system, using previously
defined values to determine speed, focussing
method and data format.

When the scan is complete, you may revisit
points of interest with a single mouse click or
copy all or part of the mosaic for distribution,
publication or discussion with colleagues.
Additionally, since the entire area scanned is now
available in digital form and at full resolution, the
image data is available for annotation or further
analysis within applications active in the Leica
Application Suite.

LAS Power Mosaic requires a Leica motorised
microscope, Leica Digital Camera, motorised
stepper stage, motorized focus with XY control
board, a high performance Windows PC and a
very large hard drive.

Time and Space!

The time needed to perform a scan depends
on a number of different factors, such as the
objective lens used, the illumination method
and the area to be scanned. As a general rule,
brightfi eld scanning of histological sections
can be done at the highest speeds whereas
scanning in fl uorescence or for specimens with
diffi cult focal characteristics (as are typical in
cytology) must be performed at lower speeds.
Some examples of the overall time needed for
different types of scan using predictive focus
are shown in the table below.

Space is also a variable. LAS Power Mosaic
saves all captured digital images to the PC
hard drive. Each individual full resolution image
captured from a Leica DFC300 FX digital camera
will require approximately 4.5 Megabytes of
storage space. Since a typical scan may
comprise of many hundreds, or even thousands,
of individual images the storage required can
quickly become several Gigabytes. Fortunately,
modern PC technology makes this possible.

As a general rule the amount of image data that
will result from a scan will increase fourfold
for each doubling of objective magnifi cation.
If, for example, a scan of 100 fi elds using a 10X
objective results in 400Mb of data then scanning

the same area at 20X magnifi cation will require

1.6Gb of disk storage. You have the choice of
when to save scans permanently and in which
format. If a single camera frame requires about
4Mb of storage then, in the example shown, a
total of 44Mb will be used to store the Z-Stack
data. When executing Z-Stack scans on patterns
with a large number of fi elds you should be
aware that very large amounts of data can be
generated.

Similarly, since it is necessary in Z-Stack
operation for a number of images to be acquired
at different Z positions at the same XY location,
the total time required for the scan will increase
signifi cantly. There are a number of factors that
may infl uence the scan time but as a broad
indication, the time needed to perform a normal
standard scan should be multiplied by the
number of Z slices + 50% to give an estimated
time for a Z-Stack scan.

Scan Times and Data Volumes (based on DFC300 FX)

Objective C Mount Camera µm/pixel

15mm

Fields X

15mm

Fields Y

Total

Fields

Scan Time

Seconds

Scan Time

Minutes

BMP

Image

Size (Mb)

5X 1X 1392 x 1040 1.29 12 16 97 31 0.49 406

10X 1X 1392 x 1040 0.65 24 32 388 116 1.93 1622

20X 1X 1392 x 1040 0.32 48 64 1553 461 7.18 6490

40X 1X 1392 x 1040 0.16 96 128 6214 1842 30.6 25960

Key Applications

LAS Power Mosaic is suitable for a diverse range
of applications, both research and routine.

Due to the ability to provide appropriate scanning
methods for different microscopy fields,
the system has great versatility and is used
successfully in many different environments
and applications.

Whilst LAS Power Mosaic is the perfect solution
for the scanning of histological sections, it is
also well suited for use in cytology, fluorescence
imaging, cytogenetics, bone research and many
other microscopy applications.

As the system is designed to supplement
and enhance Leica microscopes and digital
cameras it is a very affordable means to achieve
a massive increase in imaging capability and
performance without loss of any conventional
functionality.

Mosaic Review

A separate viewer program is available to
allow Power Mosaic images to be shared
with colleagues without the need to install the
complete LAS.

An Extra Dimension!

Many scanning applications are performed on thin
histological sections and, with the use of either
Autofocus or Predictive Focus, it is possible to achieve a
mosaic image of acceptable quality by acquiring a single
image tile at each location within the scan pattern. The
resulting mosaic image is thus 2 dimensional (X/Y).

In other cases the characteristics of the specimen make
acquisition of a single image inadequate for complete
visualisation because important detail is present at
different focal positions within a single image frame. This
situation is normal in cytological specimens (smears,
blood, mucous etc) but is often also the case with
fluorescence samples and some thick sections (such as
bone).

The Z-Stack technique has been developed as an optional
module specifically for imaging these high focal depth
specimens and can be applied to an entire scan pattern.
Note that due to the nature of Z-Stack acquisition it is
only possible in “Standard” scanning mode.

How does it work?

The Z-Stack technique acquires a series of images at
a pre-defined Z “spacing” at each location in the scan
pattern. You can control both the Z spacing and the total
number of images within the stack.

If, for example, you require images at 2 micron intervals
over a total focal range of 20 microns the resulting
Z-Stack will comprise 11 images of which the central
image in the stack will always be the point from which the
Z-stack was initiated. In this example there are 5 images
above and 5 images below the initial focal position, each
separated from its neighbour by 2 microns.

The resulting stack of mosaic images can be smoothly
replayed exactly as if the microscope focus knob is
being adjusted. Moreover, a single mosaic representing
the best focus image or the extended focus image can
be instantly played.

20µm

Z+10

Z+8

Z+6

Z+4

Z+2

Z

Z-2

Z-4

Z-6

Z-8

Z-10

Specification subject to change

LAS Power Mosaic

www.leica-microsystems.com

@

Leica Microsystems (Switzerland) Ltd
Stereo and Macroscope Systems
CH 9435 Heerbrugg
Switzerland