BNC 1420 User Manual

Instruction Manual

Model 1420

Video Microscope

2955 Kerner Blvd., #2 San Rafael, CA 94901 Ph: 415-453-9955 Fx: 415-453-9956

www.berkeleynucleonics.com

1 INTRODUCTION.....................................3

1.1 Package contents............................................................ 3

1.2 Basic functions ............................................................... 3

1.3 Computer requirements.................................................. 4

1.4 Installing the software .................................................... 5

1.4.1 Installing the Hauppauge WinTV video card......................5

1.4.2 Installing the ADS USB2.0 capture peripheral...................6

1.4.3 Installing the scopePRO Software......................................6

1.5 Setting up the Model 1420.............................................. 7

1.6 Field-upgradeable software............................................ 7

1.7 Getting help..................................................................... 8

2 SVM340 HARDWARE ............................8

2.1 Front panel controls ....................................................... 9

2.2 Back panel connections............................................... 11

2.2.1 Video output......................................................................11

2.2.2 Digital inputs and outputs .................................................11

2.2.3 External Illuminator ..........................................................11

2.2.4 RS232 serial connector......................................................12

2.3 Microscope stage.......................................................... 12

2.4 Camera module............................................................. 13

2.5 Microscope objective.................................................... 14

2.6 Fluorescence filter ........................................................ 15

2.7 Illuminator module........................................................ 15

2.8 Base stand..................................................................... 16

3 VIDEO AND ILLUMINATION TIMING..17

4 scopePRO SOFTWARE.......................18

4.1 usc files.......................................................................... 20

4.2 Online and offline operation......................................... 20

4.3 Upgrading firmware ...................................................... 21

5 RUNNING scopePRO SOFTWARE..... 22

5.1 Video options set-up..................................................... 22

5.2 Color format set-up....................................................... 24

6 VIDEO RECORDING ............................25

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6.1 Video compression....................................................... 26

6.2 Recording speed........................................................... 26

6.3 Buffering........................................................................ 26

6.4 Pre- and post trigger recording ................................... 28

6.5 Starting and stopping recording.................................. 29

6.6 Deinterlacing ................................................................. 30

7 PROBES ...............................................32

7.1 How to Use PIV Probes in scopePRO Software ......... 32

7.2 Setup.............................................................................. 32

7.3 Creating probes............................................................. 33

7.4 Probe Properties ........................................................... 34

7.5 Recording Data.............................................................. 37

7.6 Saving Probes............................................................... 38

8 SPECIFICATIONS ................................39

2

1 INTRODUCTION

The Model 1420 is an inverted fluorescence microscope with built-in
video camera, fluorescence filter, pulsed Light-Emitting Diode (LED)
illuminator, motorized x-y traverse and focusing actuator. It can directly
image fluorescent or non-fluorescent samples on a standard video monitor
or video recorder.

In addition, the Model 1420 includes an advanced programmable
synchronization unit with four inputs and three outputs for synchronizing
image acquisition to external events.

The basic functions can be controlled by the front panel controls or
through the scopePRO application software included with the instrument.

1.1 Package contents

The Model 1420 package should include the following items:
» Model 1420 microscope main body

» Camera module with one microscope objective according to your

order

» Hauppauge WinTV PCI video input card and driver disk
» Power cable
» One RS232 serial cable and one S-video cable
» Installation disk with scopePRO software
» This manual
» Extra objectives, illumination or camera modules as ordered

If any parts are missing or damaged, please contact your local dealer or
Berkeley Nucleonics Corp. immediately.

1.2 Basic functions

The Model 1420 combines an inverted fluorescence video microscope
with a programmable synchronizer and software for on-line image

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acquisition, processing and storage. You can use the instrument in several
ways:
» As a stand-alone video microscope. Connect the video output from the

Model 1420 to an analog video monitor or VCR through the BNC or
the S-video outputs on the rear panel. You can now focus, traverse and
adjust illumination intensity by the controls on the front panel while
observing the image on the monitor.

» As a software-controlled video microscope for automatic or manual

acquisition of video sequences, using the on-line image processing and
storage capabilities of the scopePRO application.

» As an integrated part of a complex experiment, synchronizing pulsed

illumination, image acquisition and external devices in response to up
to four trigger input signals.

In each of these modes, you can use microscope objectives with
magnification from 4× to 20×, and acquire and store the video output on
standard analog video storage hardware. With the scopePRO application,
you can directly store the video data on computer disk as AVI files and
perform advanced real-time video processing.

1.3 Computer requirements

The Model 1420 can be used with any computer equipped with a RS232
port or USB1.0 or greater port and a free PCI slot or USB2.0 or greater
port for the video input card. However, since the scopePRO software is
designed to stream digitized video sequences directly to disk, it is
recommended that the computer fulfills the following minimum
requirements:

» Intel or compatible processor at minimum 2.6 GHz
» Windows XP 2003 or newer
» One free PCI slot for the video capture card or a free USB2.0 port
» 1 GB of RAM
» 80 GB hard disk with 12 ms access time

The Model 1420 microscope includes a VGA-resolution analog CCD
camera which outputs a standard RS170 monochrome or NTSC color

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composite video signal. The video signal is digitized by a DirectX9.0
compliant PCI video capture card (Berkeley Nucleonics optionally
supplies a Hauppauge PCI video card) or USB2.0 video capture peripheral
(BNC optionally supplies an ADS video capture peripheral), capable of
digitizing and storing uncompressed VGA resolution video on disk.

Many PC video input devices include on-board image compression
hardware, converting the video stream into various compressed video
formats. Image compression standards like MPEG are designed for
general visual imagery and may not be suitable for all types of imagery
occurring in microfluidics device diagnostics, e. g. the images of isolated
small particles as recorded in Particle Image Velocimetry (PIV)
experiments. The ability to record uncompressed video is therefore an
important feature of the hardware and software included with the Model

1420.

Uncompressed video streams naturally take up more bandwidth and use
more computer processing power for display and storage, so a powerful
computer is recommended. When used on a newer standard PC with
moderately fast CPU and disk speed, uncompressed video sequences can
usually be stored on disk in real time. If used on slower computers, frames
may be lost during recording. Slower computers may also exhibit a
perceptible delay between an imaged event and its appearance on the
computer display.

Also, a large hard disk is recommended for storage of video data. A color
video signal will typically generate 1.6 GB per minute and thus quickly
consume hard disk space.

1.4 Installing the software

1.4.1 Installing the Hauppauge WinTV video card

1. Turn off the computer and install the card into a free PCI slot

2. Start up the computer

3. Insert the WinTV disk into your CD drive

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4. When "Found New Hardware Wizard" pops up check "Install the

software automatically (Recommended)" (this may vary with
Windows version). You can also force Windows to look on the
CDROM for the drivers.

5. A screen should pop up that says

"The software you are installing for this hardware
Hauppauge Win/TV 878/9 VFW Window Driver
has not passed Windows Logo testing..."

Click "Continue Anyway"

6. When you get the success report, click "Finish"

7. Next, the same thing may/should happen for the audio driver. You

do not need to install the audio driver for the scopePRO
application.

8. Now run setup.exe from the WinTV CD. If it tells you that you

need to install DirectX9.0, do so. DirectX9.0 can be downloaded
from the Microsoft web site. Install WinTV following the
instructions on the screen.

1.4.2 Installing the ADS USB2.0 capture peripheral

1. Insert the CDROM supplied with the ADS peripheral and follow
the on-screen instructions.

1.4.3 Installing the scopePRO Software

1. To install scopePRO, run setup.exe and follow the on-screen

directions. This setup program will link links to scopePROon your
desktop and Start menu and copy two files if they are missing from
your Windows/System32 folder: MFC42.dll and MSVCRT.dll.
Note: if your computer does not already have DirectX9.0 or greater
installed you will need to install it before running scopePRO.
DirectX9.0 is available on the installation CD supplied by BNC or
directly from Microsoft s website. Most computers will already
have this software installed.

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1.5 Setting up the Model 1420

1. Plug the power cable from the back of the Model 1420 into a 90

VAC power outlet.

2. Connect the 9-pin D-sub serial connector on the back of the Model

1420 to a free serial port on the PC. You may use a USB/RS232
converter device if your computer does not have a RS232 port. BNC
will optionally provide a converter upon request.

3. Press the power button on the front of the Model 1420

4. From your computer, launch scopePRO.exe

5. A dialog box will pop up that says "Communications properties".

Select the correct COM port and click OK. This dialog will keep
popping up until you succeed in communicating with the SVM or you
click Cancel (then you work offline and scopePRO does not try to
send commands to the 1420).

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Communications settings dialog box.

1.6 Field-upgradeable software

The firmware in the Model 1420 is field upgradeable, allowing access to
the latest features as they become available. The firmware is upgraded
through the application software scopePRO. See the detailed instructions
and precautions for upgrading the firmware in the Software section of this
manual.

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1.7 Getting help

This guide is your main source for information on operating the Model
1420 and the scopePRO software. The guide is also available on the
scopePRO CD in PDF format for viewing with Adobe Acrobat.

Check the BNC web site (www.berkeleynucleonics.com) for user manual
updates, application notes and information to help you use the Model 1420.

If you are unable to find the help you need, call BNC Technical Support at
[phone] or send an e-mail to [e-mail].
If you need support, please write down the serial number of your Model
1420 (located on the bottom of the unit) and the version of the software
you are using. To get the software version number, click Help>About
scopePRO in the scopePRO main window.

2 Model 1420 HARDWARE

Most of the access to the Model 1420 features will go through the
scopePRO application software. You can, however, access some
important functions directly from the front panel.

Storage buttons/
LED selectors

Site/light

Toggle buttons

Model 1420 front panel

Lock indicator

LED

Keypad

Focus
control

8

2.1 Front panel controls

The Power button and Power LED are located in the upper left corner of
the front panel. When the power is turned on, the LED will flash green and
red while the system runs its initial tests, and turn green when the tests
have passed.

Site-Light

A D In SITE mode, the buttons A D represent four stored

These buttons toggle between SITE mode and LIGHT mode.
When the SITE button is lit, the four storage buttons A D
represent four different stored positions, and the keypad
controls the traverse movements. The focus buttons moves
the objective up and down for focusing.

When the LIGHT button is lit, buttons A D represent the
four LED banks, and the keypad up and down buttons
control the intensity of the LED banks selected by the A D
buttons.

settings of the traverse and focus positions and LED
intensities.
To recall a stored position, select SITE mode and press and
release a storage button. The traverse will move to the
location and set the four LED intensities to the values of the
stored settings.

To store a traverse position, press one of the storage buttons
and hold it down a few seconds until the button light goes
off. This will store the current traverse position and the LED
settings in the selected storage cell.

In LIGHT mode, the buttons A D represent four LED banks,
labeled A-D. The 24 LEDs in the illuminator module are
divided into four banks, which can be controlled
individually, see section 2.6. When a LED bank is selected,
the corresponding button lights up. One or more LED banks
can be selected simultaneously by pressing the one or more

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of the A D buttons.

Keypad

Focus
up/down

Lock
indicator

In SITE mode, the four buttons will move the traverse in the
x and y directions. Pressing a button will start the traverse
motor at low speed, and after about two seconds motor speed
slowly ramp up to high speed. Pressing the button briefly
allows single stepping of the traverse.

Pressing the center button (Stop) will immediately stop any
traverse movement which may be in progress.

When in LIGHT mode, the up/down keys will
increase/decrease the intensity of those LED banks which
are selected by the A D buttons. One or more of the LED
banks can be controlled simultaneously.

Pressing the center button (Stop) with switch off all selected
LED banks.

These buttons will move the focus motor up or down to
focus the image. The focus motor will start at slow speed
and then ramp up to high speed.

The lock indicator LED on the front panel is green when the
SVM340 is in position.

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The Lock indicator LED turns red when the SVM340 is in
motion, e.g. while the traverse is moving to a preset.

2.2 Back panel connections

The Model 1420 back panel

2.2.1 Video output

The video signal is output on two connectors: a BNC connector with
composite, analog RS170 or NTSC video, and an S-video output
compatible with most video cards and analog recorders. It is generally
recommended to use the S-video for best image quality, but some
monitors without S-video input may require the composite video signal.
The supplied Hauppauge WinTV card has both S-video and composite
input connectors.

2.2.2 Digital inputs and outputs

The four digital inputs and three outputs on BNC connectors provide TTL
level communication with external equipment. The inputs can be used to
control or to strobe the four LED illuminator channels, or to trigger more
advanced behaviors. The outputs are selectable and include video timing
information, motion status information, and several advanced
programmable flags. The inputs could be connected to digital experiment
controllers like the BNC Model 725, interlock switches, sensors, or other
external devices, and the outputs connected to other apparatus to facilitate
real-time control and automation.

2.2.3 External Illuminator

This male nine-pin D-sub connector provides 5 V DC power and pulse
signals to drive 4 external illumination sources with settings similar to the
four-bank led module.

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Pin connections

1 5 V DC (max 3 A)
2 Chassis Ground (0 V)
3 Chassis Ground
4 Chassis Ground
5 Chassis Ground
6 LED A drive (TTL)
7 LED B drive (TTL)
8 LED C drive (TTL)
9 LED D drive (TTL)

The light intensity of the LED s of the Model 1420 is controlled by pulse
width modulation with a frequency synchronized to the video signal. Full
light intensity means an illumination duty cycle close to 100%.
LED drive outputs A D are negative logic, ie. TTL level is high when
LEDs are off.

2.2.4 RS232 serial connector

The female 9-pin D-sub connector is for RS232 communications. This
link allows the Model 1420 to receive programming and commands from
an external controller, e.g., a computer running the scopePRO application
or LabView through the provided serial cable. A USB/RS232 converter
can be used for computers without an RS232 connector (COM port).

2.3 Microscope stage

The Model 1420 is fitted with a replaceable microscope stage, attached to
the main body of the instrument by four magnetic locks. To remove the
stage, simply pull the stage gently up until it releases. The stage top is a
polished stainless steel plate, which can be machined to provide
application-specific mounts for the fluidic device, electrodes, fluid hoses
or other fittings.

12

Removing the microscope stage

2.4 Camera module

The camera module is attached to the traverse by magnetic holders and
can be removed by tilting the Model 1420 on its side and gently pulling
the camera module down from below the Model 1420 body until it comes
free.

Important! Before removing or inserting a camera, turn off the Model

1420 using the power button at the left of the front panel.

13

Camera module

Note: When removing or inserting the camera module, take care not

to apply excessive force since this may damage the traverse
mechanism and compromise traverse accuracy.

2.5 Microscope objective

The microscope objective is a standard DIN type objective with 160 mm
conjugate image distance. To replace the objective, remove the camera
module and unscrew the objective. The Model 1420 supports objectives
with magnifications from 4× to 20×. Objectives with higher magnification
generally have insufficient stand-off distance to clear the illuminator
LED s and can only be used with an external illuminator module or other
external light source.

14

Objective and seat for fluorescence filter

2.6 Fluorescence filter

The fluorescence filter is located in the objective mounting ring right
behind the microscope objective and can be replaced by unscrewing the
objective. The filter size is half inch (12.7 mm) diameter, and the filter fits
into a recess in the microscope mounting ring.

2.7 Illuminator module

The illuminator module consists of four independent banks of LEDs:
» Two banks of each 8 diodes (A and B)
» Two banks of each 4 diodes (C and D)
The following standard illuminator modules are standard:
LED-B: 3 blue (A, B, and D) and one white channel (C)
LED-G: 3 green and one white channel
LED-R: 3 red and one white channel
LED-W: 4 white channels
LED-RGBW: 1 red, 1 green, 1 blue, and one white channel.
The illuminator module can be removed from the traverse from the top by
pulling the module upwards.

15

Removing the illumination module

Note: When reinserting the illuminator module take care that the

connector pins are all correctly inserted in the receptacle
without bending or damaging the pins. Also take care not to
apply excessive force. Support the camera module from below
with your hand when inserting the illumination module and
press from below to ensure the traverse mechanism is
magnetically seated.

2.8 Base stand

The Model 1420 is delivered with four rubber feet attached with 8-32
screws on a 7.00 × 9.00 rectangle to place the instrument on a plane
table surface. The feet can be replaced by leveling feet which allow fine
adjustment of the instrument or standard optical posts which can be
clamped firmly to an optical table. Contact BNC for more information.

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3 VIDEO AND ILLUMINATION TIMING

The master clock for the Model 1420 is provided by the video signal
timing. The CCD camera outputs video in standard RS170 format (NTSC
in the color version), which is an analog, interlaced format compatible
with standard analog video monitors or video recorders.

Frame

Frame

Fields

Fields

Video

Video

LED drive

LED drive

Timing sequence of the illumination in relation to the video signal

The RS170 interlaced video signal is composed of two fields, called even
and odd fields, each containing every second line of the image. The
interlaced format was defined in the early days of television to avoid
flickering TV images. The even field contains lines 0, 2, 4, 524 and the
odd field lines 1, 2, 525. The field frequency is 60 Hz, with one even
and one odd field adding up to a full video frame each 33.3 ms,
corresponding to 30 Hz frame frequency.
To ensure that all lines of the video signal are equally illuminated, the
LED s flash twice during an image, once in every field. The LED pulse
starts in the frame blanking period, and its width can be varied from 0 to
near 100% of a field period, 16.6 ms.
Due to the interlaced readout of the camera sensor, images of fast moving
objects, which move a noticeable distance during the 16.6 ms between two
consecutive fields, may appear jagged at the horizontal edges. See section
below for a discussion of the implications and tools to control the
interlacing effect.

33 ms full frame

33 ms full frame

Even

Even

LED on

LED on

(variable)

(variable)

Odd

Odd

Even

Even

Odd

Odd

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4 scopePRO SOFTWARE

The scopePRO software lets you set the functions of the Model 1420 and
control the video acquisition and on-line processing. It also allows you to
recall and process stored video files.

scopePRO runs on any PC with Microsoft Windows XP operating system.

Note The scopePRO application makes extensive use of the DirectX

software, which is provided by Microsoft Corp. and installed
independently of scopePRO. If you have installed a local
language version of Windows XP, DirectX will install in the
same language. Consequently, some of the dialog boxes shown
below may appear in the language of your windows
installation.

The scopePRO main window is divided into the following sections:
» The video display window

» The LED control panel
» The focus control panel
» The presets panel
» The video recording panel
» Probe controls

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panel

controls

Probe

Presets panel

LED control

scopePRO main window

Focus

control

Traverse
control

Video
display
window

Video
recording
panel

The video display window shows the off-line or on-line (live) video as
selected in the Video menu. The position indicators to the right and below
the video display indicate the position of the x-y traverse and can be used
to move the traverse. The traverse can also be activated by the keyboard
up and down arrow keys.

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The LED control panel slider bars are used to adjust the intensity of the
four LED banks, A D. The LED intensity is adjusted by pulse width
modulation with a fixed pulse frequency that is synchronized to the video
field frequency.

Checking the Gang box will cause all LED banks to be adjusted
simultaneously when one slider is activated.

The focus control panel is used for moving the focus actuator up and down.
The + and
can also be activated by the keyboard + and

buttons move the actuator in single steps. The focus actuator

keys.

The presets panel allow saving and restoring the four traverse
position/LED illumination settings in storage cells A D. Clicking a button
will load the stored preset and adjust traverse position and LED
illumination to the stored values. Checking the Save box first will store the
current setting in the selected storage cell.

For a description of the Video recording and probe functions, see sections
6 and 7 below.

4.1 usc files

The scopePRO software saves the instrument and video settings in a file
with .usc extension.
To open a scopePROfile, choose File>Open, then locate the file on your
hard drive. You can also choose from recently opened files at the bottom
of the File menu.

4.2 Online and offline operation

scopePRO can work in both online and off-line mode. When on-line, it
communicates with a Model 1420, controls its functions and accepts live
video signals from a DirectX compliant video capture card.

When off-line, scopePRO can open a stored video file for playback and
further processing. scopePRO will go into off-line mode whenever it fails
to locate a Model 1420 on the selected serial port.

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4.3 Upgrading firmware

The firmware is the software stored inside the Model 1420 in non-volatile
memory and controls the internal functions of the instrument, such as
traverse movements, front panel lamps and buttons, and back-panels
inputs and outputs. The firmware is included in the scopePRO application
package and can be loaded into the Model 1420 from within the
scopePRO software.
To upgrade firmware to the latest version:

1. Download the newest version of scopePRO from

www.berkeleynucleonics.com

the installation procedure described in the introduction.

2. Connect and turn on the Model 1420 and start up the

scopePROapplication on the PC.

3. In online mode, choose 1420>Update Firmware>Update All

and install on your computer following

4. Click OK when the update dialog box appears

5. Wait while the firmware is updated. You can follow the progress in the

status bar at the bottom of the scopePRO main window.

6. When the progress indicator reaches 100%, the upgrade is completed.

Important: Do not turn off or disconnect the Model 1420 or the PC while

the upgrade is in progress. This may result in loss of
communication with the instrument that requires BNC
assistance to resolve.

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5 RUNNING THE scopePRO SOFTWARE

When you run the scopePRO application, it will automatically connect to
the Model 1420 if it is present on a serial port and turned on. If scopePRO
does not find a Model 1420, the communications settings box will appear
as shown above. Select the correct serial port and press OK.
The scopePRO main window below will appear.

For off-line mode, open the AVI file you want to process off-line. The
Model 1420 does not have to be connected.

For on-line (LIVE) mode, click cancel in the "Open" dialog box for on­line operation, and click Video>Process live video.

5.1 Video options set-up

If the "video capture hardware" dialog doesn't pop up (it should the first
time) click View>Video options>Input device.

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Video options menu

Click on the video capture card that you want to use. Select the
appropriate capture source.

Make sure that either the BNC composite or S-Video connector output of
the Model 1420 is connected to an input of the Hauppauge card, and select
the relevant input connector through the Input connector box. Click
View>Video options>Input connector and select the input that you want
(e.g. Input: 0: Video SVideo In, Output: 0: Video Decoder Out). Click OK.
At this point you should see live video on your screen.

23

Input connector selection box.

You do not have to worry about the audio options since they are not
currently used for the scopePRO application.

To set the video frame size you can click Video>Video options>Video
frame format. Select 320×240 for low-resolution images and 640×480 for
full-resolution images. Do not change the color space (whatever comes up,
normally RGB24, is correct).

Note: The DirectX video controls dialog boxes are of general nature

and allow settings incompatible with the Model 1420. Do not
change the Video Standard (NTSC_M) or the output aspect
ratio (the size must be 640×480, 320×240, 160×120 or 80×60)

5.2 Color format set-up

The Model 1420 can be fitted with either a grayscale (B&W) or color
camera, and the video output should be displayed and stored in
corresponding monochrome or color formats. This is done by means of

24

Look Up Tables (LUT s), which convert the analog voltage outputs of the
video signal to the appropriate gray scale or color values.

If you have a B&W camera, you want to make sure you are using an 8-bit
LUT, converting the analog voltage into 256 different gray scale levels.
Normally you would use a grayscale LUT, mapping the 256 gray scale
levels into 256 different shades of gray, but you can apply color LUT s for
false color display. The reason for using false color display is that it is
difficult to distinguish 256 different gray levels on a standard computer
monitor. Converting shades of gray into colors can significantly enhance
visibility of small differences in gray scale value.
You can experiment with false color display by: Click Video>Color
format>Spectrum LUT, etc.

If you have a color camera and you want to keep the color, click
Video>Color format>24-bit RGB. You may also select a monochrome 8
bit with a color camera to save RAM and disk space. Color video data
takes up 8 bits each for the red, blue and green colors, and thus consumes
three times as much disk space and processing time as 8 bit-per-pixel
video.

6 VIDEO RECORDING

One of the main features of the scopePRO application is the ability to
record long, unbroken video sequences without compression. These video
sequences are stored in standard AVI format, so that they can later be
viewed by Windows Media Player or other video playback software, off­line processed by scopePRO or other video processing software,
compatible with the AVI standard.

To enable uncompressed video recording, scopePRO makes use of a
double buffering system, described below. The buffering scheme also
enables pre-trigger recording, enabling you to store a video of what
happened before the trigger instant.

25

6.1 Video compression

Video compression algorithms like MPEG are great for normal TV
recording, but may not work properly when used for scientific video
sequences, which often obey completely different statistics. MPEG video
compression is particularly bad for video sequences containing small,
rapidly moving objects, which is exactly the kind of imagery likely in
microfluidics experiments. Therefore, scopePROworks entirely with
uncompressed video sequences, making no assumptions about the nature
of the imagery.

6.2 Recording speed

A standard monochrome RS-170 video signal converts into a digital data
rate of 8.9 MBytes/s, which can easily be read into PC RAM memory in
real time. It is also within the capability of modern, fast computers to write
to hard disk in real time at this data rate, provided the computer is not
overloaded by simultaneously executing other disk or CPU intensive tasks.
Color NTSC video signals convert into a data rate of 26.4 MBytes/s,
which can readily be written to RAM memory in real time, but may be too
high to write to hard disk in real time. In that case, some frames scattered
throughout the video sequence are lost, resulting in a stored video
sequence with time intervals of 33.3 ms between most images, but with

66.6 ms, 99.9 ms or some other multiple of the base frame interval

between some individual images.

Such lost frames are called dropped frames. Video sequences with
dropped frames are not suitable for accurate time history analysis, since it
is difficult to know afterwards exactly where frames are missing.

6.3 Buffering

To avoid the problem of dropped frames and to enable pre-trigger
recording, scopePRO stores digitized video date in cyclic a RAM buffer
simultaneous with the display. This is illustrated in the figure below.

26

Camera A/D

converter

RAM buffer

Buffering scheme in scopePRO

Video display

Hard disk

The analog video signal from the Model 1420 camera is digitized in the
Hauppauge WinTV card into an 8 bit data stream. This stream is
continually stored in a cyclic RAM buffer in PC memory, such that the
most recent video data is always residing in RAM. As soon as a trigger or
keyboard action stops the recording, you freeze the video sequence in the
RAM buffer, which contains the video of the events prior to the trigger.
This sequence can subsequently be stored on disk.

The duration of the video sequence depends on the amount RAM, set
aside for the buffer. The more RAM installed in the computer, the more
buffer space can be set aside without slowing down other tasks. The initial
buffer size is set to half the available RAM, but you may want to adjust
the buffer size get longer pre-trigger video sequence duration. Buffer size
is specified in The View>Video options>Buffer settings menu.

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Setting of RAM and disk buffer size

The disk buffer is a contiguous area on the system disk set aside for
storing the video sequence in AVI format. The buffer settings dialogue
box allows you to specify the name and size of the disk buffer. Once the
disk buffer runs full during a recording session, the file system will start to
allocate extra disk space to hold the new data as is comes in. This will
considerably slow down the effective disk writing speed, resulting in
dropped frames. The larger the disk buffer, the longer the video sequence
without dropped frames.

6.4 Pre- and post trigger recording

The figure below illustrates the effect of the buffer size on the pre- and
post trigger recording durations.

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Trigger

Stored video

RAM Buffer

Stored video

Disk Buffer

Pre-trigger (top) and post-trigger (bottom) recording

For pre-trigger recording, you save the video sequence occurring before
the trigger, stored in the RAM buffer. With post-trigger recording you
save the video sequence occurring immediately after the trigger and
temporarily stored in the disk buffer. The disk buffer is normally larger
than the RAM buffer.

6.5 Starting and stopping recording

The video recording panel at the bottom of the screen allows you to
control the recording duration and trigger mode.

Time

Time

The video recording panel

To record a post-trigger movie, click record at the bottom left. Click stop
to stop recording. The duration of the movie is selected by the slider bar,
the full duration determined by the disk buffer size.

Clicking the Unlimited radio button allows you to record beyond the disk
buffer duration, but at the risk of dropped frames.

To record a pre-trigger movie, click the Save buffer now button. This will
save the image sequence in the RAM buffer

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6.6 Deinterlacing

The camera built into the Model 1420 runs in standard RS-170
(monochrome) or NTSC (color) video format at a fundamental frame rate
of 30 Hz. As discussed in section 5.1, the full video frame is composed of
two interlaced fields at a field frequency of 60 Hz. This means that every
second line of a full image is recorded at a time 16.6 ms later than the
other half of the lines. As a consequence, fast-moving objects will be
recorded with a slight horizontal blur, which is caused by the image
segment in the even lines being shifted slightly from the image segment in
the odd lines.

Image of a horizontally moving particle recorded with the Model 1420
interlace camera

Zooming in on such a fast-moving particle reveals the jagged edges
caused by the interlace camera format.

To reduce the effects of the interlacing, scopePRO includes deinterlace
filters, which will reduce the visual appearance of the blurring caused by
the interlacing by various algorithms. The delinterlace method is selected
in the View>Video options>Deinterlace options dialog box.

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Selecting deinterlace filter

The best deinterlace filter depends on the nature of the video image and
should be chosen by experimentation. A brief description of the four
algorithms is given here. For more information, see the home page of the
developers, listed in the dialog box.

Weave

This method uses three fields in the calculation and works well on slow
moving material but tends to fail on fast moving material.

Bob

The basic bob algorithm uses the most recent field and fills in the lines
between by interpolation. This method detects weaving artifacts in the
current image it uses bob to get rid of them. This method has a tendency to
bob rather too much and gives poor results on fine static images.

2-frame

This method uses the current frame and the last two to determine whether
to bob or weave a given pixel. This gives better results on both stationary
and moving images than the above two methods but uses more CPU.

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Although the deinterlace filters improve the visual appearance of the video,
they are designed for general video scenery and may not be effective for
scientific imagery. All filters are based on some form of interpolation
between frames under the assumption that scene motion is continuous
between frames. When the movies are analyzed by various algorithms, the
effect of the deinterlace filter on the result will be algorithm-dependent.

7 PROBES

scopePRO has sophisticated real-time probe capabilities that allow users
to monitor image properties like color, intensity, variation and video
properties like inferred motion (e.g., particle image velocimetry) in real
time. These real-time measurements can be recorded to disk and can
trigger real-time actions.

7.1 How to Use PIV Probes in scopePRO Software

scopePRO software makes it easy to create software probes to monitor
flow characteristics. scopePRO can support as many PIV probes as your
computer s processor can handle. Each probe can have its own properties;
probes are almost always square, though it is possible to extend the probe
in one direction to increase signal-to-noise ratio along that axis.

TIP: When learning how to use scopePRO s PIV probes it is useful to

start with a stable particle flow, or a movie of a stable flow.

7.2 Setup

1. Connect the 1420 to the computer and turn on both.

2. Launch scopePRO software.

3. Prepare the microfluidic channel. Fill it out with the buffer and

introduce a sample of polystyrene fluorescent particles.

4. Adjust focus, illumination and flow characteristics.

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Alternately, you can also open an existing flow movie by choosing

Video > Process
Saved Video. The video will loop until stopped.

7.3 Creating probes

To create a probe:

1. Click the PIV toolbar button

2. Double-click in the video image at the center point for the new

probe. When you create a probe it will take on the properties of the
last probe you altered. Once created you can change each probe s
properties individually.

New probe showing correlation field, vector arrow and real time

velocity as text.

When you first create a probe scopePRO will experimentally
determine the fastest FFT algorithm to use. This process may take
up to 60 seconds to complete, at which point the software will
begin calculating velocity at the location.

.

3. Click the + and

transparent. The software will continue to calculate velocity at

toolbar buttons to make the probes more or less

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these locations even if you make the probes completely invisible.

4. To remove a probe, right click on it and choose Delete.

7.4 Probe Properties

1. Double-click on a probe to open the PIV Probe Properties dialog

box. You can also right-click on the probe and choose Properties
to open the dialog box.

PIV Probe Properties dialog box.

2. Select the Width and Height of the probe window, the area over

which statistics will be calculated. Some guidelines for setting the
probe window size are:

a. Probes should typically be the same size in both x and y

directions.

b. Smaller probes require less processing power, so use

smaller window sizes to run more probes simultaneously.

c. Increasing the probe size will improve the signal-to-noise

ratio; decreasing the size will increase spatial resolution.

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d. If the probe is located in a region of fast flow, the probe

size must be large enough that the correlation does not fall
beyond the window. The Cross Correlation field (see
below) can be an aid in setting the size.

NOTE: If you cannot achieve sufficient signal-to-noise ratio with a

required probe size you may need to adjust the illumination,
particle feed, etc. If the probe is in an area of steady flow then
increasing time averaging may also help.

3. The Averaging percent per frame values help separate the useful

flow information from the background data by weighing the
previous frames of data versus the current frame. The default
values of 95% are acceptable for most flows. Some guidelines for
setting the percentages are:

a. The Background (mean) percentage determines how much

of the image field is considered background based on its
steady presence over multiple frames. Increasing this value
increases the amount of information that is ignored, such as
stuck particles. Check the Subtract Mean box (see below)
to apply this calculation and remove the data.

b. Decreasing the Correlation value improves time

resolution; increasing the value improves noise control.

4. The Calculations Options control how the flow parameters are

calculated:

a. Enter 1 in the Frames Skipped box to calculate cross

correlation for every sequential pair of frames. Enter 2 to
use every other frame, 3 for every third frame, etc. This
option is useful for examining very slow flows.

b. Subtract Mean subtracts the background (non moving)

data from the flow calculations. The amount of data that
will be subtracted is based on the Background % value
(see above).

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NOTE: If the probe is located in an area of very slow flow then

subtracting the background could delete active particles.

c. Deconvolve Autocorrelation is an advanced option for

high precision measurements. This option deconvolves the
cross correlation by the autocorrelation, which can remove
the effects of blur and particle size such that each particle is
treated as a single point. It is most useful when the signal­to-noise ratio is extremely high.

5. The Show Field options control which data are displayed for each

probe window:

a. Cross correlation determines how far the particles move

between frames (or between every few frames, based on the
Frames Skipped option). This field is a good diagnostic
tool to help you optimize experiment parameters. The red
dot will move further from the center as the flow velocity
increases. The dot should be small and well defined to
achieve the most reliable measurements. If the flow is too
fast the red dot will move outside of the window, and
scopePRO will not be able to measure the velocity. In this
case, increase the window size, which will improve the
signal-to-noise ratio.

b. Autocorrelation is an indicator of resolution. The mass at

the center of the window will become sharper with smaller
particles and better focus.

c. Mean shows the data that is being subtracted as part of the

Background (based upon the Background % described
above). Showing the Mean can be helpful for highlighting
stuck particles and other anomalies in the flow.

d. RMS is an indicator of the amount of useful signal

available for the calculations.

e. Show Text turns on and off the text-based velocity display.
f. Show Vector displays an arrow in the direction of the flow.

The size of the arrow will change with velocity. You can
also set the Scale to increase or decrease the arrow size.

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7.5 Recording Data

Data can be recorded simultaneously from all probes. To record data:

1. Choose File >Measurement File Naming to select how the

recorded data will be save:

Naming settings for new measurements dialog box.

a. If you choose Do not auto-name, scopePRO will prompt

you for a file name and location for each new recording.

b. Choose Auto-name files to automatically name each

recording. Check Append the date, Append the time,
and/or Append counter to add these values to the new file
names. An example of how the name will appear is shown
at the bottom of the dialog box.

2. To begin recording choose File >Record, or click the Start/Stop

toolbar button. If Autonaming is selected, recording will

begin immediately. Otherwise, recording will begin after you name
the file and click OK.

3. To end recording, choose File > Record or click the Start/Stop

button again.

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The PIV output file will include four columns for each probe: the X
and Y locations of its centroid, measured from the upper left of the
window, and the X and Y velocity at each point in time. The X/Y
location columns will only have entries in the first row.

7.6 Saving Probes

A set of probes can be saved to disk and recalled later:

1. Arrange the probes and set their Properties.

2. Choose File >Save Probes As to create a new probe file.

3. Select the name and location for the file and click Save.

To recall a stored set of probes choose File > Open.

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8 SPECIFICATIONS

Traverse
Range x: 50mm, y: 75 mm, focus: 8mm
Resolution x and y: 10 µm, focus (z): 1 µm

Sample stage
Dimensions X × Y: 140mm × 200mm
Opening 55 × 80 mm

Camera module
RS-170-BW Analog, interlaced monochrome camera with 1/3

CCD 640 × 480 pixels, 30 frames/s

RS-170-C Bayer-pattern analog color camera with 1/3 CCD 640

× 480 pixels, 30 frames/s

Objectives

Illuminator
modules

Inputs
Outputs

10× plan 0.25/170
4×
20×
LED-B: 3 blue (center 460 nm, bandwidth 50 nm), one
white bank
LED-G: 3 green (center 560 nm, bandwidth 50 nm),
one white bank
LED-R: 3 red (center 660 nm, bandwidth 50 nm), one
white
LED-W: 4 white banks
LED-RGBW: 1 red, 1 green, 1 blue, 1 white bank.
4 programmable digital inputs, TTL level
Composite analog video out
S-video out
3 programmable digital outputs TTL level
4 external illuminator trigger/drivers, TTL level

Communication
interface

Serial RS232, 9 pin D-sub connector.

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Physical
Dimensions W × L × H: 208 × 267 × 85 mm
Weight 2.8 kg
Power
requirement

90 240 VAC 47 63 Hz, 100 VA

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