National Instruments IEEE 1394 User Manual
TM
IMAQ
NI-IMAQTM for IEEE 1394 Cameras User Manual
Image Acquisition Software
NI-IMAQ for IEEE 1394 Cameras User Manual
March 2005
370362C-01
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Conventions
The following conventions are used in this manual:
» The » symbol leads you through nested menu items and dialog box options
to a final action. The sequence File»Page Setup»Options directs you to
pull down the File menu, select the Page Setup item, and select Options
from the last dialog box.
This icon denotes a note, which alerts you to important information.
bold Bold text denotes items that you must select or click in the software, such
as menu items and dialog box options. Bold text also denotes parameter
names.
italic Italic text denotes variables, emphasis, a cross reference, or an introduction
to a key concept. This font also denotes text that is a placeholder for a word
or value that you must supply.
monospace Text in this font denotes text or characters that you should enter from the
keyboard, sections of code, programming examples, and syntax examples.
This font is also used for the proper names of disk drives, paths, directories,
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monospace italic
Italic text in this font denotes text that is a placeholder for a word or value
that you must supply.
Contents
Chapter 1
Introduction to NI-IMAQ for IEEE 1394 Cameras
About the NI-IMAQ Software.......................................................................................1-1
Application Development Environments ........................................................1-2
Configuring a IEEE 1394 Camera...................................................................1-2
Fundamentals of Building Applications with NI-IMAQ for IEEE 1394 Cameras........ 1-2
Architecture .....................................................................................................1-2
NI-IMAQ for IEEE 1394 Cameras Libraries ..................................................1-3
Example Programs...........................................................................................1-4
Chapter 2
Basic Acquisition with NI-IMAQ for IEEE 1394 Cameras
Introduction....................................................................................................................2-1
Acquisition Flow............................................................................................................ 2-2
Initialization.....................................................................................................2-2
Camera Name....................................................................................2-2
Camera Control Mode.......................................................................2-4
Configuration...................................................................................................2-4
One-Shot/Continuous Acquisition ....................................................2-4
Number of Buffers ............................................................................2-5
Region of Interest..............................................................................2-5
Acquisition ......................................................................................................2-6
User Buffer........................................................................................2-6
Buffer Number ..................................................................................2-6
Overwrite Mode ................................................................................2-7
Timeouts............................................................................................2-7
Decoding ........................................................................................... 2-7
Programming Examples.................................................................................................2-8
High-Level Function Examples.......................................................................2-8
Snap...................................................................................................2-9
Grab...................................................................................................2-10
Sequence ...........................................................................................2-11
Low-Level Function Examples ....................................................................... 2-11
Snap...................................................................................................2-12
Grab...................................................................................................2-13
Sequence ...........................................................................................2-14
© National Instruments Corporation v NI-IMAQ for IEEE 1394 Cameras User Manual
Contents
Chapter 3
Advanced Programming with NI-IMAQ for IEEE 1394 Cameras
Camera Attributes.......................................................................................................... 3-1
Broadcasting ..................................................................................................................3-1
Implementation ............................................................................................... 3-2
Scalable Image Size....................................................................................................... 3-3
Trigger Modes ............................................................................................................... 3-4
Trigger Mode 0 ............................................................................................... 3-5
Trigger Mode 1 ............................................................................................... 3-5
Trigger Mode 2 ............................................................................................... 3-6
Trigger Mode 3 ............................................................................................... 3-6
Trigger Mode 4 ............................................................................................... 3-7
Trigger Mode 5 ............................................................................................... 3-7
Chapter 4
Using NI-IMAQ for IEEE 1394 Cameras in LabVIEW
Introduction ................................................................................................................... 4-1
Location of the NI-IMAQ for IEEE 1394 Cameras VIs ............................................... 4-2
Common VI Parameters ................................................................................................ 4-2
IMAQ1394 Session......................................................................................... 4-2
Image Buffer ................................................................................................... 4-3
Region of Interest............................................................................................ 4-3
Acquisition VIs..............................................................................................................4-3
High-Level ...................................................................................................... 4-3
Low-Level....................................................................................................... 4-3
Buffer Management....................................................................................................... 4-4
Acquisition Types.......................................................................................................... 4-5
Snap................................................................................................................. 4-5
Grab................................................................................................................. 4-5
Sequence ......................................................................................................... 4-6
Triggering ......................................................................................................................4-7
Image Display................................................................................................................ 4-7
Camera Attributes.......................................................................................................... 4-9
Error Handling............................................................................................................... 4-9
Chapter 5
Using NI-IMAQ for IEEE 1394 Cameras in C and .NET
Using NI-IMAQ for IEEE 1394 Cameras for C............................................................ 5-1
Using NI-IMAQ for IEEE 1394 Cameras for Microsoft Visual Studio .NET 2003 ..... 5-2
Creating a New .NET Application.................................................................. 5-2
NI-IMAQ for IEEE 1394 Cameras User Manual vi ni.com
Appendix A
Register-Level Programming
Appendix B
Technical Support and Professional Services
Glossary
Index
Contents
© National Instruments Corporation vii NI-IMAQ for IEEE 1394 Cameras User Manual
Introduction to NI-IMAQ for IEEE 1394 Cameras
This chapter describes the NI-IMAQ for IEEE 1394 Cameras software,
lists the supported application development environments (ADEs),
describes the fundamentals of creating applications using NI-IMAQ for
IEEE 1394 Cameras, describes the files used to build these applications,
and explains where to find sample programs.
About the NI-IMAQ Software
NI-IMAQ for IEEE 1394 Cameras gives you the ability to use IEEE 1394
industrial digital video cameras to acquire images. You can use cameras
with the following output formats:
• Monochrome (8 bits/pixel)
• Monochrome (16 bits/pixel)
• RGB (24 bits/pixel)
• RGB (48 bits/pixel)
• YUV 4:1:1 (12 bits/pixel)
• YUV 4:2:2 (16 bits/pixel)
• YUV 4:4:4 (24 bits/pixel)
• Bayer (8 bits/pixel)
• Bayer (16 bits/pixel)
1
The cameras may operate at various resolutions and frame rates, depending
on camera capabilities.
NI-IMAQ for IEEE 1394 Cameras complies with the 1394 Trade
Association’s Industrial and Instrumentation specification for Digital
Cameras (IIDC) and controls all available modes of the digital camera.
Note Refer to the NI-IMAQ for IEEE 1394 Cameras Release Notes for the specific version
of the IIDC specification to which this driver complies.
© National Instruments Corporation 1-1 NI-IMAQ for IEEE 1394 Cameras User Manual
Chapter 1 Introduction to NI-IMAQ for IEEE 1394 Cameras
Application Development Environments
This release of NI-IMAQ for IEEE 1394 Cameras supports the following
ADEs for Windows 2000/XP:
• LabVIEW version 7.0 and later
• LabVIEW Real-Time Module version 7.0 and later
• LabWindows
• Microsoft Visual C/C++ version 6.0 and later
• Microsoft Visual Basic version 6.0 and later
• Microsoft Visual Studio .NET 2003 and later
Note Although the NI-IMAQ for IEEE 1394 Cameras software has been tested and found
to work with these ADEs, other ADEs may also work.
™
/CVI™ version 6.0 and later
Configuring a IEEE 1394 Camera
Use National Instruments Measurement & Automation Explorer (MAX) to
configure your IEEE 1394 camera. Refer to the NI-IMAQ for IEEE 1394
Cameras Help for information about configuring your IEEE 1394 camera.
You can access the NI-IMAQ for IEEE 1394 Cameras Help from within
MAX by going to Help»Help Topics»NI-IMAQ IEEE 1394.
The camera configuration is saved in a camera file, which the NI-IMAQ for
IEEE 1394 Cameras VIs and functions use to configure a camera and
supported attributes.
Fundamentals of Building Applications with NI-IMAQ for IEEE 1394 Cameras
Architecture
Figure 1-1 illustrates the NI-IMAQ for IEEE 1394 Cameras driver
architecture.
NI-IMAQ for IEEE 1394 Cameras User Manual 1-2 ni.com
Chapter 1 Introduction to NI-IMAQ for IEEE 1394 Cameras
LabVIEW
IMAQ1394.DLL
Application Level
Kernel Level
IMAQ1394K.DLL
Windows Kernel
NIPALK.SYS
OCHI1394.SYS
1394BUS.SYS
Figure 1-1. NI-IMAQ for IEEE 1394 Cameras Architecture
LabWindows/CVI
Visual C++
LabVIEW RT Kernel
NIPALP.DLL
TNF.DLL
The architecture uses a hardware abstraction layer, which separates
software API capabilities, such as general acquisition and control
functions, from hardware-specific information. This layer lets you run your
application on different operating systems and use updated versions of the
driver without having to recompile your application.
NI-IMAQ for IEEE 1394 Cameras Libraries
The NI-IMAQ for IEEE 1394 Cameras function libraries are dynamic link
libraries (DLLs), which means that NI-IMAQ for IEEE 1394 Cameras
routines are not linked into the executable files of applications. Only the
information about the NI-IMAQ for IEEE 1394 Cameras routines in the
NI-IMAQ for IEEE 1394 Cameras import libraries is stored in the
executable files.
Import libraries contain information about their DLL-exported functions.
They indicate the presence and location of the DLL routines. Depending
on the development tools you use, you can give the DLL routines
© National Instruments Corporation 1-3 NI-IMAQ for IEEE 1394 Cameras User Manual
Chapter 1 Introduction to NI-IMAQ for IEEE 1394 Cameras
information through import libraries or through function declarations.
Your NI-IMAQ for IEEE 1394 Cameras software contains function
prototypes for all routines.
Example Programs
You can find NI-IMAQ for IEEE 1394 Cameras code examples in the
following directories.
Note If you installed NI-IMAQ for IEEE 1394 Cameras in the default location, you can
find the following example directories within
National Instruments
.
C:\Program Files\
•LabVIEW—
LabVIEW\examples\imaq. For a brief description of
any example VI, open the VI, and select Windows»Show VI Info for
a text description of the example.
Tip You can access the NI-IMAQ for IEEE 1394 Cameras examples from the NI Example
Finder. From LabVIEW, go to Help»Find Examples to launch the NI Example Finder.
•CVI—
CVI\samples\imaq1394.
•C—NI-IMAQ for IEEE 1394\examples\MSVC.
• Visual Basic—NI-IMAQ for IEEE 1394\examples\VB.
• Microsoft Visual Studio .NET 2003—NI-IMAQ for IEEE
1394\examples\MSVB.NET
located in the
NI-IMAQ for IEEE 1394\examples\Images
. The images for the examples are
directory. The .NET examples are converted from the NI-IMAQ for
IEEE 1394 Cameras for Visual Basic examples. The .NET examples
are written in Visual Basic .NET and demonstrate use of the NI-IMAQ
for IEEE 1394 Cameras 2.0 Assemblies and the IMAQ Vision 7.1
Viewer control.
Refer to the
readme.rtf file located in your target installation directory
for the latest details about the example programs.
NI-IMAQ for IEEE 1394 Cameras User Manual 1-4 ni.com
Basic Acquisition with
NI-IMAQ for IEEE 1394 Cameras
This chapter contains an overview of the NI-IMAQ for IEEE 1394
Cameras library, a description of the acquisition flow of NI-IMAQ for
IEEE 1394 Cameras, and generic programming examples. The chapter also
contains flowcharts of high-level and low-level snap, grab, and sequence
operations.
Introduction
The NI-IMAQ for IEEE 1394 Cameras application programming interface
(API) is divided two main function groups: high-level and low-level.
• High-level functions—Use to capture images quickly and easily. If
you need more advanced functionality, you can mix high-level
functions with low-level functions.
– Snap functions—Capture all or a portion of a single image to the
user buffer.
– Grab functions—Perform an acquisition that loops continually on
one or more internal buffers. You can copy the last acquired buffer
to a separate user buffer for processing or analysis.
– Sequence functions—Acquire a specified number of internal
buffers and then stops.
– Trigger functions—Control the trigger mode of the IEEE 1394
camera.
• Low-level functions—Use when you require more direct control of the
image acquisition.
– Acquisition functions—Configure, start, stop, and unconfigure an
image acquisition, or examine a user buffer during an acquisition.
– Attribute functions—Examine and change the acquisition or
camera attributes.
– Utility functions—Display an image in a window, save an image
to a file, or to get detailed error information.
2
© National Instruments Corporation 2-1 NI-IMAQ for IEEE 1394 Cameras User Manual
Chapter 2 Basic Acquisition with NI-IMAQ for IEEE 1394 Cameras
Both high-level and low-level functions support snap, grab, sequence, and
triggered acquisitions. Using high-level functions, you can write programs
quickly without having to learn the details of the low-level API and driver.
The low-level functions give you finer granularity and control over the
image acquisition process, but you must understand the API and driver in
greater detail to use these functions.
Note The high-level functions call low-level functions and use certain attributes that are
listed in the high-level function description of the NI-IMAQ for IEEE 1394 Cameras
Function Reference Help. Changing the value of these attributes while using low-level
functions affects the operation of the high-level functions.
Acquisition Flow
This section describes the basic steps of performing an acquisition with the
NI-IMAQ for IEEE 1394 Cameras software. The basic steps are
initialization, configuration, and acquisition.
Initialization
To acquire images using the high-level or low-level functions, you first
must initialize a camera session. A camera session is a process-safe handle
to an IEEE 1394 camera. The driver uses a camera session to identify the
camera to which further NI-IMAQ for IEEE 1394 Cameras functions apply.
You can simultaneously open as many camera sessions as there are cameras
connected to you system.
When initializing the camera session, you need to specify two parameters:
camera name and camera control mode. Refer to the following sections for
detailed information about these parameters. When an application is
finished with the camera, call the Close function to close the camera
session.
Camera Name
NI-IMAQ for IEEE 1394 Cameras references all camera sessions by a
name. The driver creates default names for each camera in your system in
the order that the cameras are connected. The names observe the
convention shown in Table 2-1.
NI-IMAQ for IEEE 1394 Cameras User Manual 2-2 ni.com
Chapter 2 Basic Acquisition with NI-IMAQ for IEEE 1394 Cameras
Table 2-1. Camera Naming Convention
Camera Name IEEE 1394 Camera Installed
cam0
cam1
Device 0
Device 1
... ...
cam
n
Device n
Every camera has an .iid interface file and an .icd camera file.
• Interface files—Store information about which physical camera is
associated with a camera name. Each interface file can be used by only
a single camera.
• Camera files—Store all the configurable attributes. Camera files can
be shared between identical cameras. Use MAX to configure the
default state of a particular camera.
Figure 2-1 shows the relationship between cameras, interface files, and
camera files.
MyCam.icdCam0.iid
or
Default.icdCam1.iid
Figure 2-1. Relationship Between Cameras, Interface Files, and Camera Files
Use the Enumerate function to query the number and names of available cameras.
Note
When you open a camera session with the Initialize function, the camera
with the unique serial number described by the interface file
opens, where
n
is the reference to the camera. If the camera is not present
camn.iid
and a camera of the same make and model is present, as described in the
interface file, the driver opens the available camera. The interface file
updates to use the new camera. The camera file described by the interface
© National Instruments Corporation 2-3 NI-IMAQ for IEEE 1394 Cameras User Manual
Chapter 2 Basic Acquisition with NI-IMAQ for IEEE 1394 Cameras
file opens, and all the user attributes are set in the driver. If no camera of the
same make and model is present, the Initialize function returns an error.
Camera Control Mode
The camera control mode parameter has two options: controller and
listener. The default option—controller—controls the camera and receives
video data. The listener only receives video data. Use the listener option in
broadcasting applications. Refer to the Broadcasting section of Chapter 3,
Advanced Programming with NI-IMAQ for IEEE 1394 Cameras, for more
information about broadcasting.
Configuration
After initializing the interface, configure the interface for acquisition by
specifying the following parameters: whether the acquisition is one-shot or
continuous, the number of internal buffers to use, and the region of interest
for the acquisition.
During configuration, the driver validates all the user-configurable
attributes. If any attributes are invalid or out of range, the driver returns an
error and does not configure the acquisition.
If you want to reconfigure the acquisition, call the Clear Acquisition
function before calling the Configure function again.
Note National Instruments recommends that you do not configure an acquisition in a loop
because doing so is time-intensive.
One-Shot/Continuous Acquisition
Use a one-shot acquisition to start an acquisition, perform the acquisition,
and stop the acquisition using a single function. The number of images
acquired is equal to the number of images in the images collection.
With a one-shot acquisition, you specify a certain number of internal
buffers. The camera transfers each image up to and including the specified
number of buffers. The driver acquires every image during a one-shot
acquisition. National Instruments recommends one-shot acquisition for
applications that do not require real-time acquisition or processing.
Use a continuous acquisition to start an acquisition, continuously acquire
images into the internal buffers, and explicitly stop the acquisition. With
continuous acquisition, the driver acquires video data continuously from
NI-IMAQ for IEEE 1394 Cameras User Manual 2-4 ni.com
Chapter 2 Basic Acquisition with NI-IMAQ for IEEE 1394 Cameras
the camera and enables you to examine the most current buffer. National
Instruments recommends continuous acquisition for real-time acquisition
and processing.
Note If CPU activity increases during a continuous acquisition, the driver might miss
subsequent images. Check the buffer number output to determine if you have missed any
images.
Number of Buffers
Another aspect of configuration is specifying the number of internal buffers
into which you want to acquire image data. During configuration, buffers
are allocated from system memory and page-locked. Once the acquisition
starts, the camera transfers video data over the IEEE 1394 bus to the
IEEE 1394 interface card FIFO. Then, video data is directly transferred to
the internal buffer. This transfer requires negligible CPU resources.
Each internal buffer you allocate is the exact size of the raw data being
transmitted by the camera. For continuous acquisitions, allocate three or
more buffers. Allocating a single buffer for a continuous acquisition may
result in a high number of lost images. For one-shot acquisitions, specify
the number of buffers that the application requires. For example, if the
application runs for two seconds, and the camera acquires at 30 frames per
second, allocate 60 buffers to capture each image.
Region of Interest
The region of interest (ROI) specifies a rectangular portion of the image to
be captured. In Partial Image Size Format (Format 7) video modes, the ROI
defines the portion of the image to transfer from the camera to system
memory. In non-Format 7 video modes, the entire image is transferred from
the camera to system memory. In all video modes, the ROI specifies the
amount of data decoded by the driver while acquiring into a user buffer.
By default, the driver transfers the entire image. Specify a smaller ROI for
the following reasons:
• To acquire only the necessary subset of data
• To increase the acquisition speed by reducing the amount of data
transferred and/or decoded
• To allow for multiple simultaneous acquisitions by reducing
bandwidth usage
© National Instruments Corporation 2-5 NI-IMAQ for IEEE 1394 Cameras User Manual
Chapter 2 Basic Acquisition with NI-IMAQ for IEEE 1394 Cameras
Note Although you can specify an ROI of any size, the NI-IMAQ for IEEE 1394 Cameras
software coerces the ROI into one that is more compatible for the given camera. Refer to
Chapter 3, Advanced Programming with NI-IMAQ for IEEE 1394 Cameras, for more
information about defining an ROI for Format 7 images.
Acquisition
After configuring and starting your acquisition, the camera sends data to
the internal buffers. To process the acquired image data, you must copy the
data from the internal buffer into your user buffer.
User Buffer
Before starting the acquisition, you must allocate a user buffer in addition
to configuring internal buffers. The driver copies or decodes image data
from the internal buffer into the user buffer during acquisition. Then,
process and analyze the image in the user buffer.
When acquiring data into an IMAQ Vision image, the driver resizes and
casts the image as needed. However, if you acquire data into a user buffer,
you must allocate enough space for one decoded image.
Note Unlike internal buffers, you are responsible for destroying user buffers.
Buffer Number
A buffer number is a zero-based index that represents the cumulated
transferred image count. For example, during a continuous acquisition with
three internal buffers, the buffer number is updated as follows: 0, 1, 2, 3, 4,
5, and so on. Buffer numbers 0 and 3 refer to the same internal buffer in the
buffer ring.
For a one-shot acquisition, you can request only one of the available buffer
numbers. For a continuous acquisition, you can request any present or
future buffer number. You can also request the next logical buffer or the
buffer containing the most recently acquired data. With high-level grab
acquisitions, the buffer number defaults to the next transferred buffer.
When you complete the buffer acquisition step, the driver returns the actual
buffer number with the image.
NI-IMAQ for IEEE 1394 Cameras User Manual 2-6 ni.com
Chapter 2 Basic Acquisition with NI-IMAQ for IEEE 1394 Cameras
Overwrite Mode
Ideally, a continuous acquisition acquires and processes every image that
is transferred from the camera. However, because of processing time
fluctuations, some images from the camera may not be processed before the
camera transfers the next image. Using multiple internal buffers in a
continuous acquisition allows for a small amount of jitter. However, if a
delay becomes too long, the camera overwrites the requested buffer with
new image data.
NI-IMAQ for IEEE 1394 Cameras is able to detect overwritten internal
buffers. You can configure the driver to manage an overwritten buffer in one
of the following ways:
• Get newest valid buffer
• Get oldest valid buffer
• Fail and return an error
In all cases, the camera continues to transfer data when a buffer is
overwritten.
The default overwrite mode for all types of acquisition is to get the newest
valid buffer. This option, which National Instruments recommends for most
applications, enables you to process the most recent image. If you need to
get the image closest in time to a requested buffer, configure the driver to
get the oldest valid buffer. If your application requires that every image be
processed, configure the driver to fail when a buffer is overwritten so that
you are alerted.
Timeouts
A timeout is the length of time, in milliseconds, that the driver waits for an
image from the camera before returning an error. A timeout error usually
occurs if the camera has been removed from the system or when the camera
did not receive an external trigger signal.
Decoding
Except for 8-bit monochrome images, all video modes require decoding
before you can interpret the image data. For example, many color
IEEE 1394 cameras output images of type YUV 4:2:2. However, IMAQ
Vision does not natively support the YUV mode. To process and display
the image, the driver automatically decodes the YUV image into a 32-bit
RGB image.
© National Instruments Corporation 2-7 NI-IMAQ for IEEE 1394 Cameras User Manual
Chapter 2 Basic Acquisition with NI-IMAQ for IEEE 1394 Cameras
Table 2-2 lists common video modes and their corresponding image types
after being decoded by NI-IMAQ for IEEE 1394 Cameras.
Table 2-2. Decoder Inputs and Corresponding Outputs
Raw Camera Output Decoded Destination Image
8-bit monochrome 8-bit monochrome
16-bit monochrome (big endian) 16-bit monochrome (little endian)
YUV 4:1:1 32-bit color
YUV 4:2:2 32-bit color
YUV 4:4:4 32-bit color
24-bit RGB 32-bit color
48-bit RGB 64-bit color
8-bit Bayer 32-bit color
16-bit Bayer 32-bit color
Decoding images requires CPU resources. However, many of the decoding
algorithms have been optimized in the driver. If you do not want decoded
image data, you can use NI-IMAQ for IEEE 1394 Cameras to get a copy of
the raw camera output.
Programming Examples
This section contains examples of high-level and low-level image
acquisitions. Refer to the Example Programs section of Chapter 1,
Introduction to NI-IMAQ for IEEE 1394 Cameras, for directory paths to
the code examples discussed in this section.
High-Level Function Examples
Use high-level functions to write programs quickly without having to learn
the details of the low-level API and driver.
NI-IMAQ for IEEE 1394 Cameras User Manual 2-8 ni.com
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