Hardware manual

US 7,915,570 B2
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be controlled by a control loop on the input on the power
supply. During intervals when it is desirable not to send any
current through the light source, the light source may be
disconnected from the output of the switching power supply.
During these intervals the switching power supply cannot
continue to regulate its current output unless a dummy load
were connected and thus provide an alternate path for the
current output. However, using a dummy load would waste
power and increase heat output.
Instead, during intervals when the light source is discon
nected, the switching power supply may be turned off. Since
these intervals are unknown (may be short or long depending
on the application) and since during this time the switching
power supply is not operating, the values of the components
in the control loop may decay with time. Once the control
loop/switching power supply is inactive, the power supply
may take a while to reach the active state again with the
desired current accuracy.
Thus an active circuit can sample and hold the control
values, and thus provide the necessary fast response time to
achieve full current accuracy. This can be implemented using
a microcontroller having ADC (analog-to-digital converter)
and PWM (pulse width modulation) capabilities. With the
active circuit, a memory of the control variables can be main
tained from when the control loop was regulating the output
current. The active circuit memory enables the lighting cur
rent controller to keep the control loop in an inactive state, and
ready for a quick return from the inactive state to the active
state, thus providing the desired current signal. As a result, the
integrated lighting current controller may be operable to con
trol the one or more external light sources using a current
signal to provide illumination for acquisition of an image of
an object.
It is noted that the examples presented above are meant to
be illustrative only, and are not intended to limit the function
ality or use of the integrated lighting current controller.
BRIEF DESCRIPTION OF THE DRAWINGS
A better understanding of the present invention can be
obtained when the following detailed description of the pre
ferred embodiment is considered in conjunction with the
following drawings, in which:
FIG. 1 illustrates various embodiments of a general image
acquisition system;
FIGS. 2 A-C illustrate various embodiments of an image
acquisition/processing system for inspecting manufactured
objects;
FIGS. 3A-B are diagrams of a smart camera coupled to a
computer system via a network.
FIGS. 4A-C are illustration of various components that can
connect to a smart camera with an integrated lighting current
controller, according to some embodiments of the invention;
FIG. 5A-B illustrate exemplary block diagrams illustrating
some embodiments of a smart camera with an integrated
lighting current controller;
FIG. 6 is a block diagram of a smart camera with an
integrated lighting current controller, according to one
embodiment; and
FIGS. 7A-B are block diagrams of an integrated lighting
current controller, according to some embodiments.
While the invention is susceptible to various modi?cations
and alternative forms, speci?c embodiments thereof are
shown by way of example in the drawings and are herein
described in detail. It should be understood, however, that the
drawings and detailed description thereto are not intended to
limit the invention to the particular form disclosed, but on the
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contrary, the intention is to cover all modi?cations, equiva
lents and alternatives falling within the spirit and scope of the
present invention as de?ned by the appended claims.
DETAILED DESCRIPTION OF THE INVENTION
Incorporation by Reference
The following references are hereby incorporated by ref
erence in their entirety as though fully and completely set
forth herein:
Provisional US. Patent Application No. 60/953,889 titled
“New Architecture for Industrial Camera Lighting Circuit
with High Power Density and Long Strobe Intervals,” to
Cetrulo et al., ?led on Aug. 3, 2007.
US. Pat. No. 7,327,396 titled “Smart Camera with Modu
lar Expansion Capability,” to Schultz et al., issued on Feb. 5,
2008.
FIG. liImage Acquisition or Machine Vision System
FIG. 1 illustrates an image acquisition system in which a
host computer system 102 is coupled to a smart camera 110.
As used herein, the term “smart camera” is intended to
include any of various types of devices that are operable to
acquire and/or store an image and which include on-board
processing capabilities. A smart camera may thus be further
operable to analyze or process the acquired or stored image.
Examples of a smart camera include analog and digital cam
eras with on-board processors, and other similar types of
devices. The smart camera may also include all the elements
shown in FIGS. 5-7 without the chassis. Thus the smart cam
era may be built into a custom chassis at a later time.
As used herein, the term “functional unit” may include a
processor and memory or a pro grammable hardware element.
The term “functional unit” may include one or more proces
sors and memories and/ or one or more programmable hard
ware elements. As used herein, the term “memory medium”
includes a non-volatile medium, e.g., a magnetic media or
hard disk, optical storage, or ?ash memory; a volatile
medium, such as SDRAM memory.
Thus, FIG. 1 illustrates an exemplary image acquisition or
machine vision system 100, where the smart camera 110 may
include a functional unit for performing an image processing
function as described below. The smart camera 110 may
include one or more function modules 108 which may pro
vide various additional functions for the smart camera as will
be described below. The smart camera 110 may couple to the
host computer 102 through a serial bus, a network, or through
other means.
The host computer 102 may comprise a CPU, a display
screen, memory, and one or more input devices such as a
mouse or keyboard as shown. The computer 102 may operate
with the smart camera 110 to analyze, measure or control a
device or process 150. Alternatively, the computer 102 may
be used only to con?gure a functional unit in the image
acquisition device or one or more of the function modules
108. In other embodiments, the computer 102 may be omit
ted, i.e., the smart camera 110 may operate completely inde
pendent of the computer.
The image acquisition system 100 may be used in a manu
facturing assembly, test, measurement, automation, and/or
control application, among others. For illustration purposes, a
unit under test (UUT) 150 is shown which may be positioned
by a motion control device 136 (and interface card 138), and
imaged and analyzed by the smart camera 110. It is noted that
in various other embodiments the UUT 150 may comprise a
process or system to be measured and/ or analyzed.