Note: Descriptions are shown in the official language in which they were submitted.
CA 02922442 2016-02-25
1
OPTICAL ARRANGEMENT FOR PROVIDING A 360 VIEW
The invention relates to an optical arrangement which can be used in
particular as a
360 optical system for applications in which the use of a camera with a
classic
objective in the direct beam path is not possible.
Individual pivoting and/or movable cameras can be used for 3600 monitoring of
the
surroundings; or a plurality of cameras are located in such a way that all
areas can be
detected. In general, wide-angle cameras are used for this. However, the prior
art
includes known monitoring systems, with which 360 panoramic images can be
taken
indirectly by means of a camera. In this case, the camera is directed at a
convex mirror
which reflects distorted images of the surroundings onto the image plane of
the camera
via a further mirror. The distorted image data is then converted into
rectified image data
with an image analysis system.
Such an indirect optical monitoring system is described, for example, in DE
101 58 415
Al which focuses primarily on the monitoring of the internal space of a
vehicle. Using
at least one panorama camera images are generated in curvilinear coordinates,
transformed to planar or cylindrical coordinates and then subjected to an
electronic
image evaluation. Persons and/or objects are detected with this such that an
automatic
adjustment of the seat or the safety devices can be carried out, for example,
for each
seating position. In the event of a car accident the extracted information
should be
stored and/or can be conveyed to a rescue center by radio. This system can
also
monitor parts of the exterior, so that it is also suitable as a collision
warning or parking
assistance system.
In order to fulfill the functional description explained above, the aim is to
primarily use a
conventional digital camera in combination with at least one mirror. Depending
on the
objective regarding which area is to be monitored, the location and
orientation of the
camera and the mirrors are to be redefined.
In the field of the invention, an arrangement for 360 reception and for
focusing light
signals is also known from patent specification DD 219 884 Al. In the case of
this
solution, light is directed by a mirrored belt lens onto a photodetector.
An optical instrument and a method for optical monitoring of the surroundings
of slowly
moving vehicles is known from the publication EP 2 433 837 Al. In the case of
this
CA 02922442 2016-02-25
2
solution, light is directed by a mirrored belt lens onto an area detector in
order to
generate a first image, and light is directed via a combination of prisms and
lenses onto
the area detector in order to generate a second image.
A similar solution which can be used as a camera attachment is described in
European
patent specification EP 0103 301 B1.
A lantern for radiating a warning signal all around, wherein a belt optical
system is
used, is known from the utility model application DE 203 05 625 Ul.
The object of this invention is to provide an optical arrangement which avoids
the
disadvantages of the conventional solutions and which can be used in order to
reliably
detect and analyze moving objects, preferably from a bird's-eye view.
This object is achieved according to the invention by the features of Claim 1.
Expedient
embodiments of the invention are set out in the dependent claims.
A particular advantage of the optical arrangement according to the invention
is that
monitoring of the surroundings is made possible, even in adverse lighting
conditions.
This is achieved by using an optical arrangement which comprises at least one
belt
lens and at least one optical sensor. According to the invention at least one
optical
sensor is arranged directly and/or indirectly in the beam path of at least one
of the belt
lenses. It is understood that an arrangement directly in the beam path of the
belt lens is
an arrangement where no refractive and/or reflective elements such as
additional
lenses, prisms or mirrors are located in the beam path between the belt lens
and the
optical sensor. Accordingly, an arrangement indirectly in the beam path of the
belt lens
is understood to be an arrangement where the light coming from the belt lens
is
conducted by refractive and/or reflecting elements to the optical sensor,
wherein said
conducting can also include a reversal of the beam path.
According to the invention the belt lens is designed in such a way that no
reversal of
the beam path takes place inside the belt lens. In particular, optical signals
or at least a
portion of the optical signals pass through the belt lens without being
reflected. The at
least one belt lens and the at least one optical sensor are preferably
arranged such that
the optical signals or at least a portion of the optical signals travel from
the entry into
the at least one belt lens up to the at least one optical sensor without being
reflected.
The result of this is that the optical signals are attenuated less than in the
conventional
CA 02922442 2016-02-25
3
solutions.
The optical arrangement can be deemed to be a camera with a special objective.
According to the invention the special objective comprises at least one belt
lens,
wherein the at least one belt lens can be combined with one or more additional
optical
components. Such a combination of belt lens(es) and one or more optical
components
is referred to hereinafter as a belt lens optical system.
The belt lens or belt lens optical system is preferably a fast-speed belt lens
or belt lens
optical system.
The belt lens is in particular a substantially circular, transparent optical
element. The
cross-section of the belt lens preferably has two spherical sections in order
to generate
a lens effect. The belt lens preferably has a biconvex cross-section. In a
preferred
embodiment the belt lens is constructed from a plurality of optical elements
which,
together, form a substantially closed ring. In a further preferred embodiment
the belt
lens is designed as a Fresnel belt lens.
The optical sensor is preferably a photodiode array or a photodiode matrix, in
particular
a CCD sensor (CCD = Charge Coupled Device). Optical sensors which comprise
organic semiconductor materials or which are made of organic semiconductor
materials such as e.g. organic photo sensors or organic photodiodes, are
preferably
used.
It is advantageous if the optical sensor is configured as a curved sensor. In
one
preferred embodiment the optical sensor is designed as a cylinder or
cylindrical casing.
The cylinder or cylindrical casing is aligned along the axial symmetry axis of
the belt
lens or belt lens optical system. The image of the surroundings is preferably
displayed
directly on the sensor, which is in the form of a cylinder or cylindrical
casing, by the belt
lens or the belt lens optical system. In other preferred embodiments
additional optical
elements are arranged in the beam path between the belt lens and the sensor in
the
form of a cylinder or cylindrical casing, for example in order to adjust the
dimensions of
the optical arrangement and the imaging properties of the belt lens or belt
lens optical
system to one another. It may prove to be advantageous, if the optical sensor
forms at
least a part of the surface of a cone. By varying the aperture angle of the
cone, the
beam path of the optical arrangement can be adjusted, for example, to the
structure of
the optical arrangement.
CA 02922442 2016-02-25
4
In another preferred embodiment the optical sensor is configured as a planar
or flat
sensor. The planar optical sensor can be part of a digital camera. The image
information supplied by the belt lens or belt lens optical system is
preferably displayed
on the sensor via at least one optical element arranged in the beam path
between the
belt lens/belt lens optical system and the planar sensor. In a preferred
embodiment the
beam path is deflected by the at least one optical element inserted into the
beam path.
In a preferred embodiment the optical element is a conical mirror which is
aligned along
the axial symmetry axis of the belt lens or belt lens optical system.
In a preferred embodiment a first portion of the optical signals travels from
the entry
into the at least one belt lens up to at least one first optical sensor
without being
reflected, while at least one optical element is arranged in the beam path of
a second
portion of the 'optical signals, which optical element displays the second
portion of the
optical signals on at least one second optical sensor.
In a further preferred embodiment a lens, preferably an annular lens,
particularly
preferably an annular lens with a zero meniscus cross-section is arranged in
the beam
path between the belt lens/belt lens optical system and the planar sensor next
to the
mirror, in order to adjust the image size of the image supplied by the belt
lens/belt lens
optical system and the conical mirror to the optical sensor.
In general, the optical elements arranged in the beam path between the belt
lens/belt
lens optical system and the optical sensor can be light-deflecting, light-
reflecting and/or
refractive elements.
Optical sensors with a low resolution can be used for the purpose of detecting
moving
objects.
In a preferred embodiment the optical arrangement comprises at least one
energy
source for supplying at least the optical sensor, at least one multiplexer
connected to
the optical sensor and at least one AD converter in order to digitize the
analog data
supplied by the multiplexer. The digital data can then be provided to a data
processing
unit.
In a preferred embodiment the optical arrangement further comprises at least
one data
processing unit such as e.g. at least one processor. The at least one data
processing
unit is at least temporarily connected to at least one part of the optical
sensors, so that
CA 02922442 2016-02-25
signals or data can be exchanged between the optical sensors and the at least
one
data processing unit.
In another preferred embodiment the optical arrangement further comprises at
least
5 one light-emitting element such as, for example, at least one light-
emitting diode (LED).
In another preferred embodiment at least one belt lens/belt lens optical
system and at
least one optical sensor are combined in a common structural unit. The common
structural unit can, for example, be a housing, in particular a light,
preferably a street
light. In another preferred embodiment the common structural unit also
comprises at
least one data processing unit. Additionally or alternatively, one or more
data
processing units can also be provided, which are arranged outside the common
structural unit, for example as a central control unit for a plurality of
structural units.
In a preferred embodiment at least one part of the data processing units is
configured
such that the signals supplied by the optical sensors are analyzed in order to
detect
moving objects. In addition, in a preferred embodiment the light-emitting
elements are
controlled by at least one data processing unit. In a preferred embodiment at
least a
part of the light-emitting elements are controlled as a function of a moving
object. In
particular at least a part of the light-emitting elements is enabled or dimmed
up, if an
object moves in the area detected by the sensors. The controller can also be
designed
such that the light-emitting elements are disabled or dimmed down, if no
moving object
has been detected within a specified period.
In another preferred embodiment at least two, but preferably a plurality of,
structural
units are controlled by at least one data processing unit. It can be arranged
such that
multiple structural units communicate with one another, in order to announce,
for
example, an approaching object to another structural unit. In a preferred
embodiment
the movements of the object are analyzed, for this purpose, for example, by
vector
analysis, in particular by analyzing the optical flow.
It can also be the case that optical signals, in particular light signals from
the visible
and/or invisible frequency range are detected by the optical sensors of a
structural unit
and transmitted to other structural units. The signals can be passed on as
optical
signals. In this case, the signals detected by the optical sensor of a
structural unit are
transmitted to a data processing unit which is also encompassed by the
structural unit
or arranged separately from the structural unit. The data processing unit
analyzes the
CA 02922442 2016-02-25
6
signals and activates the light-emitting element of the structural unit as a
function of the
result of the analysis, said light-emitting element emitting corresponding
signals.
Alternatively or additionally, the optical signals received can also be
forwarded by the
data processing unit in other ways, for example by wire to a different data
processing
unit or by radio. The analysis of the optical signals by the data processing
unit can
comprise a decoding. Such optical arrangements can be used, for example, in
submarines in order to transmit signals over water.
In a preferred embodiment the optical arrangement is equipped both with
optical
sensors and with light-emitting elements, so that the optical arrangement can
be used
both as a (3600) light receiver unit and as a (360 ) light transmitter unit.
In another
preferred embodiment the optical arrangement is only operated as either a
separate
(360 ) light receiver unit or as a separate (360 ) light transmitter unit.
In a preferred embodiment at least one of the data processing units is
configured to
carry out at least
- an analysis of signals detected by the at least one optical sensor,
- a detection of moving objects, in particular a vector analysis,
- an execution of image processing algorithms, in particular transforming
signals
detected by the at least one optical sensor,
- a generation of signals which can be visualized by an optical output
unit, in
particular as a function of detected signals,
- an activation and/or deactivation, in particular a dimming up and/or
dimming down,
of the at least one light-emitting element as a function of moving objects
detected,
- a control of a plurality of structural units, in particular as a function
of moving
objects detected,
- a transmission of signals detected by the at least one optical sensor of
a first
structural unit to the at least one optical sensor at least one second
structural unit
and/or to a data processing unit.
In a preferred embodiment the belt lens and image sensor system are embedded
in a
common housing as a closed structural unit. The most compact design of the
series is
the symbol-providing functional unit having an image sensor, which is in the
form of a
cylinder or cylindrical casing and which is specially adapted to the
characteristics of the
lens. It can, for example, be used in a space-saving manner in street lights
in order to
activate the dimming up of LED light sources, on detecting approaching
objects,
CA 02922442 2016-02-25
7
including in dimly-lit light conditions, and for receiving data via light
signals. The multi-
channel image sensor, which is connected to a constant current source and
designed
as a photodiode matrix, receives the analog image signals transmitted by the
belt lens
directly and forwards these to the analog multiplexers located in the central
electronic
control. The signals are digitized by means of an AD converter and transferred
to the
existing computer unit for further processing. A monitor can be connected via
an
interface for symbolized visualization of the movement processes of objects.
It is also
possible to carry out a vector analysis of movements.
The term 'symbol-providing' denotes the fact that the image information
received from
an optical sensor, preferably following processing by software, as a coarse-
resolution
object image can be displayed on optical output devices, such as e.g. on a
monitor. In
a preferred embodiment detected objects are reproduced as geometric symbols,
for
example, as a flashing cross or the like.
According to a preferred embodiment of the image-providing function, the
analog
image data generated by a belt lens is deflected by means of a conical mirror
in
combination with an annular lens to a conventionally planar image sensor or
digital
camera, digitized there and then further processed and analyzed by the
computer unit
provided. The distorted images of the surroundings which are transformed into
Cartesian coordinates can be visualized on a connected monitor in real time or
on
subsequent retrieval.
The application of the belt lens, reversing the direction of the beam path,
constitutes
another preferred embodiment. LED light sources are arranged around the center
of
the lens so that their beam angles run collinearly or parallel with the focal
rays of the
belt lens, which are generated by the latter's biconvex cross-section. The
rays of light
emerging from the outlet then generate a specified cone of light as required,
for
example, for the operation of street lighting.
In another preferred embodiment a 360 camera unit is provided for monitoring
the
surroundings via a belt lens/belt lens optical system, which sends the analog
image
information from its detection area in the direct beam path to a centrally
arranged
image sensor which is in the form of a cylinder or cylindrical casing, from
which image
sensor the analog data is then routed via multiplexers and AD converters to a
separate
computer unit for further processing. The belt lens/belt lens optical system
and the
image sensor with its connection leads for the constant current source and the
outputs
CA 02922442 2016-02-25
8
identified according to the channel they belong to and PIN numbers, together
with the
housing, form a compact functional unit which is therefore also suitable for
receiving
and forwarding data via light signals.
In another preferred embodiment the analog image signals provided by the belt
lens
optical system are deflected by means of a conical surface mirror and, first
of all,
transmitted via an annular lens to an integrated area image sensor, from which
the
digitized data is then transferred by cable or radio to the separate computer
unit for
further processing. A separate digital camera can be mounted on the interface
provided
for it, dispensing with the area image sensor, for selected applications.
The invention thus provides a belt lens/belt lens optical system which has
been
developed for a 3600 view in combination with a centrally arranged image
sensor
system, which can be used in order to reliably detect and analyze moving
objects,
preferably from a bird's-eye view. The "optical axis" of the optical
arrangement
according to the invention thus preferably forms an angle with the axial
symmetry axis
of the belt lens, which angle deviates from the right angle. The conical
casing is
referred to as the "optical axis" of the optical arrangement according to the
invention,
which conical casing is created when the optical axis of a lens, which has the
same
cross-section as the belt lens, is rotated about the axial symmetry axis of
the belt lens.
The angle enclosed by the "optical axis" of the belt lens with the axial
symmetry axis is
preferably approximately 300 to approximately 80 , particularly preferably
approximately 400 to approximately 70 , very preferably approximately 60 . It
is a 360
monitoring system which operates effectively and which can be integrated
easily into
technological processes. A preferred embodiment is characterized by a belt
lens design
with a fast lens speed and a central image sensor system for monitoring the
surroundings with a movement analyzing function.
One embodiment of a 360 camera unit according to the invention is shown in
the
following drawings where:
Figure 1 shows a schematic cross-sectional view of a symbol-providing 360
camera
unit through its housing and belt lens. The cylindrical body of the image
sensor, with its photodiode arrangement which is embedded in the casing
thereof can be observed as a complete view,
Figure 2 shows a schematic cross-sectional view of an image-providing 360
camera
CA 02922442 2016-02-25
9
unit through the latter's housing, belt lens, conical surface mirror and
annular
lens for the analog output. The interface for the arrangement of an area
image sensor 6 or a digital camera is shown.
The schematic representation of Figure 1 shows the components of a 3600 camera
unit
according to the invention arranged in the housing 3. Of note are first of all
the
geometry and optical parameters of the fast-speed belt lens 1 which is made of
transparent material and has a biconvex cross-section for the effective
transmission of
moving images of the surroundings in the direct beam path to the centrally
arranged
image sensor 2 which is in the form of a cylindrical casing. This direct
transmission of
the analog image signals to the sensor prevents the losses which generally
occur in the
case of a deflection of the beam path into a different plane, therefore
allowing it to be
successfully used in poor light conditions as well.
The main application of this functional unit is the reliable detection of
moving objects
and the analysis of movements for controlling technological processes and for
receiving data via light signals. The movement processes are visualized by the
conversion of moving images of the surroundings into geometric symbols. The
housing
3 is designed with the required degree of protection in accordance with the
existing
conditions of use.
The schematic representation of Figure 2 shows the components of a modified
form of
a 360 camera unit according to the invention arranged in the housing 3. With
an
unchanged belt lens 1, with respect to the functional unit described above, a
deflection
of the beam path is required. For this purpose, a conical surface mirror 4 is
arranged in
the center of the belt lens 1. The tatter's base body is made of plastic with
a finely
machined, highly reflective coated surface. The image size of the deflected
analog
image information is adjusted by an annular lens 5, which is made of
transparent
material with a zero meniscus cross-section, to the area image sensor 6 which
is
arranged inside the housing 3 or the digital camera mounted outside on an
existing
connecting device. Due to the suitability of this functional unit for the
image-providing
representation, it can be used both for reference image comparisons in
technological
processes and in the object safety area.
The invention is not limited in its embodiment to the preferred embodiment
examples
indicated above. Rather, a number of variants which make use of the
arrangement
according to the invention, even with fundamentally different designs, are
conceivable.
CA 02922442 2016-02-25
List of reference numerals
1 Belt lens
2 Image sensor in the form of a cylindrical casing
5 3 Housing
4 Conical surface mirror
5 Annular lens
6 Planar area image sensor
