INFRARED CAMERA
Field of the Invention
This invention relates to camera technology field, in
particular to an infrared camera.
Background of the Invention
Cameras taking pictures at night are widely used, e.g.
in outdoor surveillance and hunting monitoring. According to the different
nighttime illumination modes, the cameras taking pictures at night could be
categorized in two types:
One type uses Xenon flash, also called HID Intensity
discharge lamp, as flash to take color photos. While the Xenon flash is used
for illumination, High voltage current of thousands of volts stimulates Xenon
to illuminate, generating white arcs similar to fluorescent lamp between the
two poles, which has good night illumination for clear color photographs. But
because there is a strong visible light flashes when photo is taken, animals
may be frightened or the attention may be attracted in monitoring, the use has
no concealment.
The other type uses infrared LED as illumination source
of photos or videos to take black and white images. The infrared LED emits
light not through the electronic transitions within the atom, but through
adding voltage on the two ends of PN junction, making the PN junction itself to
form energy level on which the electrons transit. Based on the light emitting
principle of LED, the instant illumination intensity in photo-taking is
generally low, far from the high intensity illumination generated by instant
high voltage of gas discharge flash, so the images has more noise and it is
easy to cause motion blur. But infrared lights emitted by the infrared LED has
good concealment, therefore current outdoor surveillance camera and hunting
monitoring camera mainly use infrared LED as illumination source.
Summary of the Invention
According to one embodiment of the present invention,
infrared camera includes: photosensitive element, the spectrum sensing range
including at least the infrared spectroscopy; flash light source, using gas
discharge flash; a first optical filter, fixedly or removablely disposed in the
emitted light path of the flash light source, the optical filter is to filter
visible light and allow infrared light to transmit; processing module, used to
execute instructions, the instructions execution includes: execute workflow,
wherein photographing process is included, the photographing process includes
controlling flash light source to flash and acquire photo data collected by the
photosensitive element.
The infrared camera according to an embodiment of the
present invention breakthrough the conventional use of gas discharge flash,
using gas discharge flash with visible light filtered creatively, providing
infrared illumination capability far from infrared LED based on different
emitting light principle, thus improving the quality of infrared photographing
at night effectively.
Hereafter the specific embodiments of the present
invention are described in detail with the drawings.
Brief Description of the Drawings
Fig.1 is structure diagram of an infrared camera
according to one embodiment of the present invention;
Fig.2 is the spectrum diagram of the Xenon flash;
Fig.3 is work flow chart of the infrared camera in
embodiment 1;
Fig.4 is structure diagram of an infrared camera
according to another embodiment of the present invention;
Fig.5 is structure diagram of an infrared camera
according to another embodiment of the present invention;
Fig. 6 is a structure diagram of the optical filter
holder according to the present invention;
Fig. 7 is a diagram when the optical filter of Fig.6
is fixed to the front cover of the camera;
Fig.8 is structure diagram of an infrared camera
according to another embodiment of the present invention;
Fig.9 is the position diagram when the second optical
filter of Fig. 8 is in working state;
Fig.10 is the position diagram when the second optical
filter of Fig. 8 is in removal state.
Detailed Description of the Invention
Embodiment 1
Refer to Fig.1, an infrared camera according to an
embodiment of the present invention includes photosensitive element 101, Xenon
flash 102 used as flash light source, a first optical filter 103, infrared
monitoring unit 104, and processing module 105. Additionally, according to the
general configuration of conventional camera, the infrared camera also includes
power supply module 11 providing power supply to various components and storage
module 12 for photographing data storage, the above two conventional modules
could be manufactured and sold independently as removable accessories.
The spectrum sensing range of photosensitive element
includes visible lights and infrared light. It should be noted that the
spectrum sensing range in present invention, such as visible lights and
infrared light, should be understood as the range substantially compliant with
the typical range of knowledge, not certain strict range of values. For
example, it is normally considered that the light with wavelength of
800nm-1000nm belongs to near infrared light, so the camera with the light
sensing range covering 800nm-1000nm can sense the infrared light; For another
example, it is normally considered that the light with wavelength of
400nm-800nm belongs to visible lights, the camera capable of filtering (e.g.
more than 50%) spectrum of 400nm-800nm can be considered to be visible lights
filtering capable.
Xenon flash 102 is generally gas light used to provide
sunlight similar illumination, a common design approach is: high pressure Xenon
is filled in the quartz tube, the two electrodes use mercury and carbon
compound, high voltage such as 4000V is used to stimulate the Xenon to ionize
and conduct through stabilizer (ballast), enabling the power stored in the
capacitor to discharge through flash tube, which is converted to luminous
energy, thus a flash is accomplished. The spectrum range of Xenon flash is
substantially illustrated in Fig.2, between 300nm and 1100nm. It can be seen
from Fig.2 that Xenon flash has very good radiation intensity in near infrared
spectrum range (800nm - 1000nm), therefore, Xenon flash could provide good
infrared illumination with the visible lights filtered, which improves the
image noise and motion blur encountered by conventional infrared LED and
acquires clear nighttime infrared (black and white) image.
The first optical filter 103 is removablely disposed
on the emitted light path of Xenon flash 102, the first optical filter 103
could filter visible lights and allows infrared light to transmit, for example,
the first optical filter could be simple black glass.
The infrared monitoring unit 104 is a device capable
of detecting the infrared radiation (e.g. infrared radiation from human being
or animal) in the monitoring area, for example, passive infrared (PIR), which
can produce monitoring trigger signal. It is easy to understand that the
monitoring trigger signal could be digital signal or analog signal based on
different sensor configuration, and could be directly sent to the appropriate
interface of the processing module 105, or sent to the appropriate interface of
the processing module 105 after common software/hardware processing, such as
analog/digital conversion, amplification, rectification, filtration.
The processing module 105 is used to execute
instructions to control various connected components, acting as logic
processing device to implement control functionality. In particular the
processing module 105 could be SCM, control chip, CPU, etc.. The instructions
executed by the processing module 105 could be stored in itself cache or the
memory(not shown) outside the processing module, the execution of the
instructions includes: executing flash working mode setting flow, executing
monitoring flow, executing workflow etc., wherein:
Flash working mode setting flow includes acquiring
input flash setting signal (for example, setting commands input by the user via
man-machine interface) and determining whether or not to set the mode to
infrared mode based on the input flash setting signal;
The monitoring flow includes acquiring the monitoring
trigger signal generated by the infrared monitoring unit 104 and start workflow
based on the monitoring trigger signal;
The workflow includes photographing flow, which could
include controlling Xenon flash 102 to flash and acquiring and processing the
photo data collected by the photosensitive element 101, in case that the flash
working mode is set to infrared mode, the predefined black and white processing
mode is used to process the photo data, in case that the flash working mode is
not set to infrared mode, the predefined color processing mode is used to
process the photo data. The processed photo data could be stored in storage 12.
Refer to Fig.3, the working flow of the infrared
camera of present embodiment includes:
Step 301. The user mounts a first optical filter and
set the flash working mode to infrared mode through the camera operation
interface. The user could choose whether or not to mount the first optical
filter according to requirements, if concealed nighttime infrared photos are
expected, the first optical filter is to be mounted and the corresponding flash
working mode is to be set, if color photos are expected, the first optical
filter is not to be mounted.
Step 302. the user powers on the camera, the infrared
monitoring unit starts working, the camera enters monitoring state, in the
monitoring state, the infrared monitoring unit could keep on monitoring whether
or not there are animals or people entering the monitored area.
Step 303. Once the infrared monitoring unit inspects
infrared radiation, the monitoring trigger signal is produced, otherwise, the
infrared monitoring unit keeps on monitoring.
Step 304. The processing module is woken up by the
monitoring trigger signal and workflow is started, go to step 305 and 306.
Step 305. Starting photosensitive element and
collecting photo data.
Step 306. Controlling Xenon flash to flash.
Step 307. Determine whether the flash working mode is
infrared mode or not, if yes go to step 308, if no go to step 309.
Step 308. Calling the predefined black and white
processing mode.
Step 309. Calling the predefined color processing
mode.
Step 310. Processing and storing the media files.
Step 311. The processing module enters hibernation to
save energy consumption, waiting for being woken up by next monitoring trigger
signal from the infrared monitoring unit.
In present embodiment, the photosensitive element not
only senses visible lights but also infrared light, in other embodiments, the
spectrum sensing range of the photosensitive element can also include infrared
spectrum, thus resulting in becoming infrared camera dedicated for infrared
image photographing.
In present embodiment, the first optical filter is
disposed in the emitted light path of the flash light source, resulting in not
only high intensity infrared illumination, but also avoiding disturbing the
photographed objects with high intensity visible lights and improving
photographing concealment. Additionally, in present embodiment, the first
optical filter uses removable configuration to facilitate Xenon flash to act as
not only infrared light source but also white light source. In other
embodiments, the first optical filter could also be fixedly disposed in the
emitted light path of the flash light source, in this case, the flash light
source is dedicated for high intensity infrared illumination, accordingly, the
camera is designed to be dedicated for infrared image photographing, or could
be provided with visible lights illumination source. If the camera is dedicated
for infrared image photographing, the processing module does not need to
execute flash working mode setting flow, accordingly, the corresponding
processing mode does not need to be selected according to whether it is color
or not when the photo data is processed.
In present embodiment, the infrared monitoring unit is
set up to enable working control automatically according to the detected
infrared radiation, applicable for the circumstance wherein automatic
monitoring is needed. In other embodiments, the infrared monitoring unit may
not be set up, the processing module executing the monitoring flow is of course
unnecessary, for example, the operator can actively control to take photos.
Xenon flash is selected as the flash light source of
present embodiment, in other embodiments, other gas discharge flashes could
also be selected, such as Neon flash, Helium flash, Nitrogen flash and Argon
flash etc. It has been hundreds of years history since gas discharge flash was
born, because the application is always used for visible lights illumination,
the research direction is along the direction of more sunshine similarity which
may result in more vivid colors in photograph, but the radiation in infrared
range has never been used independently for nighttime illumination. Base on the
conventional development orientation whose goal is high color temperature, Neon
flash, Helium flash and Nitrogen flash have been almost eliminated, that is
because their color temperature is low, the radiation range is partially red,
their lighting ability in visible lights range is inferior to Xenon flash.
However, based on the innovative ideas of present invention, it is a
breakthrough to use spectrum characteristics of the gas discharge flash which
has high intensity radiation capability in infrared spectrum, thus the
eliminated gas discharge flash in visible lights illumination becomes good
infrared flash after visible lights filtered simply, providing infrared
illumination whose intensity is far above the infrared LED. Therefore, compared
with current infrared LED camera, nighttime image quality and photographing
distance are improved a lot. Certainly, if it is considered that the camera
works in two different modes which are black and white mode and color mode,
Xenon flash is still the better choice, because it can provide sunshine similar
illumination while the first optical filter is removed, which makes the camera
work in black and white(infrared) mode as well as in color (visible lights)
mode.
Furthermore, in order to get better infrared
illumination, the used gas discharge flash could use the method of spectral
shift in manufacture process, which makes the radiation range shift to infrared
area, for example, the spectral shift method is as below: adjusting the voltage
added to the two ends of the flash (through using stabilizer outputting
corresponding voltage); changing the ratio of the internal material of the
light tube (for example, for Xenon flash, adjusting the ratio of Xenon, mercury
and carbon compound); adding magnesium arsenate or manganese powder etc. to the
material. Decreasing the color temperature of the gas discharge flash with
various spectral shift methods, enabling the emitted lights shifting to the
infrared spectrum, if the emitted lights are all infrared light, the first
optical filter could be cancelled.
Embodiment2
Refer to Fig.4(for simplicity, the components of the
following embodiments whose functionalities are similar to embodiment 1 use the
same numbering), an infrared camera according to another embodiment of present
invention is provided with lighting light source 106 which is the difference
comparing with embodiment 1.
Accordingly, the instructions executed by the
processing module 105 further includes: camera working mode setting flow, which
is to acquire input camera setting signal (for example, the setting command
input by user via man-machine interface), based on which the camera working
mode is set up photographing mode or video mode, once working flow is needed to
start, photographing mode is started if the photographing mode is set, or video
flow is started if the video mode is set;
The working flow executed by the processing module 105
further includes video flow, which includes controlling lighting light source
106 to open and acquiring video data collected by photosensitive element
101.
Present embodiment enable the infrared camera further
having video capability as well as clear infrared nighttime photographing
capability, for example, when infrared LED is selected as lighting light
source, black and white video functionality is available, when white color LED
is selected as lighting light source, color video functionality is available.
Embodiment 3
Refer to Fig.5, an infrared camera according to
another embodiment of present invention is provided with communication module
110 which is the difference comparing with embodiment 2.
Accordingly, the instructions executed by the
processing module 105 further includes: data transmission flow, which is to
sent the acquired data (for example, image or video) via the communication
module 110 according to predefined transmission mode in the execution process
of the working flow or after the working flow execution is accomplished, for
example, the acquired data is sent to predetermined cell phone, computer or
mailbox etc.
In present embodiment, communication module could be
various wireless communication module, such as generation 2, generation 3, or
generation 4 mobile communication module, could also be short-range wireless
transmission module, such as Bluetooth, Wi-Fi, 2.4G module etc.
Embodiment 4
The components structure of the infrared camera of
present embodiment could take above-mentioned description for reference,
present embodiment provides a structure to fix a first optical filter. Refer to
Fig. 6 and Fig. 7, the structure used for fixation includes optical filter
support 108, e.g. being formed as a holder, which has structures (for example,
a plurality of buckles engaging with the front cover, not shown) matching front
cover 109 of the camera, removablely engaging the front cover 109. The first
optical filter 103 is embedded in the optical filter support 108, whose size
and shape needs to adapt to the flash light source needed to be covered. (for
example, matching the size of the lamp cup or matching the overall size of the
flash). In case that the optical filter support 108 engages with the front
cover 109, the first optical filter 103 cover the emitted light path of the
flash light source 102.
In present embodiment, the first optical filter is
fixed to the front cover of the camera with the optical filter support, when
use is needed, engage the optical filter support, and clear black and white
photos could be taken, when no use is needed, the optical filter support could
be removed simply to take color photos, the support is easily to be
manufactured and conveniently to be mounted.
Embodiment 5
Refer to Fig.8-10, an infrared camera according to
another embodiment of present invention is provided with a second optical
filter 107 which is the difference comparing with embodiment 1, the second
optical filter is removablely disposed in the incident light path of
photosensitive element 101. In present embodiment, the second optical filter
107 in particular is disposed between the lens assembly and the photosensitive
element. The second optical filter filters infrared light and allows visible
lights to transmit, the first optical filter 103 and the second optical filter
107 are not in working location simultaneously.
When color photo taking is needed, for example, there
are high intensity external lights or flash light source works in white light
mode( i.e. the first optical filter removed), the second optical filter is
moved into the light path of the photosensitive element to filter infrared
light and obtain color photos, as shown in Fig. 9. When infrared photo taking
is needed, for example, there are weak external lights, the flash light source
works in infrared mode( i.e. the first optical filter is mounted in the emitted
light path of the flash light source), the second optical filter is removed
from the light path of the photosensitive element, resulting in make the
photosensitive element to sense infrared light and black and white photos can
be taken, as shown in Fig. 10.
In other embodiments, the second optical filter can
also be disposed before the lens assembly and photosensitive element, for
example, lens cover similar means could be fixed before the lens
removablely.
Present embodiment causes that the camera can get
better quality images both in infrared mode and white light mode.
The principle of present invention and embodiments are
described as above through specific examples, it should be understood that the
above embodiment is intended to assist in understanding of present invention,
not a limit to present invention. For the ordinary skilled in the art,
according to the spirits of present invention, modifications could be made to
the above embodiments.