DE102011089803A1 - System for monitoring examination space in clinical environment of e.g. C-arm X-ray diagnostic device, has depth cameras that are connected to image processing computer so as to generate three-dimensional data in accordance with object - Google Patents

Abstract

The invention relates to a system for monitoring an examination room (13) in the clinical environment of a diagnostic device (1 to 4 ', 7 to 12) during an angiographic examination or treatment of an organ, vascular system or other body regions as examination object of a patient with a device (14, FIG. 30) for detecting the position of at least one object (1 to 4 ', 7 to 12, 40) located in the examination room (13), the apparatus (14, 30) comprising a radiation transmitter (21 to 23) for transmitting a radiation beam ( 34, 39) and a camera (24 to 27) for detecting the at least one object (1 to 4 ', 7 to 12, 40) and wherein the signals of the camera (24 to 27) of a device (27, 15) supplied are generated due to these signals 3-D data corresponding to the at least one object (1 to 4 ', 7 to 12, 40) used to avoid collisions of the object (1 to 4', 7 to 12, 40) become. At least two depth cameras (14, 30) for monitoring the examination room (13) are provided, each having a monochromatic radiation source (21, 22) with mutually different wavelengths, - a beam shaper (23) and - a detector (24 to 26) for these monochromatic beams, wherein the depth cameras (14, 30) are connected to the device (27, 15) for avoiding collisions of the object (1 to 4 ', 7 to 12, 40) for generating the 3-D data ,

Description

The invention relates to a system for monitoring an examination room in the clinical environment of a diagnostic device during an angiographic examination or treatment of an organ, vascular system or other body regions as an examination subject of a patient with a device for detecting the position of at least one object located in the examination room, wherein the device a radiation transmitter for transmitting a beam and a camera for detecting the at least one object, and wherein the signals of the camera are fed to a device which, on the basis of these signals, generates 3-D data corresponding to the at least one object used to avoid collisions of the object be used.

Medical diagnosis and intervention systems in angiography, cardiology and neurology today mostly use a so-called C-arm as the basis for the imaging components, the X-ray tube and the X-ray detector. This can be positioned very flexibly around the patient for 2-D as well as 3-D imaging - powered by a motor. For example, in the context of preprogrammed rotation angiographies, i. H. during a circular movement of the C-arm around a patient, up to a few hundred images taken, which can then be reconstructed using algorithms in a 3-D volume. For rotation speeds of 60 ° / s are usually used. For future applications and to realize further dose savings, even higher rotational speeds are needed. Even manual rides that allow the operator to drive freely across all degrees of freedom with the systems become faster to optimize the clinical workflow. With faster and more flexible systems, the risk of collisions with patients, personnel, and equipment increases dramatically.

In the field of angiography devices, the path planning system is increasingly gaining access to unknown devices, such as anesthesia devices, arm or head mounts, infusion stands, etc. Due to the flexibility of the systems, more and more C-arm angiography devices are being used in the operating theater For medical reasons, there are significantly more people who are therefore also exposed to an increased risk of collision.

Such Angiographiesystem is for example from the US 7,500,784 B2 known in connection with the 1 will be explained below.

The 1 shows an exemplary biplanes X-ray system with two of each stand 1 and 1' in the form of a six-axis industrial or articulated robot held C-arms 2 and 2 ' , at the ends of each an X-ray source, such as X-ray source 3 and 3 ' with x-ray tubes and collimators, and one x-ray image detector each 4 and 4 ' are mounted as an image recording unit. The first stand 1 is on the floor 5 mounted while the second stand 1' on the ceiling 6 can be attached.

By means of the example of the US 7,500,784 B2 Known articulated robot, which preferably has six axes of rotation and thus six degrees of freedom, the C-arm 2 and 2 ' be spatially adjusted, for example, by placing them between the X-ray tubes 3 and 3 ' as well as the X-ray image detectors 4 and 4 ' lying turning centers are rotated. The angiographic X-ray system according to the invention 1 to 4 is in particular about centers of rotation and axes of rotation in the C-arm plane of the X-ray image detectors 4 and 4 ' rotatable, preferably around the center of the X-ray image detectors 4 respectively. 4 ' and around the center of the X-ray image detectors 4 respectively. 4 ' cutting axes of rotation.

The known articulated robot has a base frame, which, for example, on the ground 5 or on the ceiling 6 is firmly mounted. It is rotatably mounted about a first axis of rotation a carousel. On the carousel is pivotally mounted about a second axis of rotation a rocker arm, on which is rotatably mounted about a third axis of rotation, a robot arm. At the end of the robot arm, a robot hand is rotatably mounted about a fourth axis of rotation. The robot hand has a fastener for the C-arm 2 or 2 ' which is pivotable about a fifth axis of rotation and about a perpendicular thereto extending sixth axis of rotation rotatable.

The realization of the X-ray diagnostic device is not dependent on the industrial robot. It can also find common C-arm devices use.

The X-ray image detectors 4 and 4 ' may be rectangular or square semiconductor flat detectors, preferably made of amorphous silicon (a-Si). However, integrating and possibly counting CMOS detectors may also be used.

In the beam path of the X-ray source 3 and 3 ' there is a table top 7 a patient table 8th for receiving a patient to be examined as an examination subject. The patient table 8th is with a control panel nine Mistake. At the X-ray diagnostic facility is a system control unit 10 with an image system 11 connected to the image signals of the X-ray image detectors 4 and 4 ' receives and processes. The X-ray images can then be displayed on a monitor 12 to be viewed as.

Instead of in 1 For example, shown biplane angiographic X-ray system with the stands 1 and 1' In the form of the six-axis industrial or articulated robot, the angiographic X-ray system can also be a normal ceiling and / or floor mount bracket for the C-arm 2 exhibit.

Instead of the example shown C-arm 2 and 2 ' For example, the angiographic x-ray system may also include separate ceiling and / or floor mount brackets for the x-ray emitters 3 and 3 ' and the X-ray image detectors 4 and 4 ' have, for example, are electronically rigidly coupled.

To minimize the risk of collisions with patients, personnel, and equipment, reduced speed vehicle test runs are performed prior to releasing a high-speed test to assess collision-free performance.

In addition, in certain areas, the speed is reduced by a pre-programmed collision model and stopped by the detection of driveways after the event, the system.

From the DE 197 43 500 A1 a medical device with a device for detecting the position of at least one object located in a room is known, which has a light transmitter, for example an infrared laser, for transmitting a two-dimensional light fan and a camera for detecting the at least one object. The signals of the camera are supplied to an evaluation device, which generates due to these signals by means of triangular 3-D technology according to the at least one object 3-D data, which are used to avoid collisions of the object.

Attempts have also been made to realize such a room surveillance with a large number of RGB cameras in order to create a comprehensive 3-D model of the room. However, with reduced or switched off light in an operating room (OP), the system fails with the RGB cameras.

From the earlier patent application DE 10 2011 084 444.9 It is known to realize the space monitoring by means of time-of-flight (ToF) cameras. These work in the near-infrared (NIR) range and are independent of the lighting in the OR. A light source sends NIR light into the scene, which is received by the camera after reflection from objects. From the runtime the depth, the distance camera - object, is determined. When implementing multiple ToF cameras, each camera not only receives reflections from its own NIR source, but also the reflections of all other ToF cameras. So that the ToF cameras do not influence each other, they would have to be triggered in a time division multiplex. However, if multiple ToF cameras are used, the frame rate will decrease and thus the time for 3-D reconstruction of the room will increase significantly due to successive multiplexing.

Although such ToF cameras may have optical bandpass filters that only transmit the wavelength at which the illumination works, so much of the background light interference is eliminated. However, these merely serve to minimize, for example, the disturbing infrared component and the portion of the visible light of the sun, so that the sensor, which is sensitive to a broad spectrum of wavelengths, is not constantly operated in saturation. This is also the reason why ToF cameras can not be used in strong sunlight and especially outdoors.

Another disadvantage is that the illumination must be extremely strong, since ToF cameras use a diffuse illumination and therefore require a high optical output power for a uniform illumination of the scene. Among other things, this can lead to problems with heat removal from the system, although LEDs are used for diffuse illumination.

Even industrially used 3-D laser scanners work in the same wavelength ranges and with a broadband combination of radiation source and sensor. They therefore behave exactly like ToF systems and interact with each other during simultaneous operation in the same room.

Another consideration is depth cameras based on active triangulation. These cameras, an example of which is the current Microsoft Kinect, use "Structured Light" to determine the distance image of the room, as in the case of "Structured-light 3D scanner" from Wikipedia , the free encyclopedia, of 26 June 2011 ( http://en.wikipedia.org/wiki/Structured-light_3D_scanner ). Again, work is being done in the NIR area. With infrared LEDs, a "Structured Light Grid" is generated, by means of which the depth information can be determined. Simultaneously implementing multiple "structured light" cameras poses a challenge because the "structured light grids" of each camera overlap and a single camera no longer "recognizes" its associated "structured light grid". If triggering is possible, the system would significantly reduce the frame rate, as with ToF cameras with every other camera. A real-time tracking of objects would not be so practicable. However, for a satisfactory collision avoidance during rapid movements of the C-arm, the staff or the patient, the computational speed of these systems is not sufficient.

The invention is based on the object, a system for monitoring an examination room in the clinical environment of a diagnostic device of the type mentioned in such a way that a room monitoring by means of several simultaneously operated depth cameras is made possible, so that a space monitoring and thus tracking of objects can be done in real time ,

The object is achieved for a system for monitoring an examination room in the clinical environment of a diagnostic device of the type mentioned by the features specified in claim 1. Advantageous embodiments are specified in the dependent claims.

• – die je eine monochromatische Strahlenquelle mit voneinander unterschiedlicher Wellenlänge,
• – einen Strahlformer und
• – einen Detektor für diese monochromatische Strahlen

aufweisen, wobei die Tiefenkameras mit der Vorrichtung zur Vermeidung von Kollisionen des Objektes zur Erzeugung der 3-D-Daten verbunden sind. The object is achieved for a system for room monitoring according to the invention in that at least two depth cameras are provided for monitoring the examination room,

• - each having a monochromatic radiation source with mutually different wavelengths,
• - A beam former and
• A detector for these monochromatic beams

wherein the depth cameras are connected to the device for avoiding collisions of the object for generating the 3-D data.

With the inventive design of the system for spatial surveillance in the clinical environment of an angiography system during angiographic examination of a patient by means of multiple, simultaneously measuring high-frequency 3-D cameras, a significantly higher sampling rate can be realized, in turn, a real-time monitoring of the room and thus, for example avoidance strategies in real time. In addition, a higher coverage of the room and a higher measurement accuracy can be achieved by the multiple use possibility.

The image processing in the device for collision avoidance can be relieved, if the depth cameras each have an evaluation that can cause preprocessing.

According to the invention, the diagnostic device may be a C-arm X-ray diagnostic device.

The beam former can advantageously produce a structured light, for example a structured light grid.

Alternatively, the beamformer may comprise a beam splitter.

It has proved to be advantageous if the monochromatic beam detector has an objective, a narrow-band filter and an IR sensor.

According to the invention, the monochromatic radiation sources emit IR light.

Advantageously, the monochromatic radiation sources may comprise narrow band optical filters and LEDs or alternatively lasers as IR sources.

Elimination of continuous noise sources in the same narrowband frequency range and a positive reduction in total optical output power can be achieved when the monochromatic beam transmitters generate a pulsating NIR light so that in two consecutive frames the scene is once with NIR light active and once recorded can be subtracted from each other.

It has proven to be advantageous if the evaluation electronics of the depth cameras subtracts a recording without Structured Light and one with Structured Light.

In addition, according to the invention, the evaluation cameras of the depth cameras can transform the X, Y and Z values of each pixel into coordinates of the image processing.

It has proved to be advantageous if the evaluation electronics of the depth cameras determines the detected objects as well as static and / or dynamic areas.

In an advantageous manner, a calibration file for the depth cameras can be stored in the evaluation electronics.

The invention is explained in more detail with reference to embodiments shown in the drawing. Show it:

1 an examination room with a biplane C-arm angiography system with industrial robots as supporting devices and λ depth cameras according to the invention for room monitoring,

2 a structure of the λ-depth camera according to the invention,

3 the scanning areas or detection areas of the emitted beams of two λ depth cameras and

4 the main beam paths of useful and interfering beams in two λ depth cameras.

The in 1 presented examination room 13 with the permanently installed equipment 1 to 12 , optional devices to be introduced as well as the personnel monitor according to the invention more in the examination room 13 distributed λ-depth cameras installed 14 that with one in the Control Panel 7 provided image processing in a collision calculator 15 are connected.

In the 2 is an exemplary construction of such a depth camera 14 shown schematically.

In a camera body 20 is a monochromatic radiation source as a transmitting part of a cone-shaped beam with an IR source 21 whose beam is a narrow-band filter 22 penetrates and onto a beam former 23 For example, a "Beam Splitter", "Pattern Generators" or Piezo Actuators, which makes a division and / or a deflection of the beam of the IR source 21 causes. As an IR source 21 a laser or an LED can be used. The narrowband filter 22 however, as a monochromator, only one LED is required to produce a monochromatic light from the polychromatic light of the LED.

In the camera body 20 is still a receiver with a lens 24 , a narrow band filter 25 with the same wavelength as the filter 22 , an IR sensor 26 and an evaluation 27 arranged. The IR sensor 26 may be a CCD or a CMOS detector. The evaluation electronics 27 may be a DSP, a digital signal processor, a signal processing processor or an FPGA, a field programmable gate array, a digital integrated circuit (IC) into which a logic circuit is programmable. The evaluation electronics 27 causes preprocessing of the sensor data for further use. The subsequent image processing in the collision computer 15 summarizes the preprocessed data of each camera.

Through the beam former 23 Preferably, a "Structured Light Grid" is generated. Structured Light projects a pattern into the scene. This pattern is recorded and known as a reference pattern in a defined environment, for example, orthogonal to a white straight wall. If the pattern is now projected into a real scene, the pattern will be 'distorted' due to uneven objects or objects that are at different distances from the camera. This change of the known pattern will used to calculate in addition to the 2-D image also depth information about the scene and its objects.

The IR sensor 26 takes, like a normal camera, the scene on. Due to the narrow band filter 25 he only "sees" light in a narrow wavelength range. This light hits the IR sensor 26 and triggers electrons there. Because the IR sensor 26 consists of many cells (pixels), a charge is generated for each pixel.

The output signals from the IR sensor 26 (CCD) are analog voltage signals for each pixel. These are pre-amplified and digitized. In the variant with IR sensor 26 (CMOS) you get directly digitized signals from the IR sensor 26 because the preprocessing in the IR sensor 26 itself is made.

The evaluation electronics 27 thus receives as input for each pixel a discrete value, corresponding to a gray value in a 2-D image. This value describes whether light has hit the relevant wavelength range at the point where the pixel is located and, if so, how much (corresponds to the intensity). These values reconstruct the pattern of IR light from the scene. With suitable algorithms that are already used in known structured light systems, the depth information is transferred from the distorted pattern and, by including the pixel coordinates, these into a Cartesian coordinate system. This data is a point cloud to an image processing, for example in the collision computer 15 output.

Usually in the transmitter 27 a calibration file for the camera is stored. Thus, intrinsic parameters, such as spherical aberration, can be eliminated and extrinsic parameters, such as camera orientation with a coordinate transformation, can be implemented. Thus, in the subsequent image processing, computing power is saved because the data from the λ depth cameras 14 already transformed to the used coordinate system.

Another functionality provided by the transmitter 27 can be adopted is the subtraction of a recording without Structured Light and one with Structured Light. As a result, continuous sources of interference in the same wavelength range can be minimized.

Using the intensity values and possibly combined with a next-neighbor algorithm, a comparison of the current pixel value with that of (for example, eight) immediately adjacent neighboring pixels, a confidence map can be created which indicates how secure (eg specification in [%]) the obtained data for each pixel.

Furthermore, an object recognition in the transmitter 27 possible. If an object is detected, this knowledge becomes the image processing in the collision computer 15 passed on and allows there in the summarized representation of all camera data faster object detection.

By means of interpolation over several measured values in chronological order, a classification into static and dynamic range is possible.

In summary, the evaluation electronics 27 the intensity map, the X, Y, Z values of each pixel transformed into coordinates of the image processing (point cloud), the confidence map, the detected objects and static / dynamic areas determined and the image processing in the collision computer 15 output.

In the 3 are the detection ranges of the emitted beams from two depth cameras according to 2 shown schematically.

A first depth camera 30 a first wavelength with a first narrow band filter 31 , a sensor 32 and a first beam emitter 33 sends a first fanned out beam 34 monochromatic light of a first wavelength. A second depth camera positioned differently in the examination room 35 a second wavelength with a second narrow band filter 36 , a second sensor 37 and a second beam emitter 38 sends a second fanned beam 39 monochromatic light of a second, from that of the first depth camera 30 deviating wavelength. Both beams 34 and 39 cover a surveillance area and capture one in the examination room 13 located object 40 , The monochromatic beam transmitters 33 and 38 can the in 2 shown construction with an IR source 21 , a narrow band filter 22 permeates and one beamformer 23 exhibit. The object 40 can be a patient, the staff or operator as well as parts of the diagnostic device 1 to 4 ' and 7 to 12 but also anesthesia equipment, infusion stands, arm or head mounts.

The 4 shows different, from the object 40 reflected beam paths. A first useful jet 41 of the first ray bundle 34 the first depth camera 30 gets from the object 40 reflects and penetrates the first narrow-band filter 31 , which is tuned to this first wavelength, and meets the first sensor 32 , A first interfering beam 42 of the first ray bundle 34 falls from the first radiation transmitter 33 on the object 40 and goes to the second narrow-band filter 36 reflected and locked by this.

Starting from the second beam transmitter 38 the second depth camera 35 falls a second useful beam 43 of the second beam 39 on the object 40 , it becomes the second narrow-band filter 36 reflected, which is tuned to this second wavelength, penetrates this and falls on the second sensor 37 , One from the second beam emitter 38 the second depth camera 35 outgoing interference beam 44 of the second beam 39 which is at a different angle from the object 40 is reflected from the first narrow-band filter 31 filtered out, leaving on the first sensor 32 only the first useful jet 41 meets. This ensures that only that of the own depth camera 30 or 35 outgoing utility jet 41 or 43 on the corresponding sensor 32 or 37 falls and generates a signal.

The known room monitoring by means of depth cameras is maintained, but according to the invention for the two variants time-of-flight or "structured light" triangulation, the simultaneous use of multiple cameras is possible. With the object according to the invention, a significantly higher sampling rate can be realized, which in turn enables real-time monitoring of the space and thus, for example, avoidance strategies in real time. In addition, a higher coverage of the room and a higher measurement accuracy can be achieved by the multiple use possibility.

The technical implementation of such depth cameras requires only minor changes using standard components.

For example, the depth cameras 14 have the following standard structure and known components:
As a light source or IR source 21 can use either Continuous Wave (CW) laser diodes or LEDs in the NIR range. To create the "Structured Light Grids""BeamSplitter" 23 or "pattern generators" are used as beam shaper. Another possibility is the deflection of the light beam via micromirrors. These can be moved with piezo actuators, for example. The "Structured Light Grid" should have a suitable, on the image sensor or IR sensor 26 provide coordinated resolution to objects 40 to be able to recognize with the necessary level of detail. In front of the imaging chip of the IR sensor 26 turns on the light source or IR source 21 tuned, narrow-band optical filter 25 used.

The inventive structured light system only needs to illuminate individual points or lines in the scene, so that the use of lasers for illumination is permitted. As a result, the optical output power, which is also specified per area, be chosen significantly lower. An output side filtering with a bandpass filter is not necessary because the laser light is monochromatic. Problems with heat dissipation due to high power of the illumination source do not occur here.

In addition, by the evaluation electronics described above 27 a difference image of the scene can be recorded with and without pattern projection. As a result, the output power can be significantly optimized again, since the difference already a small amount of light is sufficient to represent the pattern, and also here a pulsed projection is made (power per time).

A fast, sensitive in the NIR range from about 780 nm to 1200 nm sensor 26 , For example, a CCD chip or CMOS chip, with a high refresh rate of, for example> 100 fps records the scene. It uses a resolution of at least 640 × 480 pixels, although lower resolutions are possible, but severely limit the detection of objects. The evaluation electronics 27 with a suitable processor or hardware (eg DSP or FPGA) takes over the pre-processing, evaluates the image and generates the depth image, ie determines the distance of the camera 30 or 36 to the object 40 ,

Each imaging chip has a dedicated light source of different wavelengths. With the help of this approach, the speed problem of the previous camera solutions can be optimized because they can be used simultaneously in the same scene. The light source should provide a very narrow wavelength range (for example, monochrome laser diodes or filtered LEDs). However, attention must be paid to the optical output power. The relationship between a harmless to human light output and the camera usable, the filtered radiation intensity must be maintained. Optical filters can have bandwidths of a minimum of 10nm with a tolerance of ± 2nm. To avoid influencing the imaging chips by the light sources of the other cameras, the distance between the wavelengths of the individual depth cameras is selected over the bandwidth of the optical filter of the other cameras.

Example:

CWL

– Mittlere Wellenlänge,

CWLTolerance

– Abweichung von der Mittleren Wellenlänge ±,

FWHM

– Bandbreite mit >50% Durchlässigkeit,

FWHMTolerance

– Abweichung von der Bandbreite ± und

K

– Selbstgewählter Sicherheitsfaktor

sind. Tabelle 1: Laser-Diode / CCD-Chip Wellenlänge Laser-Diode in [nm] FilterMin in [nm] FilterMax in [nm] k 1 790 779,5 805 1.5 2 820 809,5 835 1.5 3 850 839,5 865 1.5 ... ... ... ... ... 8 1000 986,5 1013,5 1.5 9 1050 1036,5 1063,5 1.5 10 1100 1086,5 1113,5 1.5 Industrially available narrow-band optical filters can be described and distinguished with the following formulas: FilterMin = CWL - (FWHM / 2 + FWHM _Tolerance + CWL _Tolerance ) · k (1) and FilterMax = CWL + (FWHM / 2 + FWHM _Tolerance + CWL _Tolerance ) · k, (2) in which

CWL

Middle wavelength,

CWLTolerance

- deviation from the mean wavelength ±,

FWHM

Bandwidth with> 50% transmission,

FWHMTolerance

- deviation from the bandwidth ± and

K

- Selected safety factor

are. Table 1: Laser diode / CCD chip Wavelength laser diode in [nm] FilterMin in [nm] FilterMax in [nm] k 1 790 779.5 805 1.5 2 820 809.5 835 1.5 3 850 839.5 865 1.5 ... ... ... ... ... 8th 1000 986.5 1013.5 1.5 nine 1050 1,036.5 1,063.5 1.5 10 1100 1,086.5 1,113.5 1.5

Because of the filter, each imaging chip "sees" only the reflected light coming from its associated source.

(please refer 4 All components of the camera system such as CCD chip, laser diode, pattern generator or beam splitter, bandpass filter and DSP are industrially available as individual elements. With this system structure, all the imaging chips can capture the scene at the same time, thus taking advantage of their maximum speed.

In the following, the two systems are compared using two application examples - the camera system with several ToF cameras and that with a large number of λ depth cameras.

Application Example 1

In an X-ray system with a C-arm 2 a circular arc ride is performed with the rotation speed 60 ° / s. At an assumed radius of the C-arm 2 0.9 m, the outer edges move at a speed of 0.9 m / s.

A single ToF camera works with a refresh rate of approximately 25 fps. In a setup with five ToF cameras, the refresh rate drops to approximately 5 fps, with 10 ToF cameras even to approximately 3 fps.

The introduced λ-depth camera system depends only on the chip readout rate and could work with a refresh rate of about 100 fps.

In the following Table 2, the distances can be read, which in the different camera systems of the C-arm 2 between two frames without being registered. The better you try to "illuminate" the scene (with a higher number of ToF cameras), the slower and therefore more reliable a current depth camera system becomes. The λ-depth camera system maintains the full speed with a more detailed "illumination" and thus can better detect impending collisions and allow a real-time response. Table 2: ToF-camera system λ depth camera system Number of cameras Frames per second (fps) Way / frame in [cm] Frames per second (fps) Way / frame in [cm] 1 25 about 4.8 100 approx. 1.2 5 5 about 24 100 approx. 1.2 10 3 about 40 100 approx. 1.2

Application Example 2:

Movements of the C-arm 2 and the camera system are as in the application example 1 described.

At the end of a frame, an image is output, which was obtained over the time of the frame. Within a frame, the ToF cameras must record the scene one after the other. In the ToF camera system, when used with multiple cameras, images from different time points are combined to create a complete picture. This results in a "blur" of the image and moving objects can be displayed larger or distorted. In the presented system, all recordings are started synchronously at the same time and thus also depict all the same scene.

Table 2 can be used again for this purpose. The track, by a rotating C-arm 2 can be covered with a single frame for five ToF cameras is 24 cm. If we assume that the shots of each depth cameras 14 can be made equally spaced across the frame and begin immediately after the previous frame and end just before output, then the distortion of the C-arm 2 at the outer edge up to 24 cm. A 40 cm wide detector 4 would be up to 64 cm long and curved in the frontal view.

In the presented X-ray system with C-arm 2 the distortion due to the different time points is 0 cm, since within the frame all pictures are taken at the same time. This results in a significantly higher accuracy and improved image quality.

Another point to improve the reconstruction algorithm of the λ depth camera system would be the use of subtraction images with a pulsed structured light grid. In two consecutive frames, the scene is recorded once with the NIR light active and once without. These two images are then subtracted from each other. Although the sampling rate of the imaging chip xx is halved with this method, a significantly higher frame rate than the other camera systems can still be realized due to the available high-frequency chips. The advantage of this method is the elimination of noise sources in the same narrowband frequency range and a positive reduction of the total optical output power.

The inventive step lies in the assignment of light sources with different wavelengths to a specific imaging chip, wherein a matching narrowband optical filter to this camera system eliminates disturbing influences of light sources other depth cameras. Thus, a simultaneous operation of multiple depth cameras is possible without that they influence each other.

The advantage is not only the temporally synchronous image recording of multiple camera systems of a scene and the resulting real-time reconstruction of the room but also the high-frequency scanning of the room and thus a minimization of the measurement error of objects and an increase in safety for patient, personnel and equipment.

In addition, further applications, such as intelligent, forward-looking path planning, can now also be realized technically.

The use of subtraction images, which is practicable due to the high-frequency chips, enables a further increase of the measuring accuracy.

The construction of this measuring system with industrial standard products allows a cost-effective realization.

Such a space-monitoring sensor according to the invention can initiate the stopping process even before a collision, involve avoidance strategies in real time and / or warn the operator.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 7500784 B2 [0004, 0006]
• DE 19743500 A1 [0015]
• DE 102011084444 [0017]

Cited non-patent literature

• http://en.wikipedia.org/wiki/Structured-light_3D_scanner [0021]

Claims (14)

System for monitoring an examination room ( 13 ) in the clinical environment of a diagnostic device ( 1 to 4 ' . 7 to 12 ) during an angiographic examination or treatment of an organ, vascular system or other body regions as a subject of examination of a patient with a device ( 14 . 30 ) for detecting the position of at least one in the examination room ( 13 ) ( 1 to 4 ' . 7 to 12 . 40 ), the device ( 14 . 30 ) a radiation transmitter ( 21 to 23 ) for transmitting a beam ( 34 . 39 ) as well as a camera ( 24 to 27 ) for detecting the at least one object ( 1 to 4 ' . 7 to 12 . 40 ) and wherein the signals of the camera ( 24 to 27 ) a device ( 27 . 15 ) are supplied, which due to these signals 3-D data corresponding to the at least one object ( 1 to 4 ' . 7 to 12 . 40 ) generated to avoid collisions of the object ( 1 to 4 ' . 7 to 12 . 40 ), characterized in that at least two depth cameras ( 14 . 30 ) for monitoring the examination room ( 13 ), - each having a monochromatic radiation source ( 21 . 22 ) with mutually different wavelengths, - a beam former ( 23 ) and - a detector ( 24 to 26 ) for these monochromatic beams, the depth cameras ( 14 . 30 ) with the device ( 27 . 15 ) to avoid collisions of the object ( 1 to 4 ' . 7 to 12 . 40 ) are connected to generate the 3-D data. System for monitoring an examination room ( 13 ) according to claim 1, characterized in that the depth cameras ( 14 . 30 ) one evaluation electronics each ( 27 ) exhibit. System for monitoring an examination room ( 13 ) according to claim 1 or 2, characterized in that the diagnostic device ( 1 to 4 ' . 7 to 12 ) is a C-arm X-ray diagnostic device. System for monitoring an examination room ( 13 ) according to one of claims 1 to 3, characterized in that the beam former ( 23 ) generates a structured light. System for monitoring an examination room ( 13 ) according to one of claims 1 to 3, characterized in that the beam former ( 23 ) has a beam splitter. System for monitoring an examination room ( 13 ) according to one of claims 1 to 5, characterized in that the detector ( 24 to 26 ) for the monochromatic beams a lens ( 24 ), a narrowband filter ( 25 ) and an IR sensor ( 26 ) having. System for monitoring an examination room ( 13 ) according to one of claims 1 to 6, characterized in that the monochromatic radiation sources ( 21 . 22 ) Emit IR light. System for monitoring an examination room ( 13 ) according to one of claims 1 to 7, characterized in that the monochromatic radiation sources ( 21 . 22 ) narrowband optical filters ( 22 ) and LEDs as IR sources ( 21 ) exhibit. System for monitoring an examination room ( 13 ) according to one of claims 1 to 7, characterized in that the monochromatic radiation sources ( 21 ) Lasers as IR sources ( 21 ) exhibit. System for monitoring an examination room ( 13 ) according to one of claims 1 to 9, characterized in that the monochromatic beam transmitters ( 33 . 38 ) generate a pulsating NIR light, so that in two successive frames, the scene can be recorded once with actively introduced NIR light and once without that both recordings are subtracted from each other. System for monitoring an examination room ( 13 ) according to claim 10, characterized in that the evaluation electronics ( 27 ) of the depth cameras ( 14 . 30 . 35 ) subtracted one shot without Structured Light and one with Structured Light. System for monitoring an examination room ( 13 ) according to one of claims 1 to 11, characterized in that the evaluation electronics ( 27 ) of the depth cameras ( 14 . 30 . 35 ) transforms the X, Y and Z values of each pixel into coordinates of image processing. System for monitoring an examination room ( 13 ) according to one of claims 1 to 12, characterized in that the evaluation electronics ( 27 ) of the depth cameras ( 14 . 30 . 35 ) determines the detected objects as well as static and / or dynamic areas. System for monitoring an examination room ( 13 ) according to one of claims 1 to 13, characterized in that in the transmitter ( 27 ) a calibration file for the depth cameras ( 14 . 30 . 35 ) is deposited.

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