WO2011045277A1 - Camera system - Google Patents

Abstract

The invention relates to a 3D camera having a pixel array on the basis of a mixing detection, implemented such that individual pixels of the pixel array can be merged to form pixel blocks.

Description

 description

 CAMERA SYSTEM

 The invention relates to a camera system with a 3D camera and an active illumination and a method for operating such a camera according to the preamble of the independent claims.

 Systems for three-dimensional systems are known from the prior art

 Image acquisition known, which work with the help of an active lighting. These include so-called time-of-flight (TOF) or

 Runtime measurement systems. These use amplitude modulated or pulsed illumination to illuminate the area to be detected

 three-dimensional scenery.

 With light transit time measurement system in particular all

 3D camera system may be included, which gain a time information from the phase shift of an emitted and received radiation. As a 3D camera or PMD camera in particular so-called photonic mixer detectors (PMD) are suitable, as they u.a. in the applications EP 1 777 747, US 6 587 186 and also DE 197 04 496 described and, for example, by the company, ifm electronic gmbh 'as a frame grabber O3D are available. In particular, the PMD camera allows a flexible arrangement of the light source and the detector, which can be arranged both in a housing and separately.

 From DE 100 1 1 263 A1 an object management system is known in which the object detector can be switched over in a first and second operating mode in order to be able to switch for example between a small and a large angle detection range. A radar sensor is used for the long range and an ultrasonic sensor for the near range.

 The object of the invention is the processing speed of

 Improve 3D camera.

 The object is achieved in an advantageous manner by the invention

 3D camera solved.

Advantageously, a 3D camera is provided, based with a pixel array on a photomix detection, wherein individual pixels of the pixel array to pixel blocks, are summarized. This makes it possible in an advantageous manner, for certain detection and

 Image processing situations to provide pixel blocks.

 The measures listed in the dependent claims are advantageous developments and improvements in the

 independent claims specified invention possible.

 In particular, it is advantageous a processing module such

 to design that a size, positions and / or a number of pixel blocks, can be set and evaluated depending on a given measurement task.

 In a further embodiment, it is intended to additionally design the camera with a security module that evaluates the pixel array independently of the processing module and compares the result with a result of the processing module.

 Furthermore, it is also possible for the security module to monitor the processing module to deviate from the processing module

 Pixel block size used and evaluated.

 Advantageously, a camera system is provided with a 3D camera based on a photomix detection and active illumination for illuminating a detection range of the 3D camera, wherein the active illumination is configured such that at least two areas of the detection range of the 3D camera different are illuminated. This procedure has the advantage that for certain preferred

 Detection areas, such as stripes or distant objects, the lighting can be adjusted according to the desired detection requirements.

Advantageously, a camera system is provided with a 3D camera based on a photomix detection and active illumination for illuminating a detection range of the 3D camera, in which the active illumination is designed such that at least two areas of the detection range of the 3D camera different are illuminated. This procedure has the advantage that for certain preferred Detection areas, such as stripes or distant objects, the lighting can be adjusted according to the desired detection requirements.

 Preferably, the active lighting is divided into several lighting modules. These lighting modules can in particular be divided into groups to one or more lighting modules, wherein a respective group for illuminating a particular

 Lighting area is formed.

 The division of the lighting modules in groups has the advantage that the lighting areas by aligning the modules of

 appropriate group can already be adjusted. Alternatively or additionally, it may also be provided, at least one

 To adjust the beam guiding optics of a lighting module for a particular lighting area.

 With regard to the method for operating the camera system, it may be provided that the specific illumination areas are illuminated either simultaneously or sequentially.

 The invention will be explained in more detail by means of embodiments with reference to the drawings.

 [0018] FIG.

 Figure 1 shows schematically the basic principle of photomix detection, Figure 2 schematically different detection areas of a

 PMD camera

 FIG. 3 schematically shows a processing according to the invention

 Detection areas,

 FIG. 4, a vehicle with two lighting module groups,

 Figure 5, schematically different lighting and

 Detection areas,

 FIG. 6, a side view of the different lighting and detection areas,

 FIGS. 7 and 8 show a serial and sequential evaluation of the

 different lighting areas.

FIG. 1 shows a measurement situation for an optical distance measurement a TOF camera system, as it is known for example from DE 197 04 496.

 The TOF camera system here comprises a transmitting unit or a

 Illumination module 100 with a light source 12 and associated beam shaping optics 50 and a receiving unit or 3D camera 200 with a receiving optics 150 and a photosensor 15. The photosensor 15 is preferably formed as a pixel array, in particular as a PMD sensor. The receiving optics typically consist of improving the imaging properties of a plurality of optical elements. The beam-shaping optical system 50 of the transmitting unit 100 is preferably as

 Reflector formed. However, it is also possible to use diffractive elements or combinations of reflective and diffractive elements.

 The measuring principle of this arrangement is essentially based on the fact that starting from the phase difference of the emitted and received light, the duration of the emitted and reflected light can be determined. For this purpose, the light source and the photosensor 15 via a modulator 18 together with a specific

 Modulation frequency applied to a first phase position a.

 In accordance with the modulation frequency, the light source 12 transmits an amplitude-modulated signal having the phase a. In the case shown, this signal or the electromagnetic radiation is reflected by an object 20 and hits due to the distance covered

 corresponding phase-shifted with a second phase position b on the photosensor 15. In the photosensor 15, the signal of the first

 Phase position a of the modulator 18 with the received signal, which has meanwhile assumed a second phase position b, mixed and from the resulting signal, the phase shift or the

 Object distance determined.

 FIG. 2 shows a typical measurement situation of the invention

 3D camera. In the example shown, a 3D camera is in one

 Vehicle 70 is arranged and allows the monitoring of a

Total coverage E. Due to certain Lighting situations or evaluation algorithms, it is possible within the total coverage area E different Erfassungsbzw. Select monitoring areas. In particular, these coverage areas may include or include so-called "region-of-interest" (ROI).

In Figure 2 a), a first detection area EB1 is shown, in which

 preferably objects are detected in the middle and / or long distance. Figure 2 b) shows a second and third congruent detection range EB2, EB3. Both areas EB2, 3 are suitable for detecting objects in the near range. The regions preferably differ by a different detection by the

 Pixel array and / or by a different evaluation or

 Image processing.

 FIG. 3 schematically shows a possible processing and evaluation of the different detection ranges EB1, 2, 3. The

 Processing system consists essentially of three modules, on the one hand, the PMD chip or pixel array 15, the entire

 Captured and secondly from a

 Processing module VM and a security module SM. The

 Processing module VM allows the selection of three different

 Image processing modes BVM1, 2, 3 for the individual processing of the different detection areas EB 1, 2, 3. In addition, the processing module is configured such that, for example, depending on the image processing mode used certain properties of the pixel array 15 can be specified. In the illustrated case, the pixel array can be operated in a high, medium and low resolution mode H, M, L. The different resolutions can preferably be set by combining individual pixels into blocks of pixels, the so-called binning. Further adjustments of the pixel array 15 with regard to pixel position, size and / or number of pixel blocks are possible.

 In the example shown, the second detection range is gem. Fig. 2

a vicinity, preferably a nearby street area in which objects are to be recorded, for example, in their dimensions and positions. For this purpose, it is advantageous to operate the pixel array in a high resolution H and a

 Select image processing with a suitable algorithm and appropriate parameterization.

 In the illustrated case, it is provided for the processing of the first detection area EB1 to use the first image processing module BVM1 in combination with a high resolution H of the pixel array. As a result of the image processing, for example, an object list OL1, 2, 3 with the detected objects and their parameters could be created. However, other object lists or signal outputs are also conceivable.

 For the middle and / or distant second detection range, an average resolution M and the second image processing module BVM2 is provided. This module determines, for example, in addition to position and dimension of the objects and their speed and

 Acceleration. The object list OL2 from this processing can be used in particular as PreCrash information.

 The third detection area EB3 is provided in the example shown for closest objects, which can preferably move in the immediate vicinity of the vehicle, for example, crossing pedestrians or cyclists in city traffic. This detection area is associated with a low resolution L and the third image processing module BVM3. As a result, an optional object list OL3 'could be created.

 For safety reasons, it is provided, the third

Monitor image processing module using a security module SM. The security module SM uses the same pixel array data as was available to the processing module VM or the third image processing module. The processing of the data takes place with a fourth image processing module BVM4, which is preferably based on another evaluation algorithm and / or another parameterization. The results of the third and fourth image processing modules BVM3, 4 are compared with each other and only the securely recognized objects are given as a third object list OL3.

FIG. 4 shows schematically a front view of a motor vehicle. in the

 Upper area of the windshield is a 3D camera 200

 located near the headlights are located on the right and left side of the vehicle different

 Lighting modules. The illumination modules 101 to the first group illuminate a first illumination area B1 in the far field of the

 Motor vehicle. The illumination modules 102 to the second group illuminate a lateral near area of the motor vehicle in a first and second illumination area B2, B3. The lateral ones

 Lighting areas B2, B3 can be used, for example, to detect the road edges or lane markings, while the long-range area B1 can be evaluated with respect to obstacle detection.

 The illumination areas are preferably chosen so that they

 lie within the detection range of the 3D camera 200, as shown by way of example in Figure 5. FIG. 3 schematically shows the different lighting groups 101 and 102. The illumination field spanned by the first illumination group 101 completely illuminates the detection range E of the 3D camera and even exceeds it. The illumination areas B2, B3 of the second illumination group 102 are completely within the

 Detection area E of the 3D camera and are also spatially separated.

 This provision of different possibly also spatially separated illumination areas has the advantage that with only a single 3D camera several and different applications can be covered. In particular, it is possible to use the applications not only sequentially but also simultaneously.

 From the side view in Figure 6 can also be seen that the

Lighting areas can be adjusted not only in the geometry but also in the range. In the illustrated case, the first lighting group is designed for the illumination of distant objects Namely, while the second illumination group 102 illuminates the near area. The 3D camera is preferably designed so that it can detect both the long-range and the short-range at the same time.

 The lighting modules can with one and more light sources

 be equipped, each light source with its own

 Beam guiding optics preferably a reflector is equipped.

 In principle, it is possible to optimize the beam guidance optics of each light source for the desired illumination range. In a

 However, it is provided simpler embodiment, the

 Beam guiding optics of the individual light sources the same design and define the lighting area by a suitable grouping of the light sources, positioning of the lighting module or forming lighting module groups. Furthermore, a

 Lighting module can also be integrated into an existing lighting unit, for example, the car headlights.

 The differently illuminated areas can now with a

 downstream image processing may be evaluated and / or evaluated with different algorithms or parametrizations. The targeted focusing of the light in the respective illumination areas also ensures that sufficient light arrives for a suitable evaluation in these illumination areas. To save energy or strain the

 It may be provided, in particular, to illuminate lighting modules only for a short time in order to reduce lighting modules.

 Furthermore, it is conceivable that certain lighting areas B1, B2, B3 are illuminated only if this requires a specific measurement situation.

 In principle, a simultaneous or sequential illumination of the

 different lighting areas conceivable. Possible evaluations of such lighting situations are shown by way of example in FIGS. 7 and 8.

FIG. 7 shows a simultaneous detection of the illumination areas B1, B2, B3 during a time interval t1. This time interval can be in

 present case also be a continuous operation. The recorded data of the individual lighting areas become a subsequent one

 Image processing supplied, wherein the data of the first detected

 Area of a first image processing BV1 and the data from the second and third illumination area of a second image processing BV2 are supplied.

 The illumination areas B1, B2, B3 are preferably so-called

Region-of-interest assigned. Such a "region-of-interest" could, for example, be a far-field or a near-field. For example, for the first image processing BV1 of the first illumination area B1, an algorithm and a parameterization for the recognition of

 Obstacles, vehicles, traffic signs, etc. are used, while for the second image processing BV2 of the second and third illumination area B2, B3, the algorithm and / or the parameters used preferably for the detection of pages or

 Median strip and / or lane boundaries and / or

 Road bumps or similar are optimized.

 Furthermore, it is conceivable for certain driving situations or

 Security checks to examine the different lighting areas or region-of-interest using different image processing. In the example shown, an optional evaluation of the second illumination area B2 with the first image processing BV1 is shown by way of example with a dashed line. For example, this could be

 Lighting area first with the second image processing in

 Be examined in terms of detection of a sidelobe, and preferably in parallel in the first image processing, for example on obstacles.

 Of course, other assignments of

 Lighting areas for the various image processing conceivable, as well as the use of further image processing with different algorithms and / or parameters.

The data obtained by the image processing BV1, BV2 can be serial or be made available in parallel to other processes. As an interface or data bus, for example, Ethernet, LVDS, CAN, Flexray etc. into consideration.

 FIG. 8 essentially shows that already shown in FIG

 Image processing, wherein the illumination areas are not necessarily operated in parallel, but preferably sequentially. In the example shown, it is provided to operate the first illumination area B1 in a time interval t1 and the second and third illumination areas B2, B3 in a second time interval t2.

 The duration and frequency of the time intervals can be completely

 be chosen independently. For example, first the first lighting area B1 and then the other two

 Lighting areas B2, B3 operated and recorded. However, it is also possible to operate the first illumination area B1 permanently and to switch on and off the second or third illumination area B2, B3 only when needed. Also accepting more

 Lighting areas or image processing as well as others

 Time intervals are conceivable.

 Thus, it can also be provided, depending on the evaluation, surrounding and / or driving situation, to use different time intervals, algorithms, parameters or also to switch between sequential or parallel illumination or image processing.

 In a further development stage, it is possible to define via an external command, for example via CAM, Flexray, LIN, Ethernet, or the like, the area to be illuminated and the algorithm to be used or the algorithm parameterization to be used.

Claims

claims  1. 3D camera characterized by a pixel array based on a photomix detection characterized  that individual pixels of the pixel array can be combined into blocks of pixels. 2. Camera according to claim 1, with a processing module, the like  is configured such that a size, positions and / or a number of pixel blocks are set and evaluated depending on a given measurement task.  A camera according to claim 2, including a security module that independently of the processing module evaluates the pixel array and compares the result to a result of the processing module.  4. Camera according to claim 3, wherein the security module for monitoring processing module deviates from the processing module  Pixel block size used and evaluated.  5. Camera according to one of the preceding claims, wherein an active  Lighting is divided into groups to one or more lighting modules, wherein a respective group is designed to illuminate a particular lighting area.  6. Camera according to claim 5, wherein the specific illumination areas are assigned to specific surveillance areas, in particular region-of-interest.  7. Camera system according to one of the preceding claims, wherein the  Illumination of the particular lighting area  Lighting module group can be aligned accordingly and / or at least one beam guiding optics of a lighting module for the particular lighting area is adjusted.  8. A method for a 3D camera according to any one of the preceding claims, wherein the size and / or number of pixel blocks is determined in dependence on the predetermined security requirement level.  9. The method according to any one of the preceding claims, wherein the size of the pixel blocks decreases with increasing security requirement.  10. The method according to any one of the preceding claims, in for a Close range essentially the full resolution of the pixel array and for one Remote area at least partially the single pixels to pixel blocks  be summarized. A method for a camera system according to any one of the preceding claims, wherein the illumination areas detected by the 3D camera  be evaluated differently and / or evaluated.