JPH1144515A - Active light irradiator, light detector and three-dimensional image input device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable determination of a direction of unevenness of an object to be measured and measurement of a three-dimensional shape with single image capture and also to obtain a color image by controlling a fringe pattern distance or a beam scanning interval by distance information from a distance detector for detecting a distance from the object to be measured. SOLUTION: Light emitted from a light source 102 is diffracted by a hologram element, obtains a fringe-like pattern and irradiates an object 104 to be measured. A distance between the object 104 and a camera 108 is measured by a distance detector 105. The camera 108 includes a light detector 107 having four kinds of filter sets 109 for transmitting light source light, red light, green light and blue light on an incident face. Thus as soon as a color image is captured, the light source 102 is lit up, and as soon as a focus of the camera 108 is aligned by distance information from the distance detector 105, a fringe-like pattern emitted from an active light irradiator 101 is varied, so that a fringe pattern projected on the object 104 to be measured can also be captured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a three-dimensional shape and color information input device.

[0002]

2. Description of the Related Art A conventional three-dimensional shape measuring device using moiré fringes includes: a projector for projecting a stripe pattern on an object to be measured;
It is constituted by an image pickup device such as a CCD camera for detecting the same. Actually, an image pickup device for detecting an image does not have a detection grid, and after inputting an image, a stripe-shaped transmittance is modulated as an observation grid by software. As a result of the processing, a moire fringe pattern is obtained, and since the fringes represent approximately contour lines, 3
Two-dimensional shape measurement can be realized. In addition, since the three-dimensional shape measurement by this method can capture one image, high speed and high accuracy can be realized.

[0003]

However, conventional three-dimensional moiré fringe shape measurement has a drawback in that the order of the moiré fringes cannot be determined, so that the direction of the unevenness cannot be determined. In addition, there is a disadvantage that the shape measurement accuracy changes when the distance between the image measurement device and the measured object changes. In addition, since the image is striped, a color image cannot be obtained, and a color image camera is required separately from three-dimensional measurement in order to obtain a color image.

Accordingly, the present invention has been made to solve the above-mentioned problem, and an active image capturing method capable of judging the direction of unevenness of an object to be measured, measuring a three-dimensional shape, and obtaining a color image in a single image capture. Type linear stripe pattern irradiator, and 4
A main object is to provide a photodetector with a wavelength selection filter and a three-dimensional image input device.

[0005]

According to the present invention, there is provided an active light irradiator comprising: (1) a light source having a wavelength outside the visible region and a linear stripe pattern for a wavelength outside the visible region. A light irradiator or a light beam scanner to be generated, a distance detector for detecting a distance to an object to be measured, and a stripe pattern interval or a light beam scanning interval are controlled by distance information from the distance detector.

(2) In (1), the light source having a wavelength outside the visible region is a light source that emits divergent light, such as a light emitting diode or a semiconductor laser diode, and the linear stripe pattern represented by light and shade of light. Is generated by a transmission-type or reflection-type hologram element having a substantially linear shape.

(3) In (1), the linear stripe pattern represented by shading of light is a projected image from a transmissive or reflective liquid crystal display device or a small pattern display device having a substantially linear shape. It is characterized by.

(4) In (2), the hologram element is constituted by a liquid crystal element or a piezoelectric element whose transmittance can be changed by a voltage, or a groove depth of a diffraction grating and a grating by a voltage. Is a voltage-controlled hologram element capable of changing the width and pitch of the hologram element.

(5) In (4), the voltage control type hologram element is characterized in that the width, the groove depth, and the pitch of the grating are changed according to the distance information to the object.

(6) In (1), the linear stripe pattern is generated by moving a mirror device or a diffraction grating at a high speed to scan a light beam and turning on a light source in synchronization with the movement of the mirror device. It is characterized by the following.

(7) In (6), in the optical scanner for scanning a light beam by moving the mirror device or the diffraction grating at a high speed, the mirror device and the light source are controlled based on distance information to an object, and a scanning interval is set. Is changed.

Further, in the photodetector of the present invention, the photodetector to which an image is input has a wavelength selection filter on the incident side, and this wavelength selection filter is one of the photodetectors arranged in an array. Each color filter is arranged on one photodetector, and a red transmission filter that transmits red light, a green transmission filter that transmits green light, a blue transmission filter that transmits blue light, and an outside visible range that transmits light outside the visible range. Light transmission filter 4
It is characterized in that it is a filter array having one set of filters.

Further, the three-dimensional image input device according to the present invention comprises:
(A) a light source having a wavelength outside the visible region, a linear stripe pattern irradiator or a light beam scanner for a wavelength outside the visible region, a distance detector for detecting a distance between the object to be measured, and the distance detector An active light irradiator that changes a fringe pattern interval or a light beam scanning interval based on distance information from a light source, and a photodetector provided with an optical filter that transmits the wavelength of the light source on the light incident side of the photodetector. It is characterized by.

(B) In (a), the output of the photodetector due to the transmitted light from the optical filter is taken in to obtain two-dimensional image information, and the image information is filtered by a linear comb at equal intervals. A moiré fringe pattern having unevenness information of an object is obtained by separating only components having low spatial frequencies.

(C) In (b), height information for each pixel is obtained by sine approximating the moiré fringe pattern and detecting the phase.

(D) In (b), the direction of the unevenness of the object to be measured is determined from the two-dimensional striped image information obtained by the output of the photodetector from the optical filter, and the two-dimensional image and the like are determined. It is characterized in that the moire fringe pattern is obtained by filtering a linear comb with a space and separating only low-frequency components, thereby obtaining height information of the object to be measured.

(E) In (a), a red transmission filter, a green transmission filter, and a blue transmission filter are arranged in front of the photodetector together with the optical filter, and the red transmission filter, the green transmission filter, and the blue The sum of the outputs of the photodetectors that detect the light transmitted through the transmission filter is obtained, and the output of the photodetector due to the transmitted light from the optical filter is divided by the sum to detect the light transmitted through the optical filter. It is characterized in that the output of the device is standardized.

(F) In (e), the red transmission filter, the green transmission filter, and the blue transmission filter are paired to form one pixel, and the pixel has a position and height in addition to a color signal. It is characterized by having data with information.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

(Embodiment 1) FIG. 1 is a schematic diagram showing a three-dimensional image input apparatus according to Embodiment 1 of the present invention. The three-dimensional image input device of the present invention includes an active light irradiator 101 and a distance detector 105.
And a camera unit 108. The active light irradiator 101 includes a light source 102 that emits light outside visible light and a hologram element 103. The light emitted from the light source 102 is diffracted by the hologram element and has a striped pattern. The object 104 is irradiated. Measured object 1
A distance between the measured object 104 and the camera 108 is measured by a distance detector 105 for focusing the camera 108 on the object 04. The camera unit 108 has a filter that transmits only light from a light source, a red transmission (R) filter that transmits red light, a green transmission filter that transmits green light (G), and a blue transmission light (B). And a photodetector 107 having four types of filter sets 109 on the incident surface.

Therefore, at the same time as capturing a color image,
The light source 102 is turned on, and based on the distance information from the distance detector, the camera 108 is focused, and at the same time, the stripe pattern emitted from the active light irradiator 101 is changed,
A stripe pattern projected on the object to be measured 104 can also be captured.

(Embodiment 2) FIG. 2A is a schematic view of an active light irradiator using a transmission hologram element. As the light source 201, a light source having polarized light is used. This may be a semiconductor laser light source or a non-polarized light source provided with a polarizing filter. Light 20 emitted from light source 201
4 enters the transmission hologram element 202. This transmission hologram element is made of a liquid crystal device, and the hologram pattern can be rewritten by a voltage. The light transmitted through the transmission hologram element becomes irradiation light 203 having a striped pattern. If the transmission hologram element is not a liquid crystal device, it is not necessary to provide a polarized light to the light source, and a general-purpose light source is sufficient.

FIG. 2B is a schematic view of an active light irradiator using a reflection type hologram element. The light 204 emitted from the light source 201 enters the reflection hologram element 205. This reflection type hologram element is made of a fine mirror element array, and the hologram pattern can be rewritten by a voltage. The light reflected by the reflection hologram element becomes irradiation light 203 having a striped pattern.

Here, the accuracy in the height direction of three-dimensional measurement using moiré fringes will be described. The accuracy h in the height direction can be approximately calculated assuming that the projection fringe pitch is s, the distance to the measured object is L, and the distance between the light source and the observation point is d.

[0024]

(Equation 1)

## EQU2 ## Therefore, the projection fringe pitch s,
The smaller the distance L to the measured object, the better the accuracy, and the larger the distance d between the light source and the observation point, the better the accuracy. However, the projection fringe pitch cannot be made smaller than the resolution of a photodetector, for example, a CCD, etc., the distance d between the light source and the observation point is fixed, and the distance L to the object to be measured is 3 In the dimension input device, it changes depending on the object to be measured. Therefore, if the fringe pattern is changed according to the distance to the object to be measured and the fringe pitch is adjusted to an optimum value that is higher in accuracy than the resolution of the photodetector, a three-dimensional image input that can obtain optimum accuracy in various situations Device.

The transmission hologram element 202 and the reflection hologram element 205 shown in FIGS.
Can rewrite the hologram pattern by the voltage. Therefore, the optimum stripe pattern can be illuminated based on the distance information to the object to be measured, so that accurate three-dimensional measurement can be performed even if the distance to the object to be measured changes.

(Embodiment 3) FIG. 3 is a schematic view of an active light irradiator using a display element. As the display device 301, a liquid crystal display device was used. This may be in any display device. The display device 30 by the lens 302
1 is irradiated as a projection image 303. The projected image 303 has a striped pattern, and this pattern can be changed by changing the pattern of the display device. An effect similar to that of the active light irradiator using the hologram shown in the embodiment can be obtained. That is, since the optimum stripe pattern can be radiated based on the distance information to the measured object, accurate three-dimensional measurement can be performed even if the distance to the measured object changes.

(Embodiment 4) FIG. 4 is a schematic view showing a change in a stripe pattern by an active light irradiator depending on a distance. FIG.
FIG. 3A is a schematic diagram in which a stripe pattern is set to an optimum value when an object to be measured is close. In the fringe pattern from the active light irradiator 401, the fringe interval when the measured object is at the distance S is optimal. Here, the line indicates the black portion of the stripe. However, since the fringes appear to spread depending on the distance, at a farther H, the fringes are too wide to achieve the optimum fringe pitch. Then, the stripe pattern by the active light irradiator is changed, and the stripe pitch becomes optimum at the position of the distance H as shown in FIG. At this time, the stripe pitch is too small at the distance S, and is lower than the resolution of the photodetector.

(Embodiment 5) FIG. 5 is a schematic view of a mechanism for changing the groove shape of the hologram element. This is a diagram schematically showing a change in one groove. In actuality, the elements are very small and are arranged in an array. An electrode 502 is attached to a thin silicon plate 501, and columns 504 supporting the silicon plate are arranged on both sides. The lower surface 505 is made of a plate such as glass, and the ITO
It has an electrode made of a membrane. Here, when a voltage is applied to the electrodes, the electrodes are recessed as shown by reference 506, and when the voltage applied to the electrodes is weakened, the state shown by 507 is obtained, and the depression can be controlled by the voltage. Since these microelements are arranged in an array to form a hologram element, the voltage can control the groove depth of the hologram element. In addition, since the grooves can be eliminated by weakening the voltage of the columns in which the grooves are formed, or the grooves can be generated by applying a voltage to the columns in which the grooves are not formed, the groove width and the pitch can be controlled. It is.

(Embodiment 6) FIG. 6 is a block diagram for controlling a stripe pattern from an active light irradiator according to a distance.
Distance information to the measured object is obtained by the distance detector 601. This uses the same one used for camera autofocus. The distance information is input to the CPU 602, the optimum fringe pattern based on the distance is calculated, and a control signal is output. The liquid crystal or the diffraction grating driving device 603 is driven by a control signal from the CPU, and a pattern of the liquid crystal or the hologram element 604 is formed. In the present invention, since the distance detector for auto-focusing of the camera is used, it is possible to obtain an active light irradiator capable of controlling the stripe pattern depending on the distance without adding a new function to the function of the camera.

(Embodiment 7) FIG. 7 is a schematic view of a light beam scanning type active light irradiator using a mirror element. A slit or lens 70 for linearizing light emitted from the light source 706
The light beam 707 linearized by 1 is emitted to the position of 704 when the mirror element incident on the mirror element is at the position of 702, and emitted to 705 when the mirror element changes to the position of 703. By turning off the light source or cutting off the light beam while the mirror element changes from the position 702 to the position 703, the radiated light beam becomes a discrete irradiation that is emitted only at the positions 704 and 705, and a striped pattern can be generated. Further, by controlling the angle of the mirror element and the lighting interval of the light source, the stripe interval of the stripe pattern can be changed.

(Embodiment 8) FIG. 8 is a block diagram for controlling a stripe pattern from a light beam scanning type active light irradiator using a mirror element by a distance. Distance information to the measured object is obtained by the distance detector 801. This uses the same one used for camera autofocus. The distance information is input to the CPU 802, the optimum stripe pattern based on the distance is calculated, and a control signal is output. There are two control signals, one is input to the mirror element driving device 803, and the other is input to the light source driving device 804. The mirror element driving device 803 controls the angle of the mirror element 805, and the light source driving device 804 controls lighting of the light source 806. Thereby, the stripe interval of the stripe pattern can be changed.

(Embodiment 9) FIG. 9 is a block diagram for controlling a stripe pattern from an active light irradiator using a display element by a distance. Distance information to the measured object is obtained by the distance detector 901. This uses the same one used for camera autofocus. This distance information is
The signal is input to U902, the optimum stripe pattern based on the distance is calculated, and a control signal is output. There are two control signals, one is input to the display element driving device 903 and the other is input to the focus / zoom driving device 904 of the projection device. The display element driving device 903 includes a display element 905 made of a liquid crystal or the like.
Of the projection device, and a zoom drive device 904 zooms and focuses the projected image from the display device on the object to be detected, so that an optimal stripe pattern is obtained on the object. 906 is controlled. Thereby, the stripe interval of the stripe pattern can be changed.

(Embodiment 10) FIG. 10 is a schematic view of a wavelength selection filter of a photodetector. FIG. 10A is a plan view of a wavelength selection filter. Wavelength selection filter 10
05 corresponds to each element of a photodetector such as a CCD, etc.
Each wavelength filter is arranged in an array.
A red transmission (R) filter 1001 that transmits red light;
A green transmission filter 1002 that transmits (G) green light,
A blue transmission filter 1003 that transmits (B) blue light,
Non-visible light transmitting filter 10 that transmits (I) out-of-visible light
The four filters 04 and 04 form a set, and the set is sequentially arranged on the wavelength selection filter 1005.

FIG. 10B is a sectional view of the photodetector. The incident light 1006 is collected by the microlens 1007 and passes through the microfilter 1008. Here, the wavelength is selected by each color filter, and each light receiving element 10 is selected.
09. The microlens 1007 is a lens that condenses light rays on the light receiving element, and is a lens array for reducing crosstalk between colors.

As described above, the RGB3 of the red transmission (R) filter 1001 transmitting the red light, the green transmission filter 1002 transmitting the green light (G), and the blue transmission filter 1003 transmitting the blue light (B). By adding a non-visible light transmitting filter 1004 that transmits (I) out-of-visible light in the same plane to the color filter set, an RGB color image is captured, and at the same time, a stripe pattern irradiated on the measured object is captured. I can do it. Therefore, a color image and three-dimensional information can be obtained only by the operation of pressing the shutter as in a normal camera.

(Embodiment 11) FIGS. 11 (a) and 11 (b) are diagrams for explaining moire fringe detection. In the image transmitted by the non-visible light transmitting filter that transmits (I) the out-of-visible light of the wavelength selection filter, a stripe pattern 1101 corresponding to the unevenness of the measured object appears. The same stripe pattern 1102 as the stripe pattern from the active light irradiator is superimposed on the stripe pattern image by image processing, and when a filter for cutting off a high spatial frequency is applied by image processing, moiré stripes 1103 representing uneven contour lines appear. . Therefore, if this moiré fringe 1103 is converted into a value in the height direction, three-dimensional image information can be obtained. If a striped pattern corresponding to the unevenness of the object to be measured shown in 1101 is captured, three-dimensional data can be generated by image processing thereafter. Therefore, the capturing time may be the same as the color image capturing time. Enables input of three-dimensional image information.

(Embodiment 12) FIG. 12 is an explanatory diagram for obtaining height information from moiré fringes. The moire fringe spacing is a height value, but it is a discrete numerical value, and a device is needed to increase the accuracy. Moire fringe pattern intensity distribution 120
1 indicates a sine waveform when the horizontal axis indicates the height value and the vertical axis indicates the stripe intensity. Therefore, if the height is converted into the height including the phase information of the intensity distribution 1201 of the stripe pattern, the height measurement accuracy is dramatically improved.

(Embodiment 13) FIG. 13 is an explanatory view for discriminating irregularities from a fringe detection image. FIG. 13A is a schematic diagram illustrating the image formation position of the stripe depending on the height. When a stripe 1309 irradiates an object to be measured and the object to be measured is located at a position 1307, the stripe forms an image 1310 on the photodetector 1305 by a lens 1304. If the object to be measured is at a position 1306 closer to 1307, the fringe forms an image at 1311 on the photodetector 1305.
Conversely, if the object to be measured is at a position 1308 farther than 1307, the fringe forms an image at 1312 on the photodetector 1305. FIG. 13B shows an image formation position on a plane of the stripe depending on the height. The stripe having a height of 1307 is the stripe 1 on the photodetector 1305.
When an object to be measured appears at 310 and is located at 1306 closer to 1307, the fringe is a fringe 131 on the photodetector 1305.
Shift to 1. Conversely, if the object to be measured is at a position 1308 farther than 1307, the fringe is fringe 1 on photodetector 1305.
It shifts to stripe 1312 opposite to 311. By observing the direction in which the stripes are shifted immediately after the stripes are captured, the direction of the unevenness can be determined. If this method is combined with the moiré fringe observation, it is possible to compensate for the drawback that the moiré fringes cannot be determined, and to acquire a high-accuracy and high-speed three-dimensional image.

(Embodiment 14) In the present invention, a red transmission (R) filter 100 that transmits red light is provided for one pixel.
1 and a green transmission filter 100 that transmits (G) green light.
2 and a blue transmission filter 100 that transmits (B) blue light.
3 and a non-visible light transmitting filter 1004 that transmits (I) out-of-visible light, so that one pixel has color information (RGB) and plane position information (x, y) and height information (z). Therefore, three-dimensional color image information can be taken in as easily as a digital camera, and data can be created.

[0041]

According to the present invention, (1) the provision of an active light irradiator for generating stripes for irradiating an object to be measured enables a three-dimensional height with good accuracy regardless of the distance to the object to be measured. Information can be obtained. (2) R, G, R, G,
In addition to the filter of B, a filter that transmits the wavelength of the light source of the active light irradiator outside visible light is also provided on the same plane, so that the capture time is equivalent to the color image capture time, and the camera takes a picture. Enables input of three-dimensional image information.

(3) The direction of the unevenness can be determined by observing the direction of displacement of the stripe immediately after capturing the stripe image. Since this method is combined with moiré fringe observation and moiré fringe phase detection, it compensates for the drawback that it is not possible to determine the unevenness of moiré fringes. Capture becomes possible.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a three-dimensional image input device according to a first embodiment of the present invention.

FIG. 2A is a schematic view of an active light irradiator using a transmission hologram element.

FIG. 2B is a schematic view of an active light irradiator using a reflection hologram element.

FIG. 3 is a schematic diagram of an active light irradiator using a display element.

FIG. 4 is a schematic diagram showing a change in a stripe pattern due to a distance by an active light irradiator.

FIG. 5 is a schematic diagram of a mechanism for changing a groove shape of the hologram element.

FIG. 6 is a block diagram for controlling a stripe pattern from an active light irradiator according to a distance.

FIG. 7 is a schematic view of a light beam scanning type active light irradiator using a mirror element.

FIG. 8 is a block diagram for controlling a stripe pattern from a light beam scanning type active light irradiator using a mirror element by a distance.

FIG. 9 is a block diagram for controlling a stripe pattern from an active light irradiator using a display element by a distance.

FIG. 10 is a schematic diagram of a wavelength selection filter of the photodetector.

FIGS. 11A and 11B are diagrams illustrating moire fringe detection. FIGS.

FIG. 12 is an explanatory diagram for obtaining height information from moiré fringes.

FIG. 13 is an explanatory diagram for determining unevenness from a fringe detection image.

[Explanation of symbols]

 Reference Signs List 101 active light irradiator 102 light source 103 hologram element 104 object to be measured 107 photodetector 109 color filter 1103 moiré pattern

Claims (14)

[Claims] 1. A distance detector for detecting a distance between a light source having a wavelength outside the visible region, a light irradiator or a light beam scanner for generating a linear stripe pattern for a wavelength outside the visible region, and a measured object. An active light irradiator, wherein a stripe pattern interval or a light beam scanning interval is controlled based on distance information from the detector and the distance detector. 2. The light source having a wavelength outside the visible region is a light source that emits divergent light such as a light emitting diode or a semiconductor laser diode, and the linear stripe pattern represented by light and shade has a substantially linear shape. 2. The active light irradiator according to claim 1, wherein the light is generated by a transmission type or reflection type hologram element. 3. The linear stripe pattern represented by light and shade of light is a projected image from a substantially linear transmission type or reflection type liquid crystal display device or a small pattern display device. An active light irradiator according to claim 1. 4. The hologram element is composed of a liquid crystal element or a piezoelectric element or the like whose transmittance can be changed by a voltage, or a groove depth, a grating width, and a pitch of a diffraction grating are changed by a voltage. 3. An active light irradiator according to claim 2, wherein said active light irradiator is a voltage-controlled hologram element capable of being operated. 5. The active light irradiator according to claim 4, wherein said voltage control type hologram element changes a width, a groove depth and a pitch of a grating according to information on a distance to an object. 6. The linear striped pattern is generated by moving a mirror device or a diffraction grating at a high speed to scan a light beam and turning on a light source in synchronization with the movement of the mirror device. Item 7. An active light irradiator according to Item 1. 7. An optical scanner for scanning a light beam by moving said mirror device or said diffraction grating at a high speed, wherein said mirror device and said light source are controlled based on distance information to an object to change a scanning interval. The active light irradiator according to claim 6, wherein 8. A photodetector to which an image is input has a wavelength selection filter on the incident side, and the wavelength selection filter has a color filter on each of the photodetectors arranged in an array. Are disposed, a red transmission filter that transmits red light, a green transmission filter that transmits green light, a blue transmission filter that transmits blue light, and a visible light transmission filter that transmits light outside the visible range. A photodetector comprising a set of filter arrays. 9. A light source having a wavelength outside the visible region, a linear stripe pattern irradiator or a light beam scanner for a wavelength outside the visible region, a distance detector for detecting a distance between the object to be measured, and the distance An active light irradiator that changes the fringe pattern interval or the light beam scanning interval based on distance information from the detector, and a photodetector provided with an optical filter that transmits the wavelength of the light source on the light incident side of the photodetector. A three-dimensional image input device comprising: 10. A photodetector output by transmitted light from said optical filter is taken in to obtain two-dimensional image information, and this image information is filtered in a linear comb at equal intervals to obtain a low spatial frequency. 10. The three-dimensional image input device according to claim 9, wherein a moiré fringe pattern having irregularity information of the object is obtained by separating only components. 11. A sine approximation of the moiré fringe pattern,
11. The three-dimensional image input device according to claim 10, wherein height information for each pixel is obtained by detecting a phase. 12. A two-dimensional striped image information obtained from the photodetector output from the optical filter to judge the direction of the unevenness of the object to be measured, and the two-dimensional image has a linear comb at equal intervals. 11. The three-dimensional image input apparatus according to claim 10, wherein the moiré fringe pattern is obtained by filtering a component having a low spatial frequency, thereby obtaining height information of the measured object. 13. A red transmission filter, a green transmission filter, and a blue transmission filter are disposed in front of the photodetector together with the optical filter, and transmit the red transmission filter, the green transmission filter, and the blue transmission filter, respectively. The sum of the respective outputs of the photodetectors that detect the detected light is obtained, the photodetector output due to the transmitted light from the optical filter is divided by the sum, and the photodetector output transmitted through the optical filter is normalized. 10. The three-dimensional image input device according to claim 9, wherein: 14. A set of the red transmission filter, the green transmission filter, and the blue transmission filter to form one pixel, and the pixel has position and height information in addition to a color signal. 14. The three-dimensional image input device according to claim 13, comprising: