JP2017525172A - Coded light detection - Google Patents

Abstract

The device camera acquires an image of the scene that includes light from the light source, and the light from the light source is modulated with the encoded light component. The camera includes an image sensor that is divided into a plurality of lines, whereby the lines are sequentially exposed at different times to obtain an image. The processing module detects the orientation of the light source projected onto the image sensor plane relative to the image sensor line, and based on this, the footprint of the light from the light source covers an increased number of lines in the image. Configured to determine a target reorientation of the device to perform. The user interface is configured to output an indication of the target reorientation to the user and guide the user to perform the target reorientation.

Description

  The present disclosure relates to detection of encoded light using a camera such as a rolling shutter camera that has an image sensor that acquires light for each line.

  Coded light refers to a technique in which a signal is embedded in visible light emitted by a light source such as a common luminaire. Thus, this light includes both the visible illumination contribution (typically the main purpose of this light) to the illumination of the target environment, such as a room, and the embedded signal that provides information in the environment. To do this, the light is modulated at one or more specific modulation frequencies, preferably at high frequencies that exceed human perception and thus do not affect the main lighting function.

  In some of the simplest cases, the signal may include a single waveform or a single tone modulated into light from a luminaire. The light emitted by each of the plurality of luminaires may be modulated at different modulation frequencies that are unique among these luminaires, where the modulation frequency serves as an identifier for the luminaire or its light. Can do. For example, it can be used to identify the contribution from each luminaire during the commissioning phase, or luminaire for the purpose of controlling it remotely (eg, using an RF back channel) during operation. Can be used to identify In another example, identification can be used for navigation or other location-based functions by mapping the identifier to a known location of the luminaire or information associated with that location.

  In other cases, signals containing more complex data can be embedded in the light. For example, using amplitude keying, the amplitude of the light to encode the data, for example by using high and low levels to represent bits, or by using a more complex modulation scheme to represent different symbols. Can be changed. Or by using frequency keying, a luminaire radiates at two (or more) different modulation frequencies and transmits data bits (or more generally symbols) by switching between different modulation frequencies. It is possible to operate.

  WO 2012/127439 is a technique that can detect encoded light using a common "rolling shutter" type camera, often incorporated into mobile devices such as mobile phones or tablets. Is disclosed. In a rolling shutter camera, the image sensor of the camera is divided into a plurality of lines (generally horizontal lines, ie, columns) that are exposed in order for each line. That is, to acquire a frame, first one line is exposed to light in the target environment, then the next line in the sequence is exposed slightly later, and so on. In general, this order “rolls” in the order over the frames, for example, from the top to the bottom row, and hence the name “rolling shutter”. When used to acquire encoded light, this means that light is emitted at different times in different frames of the frame, and therefore at different phases of the modulation waveform if the line speed is sufficiently high relative to the modulation frequency. Means to get. Thus, light modulation can be detected.

  In the case of rolling shutter acquisition, etc., the effective detection bandwidth depends on the appearance of the encoded light on the sensor, ie the “footprint”. The effective detection bandwidth is maximized when the optical footprint covers as many image sensor lines as possible. In this case, the detection time is minimized. In particular, although the optical footprint is ideally maximized, the improvement in detection speed may already occur when the number of sensor lines covering the optical footprint is increased. This means that the orientation of the camera greatly affects the speed of detection when the encoded light is detected by pointing the camera at a relatively thin and elongated luminaire such as a ceiling strip light. For example, this situation typically occurs when the front camera of a mobile device is being used. It is desirable to cause the user to rotate the camera device (eg, mobile phone) so that a more optimal orientation for detection of the encoded light is achieved for each new situation. The desired user line may be caused by an explicit command, or (preferably) by an implicit orientation of the user interface (eg, text orientation) such that the desired user line is achieved.

  According to one aspect disclosed herein, a device is provided that includes a user interface, a camera, and a processing module, such as a portable device such as a smartphone or tablet. The camera is operable to acquire an image of a scene that includes light from the light source, and the light from the light source is modulated with the encoded light component. The camera includes an image sensor that is divided into a plurality of lines, whereby the lines are exposed in sequence at different times, for example in the case of a rolling shutter camera, in order to acquire an image. The processing module detects the orientation of the light source projected on the plane of the image sensor relative to the line of the image sensor (ie, the light source appears or will appear in the acquired image), and based on it, the light from the light source Is configured to determine a target reorientation of the device that is desired to cover an increased number of lines in the image (and thus an increased number of lines for detection of encoded light). The The user interface is then configured to output an indication of the target reorientation to the user and guide the user to perform the target reorientation.

  Thus, for example, if the light source is a long, thin rectangular strip light and the lines are in a horizontal row, the user will see the light source appear more vertical in the acquired image, resulting in more lines for encoded light detection. You are guided to rotate your device to cover.

  Preferably, the target reorientation is that required for the footprint to cover the maximum number of lines (which can be covered by the footprint given the current distance of the device from the light source). Nevertheless, it may still be beneficial to induce a reorientation towards an increased number of lines compared to the current orientation, if not the maximum.

  In embodiments, the user interface includes a display, but it is not essential that the acquired image be visible on the display.

  In embodiments, the user interface includes a display and the indication of target reorientation is output to the user via the display.

  For example, the display is the content of the display, and the content that is rotated on the display such that properly viewing the content requires the user to rotate his device to the target reorientation Can be included. For example, the display is a sentence shown on the display, wherein reading the sentence straightly requires the user to rotate the device to the target reorientation, the sentence being oriented on the display; And / or a graphic on the screen, wherein viewing the graphic straight may include a graphic oriented on the screen such that a user needs to rotate the device to the target reorientation.

  As another example, the display may include an arrow on the display that indicates in which direction the device should be rotated to achieve the target reorientation.

  In a further example, the display may include changing the color and / or intensity on the display based on the current orientation of the device relative to the target reorientation. For example, the display may include changing the color of the border pixels of the display. For example, the color may be green to indicate that the device is rotated in a direction approaching the target reorientation, and red to indicate that the device is rotated in a direction away from the target reorientation. possible.

  In yet another example, the display may include displaying a metric that measures the current orientation of the device relative to the target reorientation. For example, the metric may represent the current number of lines of the image sensor covered by the footprint relative to the maximum number of lines that can be covered by the footprint at the current distance of the device from the light source.

  The processing module preferably determines the orientation of the light source appearing in the acquired image relative to the line of the image sensor, for example based on a footprint recognition technique for detecting the encoded light source and one or more other image recognition techniques. An image processing module configured to perform the detection by detection.

  However, alternatively or additionally, the processing module may determine the absolute orientation of the device measured using the orientation sensor, the position of the device measured using the positioning system, and the absolute orientation of the location and the light source. The detection module may be configured to perform the detection based on a mapping between predetermined knowledge and the processing module thus determines the relative orientation from the absolute orientation of the device compared to the absolute orientation of the light source.

  According to another aspect disclosed herein, using a device camera, obtaining an image of a scene including light from a light source, where the light from the light source is modulated with an encoded light component. The camera includes an image sensor that is divided into a plurality of lines, whereby the lines are exposed in sequence at different times to obtain an image, and are projected onto the image sensor for a line of the image sensor Detecting the orientation of the light source, and determining, based on the detection, a target reorientation of a device in which the footprint of the light from the light source covers an increased number of the lines in the image; Outputting a display of the target reorientation to a user via a user interface.

  According to another aspect disclosed herein, a computer program product is provided that includes code embodied on a computer-readable medium and configured to perform a corresponding operation of the device when executed. Is done. For example, the program may be stored on the server so that it can be downloaded to the device, or stored in the device's local storage or elsewhere, and the device's (micro) processor or multiple of the device if equipped It can be executed on more than one of the processors.

  In embodiments, the method may further include steps, or the computer program may be further configured to perform operations according to any of the device features disclosed herein.

  To facilitate an understanding of the present disclosure and to illustrate how embodiments may be implemented, reference is made to the accompanying drawings by way of example.

1 schematically shows a space including a lighting system and a camera. 1 is a schematic block diagram of a device with a camera for receiving encoded light. FIG. 1 schematically shows an image sensor of a rolling shutter camera. The acquisition of modulated light by a rolling shutter is schematically shown. It is the schematic of an acquisition image. It is another schematic diagram of an acquired image. It is another schematic diagram of an acquired image. It is a schematic block diagram of the structure for processing an acquired image. It is the schematic of rotation content output via a user interface. It is the schematic of the metric output by a user interface. FIG. 11 is another schematic diagram of the metric of FIG. 10.

  FIG. 1 illustrates an exemplary environment 2 in which embodiments disclosed herein can be deployed. For example, the environment can be one or more rooms at work, home, school, hospital, museum, or other indoor space and / or outdoor space such as corridors, parks, streets, or stadiums, or an observation deck or vehicle interior. May include other types of spaces. The environment 2 is installed with a lighting system including at least one lighting device 4 in the form of a luminaire. In the environment 2 there is also a user terminal 6 which is preferably a mobile device such as a smartphone or a tablet. The luminaire 4 includes an illumination element such as an LED, an LED array, a filament bulb, or a gas discharge lamp. The light emitted by each lighting element of the one or more luminaires is modulated by an encoded light component of a frequency that is substantially insensitive to the human eye.

This includes means by selecting a sufficiently high modulation frequency, and for example, limiting the variation in the frequency spectrum of the light output as a result of the data being modulated below the critical flicker frequency of the human visual system. Can be achieved. It should be noted that with respect to data dependent spectral components, the use of DC free codes and / or DC ² free codes may be particularly beneficial for limiting low frequency components in the optical output.

  FIG. 2 provides a block diagram of the mobile device 6. The device 6 includes a user interface 8 (preferably a display such as a screen or a touch screen), a camera 10 having a two-dimensional image sensor 20, and an image analysis module 12 coupled to the image sensor 20 and the user interface 8. The image analysis module 12 is operable to process a signal representing the image acquired by the imaging device and based on this, decode the encoded light component in the light from which the image was acquired. The image analysis module 12 may be implemented in the form of codes stored on one or more computer readable storage media and configured to be executed on a processor including one or more processing units. Alternatively, it is not excluded that some or all of the image analysis module 12 can be implemented with a dedicated hardware circuit or a reconfigurable circuit such as an FPGA.

FIG. 3 shows the image sensor 20 of the camera 10. The imaging device 20 includes an array of pixels for obtaining a signal representative of light incident on each pixel, for example, a square or rectangular array of generally square or rectangular pixels. In the rolling shutter camera, the pixels are arranged in a plurality of lines, for example, the horizontal row 22. In order to obtain a frame, each line is exposed in sequence during successive instances of the camera exposure time T _exp . In this case, the exposure time is the duration of individual line exposure. Of course, in the case of a digital camera, the term “exposure” or “exposure” is not a mechanical shutter action or the like (this term is historically derived from this), but is correctly from the environment. Note that it refers to when the line is actively used to acquire or sample light. Also note that the sequence in this disclosure means a time sequence, i.e., the exposure of each line begins at a slightly different point in time (and optionally the exposure of the lines may overlap in time). I want to be. For example, first, the top row 22 ₁ starts exposure for a duration T _exp , and then slightly later, the lower second row 22 ₂ starts exposure for T _exp , Next, after a slight, third row 22 ₃ below starts exposure between T _exp Again, the same up to the bottom row is exposed. This process is then repeated to expose a series of frames.

  For example, WO 2012/127439 describes how encoded light can be detected using this type of conventional video camera. Signal detection utilizes rolling shutter imaging that converts temporal light modulation into spatial intensity fluctuations over successive image sequences.

  This is shown schematically in FIG. As each successive line 22 is exposed, it is exposed at a slightly different point in time, and therefore with a slightly different phase of modulation (if the line speed is sufficiently high compared to the modulation frequency). Accordingly, each line 22 is exposed to the modulated light at the respective instantaneous level. This results in a strip pattern that periodically changes or repeats with modulation over a particular frame. Based on this principle, the image analysis module 12 can detect the encoded light component modulated into the light received by the camera 10.

  As an alternative to using a single photodetector, using a rolling shutter camera to detect the encoded light provides various advantages. One such advantage is the spatial separation of different light sources in the image plane, allowing simultaneous identification of multiple light sources on the illumination scene and separation of their light distribution (its “footprint”). .

  For example, European Patent No. 2,503,852 discloses not only the identification information or data conveyed by the encoded light component but also the individual encoded light components from different luminaires in the environment. It describes how a rolling shutter type technique can be used to detect the spatial footprint of the encoded light component. That is, the size of individual components is determined as a function of spatial coordinates in the acquired image, for example, as a function of Cartesian x and y pixel coordinates separated from among the contributions from one or more other components. be able to.

  In the case of coded light detection, the specific use of a camera with a rolling shutter image sensor is also described in connection with FIG. 4, where different time instances of successive sensor lines cause high-speed light modulation into a spatial pattern. In terms of conversion, it has an advantage over global shutter readout (the entire frame is exposed at once). However, unlike what is shown in FIG. 4, light from a particular light source 4 (or at least usable light) does not necessarily cover the entire area of the imaging device 20, and correctly only a particular footprint. Cover. As a result, the shorter the vertical spread of the acquired optical footprint, the longer the duration during which the encoded optical signal can be detected. In practice, this means that only temporal fragments of the entire encoded optical signal can be obtained in a single frame, so that the shift signal is sufficient to recover the data embedded in the encoded light. Multiple frames are required to obtain a fragment. The smaller the signal fragment in each frame, the more acquisition frames are required before data recovery is possible.

  The encoded light can be detected by pointing the camera 10 at a light source or by pointing the camera at an illuminated surface. By using the front camera of the mobile device 6, the encoded light can be detected while maintaining a free field of view on the display of the mobile device. For example, this allows the mobile device 6 to be used as part of a lighting installation phase (eg commissioning). Alternatively or additionally, after installation, the mobile device 6 may provide the lamp unique identifier embedded in the encoded light to provide various services to the end user based on the location of the end user in the building. Can be restored immediately. For example, such location-based services can provide customized control of local lighting (using an appropriate back channel, eg, RF) by adjusting lighting fixtures recognized by room navigation and / or IDs embedded in encoded light. Could be used for control).

  A common situation in large public spaces such as workplaces, shops and airports is the use of long rows of thin luminaires mounted on the ceiling. Even in the case of LED lighting, the linear shape of the luminaire often corresponds to a fluorescent luminaire (TL tube) where such LED luminaires are often substituted.

  The effective detection bandwidth of the encoded light detection using the rolling shutter camera is determined by the number of sensor lines in which the encoded optical signal exists over the sensor lines. This means that the time required for data recovery is strongly dependent on the orientation of the mobile device 6 with respect to the long axis of the luminaire 4 (the camera 10 is part of the mobile device 6 and thus mobile Suppose it moves with device 6). If the long axis of the thin luminaire 4 appears parallel to the line of the image sensor 20, the detection time can be very long. In extreme cases, detection may not be possible at all.

  5-7 show three typical cases of the appearance of an elongated ceiling luminaire as viewed by the front camera 10 of the mobile device 6, ie projected onto the plane of the image sensor 20. The arrow indicates the vertical range of the light emitting area in the camera frame. FIG. 5 illustrates a situation that is least beneficial for detection of encoded light. The rotation of the device as seen in FIG. 6 or optimally as seen in FIG. 7 improves the vertical range over which the encoded optical signal or signal fragment is acquired over the vertical range.

  If the image of the light source 4 appears parallel (eg, horizontal) or at a shallow angle with respect to the line 22 (eg, column) of the image sensor 20, it is desirable to enable or improve encoded light detection. According to the following, this detects the relative orientation between the image of the light source 4 and the line 22, and the image of the light source 4 is at a steeper angle with respect to the line 22 of the image sensor 20, preferably the line 22 Calculate the desired reorientation of device 6 (assuming that camera 10 is part of device 6 and therefore moves with device 6) so that it appears at right angles (eg perpendicular) to (eg column) Is achieved by doing The indication of target reorientation is output to a user interface 8 (preferably a screen) designed to rotate the user's mobile device to a more beneficial orientation for the user or lighting fixtures.

  FIG. 8 provides a schematic diagram of a mobile device 6 configured in accordance with an embodiment of the present disclosure. Functional blocks are shown as rectangular blocks, and related elements of the information stream are shown as rounded blocks.

  The device 6 is preferably a mobile device such as a tablet or a smartphone. As described in connection with FIG. 2, it includes an embedded camera 10 (preferably a front camera), a user interface 8 that can be a display (eg, a touch screen) with information and control devices, and a processing module 12 ( For example, this may be implemented on the embedded memory and microprocessor of device 6). The processing module 12 allows the user to rotate the device to a subsystem or algorithm for determining the orientation of the light source or illuminated surface relative to the camera 10 and the orientation that optimizes the detection of the encoded light for the user. Means for changing the orientation of the user interface 8 in a manner implicitly or explicitly suggested. Preferably, the user interface does not require that the camera image be visible on the display 8.

  As shown in FIG. 8, the processing module 12 of the device 6 includes an orientation determination block 32 and a comparison block 38. The orientation determination block 32 is configured to receive an image stream 30 from the image sensor 20 of the camera 10, the stream 30 including one or more of the environment 2 including an image of the light source 4 in at least one of the acquired images. Contains acquired image data of the image. The orientation determination block 32 includes a footprint recognition block configured to recognize the footprint of the light source 4 in the acquired image, for example using the technique disclosed in European Patent No. 2,503,852. Based on this, the orientation determination block 32 determines the current orientation of the light source 4 as shown in FIGS. 5, 6 and 7, for example, where the light source 4 appears in the acquired image. The orientation determination block 32 then outputs a first signal 34 representing this current orientation to the comparison block 38.

  Alternatively or additionally, the relative orientation can be determined in other ways. For example, the orientation determination block 32 obtains the orientation of the mobile device 6 from the orientation sensor and uses this position information derived from the positioning system to determine the relative orientation between the device 6 and the luminaire 4. Can be configured to combine with. For example, the orientation sensor may include a compass, one or more gyro sensors, and / or one or more accelerometers integrated in the mobile device 6, but the positioning system may be a satellite based positioning system (eg, GPS GLONASS or Galileo) or a local RF communication network (eg, using triangulation, triangulation or multilateration based on signals transmitted between the mobile device 6 and a wireless node of the network). The orientation sensor provides the orientation of the device 6 with respect to the world (provided that the signal is reliable), and the information received from the positioning system gives the position of the device in the world. Given access to the appropriate lighting database (stored locally on the device 6 or accessed remotely, eg over a network), this may indicate which luminaire 4 is present at the current location and eg It may be possible for the orientation determination block 32 to examine their “absolute” orientation relative to a map of the environment, a floor plan, or a 3D model. Similarly, by knowing (from the orientation sensor) the orientation of the mobile device 6 with respect to the map, floor plan, or model, the orientation determination block 32 will show the illumination that appears in the acquired image according to the relative orientation and alignment of the device 6 and the luminaire 4. The orientation of the instrument 4 can be determined. For example, the location information can be mapped to a particular store, and the database can record the local orientation of the luminaire in a generally unidirectional manner throughout the store space.

  Thus, given the above options, in various embodiments, the orientation of the mobile device 6 is based on an image acquired by a camera only or a footprint based on an orientation sensor and positioning system without a camera. Information can be determined from recognition, or information from both techniques can be combined in determining orientation.

  In any case, the comparison block 38 also extracts a second signal 36 representing the desired orientation of the light source 4 that appears in the acquired image. For example, the comparison block 38 retrieves preprogrammed knowledge that a vertical orientation is desirable (in the case of the horizontal line 22). The comparison block 38 then compares these two signals 34, 36 to determine the preferred reorientation indication 40 of the device 6 that it outputs via the user interface 8.

  In embodiments, the display 40 determines the required user interface (UI) orientation with respect to the user interface 8 so that the content can be read for proper (straight) reading. This is accomplished by being displayed on the UI 8 with an orientation such that the user needs to rotate his phone or tablet in the direction most beneficial for encoded light detection. Thus, the user is implicitly required to perform reorientation. For example, text on the display of the device is oriented such that for proper reading, the smartphone 6 needs to be rotated in the direction for optimal (or at least improved) encoded light detection. As another example, the orientation of the device's display graphic (eg, photo or picture) may be such that the smartphone needs to be rotated in a more useful direction for encoded light detection in order to properly view. is there. For example, the graphic may include a company logo, an interactive control device such as a slider that is adjusted by interaction with the touch screen, and / or an image that is of interest to the user for viewing.

  For example, see FIG. Here, the content includes a picture of the cat 44 and / or some text 42 but is rotated at an angle. Without necessarily thinking, the user notices that he / she wants to admire the cat 44 or read the sentence 42, and instinctively rotates the device so that the content is displayed straight. At this time, the angle at which the device 6 is held is the optimum angle for the encoded light detection.

  In another embodiment, the user interface content can be rotated, but the text providing a message to rotate the device is displayed straight so that the user of device 6 can view the rotation instructions in an easy-to-read manner. (And can be kept straight while device 6 rotates). This sentence can be removed when the device 6 is rotated to the optimal orientation.

  In another embodiment, the arrow on the display 8 indicates the optimal orientation for encoded light detection.

  In another embodiment, the color indicates to what extent the orientation is optimal for encoded light detection. One possible implementation is to use a colored border where the color changes from red to green depending on the orientation of the luminaire.

  In yet another embodiment, the display may be a clear metric displayed to the user that quantifies the preferred orientation relative to the current orientation of the device. For example, this metric is the ratio or ratio of the number of lines 22 currently occupied by the light source 4 to the estimated maximum number of lines 22 that the light source can potentially occupy when the device is rotated to the optimal position. And / or this metric may measure the degree to which the device 6 is to be rotated on one or more axes. This metric can be displayed to the user numerically or graphically (eg, as a position or range on a graph scale). For the end user, the metric is preferably presented using graphics, for example in the form of a circular sector spanning the range between the current orientation angle and the desired orientation angle. For example, FIGS. 10 and 11 show an example of a circular sector to show the difference between the less optimal orientation of the device and the nearly optimal orientation. The second indicator shows the relative detection speed as a percentage of the maximum expected detection speed.

  It will be appreciated that the above embodiments have been described by way of example only.

  For example, the scope of the disclosed technology is not limited to the display examples of the target orientation described above, and other displays, ie, any combination of the above displays and / or other displays may be used. In general, the target reorientation can be expressed in any form and can be expressed as a target change in orientation or a targeted absolute orientation.

  Furthermore, although it has been described above that the processing module 12 decodes the encoded light and calculates the target reorientation, this need not be the case in all possible embodiments. Alternatively or additionally, the processing module 12 on the device 6 can perform operations to determine the target reorientation of the device 6 and the acquired image can be a separate operation for extracting the encoded optical signal. Can be passed to the terminal. For example, the processing module 12 may store the image (eg, by uploading locally or by host computer or server) so that the encoded light can be decoded from the stored image later.

  Further, the disclosed technology can be used in conjunction with many different encoded light applications. Coded light adds information to the light source and lighting environment, and detection using existing (mobile) cameras adds value to the light source as embedded information can be used in a variety of new applications. To do. For example, lamp specific information can be used during commissioning of a new lighting system and / or a smartphone or tablet can be used to provide customized local control over the light. As another example, a group of coded light enabled lighting fixtures provides a high-density optical beacon network for in-room navigation and location-based services that adds value to users and provides accurate location information to service providers can do. As yet another example, the coded light illumination of a particular object can basically “tag” the object using an embedded identifier embedded in the light. The disclosed technology can potentially add robustness to any of these applications.

  It will be appreciated that the present invention also applies to a computer program adapted to implement the present invention, in particular a computer program on or in a carrier. The program may be in the form of object code, such as source code, object code, code intermediate source, and partially compiled form, or in any other form suitable for use in performing the method according to the invention. obtain.

  Another embodiment related to a computer program product includes computer-executable instructions corresponding to each means of at least one of the systems and / or products described herein. These instructions can be subdivided into subroutines and / or stored in one or more files that can be linked statically or dynamically.

  As defined above, the present invention may be further embodied in the form of a computer program product. When provided on a carrier, the carrier of the computer program can be any entity or device capable of holding the program. For example, the carrier may include a storage medium such as a ROM (for example, a CD-ROM or a semiconductor ROM) or a magnetic recording medium (for example, a hard disk). Alternatively, the carrier can be an integrated circuit in which the program is embedded, and this integrated circuit is adapted to perform the related method or to be used in performing the related method.

  Other variations to the disclosed embodiments can be understood and brought about by those skilled in the art in the practice of the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the term “comprising” does not exclude other elements or steps, and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage. The computer program may be stored / distributed on a suitable medium, such as an optical storage medium or solid medium supplied with or as part of other hardware, but via the Internet or other wired or wireless communication system, etc. Can be distributed in other forms. Any reference signs in the claims shall not be construed as limiting the scope.

Claims (15)

A user interface;
A camera for acquiring an image of a scene including light from a light source;
A device including a processing module,
The light from the light source is modulated with an encoded light component, and the camera includes an image sensor that is divided into a plurality of lines, whereby the lines are sequentially exposed at different times to acquire the image. The imaging element defines a plane;
The processing module detects an orientation of the light source projected on the plane of the image sensor relative to the line of the image sensor, and based on this, a footprint of light from the light source is detected in the image. Determining a target reorientation of the device covering an increased number of the lines;
The device wherein the user interface outputs an indication of the target reorientation to the user to guide the user to perform the target reorientation.   The target redirection is required for the footprint of light from the light source to cover the maximum number of the lines that can be covered by the footprint at the current distance of the device from the light source. The device of claim 1.   The device of claim 1 or 2, wherein the user interface includes a display and the acquired image is not displayed on the display.   The device according to claim 1, wherein the device is one of a portable device, a smartphone, or a tablet.   The device according to claim 1, wherein the user interface includes a display, and the indication of the target reorientation is output to the user via the display. The display is
Sentence shown on the display, wherein the reading of the sentence is oriented on the display such that the user needs to rotate the device to the target reorientation And / or a graphic on the display, wherein viewing the graphic directly requires the user to rotate the device to the target reorientation to be oriented on the screen. The device of claim 5, comprising at least one of the following:   7. A device according to claim 5 or 6, wherein the display includes an arrow on the display indicating in which direction the device should be rotated to achieve the target reorientation.   8. A device according to claim 5, 6 or 7, wherein the display comprises changing color and / or intensity on the display based on the current orientation of the device relative to the target reorientation.   The color that is green indicates that the device is rotated in a direction that approaches the target reorientation, and the color that is red indicates that the device is rotated in a direction away from the target reorientation. 9. The device of claim 8, shown.   10. A device according to any preceding claim, wherein the display comprises displaying a metric that measures the current orientation of the device relative to the target reorientation.   The metric represents the current number of lines of the imager covered by the footprint relative to the maximum number of lines that can be covered by the footprint at the current distance of the device from the light source. Device described in.   The said processing module contains the image processing module which performs the said detection by detecting the orientation of the said light source as an external appearance in the said image acquired with respect to the said line of the said image pick-up element. Device described in.   The processing module is configured to measure the absolute orientation of the device measured using an orientation sensor, the position of the device measured using a positioning system, and a predetermined knowledge of the position and the absolute orientation of the light source. 13. The detection is performed based on a mapping of: and the processing module thus determines a relative orientation from the absolute orientation of the device compared to the absolute orientation of the light source. Device described in. An image pickup device comprising: acquiring a scene image including light from a light source using a device camera, wherein the light from the light source is modulated with an encoded light component, and the camera is divided into a plurality of lines Whereby the lines are exposed in sequence at different times to obtain the image, and the imaging element defines a plane;
Detecting the orientation of the light source projected on the plane of the image sensor relative to the line of the image sensor;
Based on the detection, a footprint of the light from the light source determines a target reorientation of the device that covers an increased number of the lines in the image;
Outputting the indication of the target reorientation to a user via a user interface of the device. Code embodied on at least one computer-readable storage medium, retrieved from the storage medium and / or downloaded via a communication network; and
An operation of acquiring an image of a scene including light from a light source using the camera of the device, wherein the light from the light source is modulated with an encoded light component, and the camera is divided into a plurality of lines. An operation comprising: an element, whereby the lines are exposed in sequence at different times to acquire the image, and the imaging element defines a plane;
Detecting the orientation of the light source projected on the plane of the image sensor with respect to the line of the image sensor;
Based on the detection, an operation in which a footprint of light from the light source determines a target reorientation of the device that covers an increased number of the lines in the image;
A computer program comprising the code executed on the device to perform an operation to output an indication of the target reorientation to a user via a user interface of the device.

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