RU2689142C2 - Coded light detection - Google Patents

Abstract

FIELD: data processing.

SUBSTANCE: invention relates to detection of encoded light by means of a camera with an image capturing element, which captures light in line. Result is achieved by the camera capturing a scene image containing light from a light source, wherein the light from the light source is modulated with the encoded light component. Camera has an image capturing element which is divided into a plurality of lines, as a result of which, in order to capture an image, successive exposure of the lines at different moments in time is carried out. Processing module is configured to detect the orientation of the light source, as projected onto the image capturing element plane, relative to the image capturing element lines, and based on this determination of target device reorientation, so that light imprint from light source covers increased number of specified lines in image. User interface is configured to output an indication of target reorientation to the user, which forces the user to activate the target reorientation.

EFFECT: encoded light detection.

15 cl, 11 dwg

Description

TECHNICAL FIELD TO WHICH INVENTION RELATES.

The present disclosure relates to the detection of coded light by means of a camera with an image pickup element that captures light line by line, as in a camera with a roller shutter.

BACKGROUND

Coded light refers to techniques by which a signal embedded in visible light is emitted by a light source, such as a conventional lighting fixture. Thus, the light contains both the contribution of visible illumination to illuminate the target medium, such as a room (usually the primary purpose of the light), and the embedded signal, to provide information in the medium. To do this, the light is modulated at a certain frequency or modulation frequency, preferably a frequency high enough so that it is outside the human perception and, therefore, does not affect the primary lighting function.

In some of the simplest cases, the signal may contain a single waveform or even a single tone modulated in the light from a given light fixture. The light emitted by each of a variety of lighting fixtures can be modulated with a different corresponding modulation frequency, which is unique among these lighting fixtures, and then the modulation frequency can serve as an identifier of the lighting fixture or its light. For example, it can be used in the commissioning phase to identify the contribution from each light fixture, or can be used during operation to identify the light fixture in order to control it remotely (for example, via RF (radio frequency) reverse channel) . In another example, identification may be used for navigation or other location-based functionality, by building an identity mapping with a known location of the lighting fixture or information associated with the location.

In other cases, a signal containing more complex data may be embedded in the light. For example, using amplitude manipulation, the amplitude of the light can vary to encode data, for example, using high and low levels to represent bits, or using a more complex modulation scheme to represent different characters. Or, using frequency shift keying, a given lighting device is operated to emit at two (or more) different modulation frequencies, and to transmit data bits (or, in general, symbols) by switching between different modulation frequencies.

WO2012 / 127439 discloses a technique by which coded light can be detected using a conventional “roll gate” type camera, which is often integrated into a mobile device like a mobile phone or tablet. In a camera with a roller shutter, a camera image capture element is divided into a plurality of lines (as a rule, horizontal lines, i.e., rows), which are exposed in a line by line sequence. That is, in order to capture a given frame, light is exposed to a given medium of the first line, then after a slightly later time, the next line is consecutively light-exposed, and so on. As a rule, the sequence “rolls into a roll” in the sequence of frames, for example, in rows from top to bottom, hence the name “roll shutter”. When used to capture coded light, this means that different lines inside the frame capture light at different points in time and, as a result, if the line frequency is high enough relative to the modulation frequency, the different phases of the modulation waveform are in different phases. In this way, modulation in the light can be detected.

SUMMARY OF INVENTION

In the case of capture using a roller shutter or the like, the effective detection bandwidth depends on the appearance of the coded light, or “print”, on the sensor. Effective detection bandwidth is maximized when the light footprint covers as many lines of the image sensor as possible. In this case, the detection time is minimized. It should be noted that although ideally the maximization of the light imprint is performed, improvements in the detection speed may already occur when the number of sensor lines that encompass the light imprint increases. This means that when coded light is detected with a camera aimed at a relatively narrow and elongated light fixture, such as a ceiling tubular fluorescent lamp, the orientation of the camera has a significant effect on the detection rate. For example, this situation usually occurs when the front camera of a mobile device is used. It would be desirable to force the user to rotate the camera device (for example, a mobile phone) in such a way that a more optimal orientation is achieved to detect the coded light for each new situation. The desired user action can be triggered either by an explicit instruction, or (preferably) by an implicit user interface aspect (eg, text orientation), so that the desired user action is achieved.

In accordance with one aspect disclosed herein, an apparatus is provided comprising a user interface, a camera, and a processing module; for example, a portable device such as a smart phone or tablet. The camera is configured to capture an image of a scene containing light from a light source, wherein the light from the light source is modulated with a component of the coded light. The camera contains an image capture element, which is divided into multiple lines, as a result of which, in order to capture an image, consecutive exposure of lines is carried out at different times, for example, as in a camera with a roller shutter. The processing module is configured to detect the orientation of the light source, as projected onto the plane of the image capture element (i.e., how it is present or will be present on the captured image), with respect to the rows of the image capture element, and based on this, the target reorienting the device that would be desirable so that the imprint of light from the light source covers an increased number of lines in the image (and, consequently, an increased number of lines for the detected I coded light). The user interface is adapted to then output the indication of the target reorientation to the user, forcing the user to activate the target reorientation.

Thus, for example, if the light source is a long, thin rectangular tubular fluorescent lamp, and the rows are horizontal rows, the user will have to rotate his or her device so that the light source is more vertical on the captured image, thereby covering more rows to detect coded light.

Preferably, the target reorientation is such that it is required for the fingerprint to cover the maximum number of lines (covered by the fingerprint, taking into account the current distance of the device from the light source). However, even if it is not the maximum, it may still be beneficial to force a reorientation towards any increased number of lines relative to the current orientation.

In embodiments, the user interface comprises a display, but it is not required that the captured image be visible on said display.

In embodiments, the user interface comprises a display and an indication of the target reorientation is displayed to the user through the display.

For example, the indication may contain the display content rotated on the display in such a way that a correct (forward) viewing of the content requires the user to turn his or her device into a target reorientation. For example, the indication may contain text displayed on the display, oriented on the display so that in order to read the text in the forward direction, it is required that the user rotates the device into said target reorientation; and / or graphics on the screen oriented on the screen so that in order to view the graphics in the forward direction, it is required that the user rotates the device into said target reorientation.

As another example, the indication may contain an arrow on the display, indicating which way to turn the device in order to obtain said target reorientation.

In an additional example, the indication may contain a change in color and / or intensity on the display, depending on the current orientation of the device with respect to the target reorientation. For example, the indication may contain a change in the color of the pixels of the display border. For example, the color may be green to indicate that the device is rotated close to the target reorientation mentioned, and red to indicate that the device is rotated far from the target reorientation.

In yet another example, said indication may comprise displaying a metric measuring the current orientation of the device with respect to the target orientation. For example, a metric can be the current number of rows of an image capture element covered by said fingerprint with respect to the maximum number of lines that can be covered by a fingerprint at the device’s current distance from the light source.

Preferably, the processing module comprises an image processing module configured to perform the above-mentioned detection by detecting the orientation of the light source as being present in the captured image with respect to the rows of the image pickup element, for example, based on fingerprint recognition techniques for detecting coded light sources, and or or more other image recognition techniques.

However, alternatively or in addition, the processing module may be configured to perform the above detection based on the absolute orientation of the device, measured using an orientation sensor, the position of the device measured using a positioning system, and building a correspondence between the position and a predetermined knowledge of absolute orientation of the light source; the processing module thus determining the relative orientation of the absolute orientation of the device, compared with the absolute orientation of the light source.

In accordance with another aspect disclosed herein, a method is provided comprising: using a device camera to capture an image of a scene containing light from a light source, wherein the light from the light source is modulated with the coded light component; and the camera contains an image capture element divided into a plurality of lines, as a result of which, in order to capture an image, sequential exposure of the lines is carried out at different times; detecting the orientation of the light source, as projected onto the plane of the image capture element, with respect to the rows of the image capture element; based on the above detection, determine the target reorientation of the device, so that the imprint of light from the light source covers an increased number of the mentioned lines in the image; and outputting the indication of said target reorientation to the user via the user interface of the device.

In accordance with another aspect disclosed herein, a computer program product is provided comprising a code embodied on a computer-readable storage medium, and designed in such a way that, when executed, perform the corresponding operations of the device. For example, a program can be stored on a server so that it can be loaded onto a device, or stored on a local storage device, or anywhere else; and can be executed on a (micro) device processor or more than one of several device processors, if equipped.

In embodiments, the method may further comprise steps or a computer program, further configured to perform operations in accordance with any of the features of the device disclosed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

To facilitate an understanding of the present disclosure and to show how the embodiments may be put into action, reference is made to the accompanying drawings as an example, in which:

Figure 1 schematically illustrates a space containing a lighting system and a camera,

Figure 2 is a schematic block diagram of a device with a camera for receiving coded light;

Figure 3 schematically illustrates the image capture element of a camera with a roller shutter,

Figure 4 schematically illustrates the capture of modulated light by means of a roller shutter,

Figure 5 is a schematic representation of a capture image,

Figure 6 is another schematic representation of the captured image,

Figure 7 is another schematic representation of the captured image,

Figure 8 is a schematic block arrangement diagram for processing captured images,

Figure 9 is a schematic representation of rotated content output via a user interface,

Figure 10 is a schematic representation of a metric outputted by a user interface, and

Figure 11 is another schematic representation of the metric from Figure 10.

DETAILED DESCRIPTION OF EMBODIMENTS

Figure 1 shows an exemplary environment 2 in which embodiments of which are disclosed herein may be deployed. For example, a medium may contain one or more rooms and / or corridors of an office, home, school, hospital, museum, or other indoor space; or outdoor space, such as a park, street, stadium, or something similar; or another type of space, such as a belvedere or a vehicle cabin. In environment 2, a lighting system is installed, containing at least one lighting device 4 in the form of an illumination device. Also in environment 2 there is a user terminal 6, preferably a mobile device, such as a smart phone or tablet. The illuminator 4 comprises an element of illumination, such as an LED, an array of LEDs, an incandescent lamp, or a discharge lamp. The light emitted by the lighting element of each of the one or more lighting devices is modulated with a component of the coded light at a frequency that is essentially imperceptible to the human eye.

This can be accomplished by selecting a sufficiently high modulation frequency and by including measures to limit the deviations in the frequency spectrum of light output, for example, as a result of modulated data, below the critical frequency of flicker of the human visual system. With regard to data-dependent spectral components, it is noted that the use of codes without a constant component and / or codes without a square of a constant component (DC ² -free) may be particularly advantageous in order to limit the low-frequency components in the light output.

Figure 2 provides a block diagram of a mobile device 6. Device 6 comprises a user interface 8 (preferably a display, such as a screen or a touch screen), a camera 10 with a two-dimensional image pickup element 20, and an image analysis module 12 associated with the image pickup element 20 and interface 8 users. The image analysis module 12 is configured to process signals representing images captured by an image pickup element, and, on their basis, decoding components of the coded light in the light from which the image was captured. The image analysis module 12 may be implemented in the form of a code stored on a computer readable storage medium or information carriers configured to be executed on a processor containing one or more processing units. Alternatively, it is not excluded that some or all of the image analysis module 12 may be implemented in a designated hardware circuit or a reconfigurable circuit, such as FPGA.

Figure 3 is the image capture element 20 of the camera 10. The image capture element 20 comprises an array of pixels for capturing signals representing incident light at each pixel, for example, as a rule, a square or rectangular array of square or rectangular pixels. In a camera with a roller shutter, the pixels are organized in multiple rows, for example, horizontal rows 22. To capture a frame, each row is sequentially exposed, each for a subsequent instance of the camera's exposure time T _exp . In this case, the exposure time is the duration of exposure of a single line. Of course, it should be noted that in the context of a digital camera, the terminology “to carry out exposure” or “exposure” does not refer to the mechanical actuation of the shutter or something similar (from which the terminology has historically originated), but rather to the time when the line is actively used to capture or select sample of light from the environment. It should also be noted that the sequence in the present disclosure means a time sequence, i.e., so that the exposure of each row starts at slightly different times (and optionally the exposure of the rows may overlap over time). For example, the exposure of the first upper row 22 ₁ begins for the duration of T _exp , then at a somewhat later time begins to exhibit the second row 22 ₂ below for T _exp , then at a somewhat later time the third row 22 ₃ in T _exp , etc. until the bottom row is exposed. This process is then repeated to carry out the exposure of a sequence of frames.

Document WO2012 / 127439, for example, described how coded light can be detected using a traditional video camera of this type. Signal detection uses a shutter capture of the image, which causes the translation of temporal modulations of light to spatial variations in intensity over successive rows of the image.

This is schematically illustrated by Figure 4. As each consecutive line 22 is exposed, its exposure takes place at several different times and, as a consequence (if the line frequency is high enough compared to the modulation frequency), at several different modulation phases. Thus, the exposure of each line 22 is carried out with a corresponding instantaneous level of modulated light. This leads to a pattern of bands that are wave-like or cyclical in accordance with the modulation for a given frame. Based on this principle, the image analysis module 14 is able to detect the components of the coded light modulated in the light received by the camera 10.

As an alternative to using a single photodetector, using a camera with a shutter to detect coded light provides various advantages. One such advantage is the spatial separation of different light sources in the image plane, ensuring the simultaneous identification of several light sources and the separation of their light distribution (their “fingerprints”) in the illuminated scene.

For example, EP 2,503,852 describes how roll shutter type techniques can be used not only to detect identification data or data signaled by a component of the coded light, but also the spatial imprint of a single component of the coded light in the case where several components of the coded light are present. in the environment from different lighting devices. That is, the amplitude of a separate component can be defined as a function of spatial coordinates in the captured image, for example, as a function of Cartesian coordinates x and y of a pixel, separated from the contribution of another component or components.

For coded light detection, the specific use of cameras with a roller shutter image sensor also has an advantage over reading through a global shutter (where the entire frame is exposed at a time), which means that different instances of consecutive sensor lines translate fast light modulations in spatial models, as discussed in relation to Figure 4. However, unlike the one shown in Figure 4, the light (or, at least, the light used) from the rear 4 continuous source of light does not necessarily cover the entire area of the image capturing element 20, but rather only some imprint. As a result, the shorter the vertical distribution of the captured light imprint, the longer the duration during which the coded light signal can be detected. In practice, this means that only a time fragment of the entire coded light signal can be captured within a single frame, so several frames are required to capture enough displaced signal fragments to recover the data embedded in the coded light. The smaller the signal fragment in each frame, the more captured frames are required before data recovery will be possible.

The coded light can be detected either by directing the camera 10 towards the light source, or by directing the camera towards the illuminated surface. By using the front camera of the mobile device 6, the coded light can be detected while maintaining the free viewing on the display of the mobile device. For example, this allows mobile device 6 to be used as part of the lighting installation phase (for example, commissioning). Alternatively or in addition, after installation, mobile device 6 can quickly recover lamp-specific identifiers embedded in the coded light to provide a range of services to the end user based on his or her location in the building. For example, such a location-based service can be used for indoor navigation, and / or personalized control of local lighting by adjusting a lighting device that is recognized by an ID embedded in the coded light (control through a suitable return channel, such as RF).

A common situation in large public spaces, such as offices, shops and airports, is the use of long rows of narrow lighting fixtures that are mounted on the ceiling. Even in the case of LED lighting, the linear shape of lighting fixtures often corresponds to fluorescent lighting fixtures (TL tubes) for which such LED lighting fixtures often serve as replacements.

The effective detection bandwidth for detecting coded light with a camera with a roll-top shutter is determined by the number of sensor lines on which the coded light signal is present. This means that the time required for data recovery strictly depends on the orientation of the mobile device 6 with respect to the long axis of the lighting device 4 (assuming that camera 10 is part of mobile device 6 and, consequently, moves with it). If the narrow fixture 4 is present so that its long axis is parallel to the rows of the image sensor 20, the detection times may become very long. In extreme cases, detection may not be possible at all.

Figures 5 through 7 show three typical cases of the appearance of an elongated ceiling light as observed by the front-facing camera 10 of the mobile device 6, i.e. as projected onto the plane of the element 20 image capture. The arrows indicate the vertical length of the luminous zone in the frame of the camera. Figure 5 shows the least advantageous situation for detecting coded light. Rotation of the device as in Figure 6, or optimally, as in Figure 7, improves the vertical extent by which the coded light signal or signal fragment is captured.

It would be desirable to provide or improve the detection of coded light in cases where the image of light source 4 is present parallel (for example, horizontal) or at a slight angle to lines 22 (for example, rows) of image capture element 20. In accordance with the following, this is achieved by detecting the relative orientation between the image of light source 4 and lines 22, and calculating the required reorientation of device 6 (assuming camera 10 is part of device 6 and thus moving with it), so that image of light source 4 is present with a steeper angle relative to the rows of the image capturing element 20, preferably with correct angles (for example, vertically) to lines 22 (for example, rows). The indication of the target reorientation is displayed on the user interface 8 (preferably on the screen), intended to instruct the user to rotate his mobile device in the direction of a more advantageous orientation with respect to the lighting fixture (s).

Figure 8 is a schematic view of a mobile device 6, made in accordance with embodiments of the present disclosure. The functional blocks are indicated by rectangular blocks, and the corresponding elements of the information flow are indicated by rounded blocks.

Device 6 is preferably a mobile device, such as a tablet or smart phone. As discussed in relation to Figure 2, it comprises an integrated camera 10 (preferably a front facing camera), a user interface 8, which may be a display with information and controls (eg, a touch screen), and a processing module 12 (eg, which may be implemented in the internal memory of the device microprocessor 6). Processing module 12 comprises a subsystem or algorithm to determine the orientation of the light source or the orientation of the illuminated area with respect to camera 10, as well as the means to change the aspect of user interface 8 in a way that implicitly or explicitly suggests to the user that he or she turns the device in an orientation that optimizes the detection of coded light. Preferably, the user interface does not require the camera image to be visible on the display 8.

As shown in Figure 8, the processing unit 12 of the device 6 comprises an orientation determination unit 32 and a comparison unit 38. The orientation determining unit 32 is configured to receive the image stream 30 from the image capturing element 20 of the camera 10, and the stream 30 contains captured image data of one or more images of the environment 2, including the image of the light source 4 in at least one of the captured images. The orientation determination unit 32 comprises a fingerprint recognition unit configured to recognize the fingerprint of the light source 4 in the captured image, for example using techniques as disclosed in EP 2,503,852. Based on this, the orientation determination unit 32 determines the current orientation of the light source 4 as it is present in the captured image, for example, as shown in Figures 5, 6 and 7. The orientation determination unit 32 then outputs the first signal 34, which is the current orientation, in block 38 comparison.

Alternatively or in addition, the relative orientation can be determined in another way. For example, the orientation determining unit 32 may be configured to obtain the orientation of the mobile device 6 from the orientation sensor, and combine this with the location information extracted from the positioning system in order to determine the relative orientation between the device 6 and the lighting device 4. For example, the sensor orientation can be made in the form of a compass, a gyroscopic (s) sensor (s) and / or an accelerometer (s) integrated into the mobile device 6, while the positioning system can be It is designed as a satellite-based positioning system (e.g., GPS, GLONASS or Galileo), or a local RF communication network (e.g., using triangulation, trilateration and multilateration based on signals transmitted between the mobile device and wireless network 6 nodes). 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 location of the device in the world. If you have access to a suitable lighting database (either stored locally on the device or accessed remotely, for example, via a network), this may allow the orientation determining unit 32 to search for which lighting fixture (s) 4 are present in current location and their “absolute” orientation, for example, relative to a map, layout, or 3D environment model. Knowing also the orientation of the mobile device 6 relative to the map, layout, or model (from the orientation sensor), the orientation determining unit 32 can therefore determine the relative orientation of the device 6 and the lighting device 4, and therefore the orientation of the lighting device 4, as it will be present captured image. For example, location information can be correlated to a specific store, and the database can record the local orientation of the lighting fixtures, which are usually unidirectional throughout the store space.

Thus, with the options available above, in various embodiments, the orientation of the mobile device 8 can be determined from fingerprint recognition based solely on the image captured by the camera, or without the camera, on the basis of the orientation sensor and the positioning system; or information from both techniques can be combined in determining orientation.

Anyway, the comparison unit 38 also extracts the second signal 36, which is the desired orientation for the light source 4, as it will be present in the captured image. For example, comparison unit 38 retrieves a pre-programmed knowledge that vertical orientation is required (in the case of horizontal lines 22). Comparison unit 38 then compares these two signals 36, 38 to determine indication 40 of the preferred reorientation of device 6, which is output via user interface 8.

In embodiments, instruction 40 is implemented by determining the desired user interface (UI) orientation for user interface 8, with the result that that content is displayed in UI 8 in such an orientation that for the right (forward) reading, the user must rotate him or her phone or tablet in the most advantageous direction for detecting coded light. Thus, the user is implicitly forced to perform a reorientation. For example, the text on the device display is oriented so that for correct reading it is required to turn the smart phone 6 in the direction for optimal (or, at least, improved) detection of the coded light. As another example, the orientation of a graphic (for example, a photo or a drawing) on a device display is such that in order to view it correctly, you need to turn the smart phone in a direction more favorable for detecting coded light. For example, this graphic may contain a company logo, an interactive control, such as a slider, which is adjusted by interacting with a touch screen, and / or an image, in consideration of which the user is intrigued.

For example, refer to Figure 9. On it, the content contains a picture of a cat 44 and / or some text 42, but rotated by an angle. Without even thinking, the user finds in himself the desire to admire the cat 44 or read the text 42 and instinctively turns the device so that the content is displayed directly. The angle at which device 6 is now held is the optimum angle for detecting coded light.

In another embodiment, the content of the user interface can be rotated, but the text expressing the message to rotate the device is displayed directly (and can be held in the forward direction while the device 6 is rotated), so that the user of device 6 sees the instruction in respect to turning, in a readable way. Text can be deleted as soon as device 6 has been rotated to its optimal orientation.

In another embodiment, the arrow on the display 8 indicates the optimal orientation for detecting coded light.

In another embodiment, the color indicates the degree to which the orientation is optimal for detecting coded light. A possible implementation is the use of a color border, the color of which changes from red to green, depending on the orientation of the lighting fixtures.

In yet another embodiment, the indication may be an exact metric displayed to the user, quantifying the preferred orientation with respect to the current orientation of the device. For example, a metric can measure the ratio or proportion of the number of lines 22 that the light source 4 currently occupies with respect to the estimated maximum number of lines 22 that the light source can potentially take if the device is turned to the optimum position and / or the metric can measure the amount degrees by which device 6 must be rotated along one or more axes. This metric can be displayed to the user using numbers or graphically, for example, as a position or value on a graphic scale. For the end user, preferably the metric will be represented graphically, for example, in the form of a circular sector, which covers the range between the current and the desired orientation angle. For example, Figures 10 and 11 show an example of a circular sector to indicate the difference between a less optimal orientation and a more optimal orientation of the device. The second indicator represents the relative detection rate, as a percentage of the maximum expected detection rate.

It should be borne in mind that the above embodiments have been described only as an example.

For example, the scope of the disclosed techniques is not limited to the approximate indications of the target orientation discussed above, and other indications may be used, or any combination of the above indications and / or others. In general, target reorientation can be expressed in any form, and can be expressed in units of a target change in orientation or in the absolute orientation that is to be achieved.

In addition, although it has been described above that the processing module 12 decodes the coded light, as well as calculates the target reorientation, it is not required that this be the case in all possible embodiments. Alternatively or in addition, processing module 12 on device 6 can perform operations to determine the target reorientation of device 6, and the captured image can be passed to another terminal to extract the coded light signal. For example, processing module 12 may store an image (for example, locally or by uploading to a host computer or server), so that coded light can be decoded from a saved image later.

In addition, the disclosed techniques can be used in conjunction with a number of different applications of coded light. Coded light adds information to the light source, as well as the illuminated medium, and detection using existing (mobile) cameras adds value to the light source when the embedded information becomes available for a variety of new applications. For example, information specific to the lamp may be used during the commissioning of new lighting systems, and / or provide personalized local light control using a smart phone or tablet. As another example, a combination of lighting products with coded light capabilities can provide a dense grid of light beacons for indoor navigation and location-based services, adding value to the consumer and giving accurate location information to the service provider. As another example, the coded light of a specific object can essentially assign a “tag” to an object using an embedded identifier embedded in the light. The disclosed techniques can potentially add reliability to any of these applications.

It should be borne in mind that the invention also applies to computer programs, in particular computer programs on or in a carrier adapted for putting the invention into practice. The program may be in the form of source code, object code, intermediate code between the source and object code, such as in a partially compiled form, or in any other form suitable for use when implementing the method in accordance with the invention.

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

As provided above, the invention may additionally be embodied in the form of a computer software product. When provided on a carrier, the carrier of a computer program may be any object or device configured to carry the program. For example, the medium 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 may be an integrated microcircuit in which the program is embedded, an integrated microcircuit configured to be executed, or used in the execution of the corresponding method.

Other variations of the disclosed embodiments can be understood and performed by specialists in the relevant field of technology in the implementation in practice of the claimed invention, from the study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements and steps, and the singular form does not exclude a plurality. One processor or other unit may fulfill the functions of several items recited in the claims. The mere fact that certain measures are set forth in the mutually different dependent claims does not indicate that a combination of these measures cannot be used to achieve an advantage. The computer program may be stored / distributed on an appropriate storage medium, such as an optical storage medium or solid-state storage medium supplied with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunications systems. Any reference designation in the claims should not be construed as limiting the scope.

Claims (29)

1. A device (6) for detecting a component of a coded light, comprising: user interface (8); a camera (10) for capturing an image of a scene containing light from a source (4) of light, while the light from a light source is modulated with a component of coded light, and the camera contains an image capture element (20) that is divided into many lines (22) , as a result, in order to capture an image, sequential exposure of lines is performed at different times, with the image capture element specifying a plane; and processing module (12) configured to detect the angle of orientation of the light source, as projected onto the plane of the image capture element, with respect to the rows of the image capture element, and based on this definition of the target reorientation of the device so that the light imprint from the light source covers the increased number of said lines in the image; wherein the user interface is configured to output an indication of the target reorientation to the user so as to force the user to rotate the device in such a way as to bring the target reorientation into effect. 2. The device according to claim 1, wherein the target reorientation is such that it requires the imprint of light from the source (4) of light to cover the maximum number of lines (22) covered by the imprint at the current distance of the device (6) from the light source. 3. The device according to claim 1 or 2, wherein the user interface comprises a display (8) and the captured image is not shown on said display. 4. The device according to claim 1 or 2, wherein the device (6) is one of: a portable device, a smart phone, or a tablet. 5. The device according to claim 1 or 2, wherein the user interface comprises a display (8) and an indication of the target reorientation is displayed to the user through the display. 6. The device according to claim 5, in which the indication contains at least one of the following: the text shown on the display (8), oriented on the display so that in order to read the text in the forward direction, it is required that the user turns the device (6) into said target reorientation; and / or the graphics on the display are oriented on the screen so that in order to view the graphics in the forward direction, it is required that the user rotates the device into said target reorientation. 7. The device according to claim 5, in which the indication contains an arrow on the display indicating in which direction to turn the device (6) in order to obtain said target reorientation. 8. The device according to claim 5, in which the indication contains a change in color and / or intensity on the display (8) depending on the orientation angle of the device (6) with respect to the target reorientation. 9. The device according to claim 8, in which the green color indicates that the device (6) is rotated close to the mentioned target reorientation, and the red color indicates that the device is rotated far from the target reorientation. 10. The device according to claim 1 or 2, in which said indication comprises displaying a metric measuring the orientation angle of the device (6) with respect to the target reorientation. 11. The device according to claim 10, in which the metric is the current number of lines (22) of the image capture element (20), covered by said fingerprint, in relation to the maximum number of lines that can be covered by the fingerprint at the current distance of the device (6) from source (4) of light. 12. The device according to claim 1 or 2, wherein the processing module (12) comprises an image processing module, configured to perform said detection by detecting the orientation of the source (4) of the light, as present on the captured image, with respect to the rows (22) element (20) image capture. 13. The device according to claim 1 or 2, in which the processing module is configured to perform the above-mentioned detection based on the absolute orientation of the device (6), measured using an orientation sensor, the position of the device, measured using a positioning system, and building a correspondence between the position and the predefined knowledge of the absolute orientation of the light source; the processing module thus determining the relative orientation of the absolute orientation of the device, compared with the absolute orientation of the light source. 14. A method for detecting a coded light component, comprising: use the camera (10) of the device (6) to capture the image of the scene containing light from the light source (4), while the light from the light source is modulated with the component of the coded light, and the camera contains an image capture element (20) divided into a plurality of lines (22), as a result of which, in order to capture an image, consecutive exposing of lines is performed at different times, with the image capturing element specifying a plane; detecting the orientation of the light source projected onto the plane of the image pickup element with respect to the rows of the image pickup element; based on the above detection, determine the target reorientation of the device, so that the imprint of light from the light source covers an increased number of the mentioned lines in the image; and outputting the indication of the target reorientation to the user via the user interface of the device. 15. Machine-readable storage media containing a computer program, configured to prescribe, when executed, the device (6) to perform operations: using the camera (10) of the device to capture an image of a scene containing light from a light source, while the light from the light source is modulated with a component of the coded light, and the camera contains an image capture element (20) divided into multiple lines (22) in as a result, in order to capture an image, consecutive exposure of lines is performed at different points in time, with the image capture element defining a plane; detecting the orientation of the light source, as projected onto the plane of the image capture element, with respect to the rows of the image capture element; based on the above detection, the determination of the target reorientation of the device so that the imprint of light from the light source covers an increased number of said lines in the image; and output of the indication of the mentioned target reorientation to the user, through the user interface of the device.

Images