Depth sensing system, illumination unit and matching optics

Abstract

A depth sensing system is provided, the depth sensing system comprising an illumination unit and a depth sensing sensor unit, the illumination unit comprising: an illumination array, having a first aspect ratio, configured to generate light of a first wavelength range; matching optics provided on an optical path between the illumination array and projection optics of the illumination unit, the matching optics configured to match the first aspect ratio of the illumination array to a second, different, aspect ratio; and the projection optics, the projection optics being configured to project light from the illumination array to illuminate the scene with the second aspect ratio; and the depth sensing sensor unit comprising: an image sensor having the second aspect ratio configured to detect light of the first wavelength range; and receiver optics configured to image the scene on the image sensor. An illumination unit and matching optics for the same are also provided.

Description

[0001] DEPTH SENSING SYSTEM, ILLUMINATION UNIT AND MATCHING OPTICS BACKGROUND

[0002] Field of the Disclosure

[0003] The present disclosure relates to a depth sensing system. Furthermore, the present disclosure relates to an illumination unit and matching optics for the depth sensing system.

[0004] Technical Background

[0005] The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in the background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.

[0006] Depth sensing systems are systems which are able to measure distance from a device (such as a sensor) to a target (such as an object in a scene). Depth sensing systems are used in a wide range of different situations. For example, depth sensing systems are used in image capture devices, autonomous (or semi-autonomous) vehicles, robotic devices, and computer vision systems, for example.

[0007] One type of depth sensing system is an optical depth sensing system which uses an image sensor (such as a time-of-flight sensor) to determine depth information across a scene which has been illuminated by an illumination unit (such as a light source). Optical depth sensing systems can provide very precise measurements compared with some other types of depth sensing systems.

[0008] However, it can be difficult to ensure compatibility between the illumination unit and image sensor of a depth sensing system. That is, the different components of a depth sensing system (such as the illumination unit and the image sensor) may have different pressures concerning cost, manufacturability, yield and power. These differences between the components of the illumination unit and image sensor can lead to an increase in the complexity of optics for the transmitter and receiver side of a depth sensing system and can further limit the consistency with which the depth sensing system can measure depth information from a scene.

[0009] It is an aim of the present disclosure to address these issues.

[0010] SUMMARY

[0011] A brief summary about the present disclosure is provided hereinafter to provide a basic understanding related to certain aspects of the present disclosure. Embodiments of the present disclosure are defined by the independent claims. Further aspects of the disclosure are defined by the dependent claims.

[0012] With the depth sensing system, illumination unit and matching optics of the present disclosure, it is possible to improve compatibility between the illumination unit and image sensor of a depth sensing system without substantially increasing the complexity of the optics. Indeed, differences in aspect ratio of an illumination unit and the depth sensing system can be accounted for without loss of optical efficiency, thus improving the consistency with which the depth sensing system can measure depth information.

[0013] The present disclosure is not particularly limited to these advantageous technical effects. Other technical effects will become apparent for the skilled person when reading the disclosure.

[0014] BRIEF DESCRIPTION OF THE DRAWINGS

[0015] A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

[0016] Figure 1 illustrates an example apparatus in accordance with embodiments of the disclosure;

[0017] Figure 2 illustrates an example of an illumination array and an image sensor in accordance with embodiments of the disclosure;

[0018] Figure 3 illustrates an example of a known depth sensing system;

[0019] Figure 4 illustrates an example of a known depth sensing system;

[0020] Figure 5 illustrates an example of a known depth sensing system;

[0021] Figure 6 illustrates an example of a known depth sensing system;

[0022] Figure 7 illustrates an example depth sensing system in accordance with embodiments of the disclosure;

[0023] Figure 8 illustrates an example implementation of a depth sensing system in accordance with embodiments of the disclosure;

[0024] Figures 9A and 9B illustrate an example implementation of a depth sensing system in accordance with embodiments of the disclosure;

[0025] Figures 10A and 10B illustrate an example implementation of a depth sensing system in accordance with embodiments of the disclosure; Figure 11 illustrates an example implementation of a depth sensing system in accordance with embodiments of the disclosure.

[0026] DESCRIPTION OF THE EMBODIMENTS:

[0027] Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views.

[0028] Consider, now Figure 1 of the present disclosure, in which an apparatus 1000 according to embodiments of the disclosure is shown. Typically, an apparatus 1000 according to embodiments of the disclosure is a computer device such as a personal computer or a terminal connected to a server. Indeed, in embodiments, the apparatus may also be a server. The apparatus 1000 is controlled using a microprocessor or other processing circuitry 1002. In some examples, the apparatus 1000 may be a portable computing device such as a mobile phone, laptop computer or tablet computing device.

[0029] The processing circuitry 1002 may be a microprocessor carrying out computer instructions or may be an Application Specific Integrated Circuit. The computer instructions are stored on storage medium 1004 which maybe a magnetically readable medium, optically readable medium or solid state type circuitry. The storage medium 1004 may be integrated into the apparatus 1000 or may be separate to the apparatus 1000 and connected thereto using either a wired or wireless connection. The computer instructions may be embodied as computer software that contains computer readable code which, when loaded onto the processor circuitry 1002, configures the processor circuitry 1002 to perform a method according to embodiments of the disclosure.

[0030] Additionally, an optional user input device 1006 is shown connected to the processing circuitry 1002. The user input device 1006 may be a touch screen or may be a mouse or stylist type input device. The user input device 1006 may also be a keyboard or microphone for voice control or any combination of these devices.

[0031] A network connection 1008 may optionally be coupled to the processor circuitry 1002. The network connection 1008 may be a connection to a Local Area Network or a Wide Area Network such as the Internet or a Virtual Private Network or the like. The network connection 1008 may be connected to a server allowing the processor circuitry 1002 to communicate with another apparatus in order to obtain or provide relevant data. The network connection 1002 may be behind a firewall or some other form of network security.

[0032] Additionally, shown coupled to the processing circuitry 1002, is a display device 1010. The display device 1010, although shown integrated into the apparatus 1000, may additionally be separate to the apparatus 1000 and may be a monitor or some kind of device allowing the user to visualize the operation of the system. In addition, the display device 1010 may be a printer, projector or some other device allowing relevant information generated by the apparatus 1000 to be viewed by the user or by a third party.

[0033] As noted, in some examples, the apparatus 1000 may be a portable computing device such as a mobile phone, laptop computer or tablet computing device. In some examples, the apparatus 1000 may be, or may be included as part of, a robotic device, an image capture device, an autonomous (or semi-autonomous) vehicle, a computer vision system or the like. In examples, the apparatus 1000 may also include a depth sensing device for measuring distance.

[0034] As explained in the Background, one type of depth sensing system is an optical depth sensing system which uses an image sensor (such as a time-of-flight sensor) to determine depth information across a scene which has been illuminated by an illumination unit (such as a light source). Optical depth sensing systems can provide very precise measurements compared with some other types of depth sensing systems. As such, the use of optical depth sensing systems for a wide range of different applications is desired.

[0035] However, it can be very difficult to ensure compatibility between the illumination unit and image sensor of a depth sensing system. That is, the different components of a depth sensing system (such as the illumination unit and the image sensor) may have different pressures concerning cost, manufacturability, yield and power. This can lead to a mismatch between the illumination unit and the sensor which may, in turn, limit the accuracy or consistency with which the depth sensing system can measure depth information from a scene (e.g. in the case where one line from the illumination unit inconsistently aligns with different pixels of the image sensor).

[0036] Consider, now, Figure 2 of the present disclosure. Figure 2 of the present disclosure illustrates an example of an illumination array and an image sensor in accordance with embodiments of the disclosure.

[0037] That is, an illumination array 2000 and an image sensor 2002 are shown in Figure 2. The illumination array 2000 and the image sensor 2002 may be used within a depth sensing system in accordance with embodiments of the disclosure.

[0038] The illumination array 2000 is a device which can be used in order to generate light of a first wavelength range for illuminating the scene. As an example, for a depth sensing system such as a Light Detection and Ranging system (LiDAR), the illumination array may be a laser array. In examples, the laser array may be a solid-state laser array. Indeed, in the example of a LiDAR system, the illumination array may include a vertical activity surface emitting laser (VCSEL) array formed of a plurality of individual lasers.

[0039] The illumination array may generate laser light having a first wavelength range. In examples, the first wavelength range may be light outside a visible wavelength range. For example, the light produced by the laser array in a LiDAR system (or indeed, the light produced, more generally, by the illumination array) may be light in a near infrared part of the electromagnetic spectrum. In examples, the light may have a wavelength within a range of 750nm to 1550nm. In examples, the illumination array may produce light of multiple discrete wavelengths within this wavelength range (such as laser light of a first wavelength and laser light of a second wavelength both within the first wavelength range). The wavelength or wavelengths of light generated by the illumination array is not particularly limited in accordance with embodiments of the disclosure and may vary depending on the situation to which the embodiments of the disclosure are applied.

[0040] In examples, the illumination array may comprise an array formed of rows and columns of individual light sources (i.e. individual units or elements of the illumination array). In examples, different units of the illumination array may generate illumination to illuminate the scene in a predetermined pattern. In examples, certain rows or certain columns of the illumination array may be used in order to generate illumination to illuminate the scene in a predetermined emission pattern.

[0041] In examples, the predetermined pattern may comprise generating illumination for each row of the illumination array in sequence. In examples, a pseudo-random pattern of illumination may be used in order to generate the illumination (with different rows (or columns) being selected on a pseudo-random basis). In examples, the predetermined pattern may include a sequence of rows (or columns). In examples, the predetermined pattern may be determined such that adjacent rows (or columns) of the illumination array are not illuminated in turn. That is, for example, if a first row of the illumination array is used to generate illumination at a first instance of time then at a next instance of time, a row of the illumination array which is not adjacent to the first row of the illumination array should be used in order to generate the illumination.

[0042] It will be appreciated that use of a predetermined pattern (such as use of non-adjacent rows (or columns) of the illumination array) to generate illumination in this manner can mitigate negative effects arising through local heating, for example. The illumination array may include elements that are individually addressable or addressable in groups, that is to say selectively controllable, for example so that region of interest can be illuminated in a scene. In a depth sensing system which utilizes time-of-flight information (such as a LiDAR system), depth information is obtained by measuring the time taken for reflected light emitted by the illumination array to return to the sensor. Therefore, the illumination array 2000 may rapidly pulse to produce the illumination which can then be used in order to “scan” the scene (and thus produce depth information). In this way, a depth sensing system (such as a LiDAR system) may produce illumination (such as laser illumination) which can be used in order to scan across the scene and which can be used, when reflected off objects in the scene, to determine depth information concerning those objects within the scene.

[0043] It will be appreciated that the illumination array may have an aspect ratio defined by a size of the illumination array in an x-direction (X1 in the example of Figure 2) and a size of the illumination array in the y-direction (Y1 in the example of Figure 2). The size and aspect ratio of the illumination array may be determined by certain factors such as cost, manufacturability, yield, or power of the illumination array.

[0044] The image sensor 2002 is a sensor which can receive light which has been reflected from objects within a scene (having been generated by the illumination array). Therefore, the image sensor 2002 may be a sensor such as an image sensor which is configured to detect light of the first wavelength range (i.e. the wavelength range of light generated by the illumination array).

[0045] The type of the image sensor is not particularly limited in accordance with embodiments of the disclosure and may depend on the wavelength of light generated by the illumination array. Therefore, the image sensor may be any suitable type of image sensor which can detect the light reflected from the scene (which has been generated by the first illumination array).

[0046] It will be appreciated that the image sensor may be a two-dimensional image sensor, comprising an array of pixels. Each pixel of the image sensor detects light which has been reflected from objects in the scene. In examples, the image sensor 2002 may readout light from the image sensor in a certain pattern (e.g. on a row by row, or column by column basis). In examples, a readout pattern from the image sensor may be the same as the predetermined pattern used by the illumination array for illuminating the scene.

[0047] In examples, the pixels of the image sensor may be depth sensing pixels configured to acquire depth information based on time-of-flight information.

[0048] In examples, the pixels of the image sensor 2002 may comprise single photon detectors (i.e. pixels which can detect arrival of a single photon). In examples, the pixels of the image sensor 2002 may include single photon avalanche diode detectors (SPADs). A SPAD comprises a photodiode with a reverse bias voltage higher than the breakdown voltage of the photodiode. A single photon incident on the SPAD can trigger a self-sustaining avalanche. Therefore, the SPAD is very sensitive with the ability to detect a single photon.

[0049] However, it will be appreciated that the present disclosure is not particularly limited in this regard. Any other type of pixel may be used in the image sensor of the depth sensing system as required.

[0050] In examples, processing circuitry (not shown) may be provided as part of the depth sensing system.

[0051] In examples, the processing circuitry may be used in order to perform (or control) image data acquisition processing to acquire image data from the image sensor. Alternatively or in addition, in examples, the processing circuitry may be used to perform image processing.

[0052] In examples, the processing circuitry may use the data from the image sensor to generate the depth information. However, the way in which the processing circuitry generates the depth information using the data from the image sensor is not particularly limited in accordance with embodiments of the disclosure. For example, any suitable process or algorithm to produce depth information (e.g. from time of arrival information) can be used in accordance with the present disclosure depending upon the situation to which embodiments of the disclosure are applied.

[0053] For example, time of arrival information (which can be obtained from the pixels from the image sensor) and the time of emission of light (e.g. from emission by the illumination array) can be used in order to determine the distance to the object from which the light reflected (and thus depth information of the scene).

[0054] As noted, the image sensor 2002 may be a 2D image sensor. Accordingly, the image sensor 2002 may have an aspect ratio defined by a size of the image sensor in an x-direction (X2 in the example of Figure 2) and a size of the image sensor in the y-direction (Y2 in the example of Figure 2).

[0055] The size and aspect ratio of the image sensor may be determined by certain factors such as cost, manufacturability, yield, or power consumption. This may result in an image sensor 2002 having a different size and aspect ratio to the illumination array 2000 (as illustrated in the example of Figure 2 of the present disclosure). In other words, the size and aspect ratio of the illumination array 2000 may be different from a size and aspect ratio of the image sensor 2002. In examples, the difference between the size of the illumination array in the x-direction and the size of the image sensor in the x-direction may be the same as the difference between the size of the illumination array in the y-direction and the size of the image sensor in the y- direction. However, more generally, it will be appreciated that the difference between the size of the illumination array in the y-direction and the size of the image sensor in the y- direction.

[0056] This difference between the size and aspect ratio of the illumination array 2000 and the image sensor 2002 may lead to a number of compatibility problems which impact the optical efficiency of the depth sensing system and the accuracy or consistency with which the depth sensing system can measure depth information. Accordingly, it is necessary to correct for differences between the image sensor and the illumination array in a depth sensing system - however, this increases the complexity of the optics of the depth sensing system.

[0057] In some depth sensing systems, projection optics of an illumination unit and receiver optics of a depth sensing unit of the depth sensing system may be used in order to correct for the difference in size and aspect ratio between the illumination array and the image sensor.

[0058] Consider, now, the example of Figure 3 of the present disclosure. Figure 3 illustrates an example of a known depth sensing system.

[0059] The depth sensing system of Figure 3 comprises an illumination array 2000. The illumination array 2000 may be an illumination array having a first aspect ratio (defined by the size in the x-direction and y-direction) as described with reference to Figure 2 of the present disclosure.

[0060] Projection optics 3000 are included as part of the depth sensing system 3000. The projection optics 3000 are used to project the light which has been generated by the illumination array 2000 to illuminate the scene.

[0061] Light from the illumination array 2000 then reflects from a scene 3002 and, having been received by receiver optics 3004 of the depth sensing system is detected by sensor 2002 of the depth sensing system. The sensor 2002 may be an image sensor having a second aspect ratio (defined by the size in the x-direction and y-direction) as described with reference to Figure 2 of the present disclosure.

[0062] In this example, the disparity between the size and aspect ratio of the illumination array 2000 and the image sensor 2002 is to be corrected for by the projection optics 3000 and the receiver optics 3004.

[0063] That is, the projection optics 3000 and the receiver optics 3004 may apply a magnification to the light from the illumination array in order to change the light from the illumination array from the first aspect ratio to the second aspect ratio (corresponding to the aspect ratio of the image sensor 2002).

[0064] In examples, a different magnification factor may need to be applied in the x-direction and the y-direction; this requires a departure from the typical optical axis symmetry. Indeed, in this example, there is variation in the difference in size between the illumination array and the image sensor in the x-direction and the y-direction. Therefore, a different correction must be applied in the x-direction and the y-direction.

[0065] In a depth sensing system such as that illustrated in Figure 3 of the present disclosure, the magnification to correct for the difference between the illumination array and the image sensor is applied by the projection optics 3000 and the receiver optics 3004 of the depth sensing system. Accordingly, any coupling mismatch between the projection optics 3000 and the receiver optics 3004 can significantly impact the accuracy of the depth sensing system.

[0066] Consider, now, Figure 4 of the present disclosure. Figure 4 of the present disclosure illustrates an example of a known depth sensing system. Indeed, the depth sensing system illustrated in Figure 4 is the same as the depth sensing system illustrated in Figure 3 of the present disclosure. Accordingly, a detailed discussion of the individual elements of the depth sensing system will not be repeated at this stage, for brevity of the disclosure.

[0067] In this example, a current row of the illumination array 2000 used in order to illuminate the scene is illustrated (row 11 of the illumination array).

[0068] The illumination region of the light projected onto the scene and received at the image sensor is also shown in Figure 4 (namely, the illumination region I2). Ideally, one row of the illumination array 2000 would correspond exactly to one row of the image sensor 2002. However, in practice, the illumination region is likely to be different in size from a row S1 of the image sensor 2002. In examples, this may be because of (or in order to accommodate) system errors. The system errors may arise due to optical limitations of the projection and receiver optics of the depth sensing system. That is, the system errors may arise from a coupling mismatch between the projection optics and the receiver optics of the depth sensing system.

[0069] Accordingly, even a small disparity between the size of the illumination region and the width of the sensor row of the sensor may have a significant impact on the optical efficiency of the depth sensing system. Thus, small imperfections in the projection and receiver optics in a depth sensing system such as that shown in Figure 4 of the present disclosure may have significant impact on the optical efficiency of the depth sensing system. Furthermore, it will be appreciated that any error in magnification imposed by the projection and receiver optics may also significantly impact the performance of the depth sensing system. For example, a vertical magnification error (i.e. an error in the y-direction) may cause a misalignment between the projected line (from the illumination array) and the sensor row (such that the light from a certain row of the illumination array is detected by a row of the image sensor which is not the row corresponding to the row of the illumination array). On the other hand, an horizontal magnificent error (i.e. an error in the x-direction) may cause a portion of the light generated by the illumination array to be missed by the sensor (e.g. the corners may be cropped, for example).

[0070] Finally, it will be appreciated that any error introduced by a mismatch of the projection and receiver optics may also cause a distortion in the projection of the illumination region from the illumination array on the image sensor.

[0071] Consider, now, Figure 5 of the present disclosure. Figure 5 of the present disclosure illustrates an example of a known depth sensing system.

[0072] The example depth sensing system of Figure 5 of the present disclosure is the same as the depth sensing system which has been described with reference to Figure 3 of the present disclosure. Therefore, a detailed discussion of the individual elements of the depth sensing system will not be repeated at this stage, for brevity of the disclosure.

[0073] In this example, a current row of the illumination array 2000 used in order to illuminate the scene is illustrated (row 11 of the illumination array).

[0074] The illumination region of the light projected onto the scene and received at the image sensor is also shown in Figure 5 (namely, the illumination region I2). As previously explained, ideally, one row of the illumination array 2000 would correspond exactly to one row of the image sensor 2002.

[0075] However, an error or mismatch between the projection optics and receiver optics provided in the depth sensing sensor may cause a distortion which causes the projection light from the illumination array to form an illumination region I2 on the image sensor which deviates from a line of the pixels on the image sensor (i.e. a sensor row). This deviation is shown, by means of an example, in Figure 5 of the present disclosure. Only the central portion of the illumination region I2 is aligned with the sensor row S1 of the image sensor, while the end portions of the illumination region I2 are misaligned with the sensor row S1 of the image sensor. Again, this misalignment between the illumination region 12 on the sensor row S1 of the image sensor may cause a reduction in the accuracy and efficiency of a depth sensing system.

[0076] Therefore, it will be appreciated that while projection optics and receiver optics of a depth sensing system can be used in order to address a lack of compatibility between an illumination array and an image sensor of a depth sensing system, small differences or mismatches between the projection optics and the receiver optics of the depth sensing system may have a significant impact on the performance of the depth sensing system.

[0077] In order to address this problem, a further configuration of a depth sensing system has also been considered. Turn now to Figure 6 of the present disclosure, which illustrates a further example of a known depth sensing system.

[0078] In this example, only the transmitting side of the depth sensing system is shown (i.e. the side including the illumination array, which projects light to the scene). However, it will be appreciated that the depth sensing system also includes a receiver side such as that illustrated in Figure 3 of the present disclosure (namely, the side which receives reflected light from the scene - including the receiver optics and an image sensor).

[0079] Now, in the example depth sensing system shown in Figure 6, the illumination array 2000 (which may be an illumination array as described with reference to Figure 2 of the present disclosure). The illumination array generates light in order to illuminate the scene is illustrated. The light which has been generated by the illumination array then passes through projection optics of the depth sensing system (such as an objective lens of the depth sensing system). Then, the light passes through a 1D diffuser, before reaching the scene.

[0080] In this example, the magnification in the y-direction is made by two different optics of the depth sensing system (namely the projection optics and receiver optics of the depth sensing system). On the other hand, the magnification in the x-direction is made by expanding the projection on the x-direction using a 1 D diffuser. In other words, the 1D diffuser is configured to diffuse the light from the illumination array in the x-direction to correct for a difference between the size and aspect ratio of the illumination array and the size and aspect ratio of the image sensor.

[0081] However, while the example system of Figure 6 provides one way of attempting to correct for a difference between the size and aspect ratio of the illumination array and the image sensor, there are several disadvantages associated with a system such as this. Firstly, the example system of Figure 6 requires different projection and receiver optics (e.g. a different objective lens for the depth sensing system for the illumination portion of the depth sensing system (which illuminates the scene) and the receiving portion of the depth sensing system (which receives reflected light from the scene)). Accordingly, a depth sensing system such as that described with reference to Figure 6 of the present disclosure is vulnerable to the same issues which have been discussed for a depth sensing system such as that described with reference to Figure 3 of the present disclosure. Namely, any error or mismatch between the projection and receiver optics of the depth sensing system may introduce an error which limits the optical efficiency and accuracy of the depth sensing system.

[0082] Furthermore, the system such as that described with reference to Figure 6 of the present disclosure is inflexible, since for each different target field of view, a new configuration of the projection optics and diffuser would be required.

[0083] Therefore, while certain approaches have been proposed for correction of incompatibility between an illumination array and an image sensor (such as those discussed with reference to Figures 3 to 7 of the present disclosure) these approaches are vulnerable to small errors such as a mismatch between the projection and receiver optics of the depth sensing system, which limits the optical efficiency and accuracy with which the depth sensing system can measure depth information of a scene.

[0084] Accordingly, for at least these reasons, in addition to those reasons discussed in the Background, a depth sensing system, illumination unit and matching optics are provided in accordance with embodiments of the disclosure.

[0085] <Depth Sensing System, Illumination Unit and Matching Optics>

[0086] Consider, now, Figure 7 of the present disclosure. Figure 7 of the present disclosure illustrates an example depth sensing system in accordance with embodiments of the disclosure.

[0087] The example depth sensing system 8000 of Figure 7 comprises an illumination unit 8002 and a depth sensing sensor unit 8004.

[0088] The illumination unit 8002 comprises an illumination array 8004, matching optics 8006 and projection optics 8008.

[0089] The illumination array 8004 has a first aspect ratio and is configured to generate light of a first wavelength range. In examples, the illumination array may be an illumination array such as illumination array 2000 as discussed with reference to Figure 2 of the present disclosure. For example, the illumination array may be an array of VCSELs which are configured to illuminate the scene with laser light, for example.

[0090] As noted, the depth sensing system 8000 comprises matching optics 8006. The matching optics 8006 are provided on an optical path between the illumination array and projection optics of the illumination unit. The matching optics 8006 are configured to match the first aspect ratio of the illumination array to a second, different, aspect ratio. The type and configuration of the matching optics are not particularly limited and may vary depending on the situation to which embodiments of the disclosure are applied. In examples, the matching optics may be formed of reflective elements. In examples, the matching optics may be formed of refractive elements. In examples, the refractive elements may be lenses. For example, the matching optics may include Fresnel lenses, diffractive lenses, freeform lenses, freeform mirrors, cylindrical mirrors or cylindrical lenses. In some examples, the matching optics may consist only of cylindrical lenses. Further details of the matching optics 8006 will be provided later.

[0091] In examples, the optical path includes any path along which light travels. The optical path between the illumination array and the projection optics is therefore the path along which light travels between the illumination array 8004 and the projection optics 8008. As the matching optics 8006 are provided on the optical path between the illumination array 8004 and the projection optics 8008, this means that the light generated by the illumination array 8004 encounters the matching optics 8006 before reaching the projection optics 8008. In examples, the optical path can be a direct optical path (such as a path forming a line of sight between the illumination array 8004 and the projection optics 8008). However, in examples, the optical path can be an indirect optical path. An indirect optical path may include path with a number of additional optical elements arranged along the path (such as reflective optical elements) which deflect light on route to the projection optics 8008. The present disclosure is not particularly limited in this regard.

[0092] The depth sensing system of Figure 7 further comprises projection optics 8008, configured to project light from the illumination array to illuminate the scene with the second aspect ratio.

[0093] As noted, the matching optics are provided in order to match the light generated by the illumination array, having the first aspect ratio, to a second aspect ratio before that light is projected by the projection optics of the depth sensing system (since light from the illumination array 8004 encounters the matching optics before reaching the projection optics of the depth sensing system). Therefore, the projection optics 8008 of the depth sensing system do not, in themselves, provide any correction of the light generated by the illumination array.

[0094] Furthermore, the depth sensing sensor unit 8004 of the depth sensing system 8000 comprises receiver optics 8012 and an image sensor 8014. The image sensor 8014 has the second aspect ratio and is configured to detect light of the first wavelength range. Furthermore, the receiver optics are configured to image the scene on the image sensor. The type of image sensor used in the depth sensing system is not particularly limited in accordance with embodiments of the disclosure. In examples, the image sensor may be a time-of-f light image sensor, such as a SPAD based image sensor or the like.

[0095] In examples, the image sensor may produce a depth map. The depth map may be an image that contains information relating to the distance of scene objects from the viewpoint of the depth sensing system. The depth map may be obtained through time of flight information (acquired by the image sensor) and may, in examples, include a monochromatic image or pulse.

[0096] With the depth sensing system described with reference to Figure 7, the scene is illuminated with light of the second aspect ratio. Moreover, the light from the illumination array is converted from the first aspect ratio to the second aspect ratio (matching the aspect ratio of the image sensor) before that light is projected by the projection optics of the depth sensing system.

[0097] In this way, compatibility between the illumination unit and image sensor of a depth sensing system can be ensured. That is, differences in aspect ratio of the illumination array 8004 and the image sensor can be accounted for without loss of optical efficiency, thus improving the accuracy with which the image sensor can measure depth information.

[0098] As noted, this is because matching optics 8006 are provided on the optical axis between the illumination array 8004 and the projection optics 8008 to match the aspect ratio of the illumination array to the aspect ratio of the image sensor.

[0099] That is, in contrast to other depth sensing systems, such as the depth sensing system described with reference to Figure 3 of the present disclosure or the depth sensing system described with reference to Figure 6 of the present disclosure, the projection optics 8008 and the receiver optics 8012 do not perform any transformation to ensure compatibility between the illumination array 8004 and the depth image sensor 8014. Rather, since the matching optics 8006 are provided between the illumination array 8004 and the projection optics 8008, the projection optics can be the same as the receiver optics, while still projecting light to illuminate the scene with the second aspect ratio. Accordingly, a reduction in distortion errors (including systematic and / or magnification errors) can be achieved, since a same projection optics and receiver optics can be used. In examples, a same projection optics includes projection optics having the same optical characteristics (between certain tolerances)). In other words, in examples of the present disclosure, a same type projection optics includes projection optics having the same characteristics by design (allowing for manufacturing random error variability, for example). In examples, same projection optics may be produced in a same manufacturing batch, which may avoid systematic errors between production runs.

[0100] That is, since, in examples, a same type of projection optics and receiver optics can be used or, alternatively, even a single shared projection and receiver optics can be used, matching projections are made to and from the scene. Accordingly, a distortion arising from a difference in the projection and receiver optics will not impact the transformation between the size and aspect ratio of the illumination array and the size and aspect ratio of the image sensor.

[0101] The present disclosure is not particularly limited to these advantageous technical effects. It will be appreciated that other technical effects will become apparent to the skilled person when reading the disclosure.

[0102] It will be appreciated that the type and configuration of the projection optics and the receiver optics are not particularly limited and may vary depending on the situation to which embodiments of the disclosure are applied. In examples, the projection and receiver optics may be formed of reflective elements. In examples, the projection and receiver optics may be formed of refractive elements. In examples, the refractive elements may be lenses. For example, the projection (and receiver) optics may include Fresnel lenses, diffractive lenses, freeform lenses, freeform mirrors, cylindrical mirrors or cylindrical lenses. In some examples, the matching optics may consist only of cylindrical lenses.

[0103] Furthermore, it will be appreciated that while Figure 7 illustrates an example depth sensing system, the present disclosure is not particularly limited in this regard. For example, embodiments of the disclosure relate to an illumination unit - such as illumination unit 8002 of Figure 7 - comprising an illumination array, having a first aspect ratio, configured to generate light of first wavelength range; matching optics provided on an optical path between the illumination array and projection optics of the illumination unit, the matching optics configured to match the first aspect ratio of the illumination array to a second, different, aspect ratio of the image sensor of a depth sensing sensor unit of the depth sensing system; and the projection optics, the protection optics being configured to project light from the illumination array to illuminate the scene with the second aspect ratio.

[0104] Moreover, embodiments of the disclosure also relate to the matching unit itself (such as matching optics 8006 as described with reference to Figure 7 of the present disclosure. That is, embodiments of the disclosure relate to matching optics for a depth sensing system, the matching optics being provided on an optical path between an illumination array and projection optics of an illumination unit, wherein: the matching optics are configured to match a first aspect ratio of the illumination array to a second, different, aspect ratio of the image sensor of a depth sensing sensor unit of the depth sensing system.

[0105] Furthermore, embodiments of the disclosure may also relate to a system comprising matching optics for arrangement on an optical path between an illumination array having a first aspect ratio of illumination elements producing light of a first wavelength range and projection optics of the illumination unit, the matching optics being configured to match the first aspect ratio of the illumination array to a second, different, aspect ratio; and the projection optics, the projection optics being configured to project light from the illumination array to illuminate the a with the second aspect ratio; and: an image sensor having the second aspect ratio configured to detect light of the first wavelength range; and receiver optics configured to image the scene on the image sensor. That is, a system may be provided comprising the matching optics, projection optics, receiver optics and sensor. In other words, the illumination array described with reference to Figure 7 of the present disclosure may be external to the system.

[0106] Further details of embodiments of the disclosure will now be described with reference to an example implementation of a depth sensing system.

[0107] <Example lmplementation>

[0108] Consider, now, Figure 8 of the present disclosure. Figure 8 of the present disclosure illustrates an example implementation of a depth sensing system in accordance with embodiments of the disclosure. The example depth sensing system of Figure 8 may be a depth sensing system such as a LiDAR depth sensing system.

[0109] Furthermore, the example depth sensing system of Figure 8 of the present disclosure may be implemented in a device such as that described with reference to Figure 1 of the present disclosure. For example, the depth sensing system of Figure 8 of the present disclosure may be used in a device such as an autonomous vehicle. In examples, the depth sensing system may be used for interior sensing and / or exterior sensing of vehicles. Interior sensing may include sensing in-cabin environments and occupancy status (such as number of passengers present in the vehicle). Exterior sensing of vehicles may include sensing of the environment surrounding the vehicle (including for example, information concerning a distance to another vehicle). In examples, the output from the interior sensing and / or the exterior sensing may be provided as input to a secondary system. In examples, the secondary system may include a vehicle safety system such as an active or passive safety system. It will be appreciated that this applies not only to the system described with reference to Figure 8 of the present disclosure, but more generally any of the example configurations which have been described with reference to Figure 7 of the present disclosure (including, for example, a system comprising matching optics, projection optics, receiver optics and an image sensor (i.e. an example system with an external illumination unit)).

[0110] In this example implementation, the depth sensing system comprises a laser array as an example of an illumination array. The laser array may be an array of VCEL lasers, for example. Accordingly, the laser array generates light of a first wavelength range (such as light of a near infrared wavelength) which can be used to illuminate the scene with light for the purpose of measurement of depth information of the scene (e.g. based on time-of-flight information).

[0111] Light from the laser array passes through transmitter optics A of the depth sensing system. The transmitter optics A of the depth sensing system provide an example of matching optics of the present disclosure. The transmitter optics A are provided in order to match the light emitted from the laser array to the image sensor of the depth sensing system (which will be described in more detail later). More specifically, in this example, the transmitter optics A are provided in order to match the size and aspect ratio of the laser with the size and aspect ratio of the image sensor.

[0112] In this example, the laser has a size in the x-direction of X1 urn and a size in the y-direction of Y1um. The aspect ratio of the laser is defined by the size of the laser in the x-direction and the size of the laser in the y-direction.

[0113] As previously mentioned, the size and aspect ratio of the laser may not match the size and aspect ratio of the image sensor. The reason for the difference between the laser and the image sensor is not particularly limited, but may include different pressures concerning cost, manufacturability, yield and power of the laser and the image sensor. This can lead to a mismatch between the illumination unit and the sensor which may, in turn, limit the accuracy with which the depth sensing system can measure depth information from a scene.

[0114] Indeed, in this example, the image sensor has a size in the x direction of X2um and a size in the y-direction of Y2um. The aspect ratio of the image sensor is defined by the size of the image sensor in the x-direction and the size of the image sensor in the y-direction.

[0115] The difference between the size and aspect ratio of the laser and the image sensor must be corrected in order to reliably measure depth information from the scene (for the reasons which have been described hereinbefore). Accordingly, in this example, the light generated by the laser array passes through the transmitter optics A which are configured to form an intermediate image (TX intermediate image) having the aspect ratio of the second image sensor. The image TX intermediate image is a so-called intermediate image because it is formed between the laser and the projection optics (camera objective in this example).

[0116] Thus, the intermediate image formed by the transmitter optics A (the matching optics) is an image having the same aspect ratio as the image sensor (defined by a size X2 urn in the x- direction and a size Y2um in the y-direction).

[0117] Once the intermediate image has been formed by the transmitter optics A (the matching optics in embodiments of the disclosure) the intermediate image is then projected by the transmitter optics B (an example of the projection optics of embodiments of the disclosure) to illuminate the scene with light of the second aspect ratio. In this example, the transmitter optics B are formed by the camera objective of the depth sensing system.

[0118] That is, the transmitter optics B may be configured such that the light corresponding to the intermediate image which has been generated by the transmitter optics A (having the same size and aspect ratio as the image sensor) passes through the transmitter optics B such that light from the transmitter optics B is projected on the scene in order to illuminate the scene.

[0119] Together, the Laser, Transmitter optics A and Transmitter optics B of Figure 8 provide an example of an illumination unit of a depth sensing system in accordance with embodiments of the disclosure.

[0120] Light emitted from the illumination unit (i.e. light projected onto the scene from the Transmitter optics B) is reflected from one or more objects in the scene and is received by the receiver optics of the depth sensing system. In this example, the receiver optics are formed by the camera objective of the depth sensing system. The receiver optics are configured to image the scene on the image sensor. More specifically, the receive optics are configured to direct light which has been reflected from the scene to the image sensor such that the image sensor can detect the light. As the size and aspect ratio of the light from the laser has been matched (by transmitter optics B) to the size and aspect ratio of the image sensor, light emitted by one row (or one column) of the laser should be formed on a corresponding row (or column) of the image sensor.

[0121] The image sensor of the depth sensing system is configured to detect light of the first wavelength range (i.e. the wavelength of light emitted by the laser). Therefore, the image sensor can detect light which has been reflected from one or more objects in the scene. In examples, the image sensor may be configured as an array of pixels. In this example, the pixels of the image sensor are time-of-flight pixels (configured to detect the arrival of a single photon). Indeed, the pixels of the image sensor may include single photon avalanche diode detectors (SPADs).

[0122] Accordingly, the image sensor can detect light which has been emitted by the laser and reflected from one or more objects in the scene. This information can then be used (e.g. by a processing device) in order to determine depth information for the scene. Indeed, as the size and aspect ratio of the laser have been matched with the size and aspect ratio of the image sensor, the light emitted from a particular portion of the laser (e.g. a particular row or column of the laser) will be detected by a corresponding portion of the sensor (e.g. a corresponding row or column of the sensor).

[0123] Furthermore, in this example, the projection optics are formed by the camera objective and the receiver optics are also formed by the camera objective. Accordingly, the camera objective is shared between the projection optics and the receiver optics. This is possible because the conversion is applied by the matching optics before projection of the light to the scene by the projection optics, such that the projection and receiver optics are not responsible for the conversion between the first and second aspect ratio (i.e. the projection and receiver optics are not responsible for addressing the compatibility between the illumination array and the image sensor). The example of Figure 8 of the present disclosure therefore illustrates an example where the projection and receiver optics of the depth sensing system share the camera objective.

[0124] With this configuration, the depth sensing system is very flexible to changes in the field of view (FoV). That is, the FoV of the depth sensing system can be easily adjusted by merely changing the configuration of the camera objective. In examples, the adjustment can be performed by mechanical adjustment. Indeed, since the camera objective is not responsible for addressing the compatibility of the between the illumination array and the illumination array and the image sensor, the configuration of the camera objective can be changed in order to adjust the FoV of the depth sensing system without impacting the accuracy and optical efficiency of the depth sensing system.

[0125] In examples, the matching optics can be adjusted in order to compensate for manufacturing errors (such as an error in effective focal length of the matching optics). For example, adjustment (such as mechanical adjustment) of the matching optics may be performed to allow for a magnification adjustment of the intermediate image by changing the distance of the matching optics from the illumination array. This provides an easy and efficient way to compensate for manufacturing error in the focal length of the matching optics. Furthermore, with this configuration, matching projections of light both to and from the scene are made by the shared camera objective. Accordingly, even if the camera objective has an imperfection which introduces a projection distortion, that distortion does not impact the accuracy and optical efficiency of the depth sensing system (since the camera objective is used for both projection to the scene and reception of light from the scene). In other words, any distortion introduced by the camera objective when projecting light to illuminate the scene will be cancelled out by the distortion introduced by that same camera objective when receiving light from the scene.

[0126] In examples, the projection optics and the receiver optics may be separate and not share the camera objective. However, even in this situation, the projection optics and the receiver optics may use a same type of camera objective (e.g. a same type of lens or a lens that has same optical characteristics (between certain tolerances)). Indeed, as previously noted, in examples of the present disclosure, a same type of lens includes a lens having same characteristics by design (allowing for manufacturing random error variability, for example).

[0127] In the example depth sensing system described with reference to Figure 3 of the present disclosure, the projection optics and receiver optics of the depth sensing system cannot be a same type, since the difference in the projection and receiver optics is responsible for applying a magnification factor to correct for the difference between the size and aspect ratio of the illumination array and the image sensor. Likewise, in the example of Figure 6 of the present disclosure, the projection optics and the receiver optics cannot be a same type, since the projection optics and the diffuser are, together, responsible for applying a magnification factor to correct for the difference between the size and aspect ratio of the illumination array and the image sensor.

[0128] In contrast - and as has been explained - with embodiments of the disclosure, the correction between the size and aspect ratio is made by the matching optics before the light reaches the projection optics, such that neither the projection optics nor the receiver optics are responsible for correcting the difference between the size and aspect ratio of the illumination array and the image sensor.

[0129] This means that a same type of camera objective can be used for the projection and receiver optics. Since a same type of camera objective can be used for the projection and receiver optics, any distortion introduced by the transmitter and receiver optics will be very small (relating only to manufacturing differences of the same camera objective production batch, for example) and will not impact the accuracy and efficiency with which the depth sensing system can measure the depth information for a scene.

[0130] <Matching optics> As explained, in embodiments of the disclosure, the transformation which is performed to match the size and aspect ratio of the illumination array to the size and aspect ratio of the image sensor is made by the matching optics of the depth sensing system arranged on an optical path between the illumination array and the projection optics.

[0131] Consider, now, Figures 9A and 9B, which illustrate an example implementation of a depth sensing system in accordance with embodiments of the disclosure.

[0132] In particular, Figures 9A and 9B show a paraxial lens simulation for an implementation of a depth sensing system in accordance with embodiments of the disclosure (only the illumination side of the depth sensing system is shown in the example of Figures 9A and 9B).

[0133] Figure 9A relates to the yz plane, while Figure 9B relates to the xz plane.

[0134] In the example of Figure 9A and 9B, a laser array (example of an illumination array of the present disclosure) is shown. Furthermore, ray tracing of the path of light emitted from the laser array is shown (in the yz plane) as it passed through lens x and lens y. Together, in this example, lens x and lens y form the matching optics of the depth sensing system, which is provided on an optical path between the laser and projection optics (not shown) of the depth sensing system.

[0135] As an example of matching optics of the present disclosure, lens x and lens y are provided in order to transform the size and aspect ratio of light emitted by the laser to the size and aspect ratio of the image sensor of the depth sensing system (which is used to detect reflected light from one or more objects in the scene).

[0136] In this example of Figure 9A and 9B, the magnitude of the magnification which is required in order to correct for the difference between the size of the laser and the image sensor in the y direction is different from the magnitude of the magnification which is required in order to correct for the difference between the size of the laser and the image sensor in the x direction.

[0137] Accordingly, lens x and lens y are configured in order to provide a magnification of 0.507 in the y direction (thus shrinking the image in the y direction).

[0138] On the other hand, lens x and lens y are configured in order to provide a magnification of 5.802 in the x direction (thus stretching the image in the x direction).

[0139] The intermediate image generated by the matching optics (lenses x and y) in this example is therefore an intermediate image having the size and aspect ratio of the image sensor. This intermediate image can then be projected by projection optics (such as a camera objective or the like) in order to illuminate the scene as has previously been described.

[0140] While the example of Figures 9A and 9B has been described with reference to an example whereby the matching optics are formed by two lenses (lens x and lens y) it will be appreciated that the present disclosure is not particularly limited in this regard. That is, a lens is merely one example of an paraxial design which can be used as starting point for a matching optics design of the claimed invention. More generally, any suitable combination of optical elements may replace the paraxial lenses in this design and be used as part of the matching optics (including any type of refractive or reflective element, for example).

[0141] Moreover, while two lenses are shown as part of the matching optics in this example, the number of optical elements forming part of the matching optics may be less than two or much greater than two, depending on the situation to which the embodiments of the disclosure are applied.

[0142] Furthermore, while the example magnification factor applied by the matching optics is 0.507 in the y direction and 5.802 in the x direction in this example simulation, it will be appreciated that the present disclosure is not particularly limited in this respect. The magnification in the x direction and the y direction can be configured to any number required depending on the difference between the size and aspect ratio of the image sensor and the corresponding size and aspect ratio of the illumination array.

[0143] Consider, now, Figures 10A and 10B of the present disclosure. Figures 10A and 10B of the present disclosure illustrate an example implementation of a depth sensing system in accordance with embodiments of the disclosure.

[0144] In particular, the example of Figures 10A and 10B of the present disclosure show an example configuration of the matching optics of a depth sensing system (being a more specific example configuration of the depth sensing system described with reference to Figures 9A and 9B of the present disclosure).

[0145] Here, Figure 10A relates to the yz plane, while Figure 10B relates to the xz plane.

[0146] It will be appreciated that the example lens designs illustrated in Figures 10A and 10B of the present disclosure are merely one example of lens designs which can be used in accordance with embodiments of the present disclosure. Therefore, the present disclosure is not particularly limited in this regard.

[0147] More generally, the matching optics used in accordance with the present disclosure can comprise any suitable reflective optical elements or refractive optical elements which are configured in order to transform the light from the illumination array (having the first size and aspect ratio) to a size and aspect ratio matching the image sensor of the depth sensing system.

[0148] <Coupling efficiency>

[0149] As has been explained, according to embodiments of the disclosure, matching optics can be provided between the illumination array and the projection optics in order to transform the light from the illumination array (having a first size and aspect ratio) to light compatible with the image sensor (having a second size and aspect ratio).

[0150] This means that the light output from the matching optics can be projected by the projection optics to the scene.

[0151] However, in order for the light output from the matching optics to be projected by the projection optics to the scene without losses, it may be necessary to provide further correction between the matching optics and the projection optics.

[0152] Therefore, in some examples, further optional optics may be included between the matching optics and the projection optics in order to correct the chief ray angle and / or the numerical aperture of the matching optics such that they match the chief ray angle and / or numerical aperture of the projection optics. As will be appreciated, the chief ray angle defines the angle of incidence between the lens chief ray (the ray from an off-axis point that passes through the aperture stop) with the image plane.

[0153] Consider, now Figure 11 of the present disclosure. Figure 11 of the present disclosure illustrates an example of a depth sensing system in accordance with embodiments of the disclosure.

[0154] In particular, the example of Figure 11 shows two different depth sensing systems (only the illumination side of the depth sensing system is shown in the example of Figure 11). In the top panel of Figure 11 , a depth sensing system is shown comprising a laser (as an example of an illumination array in accordance with embodiments of the disclosure), lens x and lens y (as an example of matching optics in accordance with embodiments of the disclosure) and a projection camera objective (as an example of projection optics in accordance with embodiments of the disclosure).

[0155] In this example, the lens x and the lens y transforms the light generated by the illumination array to a size and aspect ratio matching the image sensor of the depth sensing system (not shown in this example). However, as can be seen in the top panel of Figure 11, the chief ray angle of the light is offset from the normal of the projection camera optics. This may impact the optical efficiency of the depth sensing system and the accuracy with which depth information can be obtained. In particular, a high chief ray angle may negatively affect the optical performance of the depth sensing system, due to loss of light. Indeed, a mismatch between the chief ray angle of the matching optics and the chief ray angle of the projection optics and / or a mismatch between the numerical aperture of the matching optics and the numerical aperture of the projection optics may introduce losses when projecting light to the scene. Accordingly, in examples, an additional optical element may be included on the illumination side of the depth sensing system (that is, as part of the illumination unit according to embodiments of the disclosure). In examples, the additional optical element may be arranged between the matching optics and the projection optics of the depth sensing system. This is illustrated in the bottom panel of Figure 11 of the present disclosure. In examples, the additional optical element may also be included as part of the matching optics.

[0156] Thus more generally, the additional optical element may be any correction optical element to match the light from the matching optics with the projection optics (e.g. to reduce the chief ray angle such that it is brought closer to the normal of the projection camera optics).

[0157] In examples, the additional optical element may include a refractive optical element. In examples, the refractive optical element may include a field lens. The field lens may be a positive-powered lens (or group of lenses). The field lens may be located at the intermediate image (the image formed by the matching optics) and thus may correct the chief ray angle such that it is closer to the chief ray angle the projection optics. Likewise, the field lens may correct the numerical aperture of the matching optics such that it is closer to the numerical aperture of the projection optics.

[0158] Advantageously, when the chief ray angle and / or numerical aperture of the system is corrected in this manner, the coupling efficiency between the matching optics and the projection optics can be improved, reducing losses when projecting light to the scene. This further improves the accuracy and consistency with which depth information can be determined.

[0159] Thus, embodiments of the disclosure may relate to a depth sensing system comprising a correction optical element provided on an optical path between the matching optics and the projection optics, the correction optical element being configured to correct a chief ray angle and / or numerical aperture of the matching unit.

[0160] <Clauses> Furthermore, embodiments of the present disclosure can be arranged in accordance with the following numbered clauses:

[0161] 1. A depth sensing system comprising an illumination unit and a depth sensing sensor unit, the illumination unit comprising: an illumination array, having a first aspect ratio, configured to generate light of a first wavelength range; matching optics provided on an optical path between the illumination array and projection optics of the illumination unit, the matching optics configured to match the first aspect ratio of the illumination array to a second, different, aspect ratio; and the projection optics, the projection optics being configured to project light from the illumination array to illuminate the scene with the second aspect ratio; and the depth sensing sensor unit comprising: an image sensor having the second aspect ratio configured to detect light of the first wavelength range; and receiver optics configured to image the scene on the image sensor.

[0162] 2. The depth sensing system according to clause 1 , wherein the projection optics and the receiver optics are a same type of optics.

[0163] 3. The depth sensing system according to clause 1 or 2, wherein the projection optics and the receiver optics are shared optics.

[0164] 4. The depth sensing system according to any preceding clause, wherein at least one of the projection optics and the receiver optics comprise: Fresnel lenses, diffractive lenses, freeform lenses, freeform mirrors, cylindrical mirrors or cylindrical lenses.

[0165] 5. The depth sensing system according to clause 4, wherein at least one of the projection optics or the receiver optics consist of only cylindrical lenses.

[0166] 6. The depth sensing system according to any preceding clause, wherein the matching optics are configured to form an illumination intermediate image having the second aspect ratio.

[0167] 7. The depth sensing system according to clause 6, wherein the projection optics are configured to project the intermediate image to illuminate the scene with the second aspect ratio. 8. The depth sensing system according to any preceding clause, wherein the matching optics are configured to match a size of the light having the first aspect ratio generated by the illumination array to a size of the depth sensing sensor.

[0168] 9. The depth sensing system according to any preceding clause, wherein the depth sensing sensor is a time-of-f light sensor.

[0169] 10. The depth sensing system according to any preceding clause, comprising a correction optical element provided on an optical path between the matching optics and the projection optics, the correction optical element being configured to correct a chief ray angle and / or numerical aperture of the matching optics.

[0170] 11. The depth sensing system according to any preceding clause, wherein the illumination array is configured to generate light to illuminate the scene for each row of the illumination array in sequence according to a scan pattern.

[0171] 12. The depth sensing system according to clause 10, wherein the scan pattern is a pseudo-random scan pattern.

[0172] 13. The depth sensing system according to any preceding clause, wherein the depth sensing system is a Light Detection and Ranging system.

[0173] 14. An illumination unit for a depth sensing system, the illumination unit comprising: an illumination array, having a first aspect ratio, configured to generate light of a first wavelength range; matching optics provided on an optical path between the illumination array and projection optics of the illumination unit, the matching optics configured to match the first aspect ratio of the illumination array to a second, different, aspect ratio of an image sensor of a depth sensing sensor unit of the depth sensing system; and the projection optics, the protection optics being configured to project light from the illumination array to illuminate the scene with the second aspect ratio.

[0174] 15. Matching optics for a depth sensing system, the matching optics being provided on an optical path between an illumination array and projection optics of an illumination unit, wherein: the matching optics are configured to match a first aspect ratio of the illumination array to a second, different, aspect ratio of an image sensor of a depth sensing sensor unit of the depth sensing system.

[0175] 16. A system comprising matching optics for arrangement on an optical path between an illumination array having a first aspect ratio of illumination elements producing light of a first wavelength range and projection optics of the illumination unit, the matching optics being configured to match the first aspect ratio of the illumination array to a second, different, aspect ratio; and the projection optics, the projection optics being configured to project light from the illumination array to illuminate the a with the second aspect ratio; and: an image sensor having the second aspect ratio configured to detect light of the first wavelength range; and receiver optics configured to image the scene on the image sensor.

[0176] Furthermore, it will be appreciated that numerous modifications and variations of the present disclosure are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the disclosure may be practiced otherwise than as specifically described herein.

[0177] In so far as embodiments of the disclosure have been described as being implemented, at least in part, by software-controlled data processing apparatus, it will be appreciated that a non-transitory machine-readable medium carrying such software, such as an optical disk, a magnetic disk, semiconductor memory or the like, is also considered to represent an embodiment of the present disclosure.

[0178] A depth sensing system, illumination unit and matching optics have been described. While certain features have been described with reference to an example implementation of the depth sensing system, it will be appreciated that the present disclosure is not particularly limited in this regard.

[0179] It will be appreciated that the above description for clarity has described embodiments with reference to different functional units, circuitry and / or processors. However, it will be apparent that any suitable distribution of functionality between different functional units, circuitry and / or processors may be used without detracting from the embodiments.

[0180] Described embodiments may be implemented in any suitable form including hardware, software, firmware or any combination of these. Described embodiments may optionally be implemented at least partly as computer software running on one or more data processors and / or digital signal processors. The elements and components of any embodiment may be physically, functionally and logically implemented in any suitable way. Indeed the functionality may be implemented in a single unit, in a plurality of units or as part of other functional units. As such, the disclosed embodiments may be implemented in a single unit or may be physically and functionally distributed between different units, circuitry and / or processors. Although the present disclosure has been described in connection with some embodiments, it is not intended to be limited to the specific form set forth herein. Additionally, although a feature may appear to be described in connection with particular embodiments, one skilled in the art would recognize that various features of the described embodiments may be combined in any manner suitable to implement the technique.

Claims

CLAIMS1) A depth sensing system comprising an illumination unit and a depth sensing sensor unit, the illumination unit comprising: an illumination array, having a first aspect ratio, configured to generate light of a first wavelength range; matching optics provided on an optical path between the illumination array and projection optics of the illumination unit, the matching optics configured to match the first aspect ratio of the illumination array to a second, different, aspect ratio; and the projection optics, the projection optics being configured to project light from the illumination array to illuminate the scene with the second aspect ratio; and the depth sensing sensor unit comprising: an image sensor having the second aspect ratio configured to detect light of the first wavelength range; and receiver optics configured to image the scene on the image sensor.2) The depth sensing system according to claim 1 , wherein the projection optics and the receiver optics are a same type of optics.3) The depth sensing system according to claim 1 , wherein the projection optics and the receiver optics are shared optics.4) The depth sensing system according to claim 1, wherein at least one of the projection optics and the receiver optics comprise: Fresnel lenses, diffractive lenses, freeform lenses, freeform mirrors, cylindrical mirrors or cylindrical lenses.5) The depth sensing system according to claim 4, wherein at least one of the projection optics or the receiver optics consist of only cylindrical lenses.6) The depth sensing system according to claim 1, wherein the matching optics are configured to form an illumination intermediate image having the second aspect ratio.7) The depth sensing system according to claim 6, wherein the projection optics are configured to project the intermediate image to illuminate the scene with the second aspect ratio.8) The depth sensing system according to claim 1 wherein the matching optics are configured to match a size of the light having the first aspect ratio generated by the illumination array to a size of the depth sensing sensor.9) The depth sensing system according to claim 1 , wherein the depth sensing sensor is a time-of-flight sensor.10) The depth sensing system according to claim 1, comprising a correction optical element provided on an optical path between the matching optics and the projection optics, the correction optical element being configured to correct a chief ray angle and / or numerical aperture of the matching optics.11) The depth sensing system according to claim 1 , wherein the illumination array is configured to generate light to illuminate the scene for each row of the illumination array in sequence according to a scan pattern.12) The depth sensing system according to claim 10, wherein the scan pattern is a pseudo-random scan pattern.13) An illumination unit for a depth sensing system, the illumination unit comprising: an illumination array, having a first aspect ratio, configured to generate light of a first wavelength range; matching optics provided on an optical path between the illumination array and projection optics of the illumination unit, the matching optics configured to match the first aspect ratio of the illumination array to a second, different, aspect ratio of an image sensor of a depth sensing sensor unit of the depth sensing system; and the projection optics, the protection optics being configured to project light from the illumination array to illuminate the scene with the second aspect ratio.14) Matching optics for a depth sensing system, the matching optics being provided on an optical path between an illumination array and projection optics of an illumination unit, wherein: the matching optics are configured to match a first aspect ratio of the illumination array to a second, different, aspect ratio of an image sensor of a depth sensing sensor unit of the depth sensing system.15) A system comprising matching optics for arrangement on an optical path between an illumination array having a first aspect ratio of illumination elements producing light of a firstwavelength range and projection optics of the illumination unit, the matching optics being configured to match the first aspect ratio of the illumination array to a second, different, aspect ratio; and the projection optics, the projection optics being configured to project light from the illumination array to illuminate the a with the second aspect ratio; and: an image sensor having the second aspect ratio configured to detect light of the first wavelength range; and receiver optics configured to image the scene on the image sensor.

Images