Scanning laser device and method using tailored radiation control pulse sets

Abstract

The embodiments described herein provide systems and methods that can improve the performance of a scanning laser device (100). Specifically, the systems and methods emit a set of emission control pulses used to detect when an object (e.g., a person) is within a relatively close safety range (222). A set of high-energy, long-range pulses is then conditionally emitted only if an object is not detected within the safety range using the set of emission control pulses. These sets of emission control pulses are emitted with variable timing and / or variable energy that is determined at least in part by whether a previous set of emission control pulses detected an object within the safety range. The use of emission control pulse sets with variable timing and / or variable energy can provide improved reliability of object detection within the safety range while continuing to meet the energy limits required for eye safety.

Description

[Technical Field]

[0001] Scanning laser devices have been developed and implemented for a wide variety of applications, including object detection. For example, light detection and ranging (LiDAR) systems have been developed to generate 3D maps of surfaces, which describe depth variations across the surface. Such object detection and depth mapping are used in a variety of applications, including object and motion sensing, navigation, and control. For example, such LiDAR devices are used in the navigation and control of autonomous vehicles, including autonomous devices used in transportation and manufacturing. [Background technology]

[0002] One issue with some LiDAR systems is the need to achieve a specific effective range while also providing eye safety. To aid in this, Non-Patent Document 1 provides examples of laser safety classes. While many different laser safety classes exist, one key difference between classes is whether a product is considered “eye-safe” or “non-eye-safe.” Eye-safe laser systems are generally considered incapable of generating damaging accessible radiation levels during operation and generally also exclude device marking requirements, control measures, or other additional safety measures. Non-Patent Document 1 classifies eye-safe products as Class 1. However, products containing high-power laser devices that would normally be classified as non-eye-safe may nevertheless be classified as eye-safe if the product includes additional safety measures that reduce accessible radiation. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] International standard IEC60825.1 Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, there remains a need for systems and methods that can provide effective sensing at relatively long ranges while also providing improved eye safety. [Brief explanation of the drawings]

[0005] [Figure 1] 1 is a schematic diagram of a scanning laser device according to various embodiments. [Figure 2A] 1 is a schematic diagram of a scanning laser device and scanning field according to various embodiments.

[0006] [Figure 2B] 1A-1C illustrate exemplary laser light pulses in accordance with various embodiments. [Figure 2C] 1A-1C illustrate exemplary laser light pulses in accordance with various embodiments.

[0007] [Figure 3A] 1 is a flow diagram of an exemplary method according to various embodiments. [Figure 3B] 1 is a flow diagram of an exemplary method according to various embodiments. [Figure 3C] 1 is a flow diagram of an exemplary method according to various embodiments.

[0008] [Figure 4A] FIG. 1 is a graph illustrating exemplary pulse set energy over time in accordance with various embodiments. [Figure 4B] FIG. 1 is a graph illustrating exemplary pulse set energy over time in accordance with various embodiments. [Figure 4C] FIG. 1 is a graph illustrating exemplary pulse set energy over time in accordance with various embodiments. [Figure 4D] FIG. 1 is a graph illustrating exemplary pulse set energy over time in accordance with various embodiments.

[0009] [Figure 5A] 1 is a schematic diagram of an optical assembly according to various embodiments of the present invention.

[0010] [Figure 5B] 10A-10C are graphs of optical expansion, scan trajectory, and energy level adjustment of a set of laser light pulses in accordance with various embodiments. [Figure 5C] 10A-10C are graphs of optical expansion, scan trajectory, and energy level adjustment of a set of laser light pulses in accordance with various embodiments. [Figure 5D] 10A-10C are graphs of optical expansion, scan trajectory, and energy level adjustment of a set of laser light pulses in accordance with various embodiments.

[0011] [Figure 5E] 1A-1C are schematic diagrams of scanning laser devices having different effective ranges and energy level adjustments of sets of laser light pulses in accordance with various embodiments. [Figure 5F] 1A-1C are schematic diagrams of scanning laser devices having different effective ranges and energy level adjustments of sets of laser light pulses in accordance with various embodiments.

[0012] [Figure 5G] FIG. 1 is a schematic diagram of a scanning laser device using multiple effective areas in accordance with various embodiments.

[0013] [Figure 6A] FIG. 1 illustrates a top view of a moving platform including a LiDAR system and the resulting scan field in accordance with various embodiments. [Figure 6B] FIG. 1 is a side view of a mobile platform including a LiDAR system and the resulting scan field in accordance with various embodiments.

[0014] [Figure 7A] FIG. 1 is a side view of a scanning laser device according to various embodiments. [Figure 7B] 1 is a top view of a scanning laser device according to various embodiments.

[0015] [Figure 8] FIG. 1 is a schematic diagram of a LiDAR system according to various embodiments.

[0016] [Figure 9] FIG. 1 is a schematic diagram of a LiDAR system according to various embodiments.

[0017] [Figure 10A] FIG. 1 is a side view of a delivery module according to various embodiments. [Figure 10B] 1A and 1B are top views of a delivery module according to various embodiments.

[0018] [Figure 11A] 1 is a side view of a receiving module according to various embodiments. FIG. [Figure 11B] 1 is a top view of a receiving module according to various embodiments. FIG.

[0019] [Figure 12] 1 is a perspective view of an integrated photonics module according to various embodiments of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020]

[0003] Embodiments described herein provide systems and methods that can facilitate improved eye safety while providing effective object detection in Light Detection and Ranging (LiDAR) systems and other scanning laser devices. Specifically, the systems and methods utilize an emission control system and method for emitting an emission control pulse set used to detect when an object (e.g., a person) is within a relatively close safety range. Then, a high-energy, long-range pulse set is conditionally emitted only if an object is not detected within the safety range using the emission control pulse set. Thus, the use of the emission control pulse set provides the ability to prevent the emission of the relatively high-energy, long-range pulse set when a person or other object is within the safety range, thereby providing improved eye safety.

[0021] According to embodiments described herein, these sets of emission control pulses are emitted with variable timing (e.g., variable time durations or delays between sets of emission control pulses) and / or variable energies (e.g., further reduced energy levels). Specifically, the sets of emission control pulses are emitted with variable timing and / or variable energies that are determined at least in part by whether the previous set of emission control pulses detected an object within a safe range. The use of sets of emission control pulses with variable timing and / or variable energies can provide improved reliability of object detection within a safe range while continuing to meet energy limits required for eye safety.

[0022] Specifically, in many scanning laser device applications, the total energy of a set of pulses over a particular time frame should be considered to provide effective eye safety. By selectively delaying with variable timing and / or further reducing the energy level of a set of emission control pulses following detection of an object within the safety range, embodiments described herein facilitate increasing the energy level of other sets of emission control pulses while maintaining or improving eye safety. Specifically, by selectively delaying and / or further reducing the energy level of a set of emission control pulses following detection of an object within the safety range, a preceding set of emission control pulses (e.g., one prior to detection of an object within the sensing region) can be emitted at a higher energy. Thus, embodiments can provide an increase in the energy level of a preceding set of emission control pulses while maintaining or reducing potential energy exposure to the eye over time. This increased energy in the preceding set of emission control pulses provides improved reliability in detecting objects within the safety range while maintaining eye safety for both sets of emission control pulses. Thus, embodiments described herein can provide improved reliability in detecting rejection within the safety range and improved eye safety.

[0023] Referring now to FIG. 1 , a schematic diagram of a scanning laser device 100 is shown in accordance with various embodiments. In one embodiment, the scanning laser device 100 is a light detection and ranging (LiDAR) system used for object detection and / or 3D map generation. The scanning laser device 100 includes a light source controller 101, a laser light source 102, an optical assembly 104, and a detector 106. The optical assembly 104 includes various optical elements for laser scanning, including extended optics 108 and scanning optics 110. During operation, the laser light source 102 generates pulses of laser light that are scanned by the optical assembly 104 along a scan trajectory 112 within a scan field 114.

[0024] These pulses of laser light impinge on objects in the scan field 114 at a series of scan locations or measurement points along the scan trajectory 112. Notably, each "scan location" or "measurement point" is not an infinitely small point in space, but rather a small, finite, contiguous section of the scan trajectory 112. Specifically, the laser light beam traverses a finite section of the scan trajectory 112 during the round-trip transit time of the laser light pulse. Furthermore, each scan location or measurement point area is also a function of the laser spot size (initial size and divergence) at the distance at which the object is encountered.

[0025] The detector 106 is configured to receive reflections of the laser light pulses from measurement points or scan locations on objects within the scan field 114. The received reflections of the laser light pulses can be used to detect objects within the scan field 114. For example, time-of-flight (TOF) measurements of the received reflections can be used to generate distance measurements. As an example, these distance measurements can be used to generate a three-dimensional point cloud that describes the depth or distance at each point, and thus can be used to generate a depth map of any detected objects.

[0026] 1, the scan trajectory 112 within the scan field 114 comprises a raster pattern. However, this is merely an example, and other trajectories or patterns of scan lines can be generated when used in other embodiments. To facilitate generation of the scan trajectory 112, drive circuitry can be implemented to control movement of the scanning optics 110, while the expansion optics provide any desired optical expansion, including output pointing angle expansion, beam width expansion, and beam divergence. Detailed examples of such devices are described below.

[0027] In some embodiments, in addition to detector 106, scanning laser device 100 is implemented to include one or more additional detectors. For example, a second detector can be implemented to receive reflections of IR laser light pulses from within the scan field through optical assembly 104.

[0028] The scanning laser device 100 may also include other elements. For example, the scanning laser device 100 may also include a time-of-flight (TOF) circuit responsive to the detector 106 to measure the distance to an object at a depth measurement point within the scan field.

[0029] According to embodiments described herein, the scanning laser device 100 includes emission control that provides improved eye safety by emitting a set of high energy, long range pulses only when an object is not detected within a defined safety range. Generally, this improved eye safety is provided by an emission control system (e.g., a light source controller 101 with emission control, emission control circuitry and pulse generation circuitry that includes or cooperates with such a light source controller, or a virtual protective housing circuit) that causes the laser light source 102 to selectively emit sets of laser light pulses at different energy levels in response to object detection.

[0030] Specifically, the light source controller 101 with emission control causes the laser light source 102 to selectively emit a set of relatively low energy emission control pulses that are used to detect when an object (e.g., a person) is within a relatively close safety range. A set of high energy long range pulses is then conditionally emitted only when an object is not detected within the safety range, thus improving eye safety. Thus, the emission control pulse set provides the ability to selectively delay or prevent emission of a set of relatively high energy long range pulses when a person or other object is within the safety range, thus providing improved eye safety.

[0031] Additionally, according to embodiments described herein, these sets of emission control pulses are emitted with variable timing (e.g., variable time durations or delays between sets of emission control pulses) and / or variable energies (e.g., at further reduced energy levels). Specifically, the sets of emission control pulses are emitted with variable timing and / or variable energies that are determined at least in part by whether the previous set of emission control pulses detected an object within a safe range. Using sets of emission control pulses with variable timing and / or variable energies can provide improved reliability of object detection within a safe range while still meeting the energy limits required for eye safety.

[0032] Specifically, in a typical implementation of scanning laser device 100, the total energy of all pulses over a particular time frame should be considered to effectively provide eye safety. By selectively delaying with variable timing and / or further reducing the energy level of a set of emission control pulses following detection of an object within the safety range, scanning laser device 100 facilitates increasing the energy level of other sets of emission control pulses while maintaining or reducing potential energy exposure to the eye over time.

[0033] For example, under some safety limit specifications and / or regulatory environments (e.g., regulatory classification limits under IEC 60825.1), a single emission control pulse set having an energy of 6.60E-07 joules can be considered eye-safe at 100 mm if no other pulses are emitted for a 5.00E-06 second time frame around the emission control pulse set (if the system meets various other parameters, e.g., wavelength, viewing angle, beam divergence, and apparent source position). Similarly, two emission control pulse sets, each having an energy of 3.30E-07 joules, can be considered eye-safe at 100 mm if no other pulses are emitted for a 5.00E-06 second time frame around the two pulse sets and the pulses themselves do not exceed other regulatory limits. Thus, in these regulatory environments, it is the total energy of all emission control pulse sets over a defined time period that determines whether the emission control pulse sets are considered eye-safe at a specified distance. Additionally, in such regulatory environments, selectively delaying with variable timing and / or further reducing the energy level of a set of emission control pulses following detection of an object within a safe range allows for an increase in the energy level of another set of emission control pulses while maintaining compliance with regulatory classification limits.

[0034] Thus, by selectively delaying and / or further reducing the energy level of the set of emission control pulses following the detection of an object within the safety range, the preceding set of emission control pulses (e.g., those prior to the detection of an object in the sensing region) can be emitted at a higher energy. This increased energy in the preceding set of emission control pulses provides improved reliability in detecting objects within the safety range while maintaining the eye safety of both sets of emission control pulses. Thus, the scanning laser device 100 can provide improved reliability in detecting rejection within the safety range and improved eye safety.

[0035] In some applications, it may be desirable to implement the scanning laser device 100 to selectively emit multiple sets of emission control pulses before emitting a longer set of ranging pulses. For example, in some embodiments, the emission of multiple sets of emission control pulses without resulting object detection within a safe range may be required before a set of ranging pulses is emitted. Specifically, two distinct sets of emission control pulses may be required in situations where the immediately preceding set of emission control pulses detected an object within a safe range. Examples of such embodiments are described below.

[0036] To facilitate such emission control techniques, the light source controller 101 can use various devices and methods to vary the energy levels of the sets of laser light pulses. For example, the light source controller 101 can be implemented to dynamically vary the pulse duration of individual laser light pulses within a set of pulses to vary the energy of the set of pulses. As another example, the light source controller 101 can be implemented to dynamically vary the pulse amplitude of individual laser light pulses to vary the set energy. As another example, the light source controller 101 can be implemented to dynamically vary the current used to drive the lasers to vary the energy of individual laser light pulses within a set of pulses. As another example, the light source controller 101 can be implemented to dynamically vary the number of lasers used to generate individual pulses within a set of pulses. As another example, the light source controller 101 can be implemented to dynamically vary the number of individual pulses within each set of pulses to vary the energy of the resulting set of pulses. Various combinations of these techniques can also be employed.

[0037] In some embodiments, the emission control of the light source controller 101 can be implemented as part of a pulse generation circuit and / or emission control circuit. In these embodiments, the pulse generation circuit and / or emission control circuit function as a light source controller so that the laser light source selectively emits a set of relatively low-energy emission control pulses that are used to detect when an object (e.g., a person) is within a relatively close safety range. A set of high-energy, long-range pulses is then conditionally emitted only when an object is not detected within the safety range, thus improving eye safety. Detailed examples of such pulse generation circuit and emission control circuit are described in more detail below.

[0038] In one embodiment, the light source controller 101 can be implemented with emission control that: emits a first set of emission control pulses at a reduced first energy level; and, in response to not detecting an object within the safe range using the first set of emission control pulses, emits a set of ranging pulses at a high energy level, the high energy level being greater than the reduced first energy level; and, in response to not detecting an object within the safe range using the first set of emission control pulses, emits a second set of emission control pulses a first time period following the first set of emission control pulses and at a reduced second energy level; and, in response to detecting an object within the safe range using the first set of emission control pulses, emits an adjusted second set of emission control pulses, the adjusted second set of emission control pulses including at least one of an extended first time period following the first set of emission control pulses and a further reduced second energy level relative to the reduced second energy level.

[0039] In another embodiment, the light source controller 101 can be further implemented to: in response to not detecting an object within the safety range using either the second emission control pulse set or the adjusted second emission control pulse set, emit a third emission control pulse set, the third emission control pulse set including a second time period following either the second emission control pulse set or the adjusted second emission control pulse set and a reduced third energy level; and in response to detecting an object within the safety range using either the second emission control pulse set or the adjusted second emission control pulse set, emit the adjusted third emission control pulse set including at least one of: an extended second time period following either the second emission control pulse set or the adjusted second emission control pulse set and a further reduced third energy level relative to the reduced third energy level.

[0040] In another embodiment, the light source controller 101 can be further implemented to dynamically adjust the relative, further reduced second energy level for each of the plurality of adjusted emission control pulse sets. In another embodiment, the light source controller 101 can be further implemented to dynamically determine the extended first time period such that the first set of emission control pulses and the adjusted second set of emission control pulses have a combined energy below the laser light pulse energy limit over a defined time frame. In such an embodiment, the energy limit can be a regulatory classification limit implemented for safety, a limit designed to protect sensitive materials from damage, or a limit to provide operational reliability, to provide some examples.

[0041] In this application, the term "pulse set" is defined as a group of one or more laser pulses emitted together over a relatively short period of time whose received reflections are used together to provide object detection and / or ranging. In this definition, a single pulse typically corresponds to an individual burst of laser light emitted during one on / off cycle of the laser source.

[0042] Pulse sets containing one or more pulses can generate reflections that are used together for object detection and ranging in a variety of different ways. For example, multiple pulses in a pulse set can be implemented to provide multiple independent rejected detection opportunities. In other embodiments, the results of multiple pulses can be combined (e.g., averaged, integrated) to provide an improved probability of detection and / or improved accuracy.

[0043] As another example, a pulse set having multiple pulses may be modulated using any of a variety of different techniques, including amplitude modulation, frequency modulation, phase modulation, etc. In these examples, the pulse set may be modulated to include a signature that may improve detection reliability and / or range of the pulse set.

[0044] As one detailed example, a ranging pulse set can be modulated to include one of several different possible signatures by varying the relative timing of the individual pulses. In some implementations, a ranging pulse set including multiple pulses can be modulated with a channel signature, and then an accepted reflection can be used for ranging only if it is modulated with the same channel signature. Otherwise, the accepted light at the detector can be rejected. Thus, in such embodiments, modulation of multiple pulses can be used to remove noise and improve the signal-to-noise ratio (SNR). This can increase the effective range of the ranging pulse set without requiring additional energy in each individual pulse. Similarly, multiple pulses can be used in an emission control pulse set to remove noise and improve the range and / or reliability of the emission control pulse set. Examples of such modulation techniques can be found in U.S. Pat. No. 11,402,476, entitled "Method and Apparatus for LIDAR Channel Encoding."

[0045] Referring now to FIG. 2A , a schematic diagram of a scanning laser device 200 is shown. In one embodiment, the scanning laser device 200 is a LiDAR system used for object detection and / or 3D map generation. As shown in FIG. 2A , the scanning laser device is implemented to scan objects within a scan field 210. In this illustrated embodiment, the scan field 210 is defined in part by an effective range 212 and an output scan angle 214. Other factors may also define the scan field 210, including an orthogonal scan angle (not shown in FIG. 2A ) and the optics of the scanning laser device 200 (e.g., laser pulse power variation, expansion optics 108, scanning optics 110). Note that this is a simplified example; complex implementations of the scan field are possible and are described below.

[0046] As described above, scanning laser device 100 includes emission control that provides improved eye safety by emitting high energy, long range pulse sets (e.g., up to effective range 212) only when no object is detected within a relatively close safety range (e.g., safety range 222). Generally, to provide eye safety, safety range 222 is implemented such that high energy, long range pulse sets are considered eye-safe at the outer edges of the safety range and beyond. Again, it should be noted that safety range 222 is a simplified example and that complex implementations are possible.

[0047] In operation, the emission control system causes the laser source to selectively emit a set of relatively low energy emission control pulses that are used to detect when an object (e.g., a person) is within the relatively close safety range 222. A set of high energy, long range pulses (having effective range 212) is then conditionally emitted only when an object is not detected within the safety range, thus improving eye safety. Thus, the emission control pulse set provides the ability to selectively delay or prevent emission of a set of relatively high energy, long range pulses when a person or other object is within the safety range 222, thus providing improved eye safety.

[0048] To provide such safety, the emission control pulse sets are generated to have reduced energy levels that reduce accessible radiation and provide eye-safe operation over at least a portion of the safety range 222. For example, if an emission control pulse set meets Class 1 accessible radiation limits under IEC 60825.1 over at least a portion of the safety range 222, it can be expected to be eye-safe over that portion. As a specific example, in some embodiments, the energy levels of the emission control pulse sets may be implemented to meet Class 1 limits that provide eye-safe operation beginning at a distance of 100 mm from the scanning laser device 200 while providing reliable object detection up to the edge of the safety range 222. For example, in extremely bright sunlight, an emission control pulse set that is eye-safe at 100 mm may not detect an object with a 20% reflectivity at a 20 meter safety range distance. -10 , and such an emission control pulse set will have a low probability of not detecting an object at close range in the safety range 222. Of course, this is just one example, and in other embodiments, the pulse set energy levels may be set to provide eye-safe operation where accessible emission begins at a distance of more than 100 mm from the scanning laser device 200.

[0049] As described above, in some embodiments, the energy of the set of emission control pulses may be increased when the platform on which the scanning laser device (e.g., LiDAR or other scanning laser device 100) is used is in motion. For example, when the vehicle is traveling at a speed above a threshold, the energy of the set of emission control pulses may be set to a level that results in accessible emission at an eye-safe level at a minimum distance of more than 100 mm. The energy of the set of emission control pulses may then be increased as the platform speed increases. For example, the energy of the set of emission control pulses may be gradually increased as the platform accelerates between 2.5 meters per second (m / s) and 25 m / s.

[0050] Increasing the energy level of the emission control pulse set in response to the velocity may again result in an increased probability of detecting an object within a safe range and / or may increase the range at which an object may be detected with the emission control pulse set.

[0051] 2B, an exemplary string of laser pulses that together comprise an emission control pulse set and a ranging pulse set in accordance with various embodiments of the present invention is shown. Specifically, FIG. 2B illustrates pulses 228 and 229 that comprise an exemplary emission control pulse set, and pulses 230 and 231 that comprise an exemplary ranging pulse set. As discussed above, the term "pulse set" is defined as a group of one or more laser pulses that are emitted together over a relatively short period of time, and whose received reflections are used together to provide object detection and / or ranging.

[0052] In this example, the first emission control pulse set (comprising pulse 228) is emitted before the first ranging pulse set (comprising pulse 230), and the second emission control pulse set (comprising pulse 229) is emitted before the second ranging pulse set (comprising pulse 231). In such an embodiment, pulse 230 of the first ranging pulse set is emitted only if pulse 228 of the first emission control pulse set did not result in the detection of an object within safety range 222. Similarly, pulse 231 of the second ranging pulse set is emitted only if pulse 229 of the second emission control pulse set did not result in the detection of an object within safety range 222.

[0053] In this example, each emission control pulse set includes only one pulse 228, 229, while each long range ranging pulse set includes five pulses 230, 231 closely spaced in time to effectively function as a single pulse set. For example, a ranging pulse set of five pulses 230 can be emitted over a time period between 30 and 90 ns. Thus, pulses 228, 229, 231, and 231 are examples of the type of radiation that may be emitted by a LiDAR or other scanning laser device (e.g., scanning laser device 100, 200) for each scan location or measurement point within scan field 210.

[0054] As described above, the emission control pulse set (consisting of pulses 228 and 229) is emitted to detect a possible object within the relatively short safety range 222, and the system then conditionally emits the long-range ranging pulse set (consisting of pulses 230 and 231) based on whether an object is detected. Specifically, FIG. 2B shows an example in which two pulses 228 and 229 for the emission control pulse set do not result in the detection of an object within the safety range 222, and therefore pulses 230 and 231 for the ranging pulse set are emitted for long-range detection up to the effective range 212. Note that pulses 228 and 230 are not effectively part of the same pulse set but instead provide separate detection events. Note, however, that the time between each pulse 228 and the subsequent pulse 230 is sufficiently short so that they both effectively scan the same scan location or measurement point, which is defined in part by the emission direction of the set of laser light pulses. This means that pulse 228 can reliably detect whether an object is within the safe range at effectively the same scan location or measurement point as the subsequent pulse 230 impinges. By way of non-limiting example, pulse 228 can be separated in time from pulse 230 by 90-500 ns.

[0055] It should also be noted that in this example, the first pulse 228 and subsequent pulse 230 correspond to a first scan position or measurement point, and the second pulse 229 and subsequent pulse 231 correspond to a next scan position or subsequent measurement point within the scan field 210.

[0056] Again, the emission control pulse set (e.g., pulses 228, 229) is generated to have energy levels that provide a very high probability of object detection within the designed short safety range 222, while providing eye safety within that short safety range 222. The long range ranging pulse set (e.g., pulses 230, 231) can be generated to have eye-safe energy levels at and beyond the short safety range 222, while providing reliable long range detection at the effective range 212.

[0057] Note that while FIG. 2B shows one pulse 228, 229 per emission control pulse set and a set of five pulses 230, 231 per ranging pulse set, any suitable number of pulses within each pulse set may be used. For example, instead of multiple sets of pulses 230, 231 for ranging at each scan position, a single pulse having a relatively high energy level may be used. As another example, instead of one pulse 228, 229 per emission control pulse set, multiple pulses of relatively low energy may be used per emission control pulse set. Furthermore, in some embodiments, multiple ranges may be provided by employing different numbers of pulses, each having the same energy level. For example, a short range in the emission control pulse set may be provided by the energy of a single pulse, while a long range in the ranging pulse set may be provided by the energy of multiple pulses, each having the same energy as the single pulse used for the emission control pulse set. As another example, a short range of emission control pulses may be defined by the energy of a single short range pulse, while a medium range may be defined by multiple pulses each having the same energy as the short range pulse, and a long range may be defined by many pulses having the same or greater energy as the short range pulse.

[0058] In some applications, it may be desirable to implement a system to selectively emit multiple emission control pulse sets before emitting a ranging pulse set. Referring to FIG. 2C , another exemplary string of laser pulses constituting an emission control pulse set and a ranging pulse set is shown, according to various embodiments of the present invention. In this example, two emission control pulse sets (first pulse configuration 232 and second pulse configuration 234) are emitted before the first ranging pulse set (comprising pulse 236), while only one emission control pulse set (comprising pulse 238) is emitted before the second ranging pulse set (comprising pulse 240). Again, in such an embodiment, the first pulse set 236 of the first ranging pulse set is emitted only if neither of pulses 232 nor 234 for the emission control pulse set resulted in the detection of an object within the safety range 222. Note that in this embodiment, the two pulses 232 and 234 are separated in time, and reflections are received and processed separately to provide two separate emission control pulse sets with two separate object detection opportunities. However, the time between pulse 232 and pulse 234 is also short enough so that both effectively scan the same scan location or measurement point, as defined in part by the direction of emission of the set of laser light pulses. As a non-limiting example, the two pulses 232 and 234 can be separated in time by between 90 and 500 ns.

[0059] 3A , a flow diagram illustrates a method 300 according to various embodiments. In some embodiments, method 300, or portions thereof, are performed by a LiDAR or other scanning laser device (e.g., scanning laser device 100, 200). For example, method 300 may be performed by a series of circuits or electronic systems that are part of, in communication with, or associated with the scanning laser device. Method 300 is not limited by the particular type of apparatus that performs the method.

[0060] In step 302, an emission control (EC) pulse set is fired for the next scan position. As described above, this emission control pulse set includes one or more laser light pulses at a reduced energy level that are fired to determine whether any objects are within a relatively close safety range (e.g., safety range 222 in FIG. 2A ). Thus, the laser light pulse set is implemented at an energy level that is considered eye-safe within at least a portion of that safety range. Note that in some embodiments, one emission control pulse set is fired in step 302 per scan position (e.g., pulse set consisting of pulse 228 in FIG. 2B ), while in other embodiments, multiple emission control pulse sets are fired in step 302 for at least some scan positions (e.g., pulse set consisting of pulses 232 and 234 in FIG. 2C ). Furthermore, in other embodiments, the number of emission control pulse sets fired in step 302 per scan position can be variable and can be changed during operation based on various factors. As will be explained in more detail below, in accordance with the embodiments described herein, the energy level of the set of emission control pulses emitted in step 302 is made relatively high, allowing for improved detection reliability while maintaining eye safety.

[0061] In step 304, it is determined whether an object is detected within a safe range using the set of emission control pulses. As described above, in one embodiment, a detector (e.g., detector 106 of FIG. 1) is configured to accept reflections of laser light pulses from objects within the scan field. The accepted reflections of the laser light pulses can then be used to detect the objects and determine the distance to them (e.g., using time-of-flight (TOF) measurements and calculating the distance from the TOF measurements). In one embodiment, step 304 can include comparing the TOF measurements to a threshold value, the threshold value corresponding to a desired safe range based on various appropriate factors. Thus, the accepted reflections of the set of emission control pulses can be used to determine whether an object is present within the designed safe range.

[0062] If an object is not detected within the safety range, method 300 proceeds to step 306. In step 306, one or more sets of ranging pulses are emitted, and any accepted reflections of the sets of ranging pulses are used to generate distance measurements. Also, note that in typical embodiments, the time between the emission of the set of emission control pulses in step 302 and the emission of the subsequent set of ranging pulses in step 306 is short enough that both the set of emission control pulses and the set of ranging pulses effectively impinge and reflect from the same measurement point or scan location.

[0063] The set of ranging pulses emitted in step 306 is provided for relatively long-range object detection and distance measurement. Therefore, the energy of the set of ranging pulses is typically much greater than the energy level of the preceding set of emission control pulses emitted in the previous step 302. In other words, the set of ranging pulses is emitted at a high energy level, which is greater than the reduced first energy level of the first set of emission control pulses.

[0064] Thus, in step 306, a relatively high energy set of pulses providing relatively long range object detection (e.g., relative to effective range 212 in FIG. 2A) is emitted only when an object was not detected within a safety range (e.g., safety range 222 in FIG. 2A) using the emission control pulse set emitted in step 302. Thus, method 300 provides improved eye safety by only emitting a relatively high energy set of ranging pulses when an object was not detected for a given scan position or measurement point within the safety range by the preceding emission control pulse set.

[0065] The received reflections of the set of ranging pulses are used to generate distance measurements. Again, in one embodiment, an IR detector is configured to receive reflections of the set of ranging pulses from objects within the scan field. The received reflections of the set of ranging pulses can then be used to detect those objects and determine the distances to those objects (e.g., using TOF measurements). In one embodiment, a plurality of calculated distances are used to generate a point cloud of data (e.g., a 3D point (X, Y, Z) cloud of data that can be written to a memory or other data storage device). Also, as mentioned above, in some embodiments, modulation techniques can be applied to the set of ranging pulses to increase SNR and range.

[0066] Using the distance measurement generated from any accepted reflections in step 306, method 300 returns to step 302, where the next set of emission control (EC) pulses is emitted for the next scan position, and the process continues. Specifically, in repeating step 302 when an object was not detected within the safety range during the previous step 302, a second set of emission control pulses is emitted at a reduced second energy after a first time period following the first set of emission control pulses.

[0067] Thus, steps 302, 304, and 306 can be continuously repeated to generate distance measurements for different scan positions within the scan field, as long as an object is not detected within the safety range. However, if it is determined in any step 304 that the emission control pulse set instead resulted in the detection of an object within the safety range, the method proceeds to an adjusted emission control process 312, which includes steps 308 and 310. In step 308, an adjusted emission control (AEC) pulse set is emitted. The adjusted emission control pulse set is again a set of laser light pulses having a reduced energy level that is provided to determine whether any objects are within a relatively close safety range (e.g., safety range 222 of FIG. 2A ). However, in this step 308, the adjusted emission control pulse set is modified relative to the emission control pulse set that would have been emitted in the next step 302 if an object was not detected within the safety range in step 304.

[0068] Specifically, the emitted adjusted set of emission control pulses includes at least one of an extended first time period following the first set of emission control pulses and a further reduced second energy level relative to the reduced second energy level. Thus, the emitted adjusted set of emission control pulses in step 308 is adjusted to have an extended time delay period before being emitted and / or a further reduced energy level compared to the set of emission control pulses that would have been emitted in the next step 302 if an object had not been detected within the safety range in step 304.

[0069] For example, in some embodiments, the emitted and adjusted set of emission control pulses in step 308 are adjusted to have a further reduced energy level compared to the set of emission control pulses that would have been emitted in the next step 302 if an object had not been detected within the safe range in step 304. Similarly, in some embodiments, the emitted and adjusted set of emission control pulses in step 308 are adjusted to have an extended time delay period before emission compared to the set of emission control pulses that would have been emitted in the next step 302 if an object had not been detected within the safe range in step 304. Finally, in some embodiments, the emitted and adjusted set of emission control pulses in step 308 are adjusted to have both an extended time delay period before emission and a further reduced energy level compared to the set of emission control pulses that would have been emitted in the next step 302 if an object had not been detected within the safe range in step 304.

[0070] Each of these embodiments can provide significant performance improvements over previous techniques for providing eye safety. Specifically, by selectively delaying with variable timing and / or further reducing the energy level of a set of adjusted emission control pulses following detection of an object within the safety range, these embodiments facilitate increasing the energy level of a previous set of emission control pulses while maintaining a desired level of eye safety. As noted above, to provide a level of eye safety, the total energy of a set of emission control pulses over a specific time frame should be considered. For example, the IEC 60825.1 specification defines the eye safety of a pulse at least in part by the amount of energy emitted by two or more pulses over a set of specific time frames while the possibility of the presence of an object remains within the safety range.

[0071] In such a regulated environment, selectively delaying and / or further reducing the energy level of the adjusted emission control pulse set following detection of an object within the safety range allows the preceding emission control pulse set to be emitted at a higher energy while maintaining the eye-safety of both pulse sets taken together. Stated another way, the adjusted emission control pulse set emitted in step 308 is delayed and / or further reduced in energy so that the emission control pulse set emitted in step 302 can have a relatively higher energy while maintaining the eye-safety of both pulse sets taken together. Furthermore, this increased energy in the emission control pulse set emitted in step 302 provides improved reliability in detecting objects within the safety range. Accordingly, improved reliability in detecting rejection within the safety range itself provides improved eye-safety.

[0072] In step 310, it is determined whether an object is detected within the safe range using the adjusted set of emission control pulses. Again, in one embodiment, the detector is configured to accept reflections of laser light pulses from objects within the scan field. The accepted reflections of the laser light pulses can then be used to detect those objects and determine the distance to those objects. Thus, the accepted reflections of the set of emission control pulses can be used to determine whether there is an object with the designed safe range.

[0073] If an object is not detected within the safety range, method 300 returns to step 302, where the next set of emission control (EC) pulses is emitted. In this implementation of step 302, the emission control pulse set can include a second time period following either the second set of emission control pulses or an adjusted second set of emission control pulses, and a reduced third energy level. Steps 302, 304, and 306 can then be repeated continuously to generate distance measurements for different scan positions within the scan field, as long as the object is not detected within the safety range.

[0074] If an object is detected within the safety range in step 310, method 300 returns to step 308. In step 308, an adjusted emission control (AEC) pulse set is again emitted. Again, the adjusted emission control pulse set is a combined set of laser light pulses having a reduced energy level that is provided to determine whether any object is within a relatively close safety range. However, in this additional implementation of step 308, the adjusted emission control pulse set is modified in step 310 relative to the emission control pulse set that would have been emitted in the next step 302 if an object had not been detected within the safety range. In this implementation of step 308, the adjusted emission control pulse set can include at least one of an extended second time period following either the second emission control pulse set or the adjusted second emission control pulse set, and a further reduced third energy level relative to the reduced third energy level.

[0075] Thus, the adjusted set of emission control pulses emitted in step 308 are adjusted to have an extended time delay period before being emitted and / or a further reduced energy level compared to the set of emission control pulses that would have been emitted in the next step 302 if an object had not been detected within the safety range in step 310.

[0076] Thus, in some embodiments, the emitted and adjusted set of emission control pulses of step 308 are again adjusted in step 310 to have a further reduced energy level compared to the set of emission control pulses that would have been emitted in the next step 302 if an object was not detected within the safe range. Similarly, in some embodiments, the emitted and adjusted set of emission control pulses of step 308 are adjusted in step 310 to have an extended time delay period before emission compared to the set of emission control pulses that would have been emitted in the next step 302 if an object was not detected within the safe range. Finally, in some embodiments, the emitted and adjusted set of emission control pulses of step 308 are adjusted to have both an extended time delay period before emission and a further reduced energy level compared to the set of emission control pulses that would have been emitted in the next step 302 if an object was not detected within the safe range in step 310.

[0077] Each of these embodiments can provide significant performance improvements by facilitating an increase in the energy level of the preceding set of emission control pulses while maintaining a desired level of eye safety. This increased energy in the set of emission control pulses emitted in step 302 provides improved reliability in detecting objects within a safety range.

[0078] It should be noted that the adjusted emission control process 312 (i.e., steps 308 and 310) may be performed continuously as objects are repeatedly detected within the safety range. In this case, an adjusted set of emission control pulses is emitted in each step 308 in response to the detection of an object within the safety range in the corresponding step 310. And, in each case, the amount of adjustment (e.g., changing the time period before the pulse set and / or the energy level of the pulse set) may be modified. For example, the amount of adjustment may be based on the number of times these steps are performed. Such adjustment allows the combined energy of all emission control pulse sets emitted when an object may be within the sensing region to be within the limit of the corresponding total time period of the emission control pulse sets.

[0079] Finally, it should be noted that in method 300, after detecting an object within the safe range, two sets of emission control pulses are required without another detection before a set of ranging pulses is emitted. Specifically, after detection in either step 304 or 310, a set of emission control pulses must be emitted in steps 308 and 302, without any resulting detection, before a set of ranging pulses can be emitted in step 306. Requiring two sets of clearing pulses after detection can further improve the reliability of the emission control system by increasing the probability that an object will be detected within the safe range before a set of ranging pulses is emitted.

[0080] 4A-4D, exemplary graphs of exemplary pulse set energy over time are shown, particularly the graphs illustrating the energy of various emission control and ranging pulse sets in accordance with exemplary operating scenarios and various embodiments described herein.

[0081] 4A, graph 400 shows the relative energy and timing of emission control pulse sets and ranging pulse sets in an exemplary operating scenario when no object is detected within a safe range. Specifically, graph 400 shows the energies 402, 406, and 410 of three emission control pulse sets and the energies 404, 408, and 412 of three corresponding ranging pulse sets.

[0082] In this depicted example, a first set of emission control pulses having energy 402 is followed by a first set of ranging pulses having energy 404, a second set of emission control pulses having energy 406 is followed by a second set of ranging pulses having energy 408, and a third set of emission control pulses having energy 410 is followed by a third set of ranging pulses having energy 412. Thus, as will be described in more detail below, Figure 4A illustrates the repeated performance of steps 302, 304, and 306 of method 300 shown in Figure 3A.

[0083] Again, the first, second, and third emission control pulse sets each include one or more pulses closely spaced in time to provide an object detection and / or ranging event. Similarly, the first, second, and third ranging pulse sets each include one or more pulses closely spaced in time to provide an object detection and / or ranging event. In such cases, the timing of the pulse sets can be referenced by the rising edge of the first pulse, the center time of the pulses, or the falling edge of the last pulse, as three non-limiting examples. Notably, in this illustrated example, energies 402, 406, 410, 404, 408, and 412 are the combined energies of all pulses within the corresponding pulse sets, with timing based on the start of the first pulse in each set.

[0084] In this example, a first set of emission control pulses having energy 402 are emitted to detect any possible objects within the safety range (e.g., performing step 302 of method 300), and if no objects are detected within the safety range (e.g., step 304), a first set of ranging pulses having energy 404 are emitted (e.g., step 306). Note again that because the time between the first set of emission control pulses and the first set of ranging pulses is relatively short, both sets of pulses are emitted in substantially the same direction and both effectively scan the same scan location or measurement point.

[0085] Then, a first time period after the emission of the first set of emission control pulses, a second set of emission control pulses having energy 406 is emitted to detect a possible object within the safety range, and if no object is detected within the safety range, a second set of ranging pulses having energy 408 is emitted (e.g., further implementation steps 302, 304, 306).

[0086] Then, a second time period after the emission of the second set of emission control pulses, a third set of emission control pulses having energy 410 is emitted to detect any possible object within the safety range, and if no object is detected within the safety range, a third set of ranging pulses having energy 412 is emitted (e.g., another implementation step 302, 304, 306).

[0087] Also, note that in this example, the first set of emission control pulses and the first set of ranging pulses correspond to a first scan position or measurement point, the second set of emission control pulses and the second set of ranging pulses correspond to a next scan position or subsequent measurement point within the scan field, and so on.

[0088] Generally, the emission control pulse sets are generated to have energies 402, 406, and 410 that provide a very high probability of detecting objects within a designed short safety range, while providing eye safety within at least a portion of that safety range (e.g., eye-safe 100 mm from the output of the scanning laser device to the outer edge of the safety range). Conversely, the ranging pulse sets are generated to have energies 404, 408, and 410 that are eye-safe at and beyond the outer edge of the safety range, while providing reliable long-range detection to effective ranges beyond the safety range.

[0089] Specifically, a first set of emission control pulses can be generated to have energy 402 at a first reduced energy level. A second set of emission control pulses can be generated to have energy 406 at a second reduced energy level. A third set of emission control pulses can be generated to have energy 410 at a third reduced energy level. Note that in various embodiments, the first, second, and third reduced energy levels can be the same energy level or different energy levels. However, in each case, the reduced energy level is less than the higher energy level of the subsequent set of ranging pulses.

[0090] Referring now to Figure 4B, graph 420 shows the energy and timing of emission control and ranging pulse sets in an exemplary operating scenario when an object is detected within a safe range using an emission control pulse set. Specifically, graph 420 shows the energies 422, 426, and 430 of three emission control pulse sets and the energy 432 of a subsequent ranging pulse set. As will be described in more detail below, Figure 4B shows another example of pulse sets emitted during method 300 of Figure 3A.

[0091] In this example, a first set of emission control pulses having energy 422 is emitted (e.g., performing step 302 of method 300) to detect any possible objects within the safety range. This results in the detection of object 424 within the safety range (e.g., step 304). Therefore, a ranging pulse set is not emitted following the first set of emission control pulses, and an adjusted second set of emission control pulses having energy 426 is emitted (e.g., step 308). In this illustrated example, the adjusted second set of emission control pulses is emitted after a delay, i.e., after the extended first time period.

[0092] The adjusted second set of emission control pulses does not result in the detection of an object within the safety range (e.g., step 310). Therefore, a third set of emission control pulses having energy 430 is emitted to detect any possible object within the safety range (e.g., step 302). This also does not result in the detection of an object within the safety range (e.g., step 304). Therefore, a set of ranging pulses having energy 332 is emitted (e.g., step 306).

[0093] As described above, in the example of FIG. 4B, the adjusted second set of emission control pulses is emitted after an extended first time period. Specifically, this extended first time period is longer than the corresponding first time period when no object is detected (e.g., the first time period in FIG. 4A). By selectively delaying the adjusted set of emission control pulses following the detection of an object within the safety range, the preceding set of emission control pulses can be facilitated to be emitted at a higher energy while maintaining the eye safety of both sets of emission control pulses together. This increased energy in the preceding set of emission control pulses can provide improved reliability in detecting objects within the safety range, and therefore improved eye safety.

[0094] Finally, note that in the example of Figure 4B, after detecting an object within the safe range using the first set of emission control pulses, two sets of emission control pulses were required without another detection before a set of ranging pulses was again emitted. Again, requiring two sets of clearing pulses after detection can further improve the reliability of the emission control system by improving the probability that an object will be detected within the safe range before a set of ranging pulses is emitted.

[0095] 4C, graph 440 illustrates the energy and timing of emission control pulse sets and ranging pulse sets in another exemplary operating scenario when an object is detected within the safety range using an emission control pulse set. In this example, a first emission control pulse set having energy 442 is emitted to detect any possible object within the safety range (e.g., performing step 302 of method 300). This results in the detection of an object within the safety range (e.g., step 304). Therefore, a ranging pulse set is not emitted following the first emission control pulse set, and an adjusted second emission control pulse set having energy 446 is emitted (e.g., step 308). In this illustrated example, the adjusted second emission control pulse set is emitted at a further reduced energy level.

[0096] The adjusted second set of emission control pulses does not result in the detection of an object within the safety range (e.g., step 310). Therefore, a third set of emission control pulses having energy 450 is emitted to detect any possible object within the safety range (e.g., step 302). This also does not result in the detection of an object within the safety range (e.g., step 304). Therefore, a set of ranging pulses having energy 452 is emitted (e.g., step 306).

[0097] As described above, in the example of FIG. 4C , the adjusted second set of emission control pulses is emitted at a further reduced energy level. Specifically, this reduced energy level is less than the corresponding energy level when no object is detected (e.g., reduced second energy level 406 of FIG. 4A ). By selectively further reducing the energy level of the adjusted set of emission control pulses following detection of an object within the safety range, the preceding set of emission control pulses can be facilitated to be emitted at a higher energy while maintaining the eye safety of both sets of pulses together. This increased energy in the preceding set of emission control pulses can again provide improved reliability in detecting objects within the safety range, and thus, improved eye safety.

[0098] Finally, note that in the example of FIG. 4C, after detecting an object within the safe range using the first set of emission control pulses, two sets of emission control pulses were required without another detection before a set of ranging pulses was emitted again.

[0099] 4D, graph 460 illustrates the energy and timing of emission control pulse sets and ranging pulse sets in another exemplary operating scenario when an object is detected within the safety range using an emission control pulse set. In this example, a first emission control pulse set having energy 462 is emitted to detect any possible object within the safety range (e.g., performing step 302 of method 300). This results in the detection of an object within the safety range (e.g., step 304). Therefore, a ranging pulse set is not emitted following the first emission control pulse set, and an adjusted second emission control pulse set having energy 466 is emitted (e.g., step 308). In this illustrated example, the adjusted second emission control pulse set is emitted after a delay, i.e., after the extended first time period.

[0100] In this example, the adjusted second set of emission control pulses again results in detection of an object within the safe range (e.g., step 310). Therefore, a adjusted third set of emission control pulses having energy 470 is emitted (e.g., re-performing step 308). In this illustrated example, the adjusted third set of emission control pulses includes both an extended delay and a further reduced energy level.

[0101] The adjusted third set of emission control pulses does not result in the detection of an object within the safety range (e.g., step 310). Therefore, a fourth set of emission control pulses having energy 472 is emitted to check for any possible object within the safety range (e.g., step 302). This also does not result in the detection of an object within the safety range (e.g., step 304). Therefore, a set of ranging pulses having energy 474 is emitted (e.g., step 306).

[0102] As described above, in the example of FIG. 4D , the adjusted second set of emission control pulses is emitted with both an extended delay and at a further reduced energy level. Specifically, the extended second time period is longer than the corresponding second time period (e.g., the second time period of FIG. 4A ) when no object is detected. Similarly, this further reduced energy 470 is less than the corresponding energy level (e.g., the reduced third energy level 410 of FIG. 4A ) when no object is detected. By selectively extending the time period and further reducing the energy level of the adjusted emission control pulse set following detection of an object within the safety range, the preceding emission control pulse set can be facilitated to be emitted at a higher energy while maintaining the eye safety of both pulse sets together. This increased energy in the preceding emission control pulse set again provides improved reliability in detecting objects within the safety range, and therefore, can provide improved eye safety.

[0103] 3B, a flow diagram illustrates a method 350 according to various other embodiments. Method 350 is an extension of method 300 shown in FIG. 3A. Thus, method 350, or portions thereof, may be performed by a LiDAR or other scanning laser device (e.g., scanning laser device 100, 200).

[0104] Method 350 differs in that adjusted emission control process 352, which includes steps 308 and 310, also includes step 354, which determines whether additional adjusted emission control checks are needed. In such an embodiment, method 350 may require additional sets of emission control pulses without detection of an object within the safety range before returning to step 302. If additional adjusted emission control checks are needed, the method returns to step 308. If additional adjusted emission control checks are not needed, the method instead returns to step 302.

[0105] Such an embodiment can be implemented in various ways. For example, this technique can be implemented by providing a count variable to track the number of adjusted sets of emission control pulses emitted since the last detection of an object within the safety range. Only when the desired number of adjusted sets of emission control pulses have been emitted without additional detections of an object within the safety range does the method return to step 302 instead of step 308. In some embodiments, the number of additional sets of emission control pulses required can be dynamically changed based on various operating parameters, including the measured distance to the last detected object within the safety range, the number of previous object detections within the safety range, ambient conditions, the speed of the vehicle using the scanning laser device, etc.

[0106] 3C, a flow diagram illustrates a method 360 according to various other embodiments. Method 360 is again an extension of method 300 shown in FIG. 3A. Thus, method 360, or portions thereof, may be performed by a LiDAR or other scanning laser device (e.g., scanning laser device 100, 200).

[0107] Method 360 differs in that the set of ranging pulses emitted in step 306 is also used to detect an object within the safe range and trigger the execution of coordinated emission control process 312, which includes steps 308 and 310. Thus, method 360 provides an additional check for objects within the safe range.

[0108] Specifically, method 360 includes step 362. In step 362, it is determined whether an object is detected within a safe range using the ranging pulse set. If an object is detected within a safe range using the ranging pulse set, method 360 proceeds to an adjusted emission control process 312, which includes steps 308 and 310. In step 308, an adjusted emission control (AEC) pulse set is emitted. As described above, the adjusted emission control pulse set is modified relative to the emission control pulse set that would have been emitted in the next step 302 if an object was not detected within a safe range using the ranging pulse set in step 304. Alternatively, if an object is not detected within a safe range using the ranging pulse set, the method returns to step 302, and method 362 continues for the next scan position.

[0109] It should be noted that in some embodiments, it may be desirable to include a variation of method 360 along with a variation of method 362, and thus include both of the additional steps of the method, 354 and 362. These are merely examples of the types of variations that may be included in the techniques described herein.

[0110] 5-12, various detailed examples of exemplary scanning laser devices are described. These examples include various specific embodiments of types of scanning laser devices that may implement emission control according to embodiments described herein. However, it should be noted that these are merely non-limiting examples of types of scanning laser devices that may be so implemented using the emission control methods described above.

[0111] Referring now to FIG. 5A , a detailed embodiment of an optical assembly 500 is shown. The optical assembly 500 includes optical elements used to scan laser beam pulses across a scan field. The optical assembly 500 is an example of a type of optical assembly that may be used in a LiDAR or other scanning laser device (e.g., scanning laser devices 100, 200) according to embodiments described herein. The optical elements shown in FIG. 5A include, by way of non-limiting example only, beam shaping optics 502, a first scanning mirror 504, expanding optics 506, and a second scanning mirror 508. Again, during operation of the scanning laser device, a laser source generates laser light pulses that are scanned by the optical assembly 500 across a scan field (e.g., scan field 114) in a scan trajectory (e.g., scan trajectory 112).

[0112] For example, the laser light source may include one or more infrared (IR) lasers implemented to generate IR laser light pulses. In one example, pulses from the multiple IR laser light sources are combined and shaped by beam shaping optics 502. Beam shaping optics 502 may include any optics for changing the beam shape of the laser light pulses. For example, beam shaping optics 502 may include optical elements for changing beam shape, changing beam collimation, combining multiple beams, and apertureing the beam.

[0113] The output of the beam shaping optics 502 is sent to a first scan mirror 504. Typically, the first scan mirror 504 provides one axis of motion (e.g., horizontal), while the second scan mirror 508 provides another, usually orthogonal, axis of motion (e.g., vertical). Thus, the first scan mirror 504 scans the laser beam pulses in one direction (e.g., horizontal), while the second scan mirror 508 scans in the other direction (e.g., vertical). Furthermore, in a typical implementation of such an embodiment, the first scan mirror 504 operates to provide scanning motion at a given rate (e.g., a relatively slow scan rate), while the second scan mirror 508 operates to provide motion at a different rate (e.g., a relatively fast scan rate). Together, this results in the scanning of the laser light pulses into a scan trajectory (e.g., scan trajectory 112). Furthermore, it should be noted that the labels "vertical" and "horizontal" used herein are somewhat arbitrary, as a 90 degree rotation of the scanning laser device completely switches between horizontal and vertical axes.

[0114] The output of the first scanning mirror 504 is sent to expansion optics 506. Generally, the expansion optics 506 is implemented to provide expansion of the scan field in one or more directions. For example, the expansion optics 506 can be implemented to provide angular expansion along the axis of motion of the first scanning mirror 504. Thus, in an example where the first scanning mirror 504 provides a relatively slow scan along the horizontal axis, the expansion optics 506 can be implemented to increase the scan angle along the horizontal direction. As a specific example, the first scanning mirror 504 can be implemented to provide a 40-degree scan angle in the horizontal direction, and the expansion optics 506 can be implemented to expand the scan angle to 110 degrees, thus expanding the size of the resulting scan trajectory and scan field.

[0115] To provide this expansion, expansion optics 506 can be implemented using one or more lenses configured to together provide the desired angular expansion. In one specific example, expansion optics 506 is implemented using three separate lenses. A description of such an embodiment is provided in detail below.

[0116] The output of the expanding optics 506 is sent to a second scan mirror 508. Again, the first scan mirror 504 provides one axis of motion (e.g., horizontal) while the second scan mirror 508 provides another, usually orthogonal, axis of motion (e.g., vertical). Additionally, the first scan mirror 504 and the second scan mirror 508 operate at different scan rates. In one particular embodiment, the second scan mirror 508 provides a high-rate vertical scan while the first scan mirror 504 provides a low-rate horizontal scan.

[0117] Thus, during operation, optical assembly 500 operates to receive laser light pulses and scan those laser light pulses in a scan trajectory pattern within a scan field.

[0118] Referring now to FIG. 5B, a representation of optical expansion within a scan field is shown in graph 510. Specifically, graph 510 shows output directivity angle expansion as a function of scan angle along a first axis, which also corresponds to a first axis within the resulting scan field. This output angle expansion is an example of the type of optical expansion that may be provided by expansion optics of a scanning laser device (e.g., expansion optics 108 of FIG. 1 , expansion optics 506 of FIG. 5A ). The optical expansion shown in graph 510 is non-uniform with respect to the first axis, and more specifically, results in non-linear optical expansion with respect to an axis within the scan field. This non-uniform, non-linear optical expansion results in a higher rate of optical expansion variation in the lateral regions of the scan field along the first axis compared to a lower rate of optical expansion variation in the central region. This is indicated by the gradually steeper slope of the function curve as the distance from the center increases.

[0119] Referring now to FIG. 5C , graph 512 illustrates an exemplary scan trajectory 513. During operation of the scanning laser device, laser light pulses impinge on an object at a series of scan locations or measurement points along scan trajectory 513. Scan trajectory 513 is an example of a type of scan trajectory that may be generated using a scanning laser device including expansion optics that provide non-uniform optical expansion relative to a first axis (e.g., expansion optics 108 of FIG. 1 , expansion optics 506 of FIG. 5A ). More specifically, scan trajectory 513 is an example of a type of trajectory that may be generated using optical expansion as illustrated in graph 510 of FIG. 5B . Thus, scan trajectory 513 illustrates the results of non-uniform, non-linear optical expansion, with higher rates of output angle expansion variation being created in lateral regions of the scan field along the first axis compared to lower rates of output angle expansion variation generated in the central region.

[0120] The scan trajectory 513 is generated by the movement of one or more scanning mirrors, which provide deflection of the laser light pulse along a first axis and a second axis, with the non-uniform expansion being provided by one or more expansion optics. In this illustrated example, the first axis of scanning motion is relatively slow, while the second axis of scanning motion is relatively fast. Also, in this example, the first axis of motion is horizontal, while the second axis of motion is vertical (although it should be noted that the labels "vertical" and "horizontal" are somewhat arbitrary).

[0121] Finally, it should be noted that scan trajectory 513 is just one example of a trajectory that may result in non-uniform variation in optical expansion, and many other implementations are possible.

[0122] 5B and 5C can result in variations in the effective range of the scanning laser detector. Specifically, variations in optical expansion can result in variations in beam width and beam divergence, which can result in variations in the effective range of the scanning laser device. Accordingly, in some embodiments, the light source controller (e.g., light source controller 101) is configured to vary the energy level of the set of laser light pulses to provide a desired effective range of the sensor by at least partially compensating for the effects of non-uniform optical expansion provided by the expansion optics.

[0123] 5D, a representation of the energy level adjustments of a set of laser light pulses is shown in graph 514. Specifically, graph 514 shows the energy level adjustments as a function of scan angle along a first axis, which also corresponds to the first axis of the resulting scan field. Notably, the illustrated energy level adjustments can be thought of as a percentage increase in energy level from a low power state or a percentage decrease in energy level from a high power state.

[0124] Again, in one embodiment, the light source controller (e.g., light source controller 101) is configured to vary the energy in proportion to the non-uniform change in optical expansion. Again, such variations can be applied to either the long-range ranging pulse set, the short-range emission control pulse set, or both. Thus, laser light pulses that experience greater optical expansion are generated at greater energy levels, and vice versa. This increase in energy level compensates for the reduction in effective range that would normally occur due to an increased amount of optical expansion in order to provide the desired effective range of the detector and scanning laser device.

[0125] As described above, in some embodiments, a scanning laser device (e.g., scanning laser device 100) is implemented to provide improved coverage that varies across the scan field, with different coverage in different areas of the scan field. In these embodiments, these different coverages are facilitated by varying the energy level of the sets of laser light pulses to adjust both the energy level of the desired coverage in an area of ​​the scan field and the amount of optical expansion in that area of ​​the scan field.

[0126] Referring now to FIG. 5E, a schematic diagram of a scanning laser device 520 is shown. Specifically, FIG. 5E shows the scanning laser device 520 implemented with three different exemplary scan fields 522, 524, and 526, each having a different effective range and a different angular field of view. As an example, these different effective ranges can be provided by implementing the scanning laser device 520 to operate in different modes at different times during operation, each having a different range and / or a different angular field of view. For example, the scanning laser device 520 can be implemented to change or otherwise switch between different range modes in response to various factors. In other embodiments, described in more detail below, the scanning laser device 520 can be implemented to provide these different ranges during different portions of the same scan trajectory.

[0127] In the example of Figure 5E, there are three range modes: close range mode, medium range mode, and long range mode. In this example, the close range mode provides a scan field 526 with a 60 meter effective range and a 110 degree angular scan field. The medium range mode provides a scan field 524 with a 120 meter effective range and a 50 degree angular scan field. Finally, the long range mode provides a scan field 522 with a 200 meter effective range and a 25 degree angular scan field. Of course, these are merely examples, and other implementations are possible.

[0128] To implement these different range modes in scanning laser device 520, a light source controller (e.g., light source controller 101) varies the energy level of a set of laser light pulses to achieve the desired range. The three different angular extents of scan fields 522, 524, and 526 can be achieved for these three modes by dynamically changing the angular range of mirror deflection. In other embodiments, the angular range of mirror deflection can remain constant, and the angular extent of scan fields 522, 524, and 526 can remain varied by selectively not delivering laser light pulses when the mirror is outside the desired angular extent of the desired angular scan field. In either case, scanning laser device 520 can provide the desired effective range and desired angular extent of the scan field for each different operating mode.

[0129] It should be noted that the near range mode, medium range mode, and long range mode may each be implemented with the same or different safety ranges for radiation control. Thus, in some examples, the safety ranges within which an object is detected by the radiation control pulse sets may differ for each range. Thus, the energy of the radiation control pulse sets may be varied to provide these different safety ranges.

[0130] Referring now to FIG. 5F, graph 530 shows a representation of the energy levels of a set of laser light pulses. Graph 530 illustrates the energy levels of a set of laser light pulses for three range modes: long range mode, medium range mode, and close range mode. These modes correspond to exemplary scan fields 522, 524, and 526 shown in FIG. 5E. Thus, in the long range mode, scanning laser device 520 operates to have a 200 meter range with a relatively narrow 25 degree field of view. In the medium range mode, scanning laser device 520 operates to have a 120 meter range and a 50 degree field of view. In the close range mode, scanning laser device 520 operates to have a 60 meter range and a relatively wide 110 degree field of view. Thus, the energy levels of the set of laser light pulses are adjusted to provide these desired ranges while also accounting for any non-uniform optical expansion provided by the expansion optics.

[0131] Graph 530 shows energy level adjustments for three different modes as a function of scan angle along a first axis, which also corresponds to the first axis of the resulting scan field. In this case, the light source controller (e.g., light source controller 101) is configured to provide a relatively constant, high energy level for the long range modes because the relatively narrow field of view limits the optical expansion of these pulses. In this example, the energy level of the set of laser light pulses is at or near 100% of the full pulse energy.

[0132] However, for the mid-range and near-range modes, the light source controller is configured to vary the energy in proportion to the non-uniform variation in optical expansion over the angular range covered by that mode, thereby allowing the desired range to be achieved for both modes while compensating for the effects of non-uniform optical expansion.

[0133] The examples of FIGS. 5E and 5F show implementations of a scanning laser device 520 with distinct modes having different effective ranges and different angular scan fields 522, 524, and 526. Again, in such implementations, the scanning laser device 520 can be implemented to switch between modes in various patterns and / or based on various factors. In these examples, each mode had a relatively constant range across its respective scan field. However, in other embodiments, the scanning laser device 520 can instead be implemented to provide these different ranges during different portions of the same scan frame, effectively providing dynamic range shaping across the scan field. To facilitate this, the scanning laser device 520 can be implemented to change its effective range at various points within each scan trajectory or scan frame. Thus, at these points within the scan trajectory, the effective range can be increased or decreased to dynamically achieve the desired range across the scan field.

[0134] 5G, there is shown a schematic diagram of a scanning laser device 520 having multiple effective ranges. Specifically, FIG. 5G shows the scanning laser device 520 implemented to provide a scan field 532 having three different effective ranges, different ranges across different angular regions of the scan field 532. Again, such dynamic range shaping can be achieved by implementing the scanning laser device 520 to adjust the pulse energy at different points within the scan trajectory.

[0135] 5G, scan field 532 has a near range region 534 having a range of 60 meters, corresponding to an extended output angle between 25 degrees and 55 degrees and between -25 degrees and -55 degrees. Similarly, scan field 532 has a medium range region 536 having a range of 120 meters, corresponding to an extended output angle between 12.5 degrees and 25 degrees and between -12.5 degrees and -25 degrees. Finally, scan field 532 has a long range region 538 having a range of 200 meters, corresponding to an extended output angle between 0 degrees and 12.5 degrees and between 0 degrees and -12.5 degrees. Thus, scanning laser device 520 provides three distinct ranges across each scan track or frame.

[0136] Note that the example of Figure 5G can be thought of as a superposition of the three range modes shown in Figure 5E. Specifically, this example also provides a "long range area" (e.g., a central region with a range of 200 meters), a "medium range area" (e.g., a middle region with a range of 120 meters), and a "close range area" (e.g., an outer region with a range of 60 meters) over each scan orbit. The scanning laser device 520 can achieve this dynamic range shaping by varying the pulse set energy to vary the effective range by 25, 12.5-12.5, and -25 degrees, while varying the pulse set energy to compensate for any effects of non-uniform optical expansion provided by the expansion optics.

[0137] Again, it should be noted that the scanning laser device can be implemented to use the same or different safety margins for each of these different areas or angular regions. Thus, in some examples, the safe margins within which an object is detected by the set of emission control pulses may be different for each of these different areas or angular region ranges. Thus, the energy of the set of emission control pulses can be varied to provide these different safety margins.

[0138] 5G provides a scan field 532 with three different effective ranges, this is merely one example implementation, and others are possible. For example, a scanning laser device can be implemented with many effective ranges. Furthermore, the number of ranges and the ranges can be asymmetric, horizontal, and / or vertical.

[0139] 6A and 6B, one application of a scanning laser device (e.g., scanning laser device 100) is shown. Specifically, FIGS. 6A and 6B show a mobile platform having a scanning LiDAR system according to various embodiments. An automobile 602 is a mobile platform on which a LiDAR system 604 is mounted. The LiDAR system may be implemented using various embodiments described above (e.g., scanning laser device 100 of FIG. 1) or any of the scanning laser devices and LiDAR systems described herein.

[0140] The LiDAR system 604 generates an exemplary scan field in which different horizontal regions have different coverage areas. Specifically, as shown in FIGS. 6A and 6B, the LiDAR system 604 can be implemented to selectively facilitate a long-range region 606, a medium-range region 608, and a close-range region 610, each of which has a different angular extent. Again, this can be achieved by operating the LiDAR system 604 in three different range modes, each of which has a different field of view angle, as shown in FIG. 5E. Alternatively, this can be achieved by operating the LiDAR system 604 to provide dynamic range shaping with different regions having different coverage areas, as shown in FIGS. 5G and 5I-4L.

[0141] To implement these different ranges in the LiDAR system 604, the light source controller varies the energy levels of the laser light pulses and pulse sets (including both ranging and emission control pulse sets) to compensate for the optical expansion of the expansion optics and the different desired ranges. In particular, in some embodiments, significant and / or non-uniform optical expansion may be provided in one or both axes. In these embodiments, any variation in energy to compensate for the optical expansion occurs only in the axis with significant optical expansion.

[0142] 7A and 7B, side and top views of an exemplary scanning laser device 700 are shown. Scanning laser device 700 is an example of a type of device that may be implemented with the emission control techniques described above (e.g., methods 300, 350, and 360). In this manner, scanning laser device 700 may be implemented to selectively emit a set of relatively low-energy emission control pulses used to detect when an object (e.g., a person) is within a relatively close safety range, and then conditionally emit a set of long-range ranging pulses only when no object is detected within the safety range, thus improving eye safety. According to embodiments described herein, these sets of emission control pulses are emitted with variable timing (e.g., variable time durations or delays between sets of emission control pulses) and / or variable energy (e.g., further reduced energy levels) based in part on the detection of an object within the safety range.

[0143] In one embodiment, scanning laser device 700 is an optical LiDAR system used for object detection and / or 3D map generation. Scanning laser device 700 includes a laser light source 702 and an optical assembly 704. Optical assembly 704 is an example of a type of optical assembly that may be used in a LiDAR or other scanning laser device (e.g., scanning laser device 100) according to embodiments described herein. Thus, optical assembly 704 includes various optical elements used to facilitate scanning. Note that FIGS. 7A and 7B are simplified examples and therefore do not show all of the elements or features of a fully implemented scanning laser device or optical assembly.

[0144] The optical assembly 704 shown in FIG. 7A includes a beam shaping optical system 714, a first prism 716, a first scanning mirror assembly 717, a first scanning mirror 718, an expansion optical system including three expansion lenses 720, 722, and 724, a second prism 726, a second scanning mirror assembly 727, and a second scanning mirror 728.

[0145] During operation of the scanning laser device 700, the laser source 702 generates laser light pulses that are scanned in a scan trajectory by the optical assembly 704. For example, the laser source 702 may comprise one or more infrared (IR) lasers driven by field effect transistors (FETs) to generate IR laser light pulses.

[0146] Generally, pulses from multiple IR laser sources are first combined and shaped by beam shaping optics 714 and associated optical elements. Thus, beam shaping optics 714 can include any optics for modifying the beam shape of the laser light pulses. For example, beam shaping optics 714 can include collimating lenses, polarization combiners, anamorphic prism pairs for improved divergence, and other such elements. In one embodiment, a pick-off beam splitter or prism 703 is implemented within beam shaping optics 714 to direct reflections to a detector (not shown in FIGS. 7A and 7B ) configured for relatively short-range pulse detection.

[0147] The output of the beam shaping optics 714 is sent to a first prism 716, which kicks the beam up to a first scanning mirror 718. In this illustrated embodiment, the first scanning mirror 718 provides horizontal scanning motion, while the second scanning mirror 728 provides vertical scanning motion. Furthermore, in this example, the first scanning mirror 718 is driven to provide scanning motion at a relatively slow scan rate, while the second scanning mirror 728 is driven to provide motion at a relatively slow scan rate. However, these are merely examples, and other implementations are possible. Together, this scanning mirror motion results in the scanning of the laser light pulses into a scanning trajectory. Again, it should be noted that the labels "vertical" and "horizontal" used herein are somewhat arbitrary, as a 90-degree rotation of the scanning laser device effectively switches between horizontal and vertical axes.

[0148] The output of the first scan mirror 718 is sent to three expansion lenses 720, 722, and 724 which together provide expansion optics. Typically, the expansion optics are implemented to provide expansion of the scan field in the horizontal direction.

[0149] Specifically, in this depicted example, three expansion lenses 720, 722, and 724 are implemented to image the output of first scan mirror 718 onto second scan mirror 728 while providing non-uniform expansion in the horizontal direction. As a specific example, first scan mirror 718 can be implemented to provide a 40 degree scan angle in the horizontal direction, and expansion lenses 720, 722, and 724 can be implemented to provide non-uniform expansion that widens the scan angle to 110 degrees.

[0150] In one example, three expansion lenses 720, 722, and 724 implement a 4F optical system that images the output of the first scan mirror 718 onto the second scan mirror 728. Specifically, the three expansion lenses 720, 722, and 724 provide a 4F optical system with magnification that varies with the angle coming from the first scan mirror 718. The result of these three expansion lenses 720, 722, and 724 is a non-uniform change in optical expansion with the output scan angle provided by the first scan mirror 718. A second prism 726 accepts the output of the third expansion lens 724 and directs the beam to the second scan mirror 728.

[0151] Referring now to FIG. 8 , a scanning light detection and ranging (LiDAR) system 800 is shown in accordance with various embodiments. The system 800 includes a pulse generation circuit 890, an infrared (IR) laser light source 830, a scanning mirror assembly 814 having a scanning mirror 816, and a mirror drive and control circuit 854. The system 800 also includes a first infrared (IR) detector 842, a first time-of-flight (TOF) measurement circuit 844, a 3D point cloud storage circuit 886, a first comparator 848, and an emission control circuit 880. The system 800 also includes a second IR detector 1842, a second TOF measurement circuit 1844, and a second comparator 1848. As described in more detail below, the second IR detector 1842 can be implemented to provide redundant, relatively short-range detection.

[0152] LiDAR system 800 is another example of a type of scanning laser device that may be implemented in accordance with embodiments described herein (e.g., methods 300, 350, 360). In this example, emission control circuitry 880 and pulse generation circuitry 890 function as all or part of a light source controller, thus controlling laser light source 830 to selectively emit a set of relatively low-energy emission control pulses used to detect when an object (e.g., a person) is within a relatively close safety range. A set of high-energy, long-range pulses is then conditionally emitted only when an object is not detected within the safety range, thus improving eye safety. According to embodiments described herein, these sets of emission control pulses are emitted with variable timing (e.g., variable time durations or delays between sets of emission control pulses) and / or variable energy (e.g., further reduced energy levels) based in part on the detection of an object within the safety range.

[0153] Laser light source 830 may be a laser light source, such as a laser diode, that can emit laser beam pulses 862. Beam pulses 862 strike a scanning mirror assembly 814, which in some embodiments is part of a microelectromechanical systems (MEMS)-based scanner or the like, and reflect off a scanning mirror 816 to generate controlled output beam pulses 834. In some embodiments, optical elements are included in the optical path between laser light source 830 and mirror 816. For example, system 800 may include a collimating lens, a dichroic mirror, extended optics, or any other suitable optical element. Also, as described above, the scanning mirror, extended optics, and other elements can cause back-reflection of the laser light pulses toward second IR detector 1842 during operation of system 800.

[0154] Scan mirror drive and control circuitry 854 provides one or more drive signals 855 to control the angular motion of scan mirror 816 so that output beam pulse 134 traverses scan trajectory 840 within scan field 828. In operation, laser source 830 generates modulated light pulses in the non-visible spectrum, and scan mirror 816 reflects the light pulses as beam pulse 834 traverses scan trajectory 840.

[0155] In some embodiments, the scan trajectory 840 is formed by combining a sawtooth component on the horizontal axis with a sinusoidal component on the vertical axis. In yet further embodiments, the horizontal sweep is also sinusoidal. Various embodiments of the present invention are not limited by the waveforms used to control the vertical and horizontal sweeps or the resulting scan trajectory pattern. One axis (e.g., horizontal) is the slow-scan axis and the other axis is the fast-scan axis.

[0156] Although scanning mirror 816 is shown as a single mirror that scans in two axes, this is not a limitation of the present invention. For example, in some embodiments, mirror 816 is implemented using two separate scanning mirrors, one scanning in one axis and a second scanning in a second axis.

[0157] In some embodiments, the scan mirror 816 includes one or more sensors for detecting the angular position or angular degree (in one or both dimensions) of the mirror deflection. For example, in some embodiments, the scan mirror assembly 814 includes a piezoresistive sensor that provides a voltage proportional to the mirror deflection on the fast scan axis. Additionally, in some embodiments, the scan mirror assembly 814 includes an additional piezoresistive sensor that provides a voltage proportional to the mirror deflection on the slow scan axis. Mirror position information is provided back to the mirror drive and control circuit 854 as one or more SYNC signals 815. In these embodiments, the mirror drive and control circuit 854 includes one or more feedback loops for modifying the drive signals in response to the measured angular deflection of the mirror. Additionally, in some embodiments, the mirror drive and control circuit 854 includes one or more phase-locked loop circuits that estimate the instantaneous angular position of the scan mirror based on the SYNC signals.

[0158] The mirror drive and control circuitry 854 may be implemented using functional circuits such as phase-locked loops (PLLs), filters, adders, multipliers, registers, processors, memory, etc. Thus, the mirror drive and control circuitry 854 may be implemented in hardware, software, or any combination. For example, in some embodiments, the control circuitry 854 is implemented in an application specific integrated circuit (ASIC). Furthermore, in some embodiments, part of the high-speed data path control is performed in the ASIC, and the overall control is software programmable.

[0159] System 800 includes two separator IR detectors, a TOF measurement circuit, and a comparator for detecting IR laser pulses. Specifically, system 800 includes a first IR detector 842 and a second IR detector 1842. Generally, first IR detector 842 is implemented to detect reflections from both the emission control (e.g., relatively short range) and ranging pulse sets (e.g., relatively long range), while the second IR detector provides redundant detection of reflections from the low-power emission control pulse set to provide improved eye safety.

[0160] The first IR detector 842 includes one or more photosensitive devices capable of detecting reflections of the IR laser light pulse. For example, the first IR detector 842 may include one or more PIN photodiodes, silicon photomultipliers (SiPMs), avalanche photodiodes (APDs), etc. Each point in the field of view illuminated with the IR laser light pulse (referred to herein as a "measurement point") may or may not reflect some amount of the incident light back to the first IR detector 842. If the first IR detector 842 detects a reflection, the IR detector 842 provides a signal 843 to the first TOF measurement circuit 844.

[0161] The first TOF measurement circuit 844 measures the time of flight (TOF) of the IR laser light pulse to determine the distance to an object within the field of view. In some embodiments, the emission control circuit 880 provides a timing signal (not shown) corresponding to the emission time of a particular IR laser light pulse to the first TOF measurement circuit 844, and the first TOF measurement circuit 844 measures the TOF of the IR laser light pulse by determining the elapsed time between emitting the pulse and receiving a reflection of the same pulse.

[0162] The first TOF measurement circuit 844 may be implemented using any suitable circuitry. For example, in some embodiments, the first TOF measurement circuit 844 includes an analog integrator that is reset when the IR pulse is emitted and stopped when the reflected pulse is received. The first TOF measurement circuit 844 may also include an analog-to-digital converter to convert the analog integrator output into a digital value corresponding to the time-of-flight (TOF) of the IR laser pulse, which corresponds to the distance between the system 800 and an object in the field of view from which the laser light pulse was reflected.

[0163] The 3D point cloud storage device 846 accepts X,Y data from the mirror drive and control circuitry 854 and distance (Z) data on node 845 from the first TOF measurement circuitry 844. A 3-tuple (X, Y, Z) is written to the 3D point cloud storage device for each detected reflection, resulting in a series of 3D points, referred to herein as a "point cloud." Not all X,Y measurement points within the field of view have corresponding Z measurements. Thus, the resulting point cloud may be sparse or dense. The amount of data contained in the 3D point cloud is not a limitation of the present invention.

[0164] The 3D point cloud storage device 846 may be implemented using any suitable circuit structure. For example, in some embodiments, the 3D point cloud storage device 846 is implemented in a dual-port memory device that can be written to one port and read from a second port. In other embodiments, the 3D point cloud storage device 846 is implemented as a data structure within a general-purpose memory device. In further embodiments, the 3D point cloud storage device 846 is implemented in an application-specific integrated circuit (ASIC).

[0165] A first comparator 848 compares the distance data (Z) on node 845 with a threshold, and if the distance is less than the threshold, the first comparator 848 asserts a safe range object detected signal at an input to OR gate 882. The safe range object detected signal passes through OR gate 882 to emission control circuit 880 to indicate the detection of an object within a "safe range," where the "safe range" is determined by the value of the threshold on node 847. For example, if the threshold is set to a value corresponding to a distance of 5 meters, and the detected distance is less than that threshold, an object closer than 5 meters is detected, and emission control circuit 880 is notified by a safe range object detected signal on node 884.

[0166] The threshold value at node 847 and the corresponding safety range distance may be modified by emission control circuit 880 based on any criteria. For example, the threshold value may be a function of IR laser pulse power, pulse duration, pulse density, wavelength, scanner speed, desired laser safety classification, etc. The method for determining the threshold value is not a limitation of the present invention.

[0167] The second IR detector 1842, the second TOF measurement circuit 1844, and the second comparator 1848 operate to provide redundant detection capability for reflections of the emission control pulse set from objects within a safe range. The redundant detection of the emission control pulse set provides an additional measure of safety. For example, if one or more of the IR detectors, TOF measurement circuit, or comparator fails, the redundancy ensures continued safe operation.

[0168] It should be noted that the first IR detector 842 and the second IR detector 1842 receive the reflected light pulses through different optical paths. Specifically, the first IR detector 842 receives the reflected light along a separate path indicated at 835, while the second IR detector 1842 shares at least a portion of the optical path with the emitted light pulses. Specifically, the reflected light from the scan field reflects back through mirror 816, the extended optics, and at least some of the other elements in the optical assembly to reach the second IR detector 1842 along path 1835.

[0169] The second TOF measurement circuit 1844 measures the time-of-flight (TOF) of the IR laser light pulses to determine the distance to objects in the field of view in a manner similar to the first TOF measurement circuit 844. Thus, the second TOF measurement circuit 1844, like the first TOF measurement circuit 844, may be implemented using any suitable circuitry.

[0170] Similarly, a second comparator 1848 compares the distance data (Z) on node 845 with a threshold, and if the distance is less than the threshold, the second comparator 1848 asserts a safe range object detected signal at an input to OR gate 882. Again, this safe range object detected signal passes through OR gate 882 to emission control circuit 880 to indicate the detection of an object within a relatively short "safe range," where the "safe range" is determined by the value of the threshold on node 1847. For example, if the threshold is set to a value corresponding to a distance of 5 meters, and the detected distance is less than the threshold, then an object closer than 5 meters has been detected, and emission control circuit 880 is notified by a safe range object detected signal on node 884.

[0171] Again, the threshold at node 1847 and the corresponding safety range distance may be modified by emission control circuit 880 based on any criteria. For example, the threshold may be a function of IR laser pulse power, pulse duration, pulse density, wavelength, scanner speed, desired laser safety classification, etc.

[0172] In some embodiments, both the detection circuitry and the TOF measurement circuitry operate to detect short-range objects (e.g., objects within a safe range), and only one of the detection circuitry and the TOF measurement circuitry operates to measure long-range distances and / or write to the 3D cloud storage device. For example, in the embodiment represented by FIG. 8, the time-of-flight measured by either the TOF measurement circuitry 1844 or the TOF measurement circuitry 1844 can be used to detect objects within the safe range using emission control pulse sets, but only the time-of-flight measured by the TOF measurement circuitry 844 is used to populate the 3D point cloud.

[0173] The emission control circuit 880 operates to manage accessible emission levels so that overall operation may remain eye-safe. For example, in some embodiments, the emission control circuit 880 controls whether a short-range emission control pulse set or a long-range ranging pulse set is generated by setting a pulse set energy value on node 885. The emitted pulse set energy may be controlled by one or more of pulse power, pulse duration, or pulse count. The emission control circuit 880 may also control the timing of the emitted pulses via a timing signal on node 857. For example, the emission control circuit may control the timing and energy of the emission control pulse set and the ranging pulse set. According to embodiments described herein, these emission control pulse sets are emitted with variable timing (e.g., variable time durations or delays between emission control pulse sets) and / or variable energy (e.g., further reduced energy levels) based in part on the detection of an object within a safe range.

[0174] The emission control circuit 880 may be implemented using any suitable circuit structure. For example, in some embodiments, the emission control circuit 880 may include one or more finite state machines implemented using digital logic to respond to object detection within a safe range, and a conditional signal pulse generation circuit 890 that emits long-range pulse sets. Furthermore, in some embodiments, the emission control circuit 880 may include a processor and memory to provide software programmability for emission control and ranging pulse set energies, thresholds, etc. The manner in which the emission control circuit 880 is implemented is not a limitation of the present invention.

[0175] 9 , a scanning light detection and ranging (LiDAR) system 1300 is shown in accordance with various embodiments. The LiDAR system 1300 includes an emission control circuit 1384, a pulse generation circuit 1390, a three-dimensional point cloud storage device 1346, an OR gate 1380, and a control circuit 1354. The LiDAR system 1300 also includes a transmission module 1310, a reception module 1330, a TOF and short range detection circuit 1340, and a TOF and short range detection circuit 1350.

[0176] LiDAR system 1300 is another example of a type of scanning laser device that can be implemented in accordance with embodiments described herein (e.g., methods 300, 350, 360). In this example, emission control circuitry 1384, pulse generation circuitry 1390, functions as a light source controller, specifically controlling send module 1310 to selectively emit a set of relatively low-energy emission control pulses used to detect when an object (e.g., a person) is within a relatively close safety range. A set of high-energy, long-range pulses is then conditionally emitted only when an object is not detected within the safety range, thus improving eye safety. According to embodiments described herein, these sets of emission control pulses are emitted with variable timing (e.g., variable time durations or delays between sets of emission control pulses) and / or variable energy (e.g., further reduced energy levels) based in part on the detection of an object within the safety range.

[0177] The LiDAR system 1300 includes two separate IR detectors and TOF and short-range detection circuitry for detecting reflections of the IR laser pulses. Specifically, the receive module 1330 includes a first IR detector implemented to detect reflections from both the short-range pulse set (e.g., the emission control pulse set) and the long-range pulse set (e.g., the ranging pool), while the transmit module 1310 includes a second IR detector that provides redundant detection of reflections from the relatively low-energy short-range emission control pulse set to provide improved eye safety.

[0178] The delivery module 1310 includes an IR laser light source for generating a pulsed laser beam, collimating and focusing optics, and one or more scanning mirror assemblies mounted together in an optical assembly for scanning the pulsed laser beam in two dimensions within a field of view. The delivery module 1310 also includes an IR laser light detector that shares an optical path with the emitted IR laser light pulses. Exemplary embodiments of the delivery module are described more fully below with reference to subsequent figures.

[0179] The reception module 1330 includes an optical device and one or more scanning mirror assemblies that scan reflected light from the field of view in two dimensions to direct it onto an integrated IR photodetector. Exemplary embodiments of the reception module are described more fully below with reference to subsequent figures.

[0180] Each of the TOF and short range detection circuits 1340 and 1350 includes a TOF measurement circuit and a comparator. For example, the TOF and short range detection circuit 1340 may include the TOF circuit 1844 and a second comparator 1848, and the TOF and short range detection circuit 1350 may include the TOF measurement circuit 844 and a comparator 848 (FIG. 8).

[0181] 8, the control circuit 1354 controls the movement of the scanning mirror in the send module 1310. The control circuit 1354 also controls the movement of the scanning mirror in the receive module 1330. In operation, the control circuit 1354 receives mirror position feedback information (not shown) from the send module 1310 and also receives mirror position feedback information (not shown) from the receive module 1330. The mirror position feedback information is used to phase lock the operation of the mirror.

[0182] Control circuitry 1354 drives the microelectromechanical (MEMS) assembly comprising the scanning mirror in transmit module 1310 with drive signals 1345 and the MEMS assembly comprising the scanning mirror in receive module 1330 with drive signals 1347, causing the mirror to move with a degree of angular mirror deflection that defines scan trajectory 1342 and the size and position of scan field 1328. Synchronization of the transmit and receive scans allows the receive aperture to receive photons only from the portion of the field of view from which the transmitted energy was emitted, thereby providing significant immunity to ambient light noise.

[0183] The emission control circuitry 1384 and the pulse generation circuitry 1390 control the timing and energy of the pulses emitted by the delivery module 1310. For example, the pulse generation circuitry 1390 may include a laser light source controller configured to vary the energy level of the laser light pulses emitted by the delivery module 1310. In this manner, the emission control circuitry 1384 may be implemented to control the timing and energy of the emitted sets of emission control pulses and ranging pulses to implement the emission control methods 300, 350, and 360 described above.

[0184] 10A and 10B, FIG. 10A shows a side view of a send module 1400, and FIG. 10B shows a top view thereof. The send module 1400 is an example of a send module that may be used in a LiDAR system (e.g., send module 1310 of FIG. 9). Thus, the send module 1400 is another example of a type of device that may be implemented using the radiation control techniques described above (e.g., methods 300, 350, and 360). The send module 1400 includes a laser light source 1410, a beam shaping optics device 1420, an incoming energy pickoff device 1460, a mirror 1462, a beam shaping device 1464, an IR detector 1466, a scanner 1428, and an output optics device 1450.

[0185] In some embodiments, the laser light source 1410 generates non-visible light, such as infrared (IR) light. In these embodiments, the IR detector 1466 detects non-visible light of the same wavelength as the IR detector in the receiving module 1600 (FIG. 11, described below). For example, in some embodiments, the laser light source 1410 may include a laser diode that generates infrared light having a wavelength of substantially 905 nanometers (nm), and the IR detector 1466 detects reflected light pulses having a wavelength of substantially 905 nm. Also, for example, in some embodiments, the laser light source 1410 may include a laser diode that generates infrared light having a wavelength of substantially 940 nanometers (nm), and the IR detector 1466 detects reflected light pulses having a wavelength of substantially 940 nm. The wavelength of the light is not a limitation of the present invention. Any wavelength, visible or invisible, may be used without departing from the scope of the present invention.

[0186] The laser source 1410 may include any number or type of emitters suitable for generating a pulsed laser beam. For example, in some embodiments, the laser source 1410 includes multiple laser diodes, shown at 1512, 1514, 1516, and 1518 in FIG. 10B . The pulsed laser light generated by the laser source 1410 is combined, collimated, and focused by the beam shaping optical device 1420 to generate a pulsed laser beam. For example, optical devices 1522, 1524, 1526, and 1528 may collimate the laser beam on the fast axis, polarization rotator 1523 and beam combiner 1520 may combine the laser beams, and optical device 1522 may fan the pulsed laser beam on the slow axis. Beam size and divergence values ​​are not necessarily uniform across various embodiments of the present invention, with some embodiments having high values ​​and some having low values.

[0187] 10A and 10B, the scanner 1428 includes two separate scanning mirror assemblies 1430, 1440, each including a scanning mirror 1432, 1442, each scanning mirror scanning the beam in one dimension. For example, the scanning mirror 1432 scans the pulsed beam in a fast scan direction, and the scanning mirror 1442 scans the pulsed beam in a slow scan direction.

[0188] Although scanner 1428 is shown as including two scanning mirror assemblies, each assembly scanning in a separate dimension, this is not a limitation of the present invention. For example, in some embodiments, scanner 1428 is implemented using a single two-axis scanning mirror assembly that scans in two dimensions. In some embodiments, the scanning device uses electromagnetic actuation achieved using a miniature assembly including a small subassembly of a MEMS die and permanent magnet and an electrical interface, although various embodiments are not limited in this respect.

[0189] The output optical device 1450 operates on the scanned pulsed laser beam as it exits the send module. In some embodiments, the output optical device 1450 performs field expansion. For example, the scanner 1428 may scan by a maximum angular extent of 20 degrees on the fast scan axis and by a maximum angular extent of 40 degrees on the slow scan axis, and the output optical device 1450 may expand the field of view to 30 degrees on the fast scan axis and 120 degrees on the slow scan axis. The relationship between the scan angle of the scanning mirror and the amount of field expansion provided by the output optical device 1450 is not a limitation of the present invention.

[0190] The received energy pick-off device 1460 deflects the received light (shown as dotted lines) that shares at least a portion of the outgoing light path with the emitted light pulse (shown as solid lines). The deflected received light is then reflected by a mirror 1462, collected by an optical device 1064, and detected by an IR detector 1466. In some embodiments, the pick-off device 1460 includes a "window" that transmits the pulsed beam generated by the IR laser source and a reflective outer portion that deflects the received energy outside the window. In other embodiments, the pick-off device 1460 is a partial reflector that transmits a portion of the incident light and reflects the remainder. For example, a reflector that transmits 90% of the incident light and reflects 10% of the incident light would provide the IR detector 1466 with 10% of the light reflected from objects within its field of view. In a further embodiment, the pick-off device 1460 may incorporate a polarizing beam splitter that transmits the pulsed laser beam (at a first polarization) and picks off the received light of a different polarization. This is effective, in part, because the reflections are randomly polarized due to Lambertian reflection. In a further embodiment, the emitted laser beam and the received energy may be directed to different portions of the scanning mirror, and the pick-off device 1460 may be an offset mirror positioned to reflect one but not the other.

[0191] Again, to facilitate reliable detection of the low-energy emission control pulse sets, the IR detector 1466 can be implemented with multiple sensors configured to accept reflections through at least some of the same optical assemblies used to transmit laser light pulses into the scan field. Specifically, the IR detector 1466 can be configured to accept laser light pulses through the same scanning mirrors 1432, 1142, output optical device 1450, and other optical elements used to transmit laser light pulses into the scan field. Because the same optical assemblies are used by multiple sensors to accept laser light reflections, damage or obstructions that prevent the multiple sensors from accepting reflections from the emission control pulse sets can also block the scanning of the laser light pulses into the scan field. Thus, the IR detector 1466 can reliably detect emission control pulse sets that strike objects within a safe range of the scan field and reflect back toward the detector, and can therefore be used to reliably determine when long-range pulse sets can be safely emitted. Furthermore, the multiple sensors in the IR detector 1466 are configured to at least partially cancel out the effects of back reflections from within the optical assemblies. Canceling the effects of back reflections from within the optical assembly can improve the sensitivity of the detector, particularly for detecting low energy radiation controlled reflections from within the scan field.

[0192] Also, as described above, the delivery module 1400 can be implemented with a laser source controller configured to vary the energy level of the set of laser light pulses depending on the position along the first axis of the scan field. The variation in the energy level of the set of laser light pulses is performed to provide the desired coverage of the sensor while at least partially compensating for the effects of non-uniform optical expansion provided by the expansion optics. For example, in one embodiment, the source controller is configured to vary the energy in proportion to the non-uniform variation in optical expansion. Thus, laser light pulses that experience greater optical expansion are generated at greater energy levels. Furthermore, the laser source controller can be configured to vary the energy to facilitate different coverage in different scan regions of the scan field.

[0193] 11A and 11B, FIG. 11A illustrates a side view of a reception module 1600, and FIG. 11B illustrates a top view thereof. The reception module 1600 is an example of a reception module that may be used in a LiDAR system (e.g., reception module 1330 of FIG. 9). As such, the reception module 1600 is another example of a type of device that may be implemented using the radiation control techniques described above (e.g., methods 300, 350, and 360). The reception module 1600 includes an IR detector 1610, a folding mirror 1612, an imaging optical device 1620, a bandpass filter 1622, a scanner 1628, and an output optical device 1650.

[0194] Scanning mirror assemblies 1630 and 1640 are similar to or identical to scanning mirror assemblies 1430 and 1440, and output optical device 1650 is similar to or identical to output optical device 1450. Bandpass filter 1422 transmits the wavelength of light generated by laser source 1410 and blocks ambient light of other wavelengths. For example, in some embodiments, the laser source generates light at 905 nm and bandpass filter 1622 transmits light at 905 nm.

[0195] Imaging optical device 1620 images a portion of the field of view onto IR detector 1610 after reflection by folding mirror 1612. Scanner 1628 scans synchronously with scanner 1428 so that detector 1610 constantly collects light from the measurement point illuminated by the scanned pulsed beam.

[0196] 12 is a perspective view of an integrated photonics module according to various embodiments of the present invention. The integrated photonics module 1800 includes both the send module 1400 (FIGS. 10A and 10B) and the receive module 1600 (FIGS. 11A and 11B). The integrated photonics module 1800 is shown having a rectangular housing with the send module 1400 and the receive module 1600 arranged side by side. In some embodiments, the send module 1400 and the receive module 1600 are arranged one on top of the other.

[0197] In the foregoing detailed description, reference has been made to the accompanying drawings, which show, by way of illustration, specific embodiments in which the invention may be practiced. These embodiments have been described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that various embodiments of the invention, although different, are not necessarily mutually exclusive. For example, a particular feature, structure, or characteristic described herein in connection with one embodiment may be implemented within other embodiments without departing from the scope of the invention. It is further to be understood that the location or arrangement of individual elements within each disclosed embodiment may be modified without departing from the scope of the invention. Therefore, the foregoing detailed description is not to be construed in a limiting sense, and the scope of the present invention is defined solely by the appended claims, appropriately interpreted, along with the full scope of equivalents to which such claims are entitled. In the drawings, like reference numerals refer to the same or similar functionality throughout the several views.

[0198] Although the present invention has been described with reference to specific embodiments, it should be understood that modifications and variations, as would be readily apparent to one skilled in the art, may be employed without departing from the scope of the invention, and such modifications and variations are considered to be within the scope of the invention and the appended claims.

Claims

1. a laser light source configured to generate pulses of laser light; an optical assembly including beam scanning optics for scanning the laser light pulses within a scan field; a detector for detecting reflections of the laser light pulses from within the scan field; a light source controller coupled to the laser light source and the detector, the light source controller comprising: emitting a first set of radiation control pulses at a reduced first energy level; emitting a set of ranging pulses at a high energy level greater than the reduced first energy level in response to not detecting an object within a safe range using a reflection of the first set of emission-control pulses; emitting a second set of emission control pulses a first time period following the first set of emission control pulses and at a reduced second energy level in response to not detecting an object within the safety range using a reflection of the first set of emission control pulses; emitting an adjusted second set of emission control pulses in response to detecting an object within the safety range using a reflection of the first set of emission control pulses, the adjusted second set of emission control pulses including at least one of an extended first time period following the first set of emission control pulses and a further reduced second energy level relative to the reduced second energy level; a light source controller adapted to control the laser light source to perform An apparatus comprising:

2. The light source controller: emitting a third set of emission control pulses in response to not detecting an object within the safety range using a reflection of either the second set of emission control pulses or the adjusted second set of emission control pulses, the third set of emission control pulses comprising a second time period following either the second set of emission control pulses or the adjusted second set of emission control pulses and a reduced third energy level; emitting an adjusted third set of emission control pulses in response to detecting an object within the safety range using a reflection of either the second set of emission control pulses or the adjusted second set of emission control pulses, the adjusted third set of emission control pulses including at least one of an extended second time period following either the second set of emission control pulses or the adjusted second set of emission control pulses and a further reduced third energy level relative to the reduced third energy level; 10. The apparatus of claim 1, further adapted to control the laser light source to perform:

3. The light source controller: emitting a plurality of adjusted emission control pulse sets in response to detecting an object within the safety range using a reflection of the adjusted second emission control pulse set, each of the plurality of adjusted emission control pulse sets including at least one of an extended first time period following the first emission control pulse set and a further reduced second energy level relative to the reduced second energy level.

10. The apparatus of claim 1, further adapted to control the laser light source to perform:

4. The apparatus of claim 3 , wherein the further reduced second energy level is dynamically adjusted relative to each of the plurality of adjusted sets of emission control pulses.

5. The light source controller: emitting the adjusted second set of emission control pulses in response to detecting an object within the safety range using a reflection of the set of ranging pulses, the adjusted second set of emission control pulses including at least one of an extended first time period following the first set of emission control pulses and a further reduced second energy level relative to the reduced second energy level.

10. The apparatus of claim 1, further adapted to control the laser light source to perform:

6. the light source controller dynamically determining the extended first time period such that the first set of emission control pulses and the adjusted second set of emission control pulses have a combined energy that is less than a pulse set energy limit over a defined time frame.

2. The apparatus of claim 1, wherein the apparatus is adapted to control the laser light source to emit the adjusted second set of radiation control pulses by:

7. The apparatus of claim 6 , wherein the energy limit is a regulatory classification limit.

8. The light source controller: dynamically determining the further reduced second energy level relative to the reduced second energy level such that the first set of emission control pulses and the adjusted second set of emission control pulses have a combined energy that is less than a pulse set energy limit over a defined time frame.

2. The apparatus of claim 1, wherein the apparatus is adapted to control the laser light source to emit the adjusted second set of radiation control pulses by:

9. 10. The apparatus of claim 1, wherein the apparatus further comprises a time-of-flight (TOF) circuit responsive to the detector for determining a distance from the detected reflection to a depth measurement point within the scan field.

10. The apparatus of claim 1 , wherein the ranging pulse set comprises a plurality of pulses modulated with a signature.

11. a laser light source configured to generate pulses of laser light; an optical assembly including beam scanning optics for scanning the laser light pulses within a scan field; a detector for detecting reflections of the laser light pulses from within the scan field; a time-of-flight (TOF) circuit responsive to the detector for determining a distance from the detected reflection to a depth measurement point within the scan field; a light source controller coupled to the laser light source and the TOF circuit, the light source controller comprising: emitting a first set of radiation control pulses at a reduced first energy level; emitting a set of ranging pulses at a high energy level in response to not detecting an object within a safe range using a reflection of the first set of emission-control pulses, the high energy level being greater than the reduced first energy level; emitting a second set of emission control pulses a first time period following the first set of emission control pulses and at a reduced second energy level in response to not detecting an object within the safety range using a reflection of the first set of emission control pulses; emitting an adjusted second set of emission control pulses in response to detecting an object within the safety range using a reflection of the first set of emission control pulses, the adjusted second set of emission control pulses including an extended first time period following the first set of emission control pulses and a further reduced second energy level relative to the reduced second energy level; emitting a third set of emission control pulses in response to not detecting an object within the safety range using a reflection of either the second set of emission control pulses or the adjusted second set of emission control pulses, the third set of emission control pulses comprising a second time period following either the second set of emission control pulses or the adjusted second set of emission control pulses and a reduced third energy level; emitting an adjusted third set of emission control pulses in response to detecting an object within the safety range using a reflection of either the second set of emission control pulses or the adjusted second set of emission control pulses, the adjusted third set of emission control pulses including an extended second time period following either the second set of emission control pulses or the adjusted second set of emission control pulses and a further reduced third energy level relative to the reduced third energy level; a light source controller adapted to control the laser light source to perform An apparatus comprising:

12. 1. A method of radiation control, said method comprising: emitting a first set of radiation control pulses at a reduced first energy level; emitting a set of ranging pulses at a high energy level greater than the reduced first energy level in response to not detecting an object within a safe range using reflections of the first set of emission control pulses; emitting a second set of emission control pulses a first time period following the first set of emission control pulses and at a reduced second energy level in response to not detecting an object within the safety range using a reflection of the first set of emission control pulses; emitting an adjusted second set of emission control pulses in response to detecting an object within the safety range using a reflection of the first set of emission control pulses, the adjusted second set of emission control pulses including at least one of an extended first time period following the first set of emission control pulses and a further reduced second energy level relative to the reduced second energy level; A radiation control method comprising:

13. emitting a third set of emission control pulses in response to not detecting an object within the safety range using a reflection of either the second set of emission control pulses or the adjusted second set of emission control pulses, the third set of emission control pulses comprising a second time period following either the second set of emission control pulses or the adjusted second set of emission control pulses and a reduced third energy level; emitting an adjusted third set of emission control pulses in response to detecting an object within the safety range using a reflection of either the second set of emission control pulses or the adjusted second set of emission control pulses, the adjusted third set of emission control pulses including at least one of an extended second time period following either the second set of emission control pulses or the adjusted second set of emission control pulses, and a further reduced third energy level relative to the reduced third energy level; The method of claim 12 further comprising:

14. emitting a plurality of adjusted sets of emission control pulses in response to detecting an object within the safety range using a reflection of the adjusted second set of emission control pulses, each of the plurality of adjusted sets of emission control pulses including at least one of an extended first time period following the first set of emission control pulses and a further reduced second energy level relative to the reduced second energy level. The method of claim 12 further comprising:

15. emitting the adjusted second set of emission control pulses in response to detecting an object within the safety range using a reflection of the set of ranging pulses, the adjusted second set of emission control pulses including at least one of an extended first time period following the first set of emission control pulses and a further reduced second energy level relative to the reduced second energy level. The method of claim 12 further comprising:

Images