Pixel sensor switched by neighborhood gates

Abstract

To provide an imaging sensor system (26) having a high detection accuracy.SOLUTION: The imaging sensor system (26) comprises a plurality of pixel sensors (1) and at least one light source. The pixel sensors (1) are grouped into clusters and each pixel sensor (1) has a photodetector (2) and a local control circuit (18). The plurality of pixel sensors (1) in each cluster are configured to output a global detection signal (15) using a local control circuit (18) upon detecting a local detection signal (10) from at least two outputs of the photodetectors (2) in the local cluster. In the imaging sensor system (26), since each detection requires at least two positive outputs of the photodetectors (2) in the local cluster, false positive detections are excluded and a high detection accuracy is obtained.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an image sensor system, and more particularly to an image sensor system having high detection accuracy. [Background technology]

[0002] In prior art active imaging scanning, a light beam, typically a laser, is moved over the area to be captured, and the position of the beam's incidence is recorded over time via multiple image sensors. By processing the difference in position from different viewpoints (sensors), the effective distance to the object illuminated by the beam can be determined by triangulation. This measurement captures voxels. The speed at which this processing is performed, the voxel rate, is limited on the one hand by the speed at which the light beam can be scanned, but on the other hand (most strongly) by the processing time required by the sensor to detect the reflected light beam, especially in relation to background radiation (ambient light) and general thermal noise. By specifically addressing this second issue, image formation can be significantly sped up.

[0003] To achieve voxel rates of tens to hundreds of millions of voxels per second, each voxel needs to be recorded in 10 ns or less. Therefore, the sensor also needs to be suitable for operating with a limited photon budget (i.e., the number of impinging photons detected by the sensor that is sufficient for detection), such as 10 photons. With a limited processing time, only a limited number of photons can be collected.

[0004] Existing image processing and imaging systems process the optical input acquired by the sensor either in parallel for all pixels, in the case of a so-called "global shutter," or over time, in the case of a "rolling shutter." In either case, a typical imaging system has a gain factor of 10 μV to 1 mV per impinging electron to generate a recordable signal above the minimum detection voltage. It should be noted that the upper limit of this range can only be guaranteed by very recent imaging devices specifically tailored for photon counting and focused on very low detection rates. Using such specialized sensors, 10 electrons can generate a 10 mV signal, which can be read as a positive by a particular pixel. To detect a package of impinging photons, a minimum of 10 photons must hit the sensor within a 10 ns time span. Prior art has traditionally limited the sensor's exposure time to, say, 10 ns, and read the sensor to trigger an event (i.e., an actual impact of the reflected beam, rather than a false positive due to ambient light or thermal noise) based on a threshold voltage. The drawback of this method is that, especially for high-resolution imagers, the time required to read the sensor dominates the process, typically significantly longer than 10 ns, creating a bottleneck.

[0005] Another drawback is that ambient light or thermal noise in one pixel sensor can result in a false positive, e.g., a false detection.

[0006] Prior art systems, such as those described in WO2019 / 060942A1, feed individual detector signals into an event circuit for each "grouping" or cluster, which generates an event trigger when a particular pattern is recognized (perhaps from a list of possible patterns). Upon recognition, the address or identifier of the identified neural feature (pattern) is read out onto a data bus. Alternatively, the address of the SPAD can be read out. However, this has many drawbacks, as the neural feature circuitry is provided for each cluster, creating potential problems.

[0007] Other systems, such as US2018 / 0225521A1, use pixel-based local event intersection detection, but do not provide an efficient way to determine the location of the event. Furthermore, by using only one "confirmed" pixel per cluster, the reliability of event detection is not high enough in this prior art.

[0008] The present invention aims to solve at least some of the problems mentioned above. Summary of the Invention

[0009] In a first aspect, the present invention provides a method for producing a medicament for the treatment of a pulmonary arthritis, comprising: A plurality of pixel sensors (1); at least one light source; 1. An imaging sensor system comprising: the plurality of pixel sensors (1) are grouped into at least one local cluster having at least two pixel sensors (1); Each of the pixel sensors (1) in the local cluster is adjacent to at least one other pixel sensor in the local cluster; The pixel sensors each include: a photodetector capable of detecting a single photon impinging thereon and having an output for providing an electrical local detection signal upon detecting a photon; a local control circuit; and the plurality of pixel sensors in the local cluster are configured to output a global detection signal using the local control circuit when detecting local detection signals from at least two outputs of the photodetectors in the local cluster; The local control circuit for each pixel sensor includes: a local enabling means; neighborhood enabling means connected to said local enabling means; and the local detection signal of the pixel sensor is supplied to the local enabling means in the pixel sensor; the neighborhood enabling means of the pixel sensor is supplied with at least one local detection signal of at least one other pixel sensor in the local cluster; the plurality of pixel sensors are configured to output the global detection signal when both the local enabling means and the neighborhood enabling means are triggered. The present invention relates to an imaging sensor system.

[0010] Preferred embodiments of this approach are described in claims 2-10.

[0011] The system includes a plurality of pixel sensors, the plurality of pixel sensors being grouped into at least one local cluster having at least two pixel sensors, each pixel sensor in the local cluster being adjacent to at least one other pixel sensor in the local cluster, the pixel sensors may be arranged in rows and columns, and it is an advantage of embodiments of the present invention that the pixel sensors in one local cluster cooperate, operate, or assist each other to obtain more accurate detection.

[0012] The system further comprises at least one light source.

[0013] Each pixel sensor includes a photodetector capable of detecting a single photon impinging thereon, the single photon being generated by the at least one light source, and the photodetector has an output for providing an electrical local detection signal upon detecting a photon.

[0014] Each pixel sensor further includes a local control circuit configured to output a global detection signal using the local control circuit when the pixel sensors in the local cluster detect local detection signals from at least two outputs of the photodetectors in the local cluster.

[0015] The global detect signals of different local clusters may be aggregated together to form a cluster detect signal, which may be output onto a cluster bus.

[0016] Each of the plurality of pixel sensors may be associated with two or more local clusters, which is an advantage of embodiments of the present invention, as it can also detect photons that impinge on a region between two neighboring local clusters.

[0017] The local control circuit of each pixel sensor includes a local enabling means and a neighborhood enabling means, the neighborhood enabling means being connected to the local enabling means, the local detection signal of the pixel sensor being supplied to the local enabling means of the pixel sensor, and the neighborhood enabling means of the pixel sensor being supplied with at least one local detection signal of at least one other pixel sensor in the local cluster, the pixel sensors being configured to output the global detection signal when both the local enabling means and the neighborhood enabling means are triggered.

[0018] It is an advantage of embodiments of the present invention that the local detection signals of the other pixel sensors in the local cluster reduce the possibility of false detection. It is an advantage of embodiments of the present invention that a false detection of one pixel sensor does not result in a global detection signal being output. It is an advantage of embodiments of the present invention that more accurate detection is obtained. It is an advantage of embodiments of the present invention that high accuracy pixel sensors are obtained. It is an advantage of embodiments of the present invention that the effect of ambient light or thermal noise on detection accuracy is reduced.

[0019] The photodetector may be a single photon detector, or may be a single photon avalanche diode.

[0020] The local enabling means and / or the neighborhood enabling means may comprise transistors.The local sense signals, the global sense signals and the cluster sense signals are preferably binary signals.

[0021] The system may further comprise a buffer connected to the output of the photodetector of each pixel sensor. The buffer may be a comparator. The buffer may compare the output of the photodetector with a predetermined threshold voltage level. It is an advantage of embodiments of the present invention that the buffer isolates the output of the photodetector from the local control circuitry. It is an advantage of embodiments of the present invention that any output of the photodetector below the threshold voltage level is not passed to the local control circuitry, thereby preventing any noise or error signals.

[0022] The system may further include a plurality of row buses and a plurality of column buses. The pixel sensors may be arranged into multiple rows and multiple columns. Each row of pixel sensors is connected to and associated with at least one row bus. Similarly, each column of pixel sensors is connected to and associated with at least one column bus.

[0023] The global sense signal for each pixel sensor may be connected to an associated row bus and column bus, and the global sense signals for each row may be summed together to form a row sense signal, and similarly, the global sense signals for each column may be summed together to form a column sense signal.

[0024] The system may further comprise synchronization means for synchronizing the row detect signal and the column detect signal.

[0025] The system may have 100 pixel sensors. A row may have up to 50 pixel sensors. A column may have up to 50 pixel sensors.

[0026] Further advantages of the present invention, particularly preferred embodiments, are disclosed in the detailed description that follows. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 1 is a circuit diagram of a pixel sensor (1) according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing four sensor clusters (19 to 22) according to an embodiment of the present invention. [Figure 3] FIG. 3 is a schematic diagram of an imaging sensor system (26) having pixel sensors (1) connected in rows and columns according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention relates to an imaging sensor system.

[0029] Unless otherwise defined, all terms used in disclosing the present invention, including technical and scientific terms, have the meanings commonly understood by one of ordinary skill in the art to which this invention belongs. For further guidance, term definitions are included to better understand the teachings of the present invention.

[0030] As used herein, the following terms have the following meanings:

[0031] As used herein, "a," "an," and "the" refer to both singular and plural referents unless the context clearly dictates otherwise. For example, "a contaminant" is , means one or more contaminants.

[0032] As used herein, "about" in reference to a measurable value such as a parameter, amount, duration, etc., is intended to encompass variations appropriate for practice in the disclosed invention. In the context of the present invention, the term "about" means to include a variation of the specified value within + / - 20%, preferably within + / - 10%, more preferably within + / - 5%, even more preferably within + / - 1%, and even more preferably within + / - 0.1% of the specified value. However, it should be understood that the value to which the modifier "about" refers is itself specifically disclosed.

[0033] As used herein, "comprise," "comprising," and "comprises," as well as "comprised of," are synonymous with "include," "including," "includes," or "contain," "containing," or "contains," and are inclusive or open-ended terms that specify the presence of what follows, e.g., components, but do not exclude or preclude the presence of additional, unlisted components, features, elements, materials, or steps that are well known in the art or disclosed therein.

[0034] The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within that numerical range, as well as the recited endpoints.

[0035] In a first aspect, the present invention provides a method for producing a medicament for the treatment of a pulmonary arthritis, comprising: A plurality of pixel sensors (1); at least one light source; 1. An imaging sensor system comprising: the plurality of pixel sensors (1) are grouped into at least one local cluster having at least two pixel sensors (1); Each of the pixel sensors (1) in the local cluster is adjacent to at least one other pixel sensor (1) in the local cluster; The pixel sensors each include: a photodetector capable of detecting a single photon impinging thereon and having an output for providing an electrical local detection signal upon detecting a photon; a local control circuit; and the plurality of pixel sensors in the local cluster are configured to output a global detection signal using the local control circuit when detecting local detection signals from at least two outputs of the photodetectors in the local cluster; The local control circuit for each pixel sensor includes: a local enabling means; a neighborhood validation means connected to the local validation means; and the local detection signal of the pixel sensor is supplied to the local enabling means in the pixel sensor; the neighborhood enabling means of the pixel sensor is supplied with at least one local detection signal of at least one other pixel sensor in the local cluster; the plurality of pixel sensors are configured to output the global detection signal when both the local enabling means and the neighborhood enabling means are triggered. The present invention relates to an imaging sensor system.

[0036] In a preferred embodiment, the system includes a plurality of pixel sensors, the plurality of pixel sensors being grouped into at least one local cluster having at least two pixel sensors, each pixel sensor in the local cluster being adjacent to at least one other pixel sensor in the local cluster. For example, each local cluster has at least two pixel sensors that are adjacent (e.g., in close proximity). In a more preferred embodiment, each local cluster has at least four pixel sensors, e.g., that are adjacent to each other in close proximity.

[0037] In a preferred embodiment, pixel sensors in one local cluster cooperate with each other. In a more preferred embodiment, adjacent pixel sensors in one local cluster cooperate, operate, or assist each other. Such cooperation allows for more accurate detection.

[0038] In a preferred embodiment, the system further comprises at least one light source, for example configured to emit light at a wavelength detectable by the pixel sensor.

[0039] In a preferred embodiment, each pixel sensor comprises a photodetector. The photodetector may be arranged in a laser beam configuration. The photodetector is capable of detecting a single photon impinging thereon. The single photon is generated by the at least one light source at a wavelength suitable for the photodetector. The photodetector has an output for outputting an electrical local detection signal upon detecting a photon. For example, the local detection signal may be represented by a signal including a logic "1" (e.g., detected), while the absence of a local detection signal may be represented by a signal including a logic "0" (e.g., not detected).

[0040] In a preferred embodiment, the photodetector may be a single photon detector, or preferably, the photodetector may be a single photon avalanche diode.

[0041] In a preferred embodiment, the photodetector may be biased, for example, by a voltage divider configuration or any other suitable configuration. For example, the photodetector may have one end connected to a voltage supply source and the other end connected to a resistor. For example, the voltage supply may have a voltage of 3 to 20 V, and the resistor may have a resistance of several hundred kilohms. The resistor is connected to a reference level, preferably ground, for example, 0 V. Those skilled in the art will understand that these values ​​depend on the design of the circuit and the breakdown voltage of the single-photon avalanche diode. The output of the photodetector (e.g., in this case, having a voltage level equal to the voltage dropped across the resistor) is between the voltage of the voltage supply source and the ground level.

[0042] In a preferred embodiment, each pixel sensor further includes a local control circuit configured to output a global detection signal when a plurality of pixel sensors in the local cluster detect local detection signals from at least two outputs of the photodetectors in the local cluster using the local control circuit. For example, in a local cluster having two adjacent pixel sensors, the local control circuit outputs a global detection signal when it detects two local detection signals from the two pixel sensors. For example, one global detection signal is output for each pixel sensor.

[0043] In a preferred embodiment, the global detection signals of different local clusters may be aggregated together to form a cluster detection signal, which may be output to a cluster bus, e.g., to provide information about in which local cluster there was a detection.

[0044] In a preferred embodiment, the bus is a data highway, for example data from more than one pixel sensor may be loaded onto the bus such that the receiver can ascertain which data belongs to which pixel sensor.

[0045] In a preferred embodiment, each of the plurality of pixel sensors may be associated with two or more local clusters. For example, a system having three pixel sensors arranged in a linear row may have two local clusters: one local cluster including the two pixel sensors from the left and one local cluster including the two pixel sensors from the right. In this case, the center pixel sensor is part of both local clusters. Having pixel sensors associated with two or more local clusters is advantageous when the required detection is located midway between two local clusters. For example, a plurality of pixel sensors, which are at least two pixel sensors positioned around each other, may be considered a local cluster. For example, one pixel sensor and one of its neighboring pixel sensors may be considered a local cluster.

[0046] In a preferred embodiment, the local control circuit of each pixel sensor may include local enabling means and neighborhood enabling means. The pixel sensors may be connected to a local enabling means, for example in series, or both may be connected to a logic gate, for example an AND gate. The local detection signal of the pixel sensor is supplied to the local enabling means of the pixel sensor. The neighborhood enabling means of the pixel sensor is supplied with at least one local detection signal of at least one other pixel sensor in the local cluster. The pixel sensors may be configured to output the global detection signal, for example when both the local enabling means and the neighborhood enabling means are triggered in at least two pixel sensors in the local cluster. For example, a pixel sensor whose local enabling means and neighborhood enabling means are triggered may generate a global detection signal.

[0047] In a preferred embodiment, the number of local detection signals required to trigger the neighborhood enabling means of a pixel sensor may be variable, depending on the time difference in receiving a photon at different pixel sensors in one local cluster. For example, in one scenario, eight neighboring pixel sensors in one local cluster may receive a local detection signal. may require local detection signals from more than half of the pixel sensors in the local cluster. For example, if a photon is not received by the one pixel sensor and the eight neighboring pixel sensors at the same time or is received with a large time difference, eight local detection signals from the eight neighboring pixel sensors may be required. For example, in another scenario, a pixel sensor having eight neighboring pixel sensors in a local cluster may require fewer local detection signals than half of the number in the local cluster. For example, if a photon is received by both the one pixel sensor and one neighboring pixel sensor at the same time, one local detection signal from the one neighboring pixel sensor may be required. In another example, if a photon is received by the one pixel sensor and the multiple neighboring pixel sensors with a time delay (e.g., a time delay between the one pixel sensor and one neighboring pixel sensor), the time delay may be used to set the number of local detection signals required to trigger the neighborhood enabling means.

[0048] In a preferred embodiment, the local detection signal of one pixel sensor and the local detection signal of a neighboring pixel sensor used to trigger the neighborhood enabling means are not generated simultaneously. For example, the local detection signal of a first pixel sensor is generated at time T1 as a result of a photon detection in the first pixel sensor. The local detection signal of the neighboring pixel sensor may be generated at time T1+D, where D is a delay. The delay may occur, for example, if the light source moves very slowly. It is possible that the local detection signal of the first pixel sensor ends before the local detection signal of the neighboring pixel sensor is generated due to a lack of photon detection. A predetermined value of the delay D may be required to determine whether the detection is a false positive.

[0049] In a preferred embodiment, a neighborhood cluster thus covers multiple pixels in the neighborhood and can be triggered by a sufficiently large optical signal by triggering at least one pixel in the neighborhood within a short time window.

[0050] In another preferred embodiment, the neighboring clusters can thus be triggered by an optical signal having a momentary special footprint, which may be one pixel or smaller, that moves spatially within a set time window D to sequentially trigger neighboring pixels within the time window D, thereby triggering the neighboring clusters.

[0051] In a preferred embodiment, for example, the neighborhood validation means of each pixel sensor includes a neighborhood validation means for one other pixel sensor in the local cluster, more preferably for more than half of the neighboring pixel sensors in the local cluster, and most preferably for all of the neighboring pixel sensors in the local cluster. The local detection signals of the neighboring pixel sensors are provided.

[0052] In a preferred embodiment, a local cluster may include at least two pixel sensors, a first pixel sensor and a second pixel sensor. For example, the pixel sensors are adjacent or nearby each other. When a photon strikes the local cluster, the local enabling means of the first pixel sensor is triggered by a local detection signal of the photodetector of the first pixel sensor. Similarly, the local enabling means of the second pixel sensor is triggered by a local detection signal of the photodetector of the second pixel sensor. The local detection signal of the second pixel sensor triggers the neighborhood enabling means of the first pixel sensor. Similarly, the local detection signal of the first pixel sensor triggers the neighborhood enabling means of the second pixel sensor. For example, when the local enabling means of both pixel sensors are triggered, the neighborhood enabling means of both pixel sensors are also triggered, and a global detection signal is output by the two pixel sensors. The global detection signal indicates that a photon has struck the photodetectors of at least two pixel sensors (e.g., nearby) in a local cluster.

[0053] In a preferred embodiment, for example, the global detection signal indicates that a photon has struck a photodetector in a pixel sensor that is adjacent or nearby. This is useful for eliminating false detections. That is, a false detection is more likely to occur as a result of a false detection in one detector, and less likely to occur as a result of a false detection in two or more detectors, e.g., a group of detectors, that cooperate and are close to each other. Detection based on two or more pixel sensors is more reliable and accurate than detection based on only one pixel sensor. For example, detection based on two pixel sensors reduces the possibility of a false detection. A false detection may be the result of ambient light or thermal noise, but is less likely to occur in two or more adjacent pixel sensors. If a false detection occurs (for example, a false detection occurs in only one pixel sensor, but not in its adjacent or nearby pixel sensors), no global detection signal is output.

[0054] In a preferred embodiment, the term "triggering" may be interpreted as receiving a high voltage signal, e.g. a logic "1" signal, e.g. a signal representing an ON state. For example, triggering the neighborhood enabling means may mean receiving a logic "1" signal at the neighborhood enabling means.

[0055] In a preferred embodiment, pixel sensors associated with more than one local cluster, e.g., two local clusters, may have their local detection signals supplied to neighborhood enabling means of pixel sensors (e.g., two pixel sensors) belonging to different local clusters.

[0056] In a preferred embodiment, the local detection signals and the global detection signals, the cluster detection signals, or any other signals in the system are preferably binary signals.

[0057] In a preferred embodiment, the local enabling means and the neighborhood enabling means may comprise transistors, which are preferably NMOS transistors, and each transistor may operate as a switch.

[0058] In a preferred embodiment, the output of the photodetector is a logic "1" when a photon is detected at the photodetector and a logic "0" when no photon is detected at the photodetector.

[0059] In a preferred embodiment, the local detection signal is either a logic "1" or a logic "0". For example, the transistor of the local enabling means is ON when the local detection signal is logic "1" and OFF when the local detection signal is logic "0".

[0060] In a preferred embodiment, for example, a transistor of the neighborhood enabling means is turned ON when the local detection signal supplied from another adjacent pixel sensor is logic "1", and is turned OFF when the local detection signal is logic "0".

[0061] In a preferred embodiment, for example, when the neighborhood enabling means of one first pixel sensor is triggered by the local detection signal of at least one adjacent pixel sensor, a transistor of the neighborhood enabling means is turned ON, and similarly, the local detection signal of the first pixel sensor triggers the transistor of the neighborhood enabling means of the at least one adjacent pixel sensor.

[0062] In a preferred embodiment, the neighborhood enabling means and the local enabling means are connected, for example, they are connected in series. For example, when both the local enabling means and the neighborhood enabling means are triggered, two elements, for example, transistors or switches, of the local enabling means and the neighborhood enabling means are turned on, and a global detection signal is output by the pixel sensor. For example, adjacent pixel sensors are supplied with each other's local detection signals, so that the adjacent pixel sensors output the same global detection signal.

[0063] In a preferred embodiment, the neighborhood enabling means and the local enabling means may include logic gates, such as AND gates. For example, when the local detection signal is logic "1" and the local detection signal of an adjacent pixel sensor is logic "1," the output of the AND gate is logic "1," and a global detection signal is generated in each of the two pixel sensors. The logic gate may also be replaced by two transistors operating as switches, or two switches. For example, one transistor of the local enabling means may be connected in series with one transistor of the neighborhood enabling means, allowing current to flow through the two transistors when both transistors are switched on.

[0064] In a preferred embodiment, the neighborhood enabling means and the local enabling means may include logic gates, such as AND gates. For example, if the local detection signal is logic "1" and two or more local detection signals of two or more adjacent pixel sensors are logic "1," the output of the AND gate is logic "1," and a global detection signal is generated in each of the three or more pixel sensors. Alternatively, the logic gates may be replaced by three transistors operating as switches, or three switches. For example, one transistor of the local enabling means may be connected in series with two series-connected transistors of the neighborhood enabling means, allowing current to flow through the three transistors when all transistors are switched on. Those skilled in the art will appreciate that different circuit configurations are possible.

[0065] In a preferred embodiment, each bus may be connected to a voltage bias. For example, when the local enable means and the neighborhood enable means are triggered, e.g., when the transistor or switch is ON, a current flows through the local enable means and the neighborhood enable means. This current flow is then sensed, e.g., by a sense amplifier, e.g., at the other end of the bus. In another preferred embodiment, the bus may be pre-charged. For example, when the local enable means and the neighborhood enable means are triggered, e.g., when the transistor or switch is ON, a charge in the bus is discharged via the local enable means and the neighborhood enable means. This discharge is then sensed, e.g., by a sense amplifier, e.g., at the other end of the bus.

[0066] In a preferred embodiment, the number of neighboring pixel sensors required to enable the generation of a global detection signal may be designed according to, for example, design requirements and may have different circuit implementations depending on said number.

[0067] In a preferred embodiment, the system may further include a buffer connected to the output of the photodetector of each pixel sensor. Preferably, the buffer may be a comparator. For example, the buffer may compare the output of the photodetector with a predetermined threshold voltage level. Preferably, the threshold voltage level is between 0.5 and 2 V, more preferably between 0.6 and 1 V. The buffer may be useful for isolating the photodetector from the local control circuitry. The buffer may also be useful for preventing signals with voltages below the threshold voltage level from passing to the local control circuitry.

[0068] In a preferred embodiment, the system may further include a plurality of row buses and a plurality of column buses, where each row of pixel sensors is connected to and associated with at least one row bus, and similarly, each column of pixel sensors is connected to and associated with at least one column bus.

[0069] In a preferred embodiment, the local enabling means may have two transistors, for example one of which is connected to the row bus and the other of which is connected to the column bus, and the output of the photodetector of each pixel sensor is connected to the row bus via one transistor in the local enabling means and to the column bus via the other transistor in the local enabling means.

[0070] In a preferred embodiment, multiple pixel sensors in adjacent rows and columns may be in one cluster. For example, a pixel sensor in row x and column y may be in one cluster with another pixel sensor in row x+1 and column y. For example, all pixel sensors included in row x-1, column y-1 to row x+1, column y+1 may be in one cluster. For example, the pixel sensors may be arranged in a matrix configuration.

[0071] In a preferred embodiment, the global detection signal for each pixel sensor may be provided to an associated row bus and column bus. The global detection signals for each row may be aggregated together to form a row detection signal. For example, the row detection signal may include the global detection signal for each pixel sensor in the row. Similarly, the global detection signals for each column may be aggregated together to form a column detection signal. For example, the column detection signal may include the global detection signal for each pixel sensor in the column.

[0072] In a preferred embodiment, the system may further comprise synchronization means for synchronizing the row detection signals and the column detection signals, for example synchronizing row detection signals of different rows with each other and column detection signals of different columns with each other.

[0073] In a preferred embodiment, the system may have 100 pixel sensors. For example, a row may have up to 50 pixel sensors. Further, for example, a column may have up to 50 pixel sensors.

[0074] Further features and advantages of embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the specific embodiments shown in these drawings or described by way of example. , and is limited only by the scope of the claims.

[0075] Figure 1 shows a circuit implementation of a pixel sensor (1). The pixel sensor (1) has a photodetector (2), such as a single-photon detector or a single-photon avalanche diode, that can detect a single photon (3) that impinges on it.

[0076] The photodetector (2) is biased by a voltage source (4) and connected in a voltage divider configuration to a resistor (5). The photodetector (2) is arranged in a reverse bias configuration. The resistor (5) is connected to a first reference potential level (6), preferably ground or 0V.

[0077] When a photon (3) strikes the photodetector (2), a reverse current is generated, resulting in a voltage drop (7) across the resistor (5). The voltage drop (7) has a logic "1" when a photon (3) is detected at the photodetector (2) and a logic "0" when no photon (3) is detected at the photodetector (2).

[0078] The voltage drop (7) is compared with a predetermined threshold voltage level (8) via a comparator (9). If the voltage drop (7) is greater than the reference voltage (8), a local detection signal (10) is generated as the output of the comparator (9). For example, a "detection" generates a logic "1" as the output of the comparator, and a "non-detection" generates a logic "0" as the output of the comparator.

[0079] Each pixel sensor (1) has a local control circuit (18). A comparator (9) acts as a buffer between the photodetector (2) and the local control circuit (18). The local control circuit (18) has a local enabling means (11) and a neighborhood enabling means (12).

[0080] The control circuitry, or parts thereof, may be physically located on different layers in the sensor system, for example, the pixel sensors (1) of the sensing array may be located on a first semiconductor layer and the control circuitry (18) for each pixel sensor (1) in the array may be located on a second semiconductor layer, forming a so-called stacked pixel sensor solution.

[0081] The local detect signal (10) is fed to a local enable means (11). The local enable means (11) comprises two NMOS transistors. However, other transistor types or configurations may be used. The local detect signal (10) is fed to the gates of the transistors. One transistor is connected to a row bus (16) and the other transistor is connected to a column bus (17). When the local detect signal (10) is received at the gate of a transistor of the local enable means (11), the local enable means (11) is triggered. In this case, the transistor acts as a switch, and when a logic "1" is received at the transistor, the switch is turned on, e.g., shorted.

[0082] The local enabling means (11) is connected to the neighborhood enabling means (12). In this case, each transistor of the local enabling means (11) is connected to the neighborhood enabling means. The neighborhood enabling means (12) comprises at least one transistor, in this embodiment three transistors with gates (13', 13", 13'"). The gates (13', 13", 13'") of the three transistors are connected to the local detection signals of the neighboring pixel sensors. These transistors are also connected to a second reference potential level (14), preferably to a level equal to the first reference potential level (6), preferably to ground or 0V. When one gate, for example (13'), receives at least one local detection signal from one neighboring pixel sensor, the neighborhood enabling means is triggered. This means that in this case, when the gate (13') has a logic "1", the transistor, which here acts as a switch, is turned on, e.g. short-circuited. When both the local enabling means and the neighborhood enabling means are triggered, i.e., when a transistor in the local enabling means is operating as a short and one transistor in the neighborhood enabling means is operating as a short, a global detect signal (15) is output to a row bus (16) and a column bus (17). The global detect signals of different pixel sensors on the row bus (16) are aggregated to form a row detect signal. The global detect signals of different pixel sensors on the column bus (17) are aggregated to form a column detect signal.

[0083] The local control circuit (18) in this example acts as an AND gate, i.e. when the local validation means (11) and the neighborhood validation means (12) are triggered, a global detection signal (15) is generated.

[0084] Two implementations are envisioned. In a first implementation, each bus (16, 17) may be connected to a voltage bias. For example, when the local enable means (11) and the neighborhood enable means (12) are triggered, a current flows through the local enable means (11) and the neighborhood enable means (12). This current flow is then sensed, for example, by a sense amplifier, for example, at the other end of the bus. This current is also referred to in this case as the global sense signal (15).

[0085] In a second implementation, each bus (16, 17) may be precharged. For example, when the local enable means (11) and the neighborhood enable means (12) are triggered, the charge in the bus is discharged via the local enable means (11) and the neighborhood enable means (12). This discharge is then sensed, for example, by a sense amplifier at the other end of the bus. This discharge is also referred to in this case as the global sense signal (15).

[0086] Figure 2 shows four clusters of pixel sensors. Each pixel sensor has coordinates. For example, the first pixel cluster (19) has a first pixel sensor (23) at position (i,j) and eight neighboring pixel sensors.

[0087] The neighboring pixel sensors include an image sensor (24) having a local detection signal, e.g., a positive detection, e.g., a logic "1" local detection signal, and an image sensor (25) having no local detection signal, e.g., a negative detection (e.g., "no detection"), e.g., a logic "0" local detection signal. In this case, a first pixel cluster (19) has one positive detection among its neighboring pixel sensors. Similarly, a second pixel cluster (20) has three positive detections among its neighboring pixel sensors, a third pixel cluster (21) has two positive detections among its neighboring pixel sensors, and a fourth pixel cluster (22) has no positive detections.

[0088] For example, if the first pixel sensor (23) in the pixel cluster (19-22) is configured to output a global detection signal (15) when there is a positive detection in the first pixel sensor (23) and one neighboring pixel sensor, this will result in the first pixel sensor and the neighboring pixel sensors in the pixel clusters (19, 20, and 21) outputting a global detection signal (15), e.g., a global detection signal of logic "1." However, if the first pixel sensor (23) in the pixel cluster (19-22) is configured to output a global detection signal (15) when there is a positive detection in the first pixel sensor (23) and two neighboring pixel sensors, this will result in the first pixel sensor and the neighboring pixel sensors in the pixel clusters (20 and 21) outputting a global detection signal (15), e.g., a positive detection. The number of neighboring pixel sensors required for the detection of the entire cluster to be considered a positive detection depends on design requirements.

[0089] 3 is a schematic diagram of an imaging sensor system 26 having pixel sensors 1 connected in rows and columns. The pixel sensors 1 in each row are connected to two row buses 16, 16' and two column buses 17, 17'. The pixel sensors 1 output a global detection signal 15, which is a binary signal.

[0090] Three cases are shown in Figure 3. In the first case, a photon strikes two or more pixel sensors simultaneously. In this case, a photon strikes four pixel sensors simultaneously. The first circle (27) indicates the area where the photon strikes. In this case, two or more pixel sensors (1) sense the photon, so the detection is correct. Each pixel sensor has a local detection signal, for example, logic "1". The local detection signal of each pixel sensor is also connected to and triggers the neighborhood enablement means of neighboring or adjacent pixel sensors. For example, in the four pixel sensors, transistors belonging to the local enablement means and the neighborhood enablement means are triggered. This causes each pixel sensor to generate a global detection signal of logic "1", which is output to the associated row bus and column bus.

[0091] In the second and third cases, the second circle (28) indicates an area where a photon detection is suspect. In this case, the detection is a false positive because none of the neighboring pixel sensors sensed such a detection. Therefore, the neighborhood enablement means is not triggered, and therefore no global detection signal is generated, or a logic "0" global detection signal is output to the associated row and column buses. This false detection may be the result of ambient light or thermal noise.

[0092] The above description details specific embodiments of the present invention. However, no matter how detailed the above description may be in this text, it will be apparent that the present invention can be applied in many ways. The use of a particular term to describe a particular feature or aspect of the present invention should not be interpreted as meaning that the term is redefined herein as being limited to the particular feature or aspect of the invention to which it pertains.

Claims

1. A plurality of pixel sensors (1); at least one light source; An imaging sensor system (26) having: the plurality of pixel sensors (1) are grouped into at least one local cluster having at least two pixel sensors (1); Each of the pixel sensors (1) in the local cluster is adjacent to at least one other pixel sensor in the local cluster; The pixel sensors each include: a photodetector (2) capable of detecting a single photon (3) impinging thereon and having an output for outputting an electrical local detection signal (1) upon detection of the single photon (3); a local control circuit (18); and the plurality of pixel sensors (1) in the local cluster are configured to output a global detection signal (15) using the local control circuit when detecting local detection signals (10) from at least two outputs of the photodetectors (2) in the local cluster; The local control circuit (18) for each pixel sensor comprises: a local validation means (11); a neighborhood validation means (12) connected to the local validation means (11); and The local detection signal (10) of the pixel sensor is supplied to the local enabling means (11) in the pixel sensor (1); The neighborhood enabling means (12) of the pixel sensor is supplied with at least one local detection signal (10) of at least one other pixel sensor in the local cluster; the plurality of pixel sensors (1) are configured to output the global detection signal (15) when both the local enabling means (11) and the neighborhood enabling means (12) are triggered; The global detection signals (15) of different local clusters are aggregated together to form a cluster detection signal; An imaging sensor system (26).

2. 2. The imaging sensor system (26) of claim 1, The plurality of pixel sensors (1) in the local cluster are configured to output a global detection signal (15) upon detecting a local detection signal (1) from the outputs of at least two of the photodetectors (2) in the local cluster within a predetermined time delay. An imaging sensor system (26).

3. 3. The imaging sensor system (26) of claim 1 or claim 2, the photodetector (2) is a single-photon detector or a single-photon avalanche diode; An imaging sensor system (26).

4. An imaging sensor system (26) according to any one of claims 1 to 3, The local validation means (11) and / or the neighborhood validation means (12) having a transistor, preferably an NMOS transistor, An imaging sensor system (26).

5. An imaging sensor system (26) according to any one of claims 1 to 4, Each of the plurality of pixel sensors (1) further comprises a buffer (9) connected to an output of the photodetector of the pixel sensor, the buffer (9) comparing the output of the photodetector with a predetermined threshold voltage level. An imaging sensor system (26).

6. An imaging sensor system (26) according to any one of claims 1 to 5, the local detection signal (10) and / or the global detection signal (15) are binary signals; An imaging sensor system (26).

7. 6. The imaging sensor system (26) of claim 5, the cluster detection signal is a binary signal; An imaging sensor system (26).

8. An imaging sensor system (26) according to any one of claims 1 to 7, each of the plurality of pixel sensors is associated with two or more local clusters; An imaging sensor system (26).

9. An imaging sensor system (26) according to any one of claims 1 to 8, the imaging sensor system (26) has a maximum of 100 pixel sensors (1), or preferably a maximum of 50 pixel sensors (1) connected in one row or in one column; An imaging sensor system (26).

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