Abstract: Techniques are provided for x-ray image data monitoring and signaling for patient safety. A methodology implementing the techniques according to an embodiment includes integrating energy associated with a received x-ray pulse at an array of pixels. The method also includes multiplexing a readout of the integrated energy from the array of pixels, as analog signals, into channels, and performing analog to digital conversion of the analog signals of the channels into digital signals. The method further includes generating an error indicator in response to determining that a calculated mean of the digital signals is either greater than an upper threshold value associated with saturation or less than a lower threshold value associated with underexposure. The method further includes transmitting the error indicator over a Universal Serial Bus, to an imaging system, to terminate transmission of further x-ray pulses.

Abstract: Techniques to provide compression and/or decompression. A method includes obtaining a first set of control points specifying a first set of compression ratios corresponding to respective first regions of a compression domain, and minimum and maximum uncompressed values within the compression domain. The method can further include scaling the first set of control points based on the minimum and maximum uncompressed values to obtain a scaled set of control points, wherein a first scaled control point is located at the minimum uncompressed value, and a last scaled control point is located at the maximum uncompressed value. The method can further include adjusting at least one scaled control point such that a first slope does not exceed 1. The method can further include compressing or decompressing between the compression domain and a range of compressed values, wherein a respective compression ratio corresponds to a respective slope of the set of slopes.

Abstract: Examples include column readout amplifiers and image sensors including same. In one example, a column readout amplifier includes a signal amplifier having an amplifier output and first and second amplifier inputs, a filter capacitor having first and second terminals, the second terminal connected to a ground terminal, a buffer amplifier having a buffer amplifier input and a buffer amplifier output, a switching network configured to switchably connect the amplifier output to the buffer amplifier input and the buffer amplifier output to the first terminal of the filter capacitor during a first time period, and to switchably connect the amplifier output directly to the first terminal of the filter capacitor during a second time period, and a low-pass filter connected in a feedback path of the signal amplifier between the amplifier output and the first amplifier input, the low-pass filter including a series resistor and a capacitor.

Abstract: Image sensor systems are disclosed that include charge coupled device (CCD) pixels integrated with CMOS readout circuitry via separately bonded substrates. According to some embodiments, columns of image sensing pixels on a first substrate are arranged with overlapping gate structures to facilitate charge transfer between the pixels. At least one pixel is coupled to a first conductive pad that contacts (or is melded with) a second conductive pad from a second substrate bonded to the first substrate. The second substrate includes a readout circuit using one or more CMOS devices coupled to the second conductive pad to receive the accumulated charge from a given column of pixels. The resulting photodetector signal from the accumulated charge can be, for instance, amplified via a source follower component and ultimately read out to a column amplifier, and subjected to further processing and/or use in a given downstream system.

Abstract: A system is provided for time delay integration in complementary metal oxide semiconductor imaging sensors, the system comprising: a two dimensional parallel charge transfer structure comprising at least one column of CMOS Image sensor pinned photodiodes; each the diode in the column being connected to the next the diode by a two phase transfer gate, each the transfer gate having a barrier and a well configured such that a flow of charge in the column is unidirectional.

Abstract: Examples include column readout amplifiers and image sensors including same. In one example, a column readout amplifier includes a signal amplifier having an amplifier output and first and second amplifier inputs, a filter capacitor having first and second terminals, the second terminal connected to a ground terminal, a buffer amplifier having a buffer amplifier input and a buffer amplifier output, a switching network configured to switchably connect the amplifier output to the buffer amplifier input and the buffer amplifier output to the first terminal of the filter capacitor during a first time period, and to switchably connect the amplifier output directly to the first terminal of the filter capacitor during a second time period, and a low-pass filter connected in a feedback path of the signal amplifier between the amplifier output and the first amplifier input, the low-pass filter including a series resistor and a capacitor.

Abstract: Techniques are provided for x-ray onset detection for an intraoral dental sensor. A methodology implementing the techniques according to an embodiment includes calculating a plurality of superpixel values for each of a plurality of rows of detector pixels of a sensor. Each of the superpixel values is based on a sum of pixel values of a set of pixels associated with the superpixel value, the set of pixels selected from the detection row of a current frame of the sensor. The method also includes calculating a difference between each of the superpixel values and a corresponding stored superpixel value generated from a previous sensor frame and determining if the differences exceed a superpixel threshold value. The method further includes incrementing a hit counter in response to the determination and generating a detection signal if the hit counter exceeds a hit count threshold, otherwise proceeding to process the next detection row.

Abstract: Examples include an image sensor comprising a pixel array having at least one column of addressable pixel sensors, and a column amplifier coupled to the at least one column of addressable pixel sensors, the column amplifier comprising a transistor bank including a plurality of transistors, and mode select circuitry coupled to the transistor bank and configured to establish one or more connections among the plurality of transistors to configure the column amplifier to operate in one of a differential mode of operation and a single-ended mode of operation.

Abstract: Techniques to provide a low-power single-photon avalanche diode (SPAD) image. An example imaging device includes a SPAD array having a plurality of pixels configured to detect electromagnetic radiation, and a processing device configured to deactivate, based on an event count, a pixel of the SPAD array for a remaining duration of a first detection frame of the SPAD array. The pixel can remain deactivated for the remaining duration, and the remaining duration can span from a deactivation time until an end of the first SPAD frame. The processing device can be further configured to reactivate the pixel in a subsequent detection frame of the SPAD array.

Abstract: Image sensor systems are disclosed that allow for charge transfer between pixels of a group included in a pixel array with a single digital readout of the accumulated charge from the group. Each of the pixels within a given group includes a photodetector. One or more pump gates are arranged between adjacent pixels of the given group to allow charge to be pumped from one pixel to the next in a serial fashion within the group. A readout circuit that includes at least a transfer gate and a capacitor may be coupled to a final pixel of the group to receive the accumulated charge and generate a photodetector signal (based on the accumulated charge) that can be amplified via a source follower component and ultimately read out to a column amplifier.

Abstract: Structures are disclosed for a binned set of two or more pixels of a pixel array that share a same readout circuit. The binned pixel design provides space-saving benefits on the chip and also improves the overall image quality. According to some embodiments, each of the binned pixels includes a photodetector and its own transfer gate. The readout circuit is coupled to the transfer gates of each of the binned pixels and includes its own second transfer gate that separates the pixels from a gain mode select block. The gain mode select block may include capacitors of different sizes and one or more switches to control which capacitors are to receive the charge from any one of the binned pixels. The readout circuit may also include a potential barrier (such as a diode), which allows for pumping charge onto the one or more capacitors of the gain mode select block.

Abstract: A given pixel of a pixel array includes various operation modes with each of the operation modes having a different conversion gain for the charge received from the photodetector of the pixel. When the modes are used in conjunction with one another, the dynamic range of the pixel can be increased. A readout circuit coupled to a photodetector within a given pixel includes a transfer gate between the photodetector and a gain mode select block that includes capacitors of different sizes and one or more switches to control which capacitors are to receive the charge from the photodetector. Depending on the state(s) of the one or more switches, different operation modes with different conversion gains can be selected to increase the dynamic range of the pixel. The adaptability of the readout circuit can allow for a high dynamic range even in extreme temperature environments by lowering the dark current.

Abstract: A given pixel of a pixel array includes various operation modes with each of the operation modes having a different conversion gain for the charge received from the photodetector of the pixel. When the modes are used in conjunction with one another, the dynamic range of the pixel can be increased. A readout circuit coupled to a photodetector within a given pixel includes a transfer gate between the photodetector and a gain mode select block that includes capacitors of different sizes and one or more switches to control which capacitors are to receive the charge from the photodetector. Depending on the state(s) of the one or more switches, different operation modes with different conversion gains can be selected to increase the dynamic range of the pixel. The adaptability of the readout circuit can allow for a high dynamic range even in extreme temperature environments by lowering the dark current.

Abstract: Techniques are provided for x-ray sensing for intraoral tomography. A methodology implementing the techniques according to an embodiment includes detecting an x-ray pulse based on energy received at one or more pixels of a pixel array. The method also includes integrating the energy received at each of the pixels of the array of pixels, in response to the detection, wherein the energy received at each of the pixels is associated with the x-ray pulse. The method further includes multiplexing readouts of analog signals from the array of pixels into two or more parallel channels. The method further includes simultaneously converting (or otherwise in parallel) the analog signals of each of the channels into digital signals and storing the digital signals in memory as frames of data. The method may further include, for example, transmitting the frames of data from the memory, over a Universal Serial Bus, to an imaging system.

Abstract: Techniques are provided for x-ray onset detection for an intraoral dental sensor. A methodology implementing the techniques according to an embodiment includes calculating a plurality of superpixel values for each of a plurality of rows of detector pixels of a sensor. Each of the superpixel values is based on a sum of pixel values of a set of pixels associated with the superpixel value, the set of pixels selected from the detection row of a current frame of the sensor. The method also includes calculating a difference between each of the superpixel values and a corresponding stored superpixel value generated from a previous sensor frame and determining if the differences exceed a superpixel threshold value. The method further includes incrementing a hit counter in response to the determination and generating a detection signal if the hit counter exceeds a hit count threshold, otherwise proceeding to process the next detection row.

Abstract: A pixel, is provided the pixel comprising: a photodiode structure built on top of an integrated circuit generating a charge; the integrated circuit comprising at least one semiconductor material and at least one interconnect layer; the at least one interconnect layer comprises an interconnect to facilitate charge flowing into a collection node disposed in the semiconductor material; the interconnect being in contact with a doped contact diffusion disposed proximate to the collection node; a transfer transistor disposed between the collection node and a conversion node, the conversion node coupled to an active transistor; the pixel having a reset configured to reset the conversion node.

Abstract: Techniques are provided for x-ray image data monitoring and signaling for patient safety. A methodology implementing the techniques according to an embodiment includes integrating energy associated with a received x-ray pulse at an array of pixels. The method also includes multiplexing a readout of the integrated energy from the array of pixels, as analog signals, into channels, and performing analog to digital conversion of the analog signals of the channels into digital signals. The method further includes generating an error indicator in response to determining that a calculated mean of the digital signals is either greater than an upper threshold value associated with saturation or less than a lower threshold value associated with underexposure. The method further includes transmitting the error indicator over a Universal Serial Bus, to an imaging system, to terminate transmission of further x-ray pulses.

Abstract: Techniques are provided for x-ray sensing for intraoral tomography. A methodology implementing the techniques according to an embodiment includes detecting an x-ray pulse based on energy received at one or more pixels of a pixel array. The method also includes integrating the energy received at each of the pixels of the array of pixels, in response to the detection, wherein the energy received at each of the pixels is associated with the x-ray pulse. The method further includes multiplexing readouts of analog signals from the array of pixels into two or more parallel channels. The method further includes simultaneously converting (or otherwise in parallel) the analog signals of each of the channels into digital signals and storing the digital signals in memory as frames of data. The method may further include, for example, transmitting the frames of data from the memory, over a Universal Serial Bus, to an imaging system.

Abstract: An apparatus for forming a color image of a scene and a method for utilizing that apparatus are disclosed. The apparatus includes a plurality of pixel sensors. Each pixel sensor includes a first photodetector includes first main photodiode and a first floating diffusion node. The first main photodiode is characterized by a first light conversion efficiency as a function of wavelength of a light signal incident thereon. The first floating diffusion node includes a parasitic photodiode characterized by a second light conversion efficiency as a function of the wavelength. The second light conversion efficiency is different from the first light conversion efficiency as a function of wavelength. A controller generates an intensity of light in each of a plurality of wavelength bands for the pixel sensor utilizing a measurement of the light signal by each of the first main photodiode and the first parasitic photodiode in that photodetector.

Abstract: A low-noise amplifier is disclosed. The amplifier includes a signal amplifier having an amplifier signal output, a first filter capacitor, a buffer amplifier having a buffer amplifier input and a buffer amplifier output; and a switching network. The first filter capacitor has first and second terminals. The second terminal is connected to a power rail. The amplifier signal output is connected to the buffer amplifier input by a first direct current path and the buffer amplifier output to the first terminal of the first filter capacitor by a second direct current path during a first time period. The amplifier signal output is connected directly to the first terminal of the first filter capacitor by a third direct current path during a second time period, and the amplifier signal output to the first terminal of the first filter capacitor through a resistor during a third time period.