Automatic exposure detection circuit for imaging applications

Abstract

Method for automatic exposure detection in imaging applications, wherein the method comprises the following: Entering a low-power state at an imaging panel; Limiting an input signal voltage to a first voltage at a detection circuit in the imaging panel; Receiving an input signal at the acquisition circuit in the imaging panel; Detecting a change in the input signal voltage, wherein the change in the input signal voltage indicates the exposure to an X-ray signal; and Exiting from the low-power state based on a change in the input signal voltage; wherein the imaging panel has an integrated readout circuit (ROIC) with a signal chain and wherein entering the low-power state involves reusing at least part of the signal chain for the acquisition circuit; and wherein the ROIC has an integrator and wherein entering the low-power state involves turning off the integrator.

Description

TECHNICAL AREA OF REVELATION

[0001] The present invention relates to the field of imaging and automatic exposure detection. BACKGROUND

[0002] Current X-ray systems generally use digital radiography, which employs digital X-ray sensors instead of traditional photographic film. Some advantages of digital imaging include efficiency, digital image storage, and techniques for enhancing digital images. Further benefits include immediate image availability, the elimination of image processing steps, and a wider dynamic range. Additionally, digital X-ray systems generally consume less radiation than traditional film-based X-ray systems. Digital imaging utilizes a digital image acquisition device instead of film.

[0003] Digital radiography systems generally feature an imaging panel, such as a flat-panel detector, for detecting an image. Many different types of detectors exist, including indirect flat-panel detectors, direct flat-panel detectors, CMOS detectors, CCD (charge-coupled device) detectors, and phosphor plate radiography detectors.

[0004] X-ray systems often include a circuit for detecting the arrival of an X-ray signal at a wireless digital X-ray panel. To optimize battery life, some systems create a separate detection path independent of the panel's readout path; however, this requires additional space and components while also increasing the panel's weight. Other systems utilize the main readout electronics, which significantly increases the system's power consumption.

[0005] US 2014 / 0 0213 65 A1 discloses a radiographic imaging device, a radiographic imaging system, a method for controlling radiation detection sensitivity and a program storage medium.

[0006] US 6 797 960 B1 discloses a self-triggered imaging device for imaging radiation.

[0007] JP H11-274524A discloses a device for taking X-ray images. SUMMARY OF THE REVELATION

[0008] The claimed subject matter is defined in the independent claims. Advantageous further connections are described in the dependent claims.

[0009] Systems and methods for detecting the arrival of an X-ray signal at a wireless digital X-ray panel are disclosed. In particular, according to some implementations, a method for automatic exposure detection in imaging applications comprises: entering a low-power state at an imaging panel, limiting an input signal voltage to a first voltage at a detection circuit in the imaging panel, receiving an input signal at the detection circuit in the imaging panel, detecting a change in the input signal voltage, wherein the change in the input signal voltage indicates exposure to an X-ray signal, and exiting the low-power state based on the change in the input signal voltage.wherein the imaging panel has an integrated readout circuit (ROIC) with a signal chain and wherein entering the low-power state involves reusing at least part of the signal chain for the acquisition circuit; and wherein the ROIC has an integrator and wherein entering the low-power state involves turning off the integrator.

[0010] In some examples, limiting the input signal voltage involves clamping the input signal voltage. In some examples, limiting the input signal voltage involves clamping the input signal voltage across a diode. In some examples, clamping the input signal voltage involves clamping the input signal voltage across a charge amplifier. In one example, the charge amplifier is optimized for X-ray detection.

[0011] In some implementations, a change in the input signal voltage is detected using a converter. In some implementations, the imaging panel has an integrated readout circuit (ROIC) with a signal chain, and entering the low-power state involves reusing at least part of the signal chain for the detection circuitry. In some examples, the ROIC has an integrator, and entering the low-power state involves turning off the integrator. In some implementations, reusing at least part of the signal chain involves reusing a terminal element of the signal chain, and entering the low-power state involves turning off other elements of the signal chain. In some implementations, detecting a change in the input signal voltage involves detecting the change using a converter.

[0012] According to some implementations, an automatic exposure detection system in imaging applications comprises the following: an imaging panel with a low-power mode, a detection circuit for receiving an input signal in low-power mode and limiting an input signal voltage to a first voltage, a transducer for detecting a change in the input signal voltage, wherein the change in the input signal voltage indicates the exposure to an X-ray signal, and an integrated readout circuit (ROIC) with a signal path, wherein the detection circuit in low-power mode uses at least a portion of the signal path; wherein the ROIC includes an integrator, and wherein the integrator is switched off in low-power mode. In some examples, the detection circuit includes a diode for clamping the input signal voltage.In some examples, the detection circuit includes a charge amplifier for clamping the input signal voltage. In some examples, the sensor is a transducer. In some implementations, the detection circuit is an electrostatic discharge circuit.

[0013] In some examples, the part of the signal path used by the detection circuit has a terminal.

[0014] According to some implementations, an automatic exposure detection system in imaging applications comprises: an imaging panel with a low-power mode, a detection circuit for limiting an input signal voltage to a first voltage and for receiving an input signal in low-power mode, a means for detecting a change in the input signal voltage, wherein the change in the input signal voltage indicates the exposure to an X-ray signal, and an integrated readout circuit (ROIC) with a signal path, wherein the detection circuit in low-power mode uses at least part of the signal path; wherein the ROIC includes an integrator and wherein the integrator is switched off in low-power mode.

[0015] In some implementations, the detection method includes a converter. In some implementations, the detection circuit is an electrostatic discharge circuit. In some implementations, the detection circuit includes a diode for clamping the input signal voltage. In some examples, the detection circuit includes a charge amplifier for clamping the input signal voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] To provide a more complete understanding of the present disclosure and its features and advantages, reference is now made to the following description, which is given in conjunction with the accompanying figures, where the same reference numbers represent the same parts in which the following applies: Fig. 1 is a diagram illustrating the X-ray detection signal path according to some embodiments of the disclosure; Fig. Figure 2 is a graph illustrating the output of an integrated readout circuit switching from an imaging mode to an X-ray detection mode, according to some embodiments of the disclosure; Fig. Figure 3 is a graph illustrating the total X-ray detection performance versus the conduction time according to some embodiments of the disclosure; Fig. Figure 4 is a graph illustrating an X-ray signal path; Fig. 5 is a block diagram illustrating an X-ray detection signal path according to some embodiments of the disclosure; Fig. Figure 6 is a detailed diagram illustrating an X-ray detection signal path according to some embodiments of the disclosure; Fig. Figure 7 is an enlarged view of a detection circuit according to some embodiments of the disclosure. Fig. Figure 8 is a graph illustrating the results of a simulation of an X-ray detection signal path according to some embodiments of the disclosure; and Fig. Figure 9 is a flowchart illustrating a method for automatic exposure detection in imaging applications according to some embodiments of the disclosure. DESCRIPTION OF EXAMPLES OF THE REVELATION'S IMPLEMENTATION

[0017] X-ray systems incorporate a circuit for detecting the arrival of an X-ray signal at a wireless digital X-ray panel. However, current methods for detecting the arrival of X-ray signals consume additional space and components or significantly increase the system's power consumption. For example, some systems generate a separate, independent channel optimized for X-ray detection within the detection path, capturing X-rays while the entire readout signal path is switched off. This type of system is power-efficient but requires additional components in the design, increasing the panel's cost and weight. Other systems reuse the main readout signal path, either in a low-power state or by using a subset of channels while others are switched off.This simplifies the circuit board design and does not increase weight, but significantly increases the system's power consumption, which directly affects battery life. Systems and methods for detecting the arrival of an X-ray signal in a wireless digital X-ray panel without adding cost, area, weight, or increasing power consumption are disclosed.

[0018] Integrated readout circuits (ROICs) for imaging are used to convert the charge from an imaging sensor into a high-precision digital value. In some examples, the charge is a current. The efficiency of the analog-to-digital conversion determines the image quality. Quality can be improved by optimizing the noise, linearity, speed, and power used for the conversion function. In some implementations, the signal chain for the ROIC includes a low-noise charge amplifier circuit, a correlated dual sampler, and a high-resolution ADC. In many X-ray applications, the ROIC panel is wireless and independent of the X-ray source. To extend battery life, the ROIC panel remains in a lower-power state until an X-ray beam is detected.

[0019] In some systems, the readout integrated circuits (ROICs) for a low-power X-ray detection mode are reconfigured via software to a different low-power state. In the low-power state, the ROIC does not operate at full power, but some functionality is retained to detect the arrival of an X-ray signal. In some systems, many ROICs are switched off for a low-power mode to conserve power, while others remain switched on to detect X-ray signals. Switching off some ROICs while keeping others switched on reduces overall power consumption. However, the problem with these systems is that the system design is constrained by the characteristics of the ROIC and the time required to stabilize the system's performance upon waking.Furthermore, the ROICs that remain switched on still consume a lot of power, so the system consumes more power than is required for X-ray detection.

[0020] Systems and methods for adding an automatic exposure detection feature to an X-ray panel readout device are provided. Readout integrated circuits (ROICs) are used to convert the charge on pixels in an X-ray panel into digital values ​​to produce a visible image. The accuracy and precision of these circuits correlate with image quality. Many applications use an automatic exposure detection (AED) circuit that can remain in a low-power state until the X-ray signal is detected. When the X-ray signal is detected, the AED circuit turns on the imaging panel and acquires the image. After image acquisition is complete, the AED circuit returns to a low-power state.

[0021] Systems and methods are provided to reuse one or more of the high-power ROIC components in an X-ray detection function. The X-ray detection function is optimized for X-ray detection and consumes approximately 95-98% less power than the ROIC function. The systems and methods for reusing the high-power ROIC components have no significant impact on the circuit design or circuit area. Furthermore, the systems and methods for reusing the high-power ROIC components do not impair performance during the main imaging function. As described in more detail below, in some implementations, the terminal element of an ROIC can be used for X-ray detection while other elements of the ROIC are switched off. In one example, the terminal element is a diode.

[0022] According to various implementations, the high-performance imaging signal chain is reused for a much lower-power, lower-resolution signal chain, which is then re-optimized for X-ray detection. Reusing the imaging signal chain for a lower-power, lower-resolution signal chain enables a low-power X-ray detection mode without impacting chip area or performance during normal (imaging) operation.

[0023] According to one implementation, the high-performance blocks of the ROIC signal chain are replaced by lower-performance blocks optimized for X-ray detection. According to other implementations, selected elements of the ROIC signal chain are used for X-ray detection, while the remaining elements enter a low-power state or are switched off.

[0024] An X-ray detection signal path is designed to be added to an X-ray panel, allowing the panel to easily enter and exit a low-power standby mode. In low-power standby mode, the X-ray signal can still be detected. When an X-ray signal is detected in low-power standby mode, the system switches to imaging mode and the high-power ROIC imaging system is activated. The X-ray panel, including the X-ray detection signal path, incorporates circuitry and techniques that can drastically reduce the power consumption of the X-ray detection function by approximately 95-98% compared to previous approaches.

[0025] Fig. Figure 1 is a diagram illustrating an X-ray detection signal path 100 that can be used to detect X-ray signals in a low-power mode, according to some embodiments of the disclosure. The X-ray detection signal path 100 has input lines 102, sensors 104, a multiplexer 106, and an analog-to-digital converter 108. The input lines 102 are analog input lines. According to one implementation, X-ray signals directed at an X-ray panel are received at the input lines 102. According to various examples, the X-ray detection signal path 100 has multiple sensors 104 and can have one sensor 104 for each input line 102. The output from the sensors 104 is input to the multiplexer 106, and the output from the multiplexer 106 is input to the analog-to-digital converter 108.In one example, 256 analog inputs are received on input lines 102 and fed into 256 sensors 104, and the output from the 256 sensors 104 is fed into the multiplexer 106. In some examples, the X-ray detection signal path 100 is driven to a voltage controlled by the VT input, a selected input voltage. The power of the X-ray detection signal path 100 scales with the line time.

[0026] Readout requirements for X-ray detection can differ significantly from those for imaging, as readout time, noise, and dynamic range are less critical, while power savings and recovery time are more important. The X-ray Acquisition Signal Path 100 leverages these differences to optimize performance in both readout and detection modes without sacrificing readout process performance. Depending on the implementation, modifications are made to the ROIC design to optimize automatic exposure detection (AED) performance. In one example, a change to the ROIC design for low-power X-ray detection mode involves completely disabling the charge integrators, which significantly reduces system performance.In one example, a change to the ROIC design for low-power X-ray detection mode includes power scaling of the ADC and amplifiers to dynamically reduce power loss. In another example, a change to the ROIC design for low-power X-ray detection mode includes minimizing the power used for the system reference bias, thereby reducing the turn-on time once the X-ray beam is detected. A digital output interface can be used for maximum power savings. In one example, the digital output interface is a CMOS input / output (I / O) interface.

[0027] In X-ray acquisition mode, the X-ray acquisition signal path 100 uses a very low-power acquisition circuit that does not bias the panel to a thin-film transistor reference voltage (REF_TFT). In imaging mode, however, the panel is biased to REF_TFT. Instead, in X-ray acquisition mode, the panel is driven to a voltage controlled by the VT input (or an optional VDD / 2 voltage). The VT input voltage clamps the input to VT+ / -V. BE , where V BE The base-emitter voltage is the limiting factor. Consequently, in X-ray detection mode, the final panel voltage is a function of the leakage current on each channel. In X-ray detection mode, the input bias current is on the order of several hundred picoamperes (pA). Thus, without any additional input load, the input bias current causes the input to be set to VT-V. BEis controlled. Since the input leakage loss can vary greatly, each channel in X-ray detection mode can settle at a different output code. In one example, REF_TFT is one volt.

[0028] Fig. Figure 2 is a graph 200 showing different channels of the ROIC output that switch from imaging mode to X-ray detection mode at different input leakage losses over time (across a number of views shown on the x-axis), according to some embodiments of the disclosure. In particular, in X-ray detection mode, each channel oscillates to a different output code depending on the input leakage loss. As in Fig. As shown in Figure 2, the input bias current, without an additional input load, causes the input to VT-V BEWhen the ROIC output is switched from imaging mode to X-ray detection mode, the channel settles at code 10000 with no input load. Similarly, when the ROIC output is switched from imaging mode to X-ray detection mode with a 20 pF (picofarad) load, the channel settles at code 9700. When the ROIC output is switched from imaging mode to X-ray detection mode with a 68 pF load, the channel settles at code 9600. When the ROIC output is switched from imaging mode to X-ray detection mode with a 150 pF load, the channel settles at code 9400. When selecting the voltage for VT, the voltage lies within the input range of the ADC [0.5 V to 4.5 V]. Furthermore, the voltage VT is equal to or less than the absolute maximum values ​​specified in the datasheet.

[0029] According to some implementations, there are two steps to entering X-ray detection AED mode. First, the desired mode is selected in the configuration register. This is programmed once at power-on, as it is a configuration. The second step to entering X-ray detection mode is a small digital pattern used to start and exit the mode. Once the correct digital pattern for entering X-ray detection is provided, the device reconfigures itself and operates with the standard or modified system timing. In some examples, the part that reconfigures itself is the ROIC (Release of Operation Instruction). In some implementations, the selected readout timing is reused for X-ray detection, but at a much lower frequency.

[0030] Due to the wide variety of panel characteristics and the sensitivity of the X-ray detection, the system implementation can be tailored to any application. As discussed above, this shows Fig. 2. The offset of the X-ray panel entering X-ray acquisition mode. In this example, REF_TFT is 1 V, which results in an output offset of -8000 µsbs under normal readout conditions in imaging mode. At view 100 (on the x-axis), the setup switches from imaging mode to X-ray acquisition mode, and due to internal leakage losses (~100 pA), the inputs begin to decrease towards VT-0.5 V. According to one example, VT = 1.5 V. As in Fig. As shown in Figure 2, switching to X-ray acquisition mode stabilizes after 10-20 views, depending on the input load. In one example, the X-ray radiation is strong enough to push the signal above 0.5 V and into the ADC range.

[0031] The various channels of the X-ray panel can be monitored for X-ray detection. In some examples, only one channel within a ROIC is monitored, while in others, all channels within the panel are monitored. In one implementation, one X-ray panel is used for X-ray detection, and the remaining facilities are completely switched off for further power savings. Using fewer than 256 channels within an X-ray panel does not result in a significant power saving for the X-ray panel itself; however, using fewer than 256 channels within an X-ray panel does save computational power in system processing. In one implementation, the results of all monitored channels are averaged to reduce noise.

[0032] In some implementations, X-ray detection systems use a voltage VT = 2.5 V. In one example, the X-ray source is emulated using a current pulse, and the current pulses are stepped down from near 0, increasing in steps of ~200 nA at a pixel. In another example, the gate drivers remain turned on throughout the X-ray detection process to maximize sensitivity to the X-ray pulse. Binning many pixels can improve sensitivity. According to various implementations, different pixels can be selected for binning for optimal detection. Any number of pixels can be binned; for example, dozens, hundreds, or thousands of pixels can be binned. In some examples, columns of pixels are binned.In other examples, rows of pixels can be binned. Sensitivity increases as more pixels are binned, with a slight reduction in settling time when switching modes due to the increased input load capacity (see ). Fig. 2) Increased noise due to input load is not significant for the X-ray detection mode because of the relatively low resolution requirement for X-ray detection. The inputs do not need to fully settle when entering the X-ray detection mode; as long as the X-ray signal is greater than the noise and the settling error, the X-ray signal can be easily detected.

[0033] According to some implementations, switching from X-ray acquisition mode to imaging mode results in specific output characteristics. Depending on the application-specific details, an additional thermal settling-in period may occur when switching to imaging mode due to increased power loss and the self-heating of the X-ray panel. Therefore, it may take several views for the output to normalize when switching from X-ray acquisition mode to imaging mode.

[0034] One advantage of the X-ray acquisition systems and methods discussed herein is power savings. The system architecture was designed to minimize power loss while maintaining features such as proper panel bias, resolution, and fast wake-up time during AED. In some implementations, the system uses an LVDS (Low Voltage Differential Signaling) interface. In others, the system uses a CMOS I / O interface. In addition to static power, there is dynamic power loss, which is a function of the conduction time and is largely independent of the type of I / O used. The slower the conduction time, the lower the overall power loss. In some examples, the conduction time in X-ray acquisition mode is much slower than typical readout times, around 1 kHz or less.

[0035] Fig. Figure 3 is a graph 300 illustrating the total X-ray detection performance versus conduction time according to some embodiments of the disclosure. In particular, graph 300 shows Fig. 3 the dynamic effect of the overall power loss.

[0036] Fig. Figure 4 is a diagram showing an X-ray signal chain 400 comprising a first circuit module 402, a second circuit module 404, a control logic 406, a low-voltage differential signaling module (LVDS) 408, a random-access memory (RAM) 410, a read-only memory (ROM) 412, registers 414, and a sequencer 416. The first circuit module 402 includes a terminal 420, an integrator 422, comparators 424a and 424b, and CDS elements 426a and 426b. The first circuit module 402 receives an input signal at terminal 420. In some examples, terminal 420 is a terminal diode. The input signal is an analog input signal received at the terminal. In some examples, the input signal is an X-ray signal. As shown in Fig. As shown in Figure 4, the input signal is AN0. Terminal 420 outputs a signal to the integrator 422. In some examples, the integrator 422 also receives a reference input REF_TFT. The integrator 422 integrates the input signal(s) over time to produce an output signal. The output from the integrator 422 is fed into the comparators 424a and 424b. The output from the integrator 422 is fed into the CDS elements 426a and 426b. In some examples, the integrator 422 acts as an amplifier / integrator. In one implementation, the CDS elements 426a and 426b reduce the noise of the signal. The second circuit module 404 includes multiplexers 430a and 430b, sample-and-hold amplifiers 432a and 432b, and an ADC 434.

[0037] According to one implementation, an X-ray signal chain 400 has several first circuit modules 402 and several second circuit modules 404. In some implementations, several first circuit modules 402 are fed into a second circuit module 404. Specifically, outputs from several first circuit modules 402 are fed into the multiplexers 430a and 430b in the second circuit module 404. In one example, an X-ray signal chain 400 has 256 first circuit modules 402 and eight second circuit modules 404, and 32 first circuit modules 402 are fed into each second circuit module 404 at the multiplexers 430a and 430b.

[0038] According to various examples, and as measured in different X-ray panels, the integrator consumes a significant amount of power in conventional X-ray panels. In conventional systems with a low-power X-ray detection mode, the integrator typically remains switched on in low-power X-ray detection mode to maintain a constant voltage across the panel. This panel voltage is used to detect X-rays in the X-ray systems. According to some embodiments of the disclosure, the integrator is switched off in low-power X-ray detection mode.

[0039] In particular, the X-ray panel with the X-ray acquisition system described herein disables the low-noise, high-precision integrator 422. In some implementations, the X-ray acquisition system operates without an integrator. In other implementations, the X-ray acquisition system includes a low-power integrator for use in X-ray acquisition mode.

[0040] In some implementations, terminal 420 is used in X-ray detection mode to drive the input for electrostatic discharge (ESD) events. The input voltage is held at a fairly constant level, and a transducer is used to detect any change in voltage indicating the presence of an X-ray beam. This allows the rest of the chip, including the integrator 422, comparators 424a and 424b, CDS elements 426a and 426b, multiplexers 430a and 430b, sample-and-hold amplifiers 432a and 432b, and ADC 434, to enter a low-power state, thus increasing the efficiency of the X-ray panel.

[0041] Fig. Figure 5 is a block diagram illustrating an X-ray detection signal path 500 according to some embodiments of the disclosure. The X-ray detection signal path includes a panel 502, a detection circuit 504, an integrator 506, a low-pass filter (LPF) 508, a correlated dual-scan sensor (CDS) 510, and a sample-and-hold amplifier (SHA) 512. In some implementations, the panel 502 is an X-ray panel and has approximately 1,000 activated pixels per line. The input received at the panel 502 is output to the detection circuit 504. In some examples, the detection circuit is an electrostatic discharge (ESD) circuit. The output from the detection circuit 504 is input to the integrator 506. In some implementations, the integrator 506 has a reset switch. The output from the integrator 506 is input to the low-pass filter 508. The low-pass filtered signal output by the LPF 508 is input into the CDS 510.The CDS 510 reduces the noise in the signal and outputs a signal to the SHA 512. In some implementations, in low-power mode (X-ray acquisition mode), the panel 502 and the acquisition circuit 504 are switched on, and the integrator 506, the LPF 508, the CDS 510, and the SHA 512 are switched off.

[0042] Fig. Figure 6 is a detailed diagram illustrating the circuit elements in the X-ray detection signal path 500 according to some embodiments of the disclosure. The diagram shown in Fig. The illustrated system simplifies the automatic exposure detection (AED) function. Specifically, no additional components beyond those used in imaging mode are added for the AED or X-ray detection mode. Eliminating these additional components saves space and reduces system costs. The system described in Figure 6... Fig. The system illustrated in Figure 6 features an X-ray acquisition panel 602. In some examples, the X-ray acquisition panel 602 has approximately 1,000 activated pixels per row. The one shown in Figure 6... Fig. The illustrated system further includes an ESD circuit 604, an integrator and reset switch 606, a low-pass filter 608, a CDS 610, and a sample-and-hold circuit 612. In some examples, the X-ray detection panel 602 has multiple gate drivers that are activated in parallel. Using multiple gate drivers produces a larger signal than using a single gate driver. Additionally, activating the entire X-ray detection panel 602 averages the signal across the panel. In one example, the X-ray detection panel 602 operates at close to 2.5 volts in X-ray detection mode. The Fig. The system shown in Figure 6 reduces the ROIC power in X-ray detection mode by about 98% compared to previous systems by using the ESD circuit 604 for X-ray detection while switching off the higher power components, including the integrator and reset switch 606, the low-pass filter 608, the CDS 610 and the sample-and-hold circuit 612.

[0043] Fig. Figure 7 is an enlarged view of the ESD circuit 604 according to some embodiments of the disclosure. The ESD circuit 604 receives first 702 and second inputs 704 from the in Fig. The X-ray detection panel 602 is shown in Figure 6. In addition, the ESD circuit 604 has a first VDD input 706, a test input 708, a ground 710, and a second VDD input 714. The first VDD input 706, the test input 708, the ground 710, and the second VDD input 714 are fed into a summing terminal 712. The ESD circuit 604 also has a capacitor 718, which is connected to the first and second inputs 702 of the panel 602. The ESD circuit 604 also has a resistor 716, which is connected to the first and second inputs 702 and the capacitor 718. The ESD circuit 604 features a first 720, second 722, third 724, and fourth PN diode 726 connected in series. The first 720, second 722, third 724, and fourth diode 726 are also connected to the inputs, as shown in Fig. Figure 7 shows the circuit. Capacitor 718 and resistors 716 are connected between the first diode 720 and the second diode 722. The output of the summing circuit 712 is connected between the third diode 724 and the fourth diode 726. The ESD circuit 604 has an input node 730 and an output node 732.

[0044] Since the integrators 606 (in Fig. When the X-ray detection mode is switched off (shown in 6), the control signal for panel 602 comes from the ESD circuit 604.

[0045] The ESD circuit 604 is used to detect X-ray signals. The test input is used to bias the first 720, second 722, third 724, and fourth diode 726 to 2.5 V. Biasing these diodes to 2.5 V clamps the line voltage to 2.5 V ± ± V, depending on leakage losses. BEIn some implementations, the 2.5 V is generated using an internal resistor divider. In other implementations, the VT can be used for the input. In various implementations, the voltage is + / -V. BE 100-200 mV within the ADC range. When a charge is applied to the ESD circuit, the voltage across the diode changes. A converter detects this voltage change.

[0046] As demonstrated by various examples, X-ray acquisition systems and methods are highly configurable and can be optimized for different applications. In some implementations, the X-ray acquisition system can be used for full-panel acquisition. In other implementations, the X-ray acquisition system is applied to a limited area of ​​an X-ray panel, with other parts of the panel being switched off, resulting in even greater power savings. The systems and methods described herein provide fast acquisition at any X-ray dose, thus providing maximum time to minimize start-up settling and image artifacts.

[0047] According to various implementations, this is indicated in the Fig. 5 and Fig. The panel shown in Figure 6 has multiple gate drivers that are activated in parallel. Activating the entire panel results in an averaging of the signal across the panel. In some implementations, multiple gate drivers may be required to generate a sufficiently strong signal for detection. In some examples, the number of gate drivers required for signal detection depends on the X-ray beam intensity. In one implementation, the panel operates near 2.5 V for the X-ray detection mode.

[0048] According to various implementations, the integrators, as they are described in the Fig. 5 and Fig. Figure 6 shows that during X-ray detection mode, the integrator is switched off and the reset switch is closed. Thus, the input directly drives the CDS capacitor. In some implementations, a CDS capacitor is used to sample the line voltage. In various examples, full CDS differentiation is not used. According to some implementations, a single-ended ADC conversion with logic changes is enforced.

[0049] According to various implementations, the SHA and ADC typically operate and are configured for power scaling mode. The reference buffers for the ADC and REF_DAC remain in a keep-alive state to minimize power consumption, while the heavily filtered nodes remain biased as needed. Some implementations use a low-power ADC reference buffer during conversions.

[0050] Some implementations use a CMOS I / O in the X-ray acquisition system to achieve optimal power savings. In one example, one X-ray panel is used for the AED, and the other X-ray panels are switched off.

[0051] Fig. Figure 8 is a graph illustrating the results of a simulation of an X-ray detection signal path according to some embodiments of the disclosure. As shown in the upper graph, the input drifts towards 1 Vbe as a function of leakage loss and charge injection from the CDS capacitor. As shown in the lower graph, the line voltage can be unstable over time. An algorithm can be used to monitor the output data and determine a valid X-ray signal.

[0052] Fig.Figure 9 is a flowchart illustrating a method 900 for automatic exposure detection in imaging applications according to some embodiments of the disclosure. Method 900 features, in step 902, the entering of a low-power state at an imaging panel. Once the imaging panel is in a low-power state, in step 904, an input signal voltage at a detection circuit in the imaging panel is limited to a first voltage. In some examples, the input signal voltage is limited by clamping the voltage. In some examples, limiting the input signal voltage involves clamping the input signal voltage at a diode. In other examples, clamping the input signal voltage involves clamping the input signal voltage at a charge amplifier.In one example, the charge amplifier is optimized for X-ray detection.

[0053] In step 906, an input signal is received at the detection circuitry in the imaging panel. In several examples, the input signal is an X-ray signal. In step 908, a change in the input signal voltage is detected, where the change in input signal voltage indicates exposure to an X-ray signal. In some examples, the change in input signal voltage is detected using a transducer. In step 910, the imaging panel exits the low-power state based on the change in input signal voltage. In some examples, the imaging panel enters an imaging mode when it exits the low-power state.

[0054] In some implementations, the imaging panel has an integrated readout circuit (ROIC) with a signal chain, and entering the low-power state involves reusing at least part of the signal chain for the acquisition circuit. In some examples, the ROIC includes an integrator, and entering the low-power state involves turning off the integrator.

[0055] According to various implementations, the systems and methods discussed herein can be used for imaging applications such as X-ray and CT scans.

[0056] In various implementations, the automatic detection and exposure systems and procedures discussed herein can be integrated into a digital-to-analog front end. In one example, a digital-to-analog front end features 256 channels and 16 bits, integrating the charge-to-digital conversion signal chain onto a single chip. A digital-to-analog front end enables a wide range of digital X-ray modalities, including portable radiology and mammography, as well as high-speed fluoroscopy and cardiac imaging. A digital-to-analog front end can be supplied on a high-density system-on-flex (SOF) package that can be directly mounted onto a digital X-ray panel. In some examples, converted channel results are output on a single self-clocked serial LVDS interface, significantly reducing the external hardware required.A serial interface compatible with the Serial Peripheral Interface (SPI) allows the configuration of the digital-to-analog front end using the serial digital interface input. Multiple digital-to-analog front ends can be cascaded on a single 3-wire bus via serial data output. In some examples, an integrated timing sequencer of the digital-to-analog front end controls its sampling activity. The sequencer is programmed via the SPI port and clocked by a single clock signal. Variations and implementations

[0057] In the discussions of the embodiments above, the capacitors, clocks, DFFs, dividers, inductors, resistors, amplifiers, integrators, switches, digital cores, transistors, and / or other components can be easily replaced, substituted, or otherwise modified to accommodate specific circuit layout requirements. Furthermore, it should be noted that the use of complementary electronic devices, hardware, software, etc., provides an equally viable option for implementing the teachings of this disclosure.

[0058] In one embodiment, any number of electrical circuits shown in the figures can be implemented on a circuit board of an associated electronic device. The circuit board can be a general-purpose printed circuit board that accommodates various components of the electronic device's internal electronic system and also provides connectors for other peripherals. More specifically, the circuit board can provide the electrical connections through which the other components of the system can communicate electrically. Any suitable processors (including digital signal processors, microprocessors, supporting chipsets, etc.), computer-readable non-volatile memory elements, etc., can be appropriately coupled to the circuit board based on specific configuration requirements, processing requirements, computer designs, etc.Other components, such as external memory, additional sensors, audio / video display controllers, and peripherals, can be connected as plug-in cards, via cables to the board, or integrated into the board itself. In various embodiments, the functionalities described herein can be implemented in emulation form as software or firmware running on one or more configurable (e.g., programmable) elements arranged in a structure that supports these functions. The software or firmware providing the emulation can be provided on a non-volatile, computer-readable storage medium containing instructions that enable a processor to execute these functionalities.

[0059] In another embodiment, the electrical circuits of the figures can be implemented as standalone modules (e.g., a device with associated components and a circuit configured to perform a specific application or function) or as plug-in modules in application-specific hardware of electronic devices. It should be noted that specific embodiments of the present disclosure can be readily integrated, either wholly or partially, into a system-on-a-chip (SOC) package. An SOC represents an integrated circuit (IC) that integrates components of a computer or other electronic system onto a single chip. It can include digital, analog, mixed-signal, and often high-frequency functions; all of these can be provided on a single chip substrate.Other embodiments may include a multi-chip module (MCM) with several separate ICs located within a single electronic package and configured to interact with each other through the electronic package. In various other embodiments, the clocking and filtering functionalities may be implemented in one or more silicon cores in application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), and other semiconductor chips.

[0060] It is also essential to note that all specifications, dimensions, and relationships outlined herein (e.g., the number of processors, logical operations, etc.) are presented for illustrative and teaching purposes only. Such information may be substantially modified without deviating from the intent of the present disclosure or the scope of the appended claims. The specifications apply only to a non-limiting example and should be interpreted accordingly. In the preceding description, exemplary embodiments were described with reference to specific processor and / or component arrangements. Various modifications and changes to such embodiments may be made without deviating from the scope of the appended claims. The description and drawings should therefore be considered illustrative rather than limiting.

[0061] It should be noted that the activities discussed above with reference to the figures are applicable to any integrated circuits that incorporate signal processing, particularly those that use sampled analog signal processing, some of which may be associated with real-time data processing. Certain embodiments may involve multi-DSP signal processing, floating-point processing, signal / control processing, fixed-function processing, microcontroller applications, etc.

[0062] In certain contexts, the features discussed here can be applied to medical systems, scientific devices and instruments, wireless and wired communications, radar, industrial process control, audio and video systems, power sensing, devices and instruments (which may be highly accurate), and other systems based on digital processing.

[0063] Furthermore, certain embodiments of the above-discussed digital signal processing technologies can be deployed for medical imaging, patient monitoring, medical measurement equipment, and home healthcare. This could include lung function monitoring devices, accelerometers, heart rate monitors, pacemakers, and so on. Other applications may include automotive technologies for safety systems (e.g., stability control systems, driver assistance systems, braking systems, infotainment, and interior applications of all kinds). Additionally, powertrain systems (for example, in hybrid and electric vehicles) can utilize high-precision data conversion products for battery monitoring, control systems, reporting controls, maintenance activities, and so forth.

[0064] In other exemplary scenarios, the lessons of this disclosure can be applied in industrial markets that feature process control systems which help drive productivity, energy efficiency, and reliability. In consumer applications, the lessons of the signal processing circuits discussed above can be used for image processing, autofocus, and image stabilization (e.g., for digital cameras, camcorders, etc.). Other consumer applications may include audio and video processors for home theater systems, DVD recorders, and high-definition televisions. Still other consumer applications may include advanced touchscreen controls (e.g., for any type of portable media device). Therefore, such technologies can easily be incorporated into smartphones, tablets, security systems, PCs, gaming technologies, virtual reality, simulation training, and so on.

[0065] It should be noted that the numerous examples provided here may describe interactions involving two, three, four, or more electrical components. However, this is done solely for clarity and illustrative purposes. It is understood that the system can be assembled in any suitable manner. Along with similar design elements, any of the illustrated components, modules, and elements of the figures can be combined in various possible configurations, all of which clearly fall within the broad scope of this description. In certain cases, it may be easier to describe one or more of the functionalities of a particular set of processes by mentioning only a limited number of electrical elements.It is understood that the electrical circuits in the figures and their teachings are easily scalable and can accommodate a large number of components as well as more intricate / complex arrangements and configurations. Accordingly, the examples provided should not limit the scope of protection or restrict the broad teachings of the electrical circuits as they may be applied to a variety of other architectures.

[0066] It should be noted that in this specification, references to various features (e.g., elements, structures, modules, components, steps, actions, characteristics, etc.) contained in "one embodiment," "an exemplary embodiment," "another embodiment," "some embodiments," "different embodiments," "other embodiments," "an alternative embodiment," and the like, are to be understood as meaning that such features are contained in one or more embodiments of the present disclosure and may be combined in the same embodiments, but need not necessarily be.

[0067] It is also important to note that some of the processes may be deleted or removed, or that these processes may be substantially modified or altered, without deviating from the scope of protection of this disclosure. In addition, the timing of these processes may be substantially altered. The preceding operational flows have been presented for illustrative and discussion purposes only. Significant flexibility is provided by the embodiments described herein insofar as any suitable arrangements, chronologies, configurations, and timing mechanisms may be provided without deviating from the teachings of this disclosure.

[0068] Skilled persons may identify numerous other changes, substitutions, variants, variations, and modifications, and it is intended that the present disclosure encompasses all such changes, substitutions, variants, variations, and modifications as falling within the scope of protection of the appended claims. To assist the United States Patent and Trademark Office (USPTO) and, additionally, any readers of any patent granted on this application in interpreting the claims appended herein, the applicant wishes to state that the applicant (a) does not intend that any of the appended claims violate paragraph (6) of 35 USC, section 112, as it exists at the date of the present filing, unless the words “means to” or “steps to” are specifically used in the specific claims; and (b) does not intend, by any statement in the description, to limit the present disclosure in any way that is not otherwise reflected in the attached claims. OTHER COMMENTS, EXAMPLES AND IMPLEMENTATIONS

[0069] It is noted that all optional features of the device described above can also be implemented with respect to the method or process described herein, and details in the examples can be used anywhere in one or more embodiments.

[0070] In a first example, a system is provided (which may include any suitable circuits, dividers, capacitors, resistors, inductors, ADCs, DFFs, logic gates, software, hardware, connections, etc.) that can be part of any type of computer, which may further include a printed circuit board coupled with several electronic components.The system may include means for clocking data from the digital core to a first data output of a macro using a first clock, wherein the first clock is a macro clock; means for clocking the data from the first data output of the macro to the physical interface using a second clock, wherein the second clock is a clock of the physical interface; means for clocking a first reset signal from the digital core to a reset output of the macro using the macro clock, wherein the first reset signal output is used as a second reset signal; means for sampling the second reset signal using a third clock, which provides a clock rate greater than the rate of the second clock, to generate a sampled reset signal; and means for resetting the second clock to a predetermined state in the physical interface in response to a transition of the sampled reset signal.

[0071] The “means to” in these cases (above) can (but is not limited to) include the use of any suitable component discussed herein, together with any suitable software, circuit, hub, computer code, logic, algorithms, hardware, controller, interface, link, bus, communication path, etc. In a second example, the system includes memory which further contains machine-readable instructions which, when executed, cause the system to perform one of the activities discussed above.

Claims

[1] Method for automatic exposure detection in imaging applications, wherein the method comprises the following: Entering a low-power state at an imaging panel; Limiting an input signal voltage to a first voltage at a detection circuit in the imaging panel; Receiving an input signal at the acquisition circuit in the imaging panel; Detecting a change in the input signal voltage, wherein the change in the input signal voltage indicates the exposure to an X-ray signal; and Exiting from the low-power state based on a change in the input signal voltage; wherein the imaging panel has an integrated readout circuit (ROIC) with a signal chain and wherein entering the low-power state involves reusing at least part of the signal chain for the acquisition circuit; and wherein the ROIC has an integrator and wherein entering the low-power state involves turning off the integrator. [2] Method according to claim 1, wherein limiting the input signal voltage comprises clamping the input signal voltage at a diode. [3] Method according to claim 1, wherein the clamping of the input signal voltage comprises clamping the input signal voltage at a charge amplifier. [4] Method according to claim 1, wherein the reuse of at least part of the signal chain comprises the reuse of a clamping element of the signal chain, and wherein entering the low-power state comprises switching off other elements of the signal chain. [5] Method according to claim 1, wherein the detection of a change in the input signal voltage comprises detection of a change using a converter. [6] System for automatic exposure detection in imaging applications, wherein the system comprises: an imaging panel with a low-power mode; a detection circuit for limiting an input signal voltage to a first voltage and for receiving an input signal in low-power mode; a sensor for detecting a change in the input signal voltage, wherein the change in the input signal voltage indicates the exposure to an X-ray signal; and an integrated readout circuit (ROIC) with a signal path, wherein the acquisition circuit is configured to use at least part of the signal path in low-power mode; wherein the ROIC includes an integrator and wherein the integrator is configured to be switched off in low-power mode. [7] System according to claim 6, wherein the detection circuit has a diode for clamping the input signal voltage. [8] System according to claim 6, wherein the detection circuit has a charge amplifier for clamping the input signal voltage. [9] System according to claim 6, wherein the part of the signal path used by the detection circuit has a terminal. [10] System according to claim 6, wherein the sensor is a transducer. [11] System according to claim 6, wherein the detection circuit is an electrostatic discharge circuit. [12] System for automatic exposure detection in imaging applications, wherein the system comprises: an imaging panel with a low-power mode; a detection circuit for limiting an input signal voltage to a first voltage and for receiving an input signal in low-power mode; a means for detecting a change in the input signal voltage, wherein the change in the input signal voltage indicates the exposure to an X-ray signal; and an integrated readout circuit (ROIC) with a signal path, wherein the acquisition circuit is configured to use at least part of the signal path in low-power mode; wherein the ROIC includes an integrator and wherein the integrator is configured to be switched off in low-power mode. [13] System according to claim 12, wherein the means for detection comprises a transducer. [14] System according to claim 13, wherein the detection circuit is an electrostatic discharge circuit. [15] System according to claim 12, wherein the detection circuit has a diode for clamping the input signal voltage. [16] System according to claim 12, wherein the detection circuit has a charge amplifier for clamping the input signal voltage.

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