Intraoral X-ray sensor for automatic exposure control

Abstract

The present invention relates to an intraoral X-ray sensor (1) for use with an intraoral X-ray system (3) having an automatic exposure control (AEC) function, characterized in that the intraoral X-ray sensor (1) comprises an exposure analysis unit (1.2), an imaging X-ray detector (1.3) and a communication interface (1.1), in which scout shots or scout video streams received from the imaging X-ray detector (1.3) are analyzed by the exposure analysis unit (1.2) in the intraoral X-ray sensor (1) in order to record information regarding the exposure level of the scout images or video streams and to forward this information by means of the communication interface (1.1) to a decision unit (2.2) of the intraoral X-ray system (3) located outside the intraoral X-ray sensor (1) and adapted for further exposure evaluation and decision.

Description

Technical Field

[0001] The present invention relates to an intraoral X-ray system having an automatic exposure control (AEC) function, comprising an intraoral X-ray sensor and a dental X-ray unit.

Background Art

[0002] Automatic exposure control (AEC), that is, the AEC technique is well known, and is also well known in the dental field for intraoral X-rays using a digital X-ray image receiver. See, for example, EP1859659A1 and US Patent No. 6,898,268 (B2).

[0003] The X-ray image detector has an optimized dynamic range for general exposure situations in intraoral X-ray diagnosis. Images with insufficient exposure are characterized by increased noise, and areas of overexposure can no longer resolve signals due to pixel saturation effects. Using the AEC technique, the saturation limit can be solved by performing multiple exposures and summing the individual records. By reducing the saturation limit, the X-ray image receiver can be optimized for low exposures. In this constellation, the user can specifically determine the minimum image quality required in each case according to that instruction in order to keep the patient dose as low as possible.

[0004] The exposure situation can be measured using a scout shot. Information regarding the exposure level of this first shot is used for this purpose. This indicates which maximum value of a certain number of pixels has been reached or exceeded. It can also be, for example, a relative value regarding the maximum allowable value in percentage units with respect to the saturation limit. Information regarding the exposure level may also be included in each respective histogram.

[0005] In AEC X-ray systems using Scout Shot, rapid evaluation of pre-exposed images is required to determine the completed X-ray exposure in order to reduce movement artifacts that may be caused by movement of the recording geometry during the recording session. Until now, the evaluation of the exposure level of Scout Shot has been performed by an evaluation unit located in the X-ray device (or in a connected computer), detached from the intraoral X-ray sensor (hereinafter also referred to as the "sensor"). The procedure to date is as follows:

[0006] 1. The sensor detects the first shot. 2. The sensor transmits the first shot to the X-ray device. 3. The evaluation unit analyzes the first shot in the X-ray device. 4. The evaluation unit determines the exposure level for the second shot. 5. The sensor detects the second shot. 6. The sensor transmits a second shot to the X-ray device. 7. The evaluation unit calculates the combined image from the first and second shots in the X-ray device. Generally, intraoral X-ray devices with AEC (Automated Electron Computing) functionality are connected to a computer or the cloud. When set to exposure readiness, the intraoral X-ray sensor detects the start of the X-ray image and captures the image. After exposure, the X-ray image data is read from the intraoral X-ray detector and forwarded to the computer. [Overview of the Initiative]

[0007] The object of the present invention is to provide an intraoral X-ray sensor with integrated AEC (Autonomous Electronic Control) functionality for use with an intraoral X-ray system.

[0008] This objective is achieved by the intraoral (IO) X-ray sensor with integrated AEC functionality described in claim 1. The subject matter of the dependent claims relates to further developments and preferred embodiments.

[0009] According to the present invention, the analysis of scout images or video streams regarding exposure levels is performed by an IO X-ray sensor, rather than by an X-ray device. For this purpose, the video stream can be used, for example, as an independent sequence of individual images.

[0010] When the above evaluation is moved to an IO X-ray sensor (hereinafter also referred to as the "sensor"), the data transfer and complexity on the X-ray device side are reduced. The process according to the present invention is then, for example, as follows:

[0011] 1. The sensor detects the first shot (scout shot). 2. An evaluation unit (for example, a sensor exposure analysis unit) analyzes the first shot and compiles information about the exposure level. 3. Information regarding the exposure level, and, where applicable, sensor characteristics, are transmitted to a decision unit outside the sensor. 4. The decision unit determines the exposure parameters for further shots based on this and other information. 5. In accordance with this decision, the sensor will either not perform an exposure or perform one or more exposures. 6. The sensor transmits individual records and / or (optionally) at least one aggregated record to an X-ray device or PC.

[0012] An essential feature of the present invention is that electronic equipment associated with the IO X-ray sensor (e.g., an exposure analysis unit) can capture information about the exposure level of a scout image or video stream and communicate this information to the X-ray device. This reduces initialization work and increases the speed of the process.

[0013] X-ray devices, particularly the determination unit of an X-ray device, use this information and other specifications regarding the exposure level, preferably sensor-specific characteristics, required image quality, indication, kV adjustment for dual energy, increased dynamic range (high dynamic range (HDR)), dose-dependent noise behavior, etc., to set exposure parameters for subsequent exposures, such as the number of recordings, exposure time, tube current, and tube voltage. This may be one further exposure, several further exposures, or no further exposures at all.

[0014] In the case of a video stream, exposure is preferably stopped by the X-ray device when it reaches a value calculated by the determination unit of the X-ray device.

[0015] An IO X-ray sensor head or X-ray sensor connector is a preferred adaptation for evaluation units (e.g., exposure analysis units). Alternatively, the sensor head may be wirelessly connected to the X-ray device, eliminating the need for a connector.

[0016] In the following description, the present invention will be described in more detail by examples of embodiments with reference to the drawings. [Brief explanation of the drawing]

[0017] [Figure 1] A schematic diagram of an intraoral X-ray system (3) having an AEC-capable IO X-ray sensor according to one embodiment of the present invention. [Modes for carrying out the invention]

[0018] The reference numerals shown in the drawings specify the elements described below, which are referenced in the following description of exemplary embodiments.

[0019] 1. Intraoral X-ray sensor with AEC function 1.1 Communication Interface 1.2 Exposure Analysis Unit 1.3 Imaging X-ray detector 1.4 Controller 1.5 Sensor specific characteristics (memory) 1.6 Image memory 2. X-ray device 2.1 Communication interface 2.2 Decision unit 2.3 X-ray source 2.4 Controller 2.5 Communication interface 2.6 Power supply and high voltage source 2.7 User interface 3. Intraoral X-ray system 4.1 Computer 4.2 User interface and display 5. Network 6. Cloud Figure 1 shows a schematic diagram of an intraoral X-ray system (3) according to one embodiment of the present invention. The intraoral X-ray system (3) has an intraoral X-ray device (2) connected to an intraoral X-ray sensor (1). The connection is preferably a cable connection. The IO X-ray sensor (1) consists of a sensor head (housing), a cable, and a connector. The IO X-ray sensor (1) is connected to the intraoral X-ray device (2) via this connector. Preferably, other sensors (1) having the same AEC function may be connected to the IO X-ray device (2) simultaneously via their connectors. Alternatively, a wireless connection may be used. The intraoral X-ray sensor (1) has a communication interface (1.1), an exposure analysis unit (1.2), an imaging X-ray detector (1.3), a controller (1.4), a memory (1.5) containing sensor-specific characteristics, and an image memory (1.6). The controller (1.4) has access to and controls all components of the IO X-ray sensor (1), including the communication interface (1.1), the exposure analysis unit (1.2), the imaging X-ray detector (1.3), the memory (1.5), and the image memory (1.6). The image memory (1.6) stores some or all of the image data received from the imaging X-ray detector (1.3). The image memory (1.6) is useful when the pixel image data from the imaging X-ray detector (1.3) cannot be read out for evaluation without signal loss, or when signal loss is unacceptable for radiation hygiene reasons. Preferably, the X-ray sensor (1) can be equipped with a battery and wireless communication, which eliminates the need for cables. Wired data communication and / or power supply may also be considered as alternatives. Here, a USB interface or Power over Ethernet® (PoE) is preferred as the standard.

[0020] The intraoral X-ray sensor (1) includes components for automatic exposure control (AEC) functionality, which are described in more detail below. Scout shots or scout video streams received from the imaging X-ray detector (1.3) are analyzed locally in the intraoral X-ray sensor (1) by an exposure analysis unit (1.2) to record information regarding exposure levels. The analysis results, including exposure level information, are forwarded by a communication interface (1.1) to an intraoral X-ray device (2) or another external device (e.g., a computer). The intraoral X-ray device (2) has corresponding communication interfaces (2.1, 2.5) for this purpose. The intraoral X-ray unit (2) has a determination unit (2.2) that evaluates the analysis results, including the recorded information regarding exposure levels, and determines a sequence of further exposures, in particular the number of shots and their duration. In the case of video streams, this may also be done during the ongoing exposure. When using a video stream, the first and second shots expand to a set of first "m" shots and second "n" shots. In this case, the process can also be repeated multiple times. The IO X-ray sensor (1) remains in the corresponding recording ready state until the end of the recording session. The intraoral X-ray unit (2) also includes an X-ray source (2.3), a power supply and high voltage source (2.6), and a controller (2.4). The controller (2.4) also has access to the IO X-ray sensor (1), in particular. The intraoral X-ray device (2) is preferably, in particular, a small form of X-ray device for dental treatment. The determination unit (2.2) is further designed to take into account sensor-specific characteristics (1.5) and / or image quality parameters specified by the user. Sensor-specific characteristics (1.5) include, in particular, information regarding the sensor dimensions, local pixel error, dose / signal behavior, and the maximum saturation level above which a saturation effect occurs, either preventing or enabling limited digitization of the analog exposure signal. Image quality parameters can be input directly or indirectly by the user through a user interface (2.7) on the X-ray device (2).Indirect designation may be made via medical instructions (e.g., suspected caries, periodontitis, root cause), which are converted into exposure parameters, e.g., maximum exposure, dual energy, etc., by an intraoral X-ray system (3) having a decision unit (2.2). Alternatively, this may also be made via a user interface (4.2) of a computer (4.1) connected to an intraoral X-ray device (2). The intraoral X-ray device (2) is connected to the computer (4.1) via its communication interface (2.5), preferably via a network (5). The intraoral X-ray device (2) and the computer (4.1) may also have connectivity to a cloud (6). Instead of the IO X-ray sensor (1) or IO X-ray device (2) performing the image processing function, this may be done in the cloud (6) or by a PC (4.1). The received raw image material is processed to obtain an initial raw image to compensate for sensor-specific and recording-specific deficiencies. These include Gain, Blemish and DC correction (classic), Dynamic Range Expansion (High Dynamic Range (HDR)), and Motion Artifact Compensation (anti-shake).

Claims

1. In an intraoral X-ray sensor (1) for use with an intraoral X-ray system (3) having an automatic exposure control (AEC) function, The intraoral X-ray sensor (1) comprises an exposure analysis unit (1.2), an imaging X-ray detector (1.3), and a communication interface (1.1). To record information regarding the exposure level of a scout image or video stream, and to forward the information via the communication interface (1.1) to a determination unit (2.2) of the intraoral X-ray system (3), which is located outside the intraoral X-ray sensor (1) and adapted for further evaluation and determination of exposure, An intraoral X-ray sensor (1) is characterized in that a scout shot or scout video stream received from the imaging X-ray detector (1.3) is analyzed by the exposure analysis unit (1.2) in the intraoral X-ray sensor (1).

2. The intraoral X-ray sensor (1) according to claim 1, characterized in that the intraoral X-ray sensor (1) comprises an image memory (1.6) that partially or completely stores image data received from the imaging X-ray detector (1.3).

3. The intraoral X-ray system (3) comprises an intraoral X-ray sensor (1) as described in claim 1 or 2 and an intraoral X-ray device (2) having an automatic exposure control (AEC) function, wherein the intraoral X-ray device (2) and the intraoral X-ray sensor (1) are connected by their respective communication interfaces (1.1, 2.1), and the intraoral X-ray device (2) includes a determination unit (2.2) that evaluates the information regarding the exposure level and determines a sequence of further exposures, particularly the number of shots and their duration.

4. The intraoral X-ray system (3) according to claim 3, characterized in that the determination unit (2.2) is further adapted to take into account sensor-specific characteristics (1.5) and / or image quality parameters specified by the user.

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