Dental X-ray imaging system for producing intraoral X-ray images

Abstract

The present invention relates to a dental x-ray imaging system for generating intraoral x-ray images, in particular x-ray images of dental tissue, with the aid of an intraoral x-ray sensor, which can be placed in the oral cavity in the beam path of an x-ray emitter positioned outside the oral cavity, wherein the x-ray imaging system is configured to record two or more time-sequential individual x-ray images and to reconstruct an overall x-ray image from the individual images in such a way that the results of the exposure of the x-ray images are combined and movements occurring between and / or during the sequential individual x-ray images are compensated.

Description

Technical Field

[0001] The present invention relates to a dental x-ray imaging system for generating intraoral x-ray images, in particular intraoral x-ray images of dental patient tissue, by means of an intraoral x-ray sensor, which can be placed in the patient's oral cavity in the beam path of an extraoral x-ray transmitter, in particular a handheld x-ray transmitter. Background Art

[0002] Various x-ray based imaging systems are available in the field of dental radiology, whereby the imaging systems can be subdivided into extraoral and intraoral x-ray systems. Extraoral x-ray technology (EO x-ray) is typically used for two-dimensional panoramic imaging, for remote x-ray imaging, or for three-dimensional digital volume tomography (DVT). On the other hand, intraoral x-ray systems (IO x-ray) are generally used to image limited areas of the jaw (e.g., one or more teeth).

[0003] When using intraoral x-ray technology, an x-ray sensor (i.e., an x-ray detector, or in the case of analog recordings, an x-ray film) is placed inside the patient's oral cavity so that x-ray radiation can penetrate the relevant area of ​​the jaw from outside the oral cavity and expose the x-ray sensor in the mouth. An x-ray tube is used as part of an x-ray emitter, which can be attached, for example, to a movable support arm, or can also be designed as a movable handheld device, to generate x-ray radiation.

[0004] On the one hand, care must be taken to ensure correct positioning of the x-ray sensor and the x-ray emitter relative to each other and to the jaw area to be irradiated in order to create high-quality intraoral x-ray images and thus the best possible dental diagnosis. On the other hand, correct and coordinated setting and control of the radiation and detection parameters is important.

[0005] Depending on the size of the patient, the jaw area, and the output of the emitter, the exposure time when using modern detectors for intraoral diagnostic radiography can be between, for example, 40 and 200 milliseconds. The longer this exposure time, the greater the effect of motion of the emitter, sensor, and patient, which can adversely affect the resolution of the resulting x-ray image and can cause motion blur or motion artifacts. This lack of clarity or artifacts caused by motion of the patient, sensor, and / or emitter during exposure can be shown as visible blur in the image.

[0006] When using an x-ray emitter with a fixedly mounted support arm, the motion of the emitter can at least be minimized, but the motion of the sensor and the patient that can cause motion blur still remains. On the other hand, when using a handheld emitter (handheld x-ray emitter), because intraoral radiography is an exposure technique, the motion of the emitter can also cause or contribute to motion blur. When using a handheld emitter, the common use of relatively low dose output is an additional complicating factor. Therefore, the exposure time is generally longer, which further promotes undesirable motion blur and / or artifacts.

[0007] Another problem that can occur in intraoral imaging is local underexposure or, in the worst case, complete lack of exposure of the x-ray sensor. Such exposure occurs in particular if the emitter, sensor and patient tissue are not correctly aligned relative to each other. This can again also be due to unwanted movements that occur during or even before the exposure. This problem is exacerbated when handheld x-ray emitters are used. As a result, the x-rays, which are usually limited to a specific diameter by collimation, only partially or possibly not at all reach the sensor surface. Although the full patient dose is used, this results in no usable image being produced.

[0008] In conclusion, it can be said that the recording of x-ray images for intraoral diagnosis, in particular when using handheld transmitters, still leaves room for improvement.

[0009] Therefore, the underlying object of the present invention is to facilitate the creation of intraoral x-ray images such that motion blur or motion artifacts are minimized or avoided and an x-ray recording can be obtained with the highest possible accuracy and clarity and showing the maximum possible amount of anatomical details.

[0010] Another aspect of the object is to minimize or avoid x-ray exposure, or if there is exposure, then at least keep the patient dose low. Therefore, another aspect of the object is to increase the likelihood of obtaining a usable x-ray image.

[0011] The object of the invention is achieved by the subject matter of the independent claims. Advantageous further developments of the invention are defined in the dependent claims.

[0012] The present invention provides a dental x-ray imaging system for producing intraoral x-ray images with reduced motion blur.

[0013] The x-ray imaging system includes an intraoral x-ray sensor that may be placed behind patient tissue to be irradiated, within the patient's mouth, in the beam path of an x-ray emitter positioned outside the patient's mouth.

[0014] The intraoral x-ray sensor is particularly implemented as a sensor (detector) having a matrix structure, which is configured to decompose the x-ray image projection into pixels. The detected signal intensity of each pixel preferably corresponds to the locally absorbed x-ray beam energy. The x-ray imaging system may also include an x-ray emitter, for example, implemented as a handheld device, as will be explained in more detail below.

[0015] According to the invention, the x-ray imaging system is configured to record at least two and preferably several or even a large number of chronologically sequential individual x-ray images of the patient tissue during respective exposures, wherein the individual x-ray images are recorded in particular in one recording session.

[0016] The time-sequential individual x-ray images are generally the result of individual exposure, whereby, as will be discussed later, continuous radiation generated by the emitter may also be an option. It is worth mentioning that the time-sequential individual x-ray images are particularly not fully exposed, i.e., for example, do not reach a predetermined exposure range or level, and therefore are generally not used for medical diagnosis.

[0017] The individual x-ray images of the time sequence may also not have been processed further, so that they are still present in the form of raw data and can, for example, advantageously be compensated by means of histograms and / or corrected for sensor deficiencies.

[0018] According to the invention, the x-ray imaging system is configured to create an overall x-ray image from one or some of the individual x-ray images in a temporal sequence such that (i) on the one hand, the corresponding exposures, or more specifically, the results of the corresponding exposures are merged, and (ii) on the other hand, motion occurring between and / or during the sequential individual x-ray images is compensated. Thus, it is possible to obtain an exposure-blended intraoral x-ray image with reduced motion blur.

[0019] The obtained intraoral x-ray image combines the image information of two or more time-sequential individual x-ray images and is in particular sufficiently exposed, i.e., for example, a predefined exposure range is achieved, and can therefore generally be used for diagnosis. In other words, the x-ray imaging system is in particular configured to merge two or more time-sequential individual x-ray images in a later step, for example, into one final intraoral x-ray image, which images may originate from a pre-exposure and a main exposure. This "summed" final IO x-ray image preferably has a predefined exposure range (intensity) which represents a compromise between radiation hygiene and sensor saturation on the one hand and a desired image quality for a reliable diagnosis on the other hand.

[0020] Thus, the use of the present invention advantageously avoids long total exposure times which certainly ensure an exposure range suitable for diagnosis, but which is sensitive to shake and motion blur. Motion blur which would otherwise occur during long total exposures due to movement of the focus, the patient and / or the detector and which appears as "smearing" in at least parts of the x-ray image can thus be successfully minimized or avoided. The advantage of reducing motion blur is particularly useful for handheld x-ray emitters, but can be used generally as a basic principle.

[0021] Motion compensation is performed during or before merging the individual x-ray images of the time sequence. Thus, motion occurring between and / or during the individual x-ray images, such as movement of the focus, the patient and / or the detector, is compensated. In this way, the effects of motion, which would otherwise result in motion blur or motion artifacts, can advantageously be reduced or avoided. This also means that, in particular in the case of handheld transmitters, the likelihood of 10 x-ray images being useful for diagnosis is increased. Thus, no further x-ray images are required, which in turn also reduces the radiation exposure of the patient.

[0022] Motion compensation can in particular be achieved by using a motion compensator. As will be explained in further detail below, in principle a hardware solution can be provided to generate a motion in the opposite direction, or the motion compensation is preferably performed in a subsequent step (i.e. after recording the individual x-ray images). In this case, compensation of motion refers in particular to compensating for the influence of motion on the individual x-ray images.

[0023] As already mentioned, the time-sequential individual x-ray images may be obtained unprocessed as raw sensor data.However, the x-ray imaging system preferably comprises an image optimizer configured to optimize and correct the individual images.

[0024] The image optimizer can be configured in particular to correct the individual images for sensor deficiencies. To this end, the x-ray imaging system can be configured to record a dark current image, in which the sensor is not exposed to x-ray radiation, for example before the first individual image and / or after the last individual image. The image optimizer can then use one or more dark current images to optimize the sequential x-ray images and / or the overall x-ray image of the patient's tissue, which may still exist in the form of raw data, or at least one of them.

[0025] To this end, the image optimizer may be configured in particular to perform calculations based on x-ray sensor signal values ​​associated with pixels of the dark current image on the one hand and on x-ray sensor signal values ​​associated with pixels of one of the sequential x-ray images and / or the overall x-ray image of the patient tissue on the other hand. In other words, the image optimizer may be configured to offset the x-ray sensor signal values ​​associated with pixels of the dark current image by the x-ray sensor signal values ​​associated with pixels of the sequential x-ray images and / or the overall x-ray image.

[0026] The image optimizer may additionally be configured to perform further corrections, such as histogram compensation and / or linearization of brightness values ​​associated with the pixels.

[0027] The image optimizer included in the x-ray imaging system can be implemented as a hardware component, which preferably comprises an FPGA module or a module with the same or similar functions, or is implemented as such. On the other hand, it can also be provided that the image optimizer or parts thereof are implemented as a computer program, wherein the program comprises instructions which, when executed by a computer, cause the computer to optimize at least one of the time-sequential individual x-ray images and / or the overall x-ray image of the patient's tissue, in particular with the aid of a dark current image.

[0028] The x-ray imaging system may further include an image selector, wherein the image selector is configured to select or reject a particular x-ray image from the or some of the sequential individual x-ray images.

[0029] The image selector can in particular be configured to evaluate the or some sequential individual x-ray images using predefined criteria in order to select suitable, in particular sufficiently consistent x-ray images from them, or to reject unsuitable, in particular too inconsistent x-ray images.

[0030] By selecting and / or rejecting x-ray images, motion compensation can be achieved. In a sense, individual images can be "pulled in" until a certain quality measure is achieved. An image selector configured in this way is particularly suitable for recording several or a large number of individual x-ray images in a time sequence.

[0031] The minimum degree of agreement or disagreement can be used as a criterion for selecting and / or rejecting individual x-ray images.For this purpose, for example, brightness values ​​associated with the or several uniformly or statistically distributed pixels can be used.

[0032] The image selector can be implemented as a hardware component, preferably comprising or implemented as an FPGA module or a functionally identical or similar module. It can also be provided that the image selector or parts thereof are implemented as a computer program, wherein the program comprises instructions which, when executed by a computer, cause the computer to select and / or reject individual x-ray images.

[0033] The x-ray imaging system further preferably comprises a motion detector, wherein the motion detector is configured to detect motion occurring between and / or during the or some of the sequential individual x-ray images.

[0034] In the context of the present application, detection may generally be simply determining the presence of motion. As described above, for example, a motion detector that detects the presence or absence of motion may be connected to an image selector and provide criteria for selection or rejection to the image selector.

[0035] However, preferably, in addition to merely determining the presence of a motion, the detection also includes a quantification of the motion. In an advantageous design, the motion detector is configured to detect a motion trajectory or a component of a motion trajectory. Such a detection may have occurred during the exposure and / or be reconstructed in a subsequent step.

[0036] With respect to the subsequent reconstruction, the motion detector can be configured to assign pixels of the temporally sequential individual x-ray images to the same segment of the patient tissue in order to thereby detect the motion occurring between the sequential exposure times. In other words, by evaluating the individual images generated within one or a specific exposure time, knowledge of the motion trajectory can be obtained. Thus, the motion detector is able to, for example, detect the trajectory of the relative motion between the x-ray emitter, the patient tissue and / or the x-ray sensor, in particular the relative trajectory between the image of the patient tissue in the sensor plane and the x-ray sensor.

[0037] The motion detector included in the x-ray imaging system can be implemented as a hardware component, preferably as or including an acceleration sensor and / or an FPGA module or a module with the same or similar functions. If the motion detector is implemented as a hardware component, in particular including an acceleration sensor, then motion detection can already be performed during exposure. It can also be provided that the motion detector includes a plurality of acceleration sensors, wherein, for example, one acceleration sensor is associated with the x-ray emitter in order to detect the movement of the emitter, and one or more further acceleration sensors are associated with the x-ray emitter and / or the patient in order to detect corresponding movements of the sensors or of the patient. Thus, the motion detector can also, for example, detect an absolute motion trajectory and preferably convert it into a relative motion trajectory.

[0038] It can also be provided that the motion detector or its components are implemented as a computer program, wherein the program comprises instructions which, when executed by a computer, cause the computer to detect the motion. In this case, or if the motion detector comprises an FPGA module or a module with the same or similar functions, a reconstruction of the motion can be provided in a subsequent step. A combination of this design with one or more acceleration sensors is also possible.

[0039] The detected motion, in particular the detected motion trajectory, may generally comprise a temporal profile of a position and / or a temporal profile of an orientation. Thus, the motion detector may also be configured to detect, for example, a temporal profile of a tilt of the sensor plane relative to the central beam.

[0040] Furthermore, the x-ray imaging system preferably comprises a motion compensator, wherein the motion compensator is configured to compensate for motion, thereby preferably coordinating sequential individual x-ray images or some of them with each other. As discussed above, in the context of the present application, compensation of motion is in particular compensation for the influence of motion on the individual x-ray images.

[0041] The motion to be compensated is in particular a motion detected by means of a motion detector. In particular, the motion compensator can be configured to align pixels of temporally sequential individual x-ray images assigned by the motion detector to the same segment of the patient's tissue by means of an image transformation (e.g., to achieve consistency) in order to coordinate the x-ray images with one another.

[0042] For example, it is possible to determine the respective movements of the emitter relative to the patient and the sensor via an image recognition algorithm, in particular with the aid of a motion detector. With the aid of a motion compensator, one, several or each separate temporally sequential individual x-ray image can then be corrected according to the movement via an image processing method. The image processing method can include one or more geometric image transformations, such as translation, rotation, scaling, deformation or a combination thereof. For example, it is possible to identify a plurality of first positions on a first individual x-ray image and a plurality of second positions on a second individual x-ray image as corresponding to each other relative to the imaged patient tissue, and for at least one of the individual x-ray images to be transformed in this way, the first positions and the second positions are aligned (e.g., transformed so as to be consistent).

[0043] In this way, in particular when the motion trajectory is known, motion or motion artifacts can be removed from one or more individual x-ray images by using appropriate methods.

[0044] The motion compensator included in the x-ray imaging system can be implemented as a hardware component, preferably including an FPGA module or a module with the same or similar functions. In general, a hardware solution in which the focus and / or the detector move in opposite directions is possible. However, the motion compensator can also be implemented as a computer program, which includes instructions that, when executed by a computer, cause the computer to compensate for the motion.

[0045] The x-ray imaging system preferably further comprises an image combiner which is configured to combine sequential, in particular coordinated, individual x-ray images into an overall x-ray image such that the respective exposures are merged.

[0046] The image combiner can in particular be configured to offset x-ray sensor signal values ​​associated with pixels of time-sequential, in particular coordinated, individual x-ray images relative to each other in order to combine the x-ray images or parts thereof into an overall x-ray image. For example, the image combiner can be configured to perform calculations based on x-ray sensor signal values ​​associated with pixels of time-sequential, in particular coordinated, individual x-ray images. In particular, the x-ray sensor signal values ​​can be offset with respect to each other by means of a weighted sum method. Then, an overall x-ray image, in particular an exposed-mixed intraoral x-ray image with reduced motion blur or motion artifacts, can be provided for diagnosis.

[0047] When the individual x-ray images are combined into an overall x-ray image, in particular by offsetting the signal values ​​(e.g., performing calculations based on these values), the information about the patient's tissue displayed by each individual x-ray image is preferably preserved and / or contributes to the overall x-ray image. In other words, the image content of the individual x-ray images is combined. Therefore, the individual x-ray images are preferably used as a whole. For example, all pixels of an individual x-ray image or at least a continuous two-dimensional area with a plurality of directly adjacent pixels of an individual x-ray image (e.g., accounting for more than 10% or more than 50% or more than 90% of the total pixels) may be included in the overall x-ray image. In particular, it may be unnecessary to analyze only a plurality of individual pixels or individual x-ray images of a sensor during or after exposure.

[0048] The image combiner can be implemented as a hardware component, preferably comprising an FPGA module or a module with the same or similar functionality, and / or as a computer program comprising instructions which, when executed by a computer, cause the computer to combine corresponding individual x-ray images into an overall x-ray image.

[0049] Thus, a final x-ray image can be calculated from a plurality of individual images. The individual images originate in particular from one recording session. For example, a recording session can be started by pressing a recording switch. Subsequently, radiation can be generated in an automatic manner and x-ray image information can be acquired. A final 10 x-ray image can then be created for each recording session, in particular with the aid of an image optimizer, an image selector, a motion detector, a motion compensator, an image combiner or at least some of these components, which can be integrated or incorporated into one or more common modules. The image processing system can, for example, include several or all of the components described.

[0050] As described above, since an x-ray imaging system may be used to record two, more or even many sequential individual x-ray images, the x-ray imaging system is preferably configured to record individual x-ray images rapidly. Therefore, the IO x-ray sensor is preferably implemented as a fast sensor.

[0051] The x-ray imaging system is particularly configured to record one or more sequential individual x-ray images in a time span of less than 500 milliseconds, in particular less than 250 milliseconds, in particular less than 100 milliseconds, in particular less than 50 milliseconds, in particular less than 25 milliseconds, in particular less than 10 milliseconds, in particular less than 2.5 milliseconds, in particular less than 0.25 milliseconds, respectively, wherein a plurality of sequential individual x-ray images may in particular be recorded in time spans of different lengths. For example, the time span of an initially recorded x-ray image may be smaller than the time span of a subsequently recorded individual x-ray image.

[0052] The time span for recording or acquiring individual x-ray images may in particular include an integration phase and a readout phase of the x-ray sensor. X-ray imaging systems are usually configured to record more individual x-ray images the shorter the time span between the individual images.

[0053] Therefore, the x-ray imaging system can also be configured to record a series of time-sequential individual x-ray images of patient tissue, in particular to record at least 2, in particular at least 3, in particular at least 10, in particular at least 100, in particular at least 1000, in particular at least 10000, in particular at least 10000 time-sequential individual x-ray images of patient tissue.

[0054] An x-ray emitter that emits x-rays for recording time-sequential individual x-ray images may be operated in a single operation, a continuous operation, or a pulsed operation. Thus, the x-ray imaging system may be configured to record time-sequential individual x-ray images in a single operation, a continuous operation, or a pulsed operation of the x-ray emitter.

[0055] Provision can be made, for example, to record an individual x-ray image within a recording period of between 10 and 100 milliseconds, and for this purpose the x-ray emitter emits radiation in a single operation within a radiation period, the length of which is equal to or less than the length of the recording period. After a certain time span, for example, a further individual x-ray image can be recorded in a recording period of between 0 and 500 milliseconds, whereby for this purpose the x-ray emitter again emits radiation in a single operation within a radiation period, in particular equal to or less than the length of the recording period.

[0056] However, it can also be provided that, for example, at least 3, in particular at least 10, in particular at least 100, in particular at least 1000, in particular at least 10000 individual x-ray images are recorded in a time span between 0.1 and 10 milliseconds and that the x-ray emitter is operated in continuous operation or in pulsed operation synchronously with the recording.

[0057] Due to the lower emitter output, the exposure times of handheld x-ray emitters are generally longer. In particular for handheld emitters, and in general, the time period from the start of the first shot to the end of the last shot can be at least 0.25 seconds, in particular at least 0.5 seconds; however, it can also be significantly more. This applies both to the case where a longer recording is performed and to the case where several shorter recordings are performed. X-ray recordings with radiation times that suggest that motion artifacts may occur should then be divided into separate recordings, which are then offset (e.g. calculated together). Therefore, the x-ray imaging system can generally be configured to record individual x-ray images (in particular all of them) in a time sequence during a total time period of at least 0.25 seconds, in particular during a total time period of at least 0.5 seconds.

[0058] Furthermore, the x-ray imaging system may include an exposure analyzer configured to analyze exposure of at least one of the time-sequential x-ray images.

[0059] The x-ray imaging system preferably also comprises a control device which is configured to control the x-ray sensor and / or the x-ray emitter based on the analysed exposure, preferably in such a way that the exposure of further images in the sequence of individual x-ray images, in particular the recording period (duration) and / or the number of such further images, is such that the overall x-ray image reaches a predetermined exposure range (intensity and / or level).

[0060] In particular, the x-ray imaging system can be configured based on the analyzed exposure to determine whether the exposure is below a predetermined exposure range, and if the exposure is already below the exposure range, the x-ray sensor and / or x-ray emitter are controlled in the following manner: a) continue to acquire additional time-sequential individual x-ray images, and / or b) achieve the predetermined exposure range with subsequent individual x-ray images.

[0061] The x-ray imaging system can also be configured to determine, based on the analyzed exposure, whether the exposure has not reached a predetermined minimum exposure range, and if the exposure has not reached the minimum exposure range, control the x-ray sensor and / or the x-ray emitter in such a way that the acquisition of further time-sequential individual x-ray images is terminated. Thus, in particular in the case of incorrect or insufficient positioning of the x-ray sensor and / or the x-ray emitter, early termination is possible. This makes it possible to reduce the radiation exposure of the patient.

[0062] The x-ray imaging system can also be configured based on the analyzed exposure of at least one, several or all acquired single x-ray images acquired so far to determine whether the exposure for this recording session has reached or exceeded a predetermined exposure range, and if the exposure has reached or exceeded the exposure range, then control the x-ray sensor and / or x-ray emitter in the following way: end the acquisition of additional individual x-ray images in a time sequence so as to avoid unnecessary radiation exposure.

[0063] If an exposure analyzer is used, it can be provided, for example, that a first individual x-ray image (pre-exposure image) is recorded with a fixed time span (e.g. between 10 and 100 milliseconds), the exposure of said image is analyzed, and subsequently a second x-ray image (main exposure image) is recorded with a variable time span (e.g. between 0 and 500 milliseconds), wherein the variable time span depends on the exposure range of the first x-ray image.

[0064] However, the exposure analyzer can also be configured to analyze the exposure continuously, for example, during the recording of an individual x-ray image or during the recording of a series of individual x-ray images (for example, when at least 3, in particular at least 10, in particular at least 100, in particular at least 1000, in particular at least 10000 x-ray images are recorded). The exposure analyzer can then, for example, analyze the exposure of a plurality of sequential individual x-ray images of the series and end the recording of a further series of images when a predetermined exposure range is reached.

[0065] The exposure analyzer and the control device can thus in particular form a unit for automatic exposure control (AEC). As described, for example, at least two records (pre-exposure and main exposure) can be created, which are added together in a subsequent step to form a 10 x-ray image. Thus, two or more time-sequential individual x-ray images can be used in a coordinated manner for compensation of motion (or motion artifacts) and for exposure control.

[0066] When concluding further recording using the exposure analyzer, the x-ray imaging system can also be configured so that a forced interruption occurs after concluding the recording of further time-sequential individual x-ray images, in particular for repositioning the x-ray sensor and / or the x-ray emitter, wherein the forced interruption is in particular at least 0.5 seconds.

[0067] When further recording is terminated using an exposure analyzer, communication between the recording system and the transmitter can be used to terminate the recording as soon as a critical number of individual images are locally insufficiently exposed.

[0068] The x-ray imaging system, in particular the control device, can also be configured to synchronize the pulsed operation of the x-ray emitter with the x-ray images recorded by the x-ray sensor. For synchronization purposes, a connection can also be provided between the sensor (recording system) and the emitter, both for continuous operation and for pulsed operation. However, it is also possible to omit the connection between the sensor and the emitter (the calibration record can measure the pulsed operation).

[0069] The exposure analyzer and / or the control device can again be implemented as a hardware component, preferably comprising an FPGA module or a module with the same or similar functionality, and / or as a computer program, the program comprising instructions which, when executed by a computer, cause the computer to analyze the exposure.

[0070] The x-ray imaging system may also include an x-ray emitter that may be positioned outside the patient's mouth, and an intraoral x-ray sensor may be placed within the patient's mouth in the beam path behind the patient's tissue to be irradiated.

[0071] A holding system may also be included, which may be fastened or adapted to the x-ray emitter and / or the x-ray sensor in order to align the x-ray emitter relative to the x-ray sensor. The holding system serves in particular as an adjustment aid for the x-ray emitter.

[0072] The present invention also relates to a dental x-ray imaging method, which produces intraoral x-ray images with reduced motion blur, in particular with the aid of an x-ray imaging system as described above, wherein an intraoral x-ray sensor is placed in the patient's mouth behind the patient tissue to be irradiated, in the beam path of an, in particular handheld, x-ray transmitter positioned outside the patient's mouth, and wherein two or more time-sequential individual x-rays of the patient tissue are recorded during corresponding exposures, and wherein an overall x-ray image is created from the time-sequential individual x-ray images or some of the time-sequential individual x-ray images, so that on the one hand the corresponding exposures are merged and then on the other hand motion occurring between the sequential individual x-ray images is compensated, thereby producing an exposure-blended intraoral x-ray image with reduced motion blur.

[0073] The present invention also relates to a method for generating x-ray images with reduced motion blur about an x-ray phantom, in particular with the aid of an x-ray imaging system as described above, wherein an x-ray phantom having a phantom structure to be irradiated, which in particular simulates dental patient tissue, is provided, and wherein an intraoral x-ray sensor is placed behind the phantom structure to be irradiated in the beam path of, in particular, a handheld x-ray emitter, and wherein two or more time-sequential individual x-ray images of the phantom structure are recorded during corresponding exposures, and wherein an overall x-ray image is created from the time-sequential individual x-ray images or some of them, so that, on the one hand, the corresponding exposures are merged and, on the other hand, movements occurring between two exposures are compensated to generate an exposure-blended x-ray image with reduced motion blur.

[0074] The present invention also relates to a method for post-processing time-sequential intraoral individual x-ray images, the method in particular for producing an exposure-blended intraoral x-ray image with reduced motion blur with the aid of an x-ray imaging system as described above, wherein two or more time-sequential intraoral individual x-ray images are read from a memory and wherein an overall x-ray image is created from the time-sequential individual x-ray images or some of the time-sequential individual x-ray images so that, on the one hand, the corresponding exposures are merged and, on the other hand, motion occurring between the sequential x-ray images is compensated so as to produce an exposure-blended x-ray image with reduced motion blur.

[0075] The invention also relates to a computer program for a dental x-ray imaging system as described above, or for a dental x-ray imaging method as described above, or for a method for generating x-ray images about an x-ray phantom as described above, or for a method for post-processing of intraoral individual x-ray images as described above, comprising: instructions which, when executed by a computer, cause the computer to record two or more temporally sequential individual x-ray images of a patient's tissue or phantom structure during corresponding exposures and / or to read said images from a memory, and / or instructions which, when executed by a computer, cause the computer to analyze the exposure of at least one of the sequential x-ray images, and / or instructions which, when executed by a computer, cause the computer to optimize the sequential x-ray images with the aid of one or more dark current images. The computer comprises instructions for selecting or rejecting specific individual x-ray images from the sequence of individual x-ray images or some sequential individual x-ray images when executed by a computer, and / or instructions for detecting movement occurring between the sequence of individual x-ray images or some sequential individual x-ray images when executed by a computer, and / or instructions for coordinating the sequence of individual x-ray images or some sequential individual x-ray images with each other so that movement is compensated when executed by a computer, and / or instructions for combining sequential, in particular coordinated, individual x-ray images or some of them into an overall x-ray image when executed by a computer.

[0076] Finally, the invention relates to a data carrier or a data signal comprising a computer program as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] The accompanying drawings show:

[0078] Figure 1 is a block diagram of an example of a dental x-ray imaging system,

[0079] Figure 2 is a timing diagram of a first example of an operating mode of a dental x-ray imaging system,

[0080] Figure 3 is a timing diagram of a second example of an operating mode of the dental x-ray imaging system. DETAILED DESCRIPTION

[0081] refer to Figure 1, the x-ray imaging system 100 may include an intraorally placed x-ray sensor 110, which is configured to detect x-rays of an extraorally placed x-ray emitter 120. Before striking the x-ray sensor 110, the x-rays pass through an intraoral recording area of ​​the patient 130, so that the x-ray sensor can record an x-ray image of the patient's tissue. A sensor holding system 210 may be fixedly attached to the x-ray sensor 110. Furthermore, the sensor holding system 210 may be fixed to the patient, in particular in the patient's mouth, so that the x-ray sensor 110 is substantially fixed relative to the patient's tissue 130 to be irradiated via the holding system 210. The holding system 210 may also include a positioning aid for the x-ray emitter 120, which preferably protrudes from the patient's mouth and forms, for example, a ring-shaped structure with corresponding contact surfaces, the x-ray emitter 120 may be guided, in particular together with its tube, in order to ensure correct alignment of the emitted x-rays.

[0082] In the depicted example, the x-ray sensor 110 is part of an x-ray sensor unit 105 (sometimes also simply referred to as an x-ray sensor) having a housing that can be placed in the patient's mouth and can contain further components. The x-ray sensor unit 105 can, for example, include a sensor control 112 that can be configured to control the sensor in such a way that x-rays are acquired (integration phase) and / or x-ray images are output in the form of x-ray sensor signal values ​​(readout phase), in particular depending on predefined criteria. The individual x-ray images acquired by the x-ray sensor can then be temporarily stored in an image memory 114. The x-ray sensor unit 105 can also include a power unit 116 that supplies electrical energy to the other components, in particular the sensor control 112, the image memory 114 and / or the x-ray sensor 110. A transmission / reception unit 118 can also be provided that allows, in particular, wireless transmission of x-ray images. However, the above components can also be provided external to the x-ray sensor unit 105 and can optionally form a separate unit or be included in another unit. For example, an option is an external interface 132, which is used, for example, between the sensor and the transmitter unit, i.e., physically decoupled from these two components. The sensor can then be made smaller if appropriate. This can provide advantages in terms of space and cost. To ensure the above-mentioned transmission, such an external interface can be connected to the internal interface 134 by means of a cable or wirelessly.

[0083] In the depicted example, the x-ray emitter 120 is part of an x-ray emitter unit 115 (sometimes also simply referred to as an x-ray emitter), which may again include a separate housing in which further components may be located. The x-ray emitter unit 115 may include, for example, an emitter control 122, which may be configured to activate or deactivate the emitter. The emitter control 122 may be connected to the sensor control 112. The x-ray emitter unit 115 may also include an image memory 124. The x-ray imaging system 100 may be configured to transfer individual x-ray images from the image memory 114 of the sensor unit 105 to the image memory 124 of the emitter unit 115. To this end, a connection of the two units may be provided, for example, via a cable, or the transmission may be performed by means of a transmission / reception unit 118. The emitter unit 115 preferably also includes a power unit 126, which supplies electrical energy to other components, in particular those described above or below. In order to control the x-ray emitter 120 and / or set radiation parameters, the emitter unit 115 may also include a user interface 127. In a preferred embodiment, emitter unit 115 is implemented as a handheld x-ray emitter 250 .

[0084] Furthermore, the x-ray imaging system 100, in particular the x-ray emitter unit 115, may include an image evaluation unit 220, which may be configured for rapid image evaluation and may have an exposure analyzer 190. The exposure range of the individual x-ray images temporarily stored in the image memory 124 may be analyzed, for example, by means of the exposure analyzer 190. Depending on the exposure range, a control signal for controlling the x-ray emitter may be sent to the emitter control 122, which control signal causes the exposure range of the further individual x-ray images and / or the number of the further x-ray images to be affected. The control signal may also be an on / off signal to activate or deactivate the emitter.

[0085] The x-ray imaging system 100, in particular the x-ray emitter unit 115, may further comprise one or more image processing units 230, 230'. The image processing units may in particular comprise an image optimizer 140, an image selector 150, a motion detector 160, a motion compensator 170 and / or an image combiner 180. The image processing unit 230 may for example comprise the image optimizer 140 in order to optimize the individual x-ray images present as raw data in the image memory 124, for example by means of a dark current image. The image processing unit 230 may further comprise the motion detector 160 and / or the motion compensator 170 in order to compensate for motion, in particular by means of an image transformation. The image processing unit 230 may further comprise the image combiner 180 in order to combine a plurality of individual x-ray images after motion compensation by merging the exposures into one final, exposure-blended 10 x-ray image with reduced motion blur. The image processing unit thus receives analog or digital x-ray image information and processes the information, for example via image optimization. The information may also be archived and / or displayed.

[0086] For example, the final 10 x-ray image can be directly displayed by means of the image display unit 128 (the image display unit 128 can be part of the emitter unit 115) (live image). The image processing unit 230 for generating the final 10 x-ray image for direct display can, for example, operate with a limited resolution. An image processing unit 230' can also be provided for generating the final 10 x-ray image for external display, for example on a computer 240 with an image memory 242, an image display unit 244 and, if appropriate, a user interface 246.

[0087] The components described above as part of the x-ray emitter unit 115 may also be provided externally to the x-ray emitter unit 115 and may optionally form a separate unit or be included in another unit. The image processing unit 230 ′ may also be implemented as part of the computer 240 , for example.

[0088] In the context of the present application, an x-ray sensor that can be placed in the mouth can generally be understood as an x-ray sensor 110 in a narrow sense. However, in a broad sense, the x-ray sensor can also be placed in the mouth together with the housing and, if applicable, further components (x-ray sensor unit 105). Correspondingly, an x-ray emitter is generally understood as an emitter 120 in a narrow sense, i.e., for example, an x-ray tube or a component including an x-ray tube. However, in a broad sense, the x-ray emitter can also be located outside the mouth together with the housing and, if applicable, further components (x-ray emitter unit 115, handheld x-ray emitter 250).

[0089] refer to Figure 2, the x-ray imaging system can be configured as an example of an operating mode presented below. The (x-ray) recording session can initially be started by actuating a recording switch. The initiation of actuation 300 can thus occur. A preheating cycle 302 can be provided, in which the x-ray emitter or x-ray tube is heated before applying the high voltage, preferably for a period between 400 and 1600 milliseconds, for example 800 milliseconds. The preheating phase is particularly used to ensure reproducible radiation after adding the high voltage. Then, for example, at least two sequential exposures 304, 306 can be performed, wherein the x-ray radiation is activated in the corresponding radiation cycles 304', 306'. The first radiation cycle 304' can be between 0 and 80 milliseconds, for example 40 milliseconds. The second radiation cycle can be between 0 and 500 milliseconds, for example between 0 and 200 milliseconds. The exposure time can particularly represent the exposure duration over which the x-ray radiation extends. Exposure is the process of exposing the detector medium to the x-ray radiation. For IO x-ray irradiation, the exposure time may also be, for example, between 10 and 500 milliseconds, in particular between 50 and 200 milliseconds.

[0090] During the emission of x-ray radiation, the x-ray sensor may be in a respective integration mode 308, 310 in a plurality of sequential integration periods 308', 310' in order to acquire said x-ray radiation. The respective integration period 308', 310' is preferably at least as long as the associated radiation period 304', 306'. Preferably, each integration phase 308, 310 is followed by a readout phase 312, 314, which extends over a readout period 312', 314', respectively. An integration period and a subsequent readout period contribute to a recording period (image acquisition) 316, 318 of an x-ray image, respectively. In other words, a recording period (i.e., image acquisition) in particular comprises an exposure process and a subsequent readout from the sensor. For example, provision may be made for recording a first x-ray image during a recording period comprising an integration period between 10 and 100 milliseconds (e.g., 50 milliseconds) and a readout period between 5 and 50 milliseconds (e.g., 20 milliseconds).

[0091] The individual x-ray images can then be subjected to an exposure analysis 322 by means of an exposure analyzer. The intensity of one or more received x-ray images is thereby evaluated in order to achieve a specified exposure quality or a predetermined exposure range (intensity). Depending on this evaluation, a second individual x-ray image can then be recorded. For example, provision can be made for recording the second x-ray image during a recording period comprising an integration period between 0 and 500 milliseconds (e.g., 200 milliseconds) and a readout period between 5 and 50 milliseconds (e.g., 20 milliseconds).

[0092] One or more dark current images may be recorded during corresponding recording cycles 320 , 324 before and / or after the recording of the chronologically sequential x-ray images, wherein here too a corresponding integration phase and readout phase are provided in each case.

[0093] After at least two time-sequential x-ray images have been recorded, an optimization 326 can be performed on the individual images, in particular by shifting the images with one or more dark current images, for example by performing calculations based on the respective individual images and the dark current images. Motion compensation 328 can then be performed in order to finally obtain a final 10 x-ray image 330 by means of a combination.

[0094] Thus, the final IO x-ray image is a product of the x-ray imaging system and represents an x-ray depiction created intraorally. Just as with individual time-sequential x-ray images, the minimum spatial resolution is also destroyed by the image pixels. The generation process proceeds through the different stages described above, particularly after digitization as an unprocessed data set (e.g., 16 bits, possibly based on multiple exposures) to storage as a processed, filtered (un) compressed data set with histogram compensation (e.g., 8 bits). From the user's perspective, the x-ray image is ultimately displayed or printed as a black and white negative 2D rendering, such as on a monitor or film. As described, reduced motion blur or reduced motion artifacts are achieved in the final x-ray image, whereby artifacts may also appear due to the processing of the image. Thus, the final x-ray image is an exposed-mixed image with reduced motion blur or reduced motion artifacts.

[0095] Thus, in summary, after initiation of a recording session, in particular by actuating a switch, radiation is subsequently generated and x-ray image information is acquired in an automated manner. In particular, one final 10 x-ray image may be created for each recording session.

[0096] refer to Figure 3 , the x-ray imaging system can also be configured as examples of operating modes presented below. First, the initiation of actuation 300 can be performed again, and a preheating cycle 302 of the x-ray tube can be provided. Subsequently, a pulse-free continuous radiation or a pulsed radiation 404 can be provided over a radiation cycle 404', for example with a cycle duration between 0.1 and 10 milliseconds.

[0097] During the radiation period 404', the x-ray sensor can record several or a large number of sequential x-ray images during a corresponding recording period 416, whereby in particular the recording period 416 in turn comprises a corresponding integration and readout period. In this operating mode, the recording period 416 can in particular be between 0.1 and 10 milliseconds. During pulsed operation of the emitter, the recording period is preferably synchronized with the emitter.

[0098] By means of the exposure analyzer, a continuous exposure analysis 422 of the individual x-ray images can be performed. Thereby, in particular, the intensity of the x-ray images can be evaluated in general, so that the recording of further individual x-ray images is suspended as soon as a predefined intensity is reached. Depending on the exposure range, the number of further x-ray images can be additionally determined.

[0099] After a plurality of time-sequential individual x-ray images have been recorded, an optimization 326 of the individual images, a motion compensation 328 and finally the generation of a final 10 x-ray image 330 can again be performed by means of a combination.

[0100] It is clear to a person skilled in the art that the above embodiments are merely examples and that the present invention is not limited thereto but may be varied in many ways without departing from the scope of protection of the claims. Furthermore, it is clear that, regardless of whether these features are disclosed in the specification, claims, drawings or otherwise, even if these features are described together with other features, these features individually define the essential components of the present invention and may therefore be considered to be disclosed independently of one another. The description of the features of one design example also applies to other design examples, respectively.

[0101] Reference numerals list

[0102] 100 X-ray Imaging Systems

[0103] 105 x-ray sensor unit

[0104] 110 Intraoral X-ray Sensor

[0105] 112 Sensor Controls

[0106] 114 Image memory of sensor unit

[0107] 115 X-ray emitter unit

[0108] 116 Power unit for sensor unit

[0109] 118 Transmit / Receive Unit

[0110] 120 X-ray emitters

[0111] 122 Transmitter Controls

[0112] 124 Image memory for transmitter unit

[0113] 126 Power unit for transmitter unit

[0114] 127 User Interface

[0115] 128 Image display unit

[0116] 130 Patient tissue to be irradiated

[0117] 132 External Interface

[0118] 134 Internal Interface

[0119] 140 Image Optimizer

[0120] 150 Image Picker

[0121] 160 Motion Detector

[0122] 170 Motion Compensator

[0123] 180 Image Synthesizer

[0124] 190 Exposure Analyzer

[0125] 200 Control Devices

[0126] 210 Holding System

[0127] 220 Image Evaluation Unit

[0128] 230, 230' Image processing unit

[0129] 240 Computer

[0130] 242 Computer image memory

[0131] 244 Computer image display unit

[0132] 246 Computer User Interface

[0133] 250 Handheld X-ray Transmitter

[0134] 300 Actuation Initiation

[0135] 302 Warm-up cycle

[0136] 304, 306, 404 exposure

[0137] 304', 306', 404' radiation cycle

[0138] 308, 310 Points Mode

[0139] 308', 310' Integration period

[0140] 312, 314 Readout mode

[0141] 312', 314' Read cycle

[0142] 316, 318, 324, 416 Recording cycles

[0143] 322, 422 Exposure Analysis

[0144] 326 Optimization

[0145] 328 Motion Compensation

[0146] 330 Final IO x-ray image

Claims

1. A dental x-ray imaging system (100) for producing intraoral x-ray images with reduced motion blur, comprising: An intraoral x-ray sensor (110, 105) is positionable within the patient's mouth, in the beam path of a handheld x-ray emitter (120, 115, 250) positioned outside the patient's mouth and behind the patient tissue (130) to be irradiated, a control device (200) configured to control an x-ray sensor and / or an x-ray emitter, wherein the x-ray imaging system (100) is further configured to record two or more time-sequential individual x-ray images of the patient tissue (130) during respective exposures in a recording session, an image optimizer (140) configured to optimize the sequence of individual x-ray images and / or the overall x-ray image of the patient tissue (130) or at least one thereof by means of one or more dark current images, an image selector (150) configured to select or reject a particular individual x-ray image from the sequence of individual x-ray images or some of them, a motion detector (160) configured to detect motion occurring between and / or during the individual x-ray images or some of them of the sequence, a motion compensator (170) configured to coordinate the individual x-ray images of the sequence or some of them with each other so that motion is compensated, an image combiner (180) configured to combine the sequential coordinated x-ray images or some of them into an overall x-ray image such that the results of the respective individual exposures are merged; an exposure analyzer (190) configured to analyze the results of the exposure of at least one, several or all of the chronologically sequential individual x-ray images acquired so far, A control device (200) configured to control the x-ray sensor and / or the x-ray emitter based on the analysis result of the exposure in such a way that the exposure of further individual x-ray images in the sequence of individual x-ray images and the number of said further images are such that the overall x-ray image reaches a predetermined exposure range, Wherein the x-ray imaging system (100) is also configured to create an overall x-ray image based on the time-sequential individual x-ray images or some of them so that, on the one hand, the results of the corresponding exposures are merged and, on the other hand, motion occurring between and / or during the sequential individual x-ray images is compensated to produce an exposed-blended intraoral x-ray image with reduced motion blur.

2. The dental x-ray imaging system according to claim 1, Wherein the x-ray imaging system (100) is configured to record the sequence of individual x-ray images or at least one thereof during a time span of less than 250 milliseconds, or less than 25 milliseconds, or less than 2.5 milliseconds, or less than 0.25 milliseconds.

3. The dental x-ray imaging system according to claim 1 or 2, wherein the x-ray imaging system (100) is configured to record a series of time-sequential individual x-ray images of the patient tissue (130), or at least 2, or at least 10, or at least 100, or at least 1000 time-sequential individual x-ray images of the patient tissue (130), and / or The x-ray imaging system (100) is configured to record time-sequential individual x-ray images during pulsed operation of an x-ray emitter.

4. The dental x-ray imaging system according to claim 1, The x-ray imaging system (100) is configured to determine, based on an analysis result of the exposure of at least one, several or all individual x-ray images acquired so far, whether the exposure for this recording session has failed to reach a predetermined exposure range, and if the exposure has failed to reach the exposure range, to control the x-ray sensor and / or the x-ray emitter in the following manner: a) continue to acquire further individual x-ray images in a time sequence, and / or b) subsequent individual x-ray images achieve the predetermined exposure range, and / or The x-ray imaging system (100) is configured to determine, based on the analyzed exposure of at least one, several or all individual x-ray images acquired so far, whether the exposure for this recording session has failed to reach a predetermined minimum exposure range, and if the exposure has failed to reach the minimum exposure range, to control the x-ray sensor and / or the x-ray emitter in such a way that: the acquisition of further time-sequential individual x-ray images is terminated in order to avoid unnecessary radiation exposure, and / or The x-ray imaging system (100) is configured to determine, based on the analyzed exposure of at least one, several or all individual x-ray images acquired so far, whether the exposure for this recording session has reached or exceeded a predetermined exposure range, and if the exposure has reached or exceeded the exposure range, to control the x-ray sensor and / or the x-ray emitter in such a way that the acquisition of further time-sequential individual x-ray images is terminated in order to avoid unnecessary radiation exposure.

5. The dental x-ray imaging system according to claim 1 or 2, wherein the image optimizer (140) is configured to perform calculations based on both x-ray sensor signal values ​​associated with pixels of the dark current image and x-ray sensor signal values ​​associated with pixels of one of the sequential x-ray images and / or the overall x-ray image of the patient tissue in order to optimize the x-ray image, and / or wherein the image selector (150) is configured to evaluate the sequence of individual x-ray images or some of them using predefined criteria in order to select suitable sufficiently consistent individual x-ray images therefrom or to reject unsuitable excessively inconsistent individual x-ray images, and / or wherein the motion detector (160) is configured to assign pixels of the temporally sequential individual x-ray images to substantially the same section of the patient tissue so as to detect motion occurring between and / or during the sequential individual x-ray images, and / or wherein the motion compensator (170) is configured to align pixels of temporally sequential individual x-ray images assigned to substantially the same section of the patient tissue by means of an image transformation so as to make them consistent so as to coordinate these x-ray images with one another, and / or The image combiner (180) is configured to perform calculations based on x-ray sensor signal values ​​of corresponding pixels of the time-sequential coordinated individual x-ray images to combine the individual x-ray images into an overall x-ray image.

6. The dental x-ray imaging system according to claim 1 or 2, wherein the exposure analyzer (190) is implemented as a computer program comprising instructions which, when executed by a computer, cause the computer to analyze the results of the exposure, and / or wherein the image optimizer (140) is implemented as a computer program comprising instructions which, when executed by a computer, cause the computer to optimize individual x-ray images and / or an overall x-ray image of the patient's tissue by means of dark current compensation, and / or wherein the image selector (150) is implemented as a computer program comprising instructions which, when executed by a computer, cause the computer to select or reject individual x-ray images, and / or wherein the motion detector (160) is implemented as a computer program comprising instructions which, when executed by a computer, cause the computer to detect motion, and / or wherein the motion compensator (170) is implemented as a computer program comprising instructions which, when executed by a computer, cause the computer to compensate for motion, and / or Therein the image combiner (180) is implemented as a computer program comprising instructions which, when executed by a computer, cause the computer to combine the respective individual x-ray images into an overall x-ray image.

7. The dental x-ray imaging system according to claim 1 or 2, The exposure analyzer (190) is implemented as a hardware component, including an FPGA module or a module with similar functions, and / or The image optimizer (140) is implemented as a hardware component, including an FPGA module or a module with similar functions, and / or The image selector (150) is implemented as a hardware component, including an FPGA module or a module with similar functions and / or an acceleration sensor, and / or The motion detector (160) is implemented as a hardware component, including an FPGA module or a module with similar functions and / or an acceleration sensor, and / or The motion compensator (170) is implemented as a hardware component, including an FPGA module or a module with similar functions, and / or The image combiner (180) is implemented as a hardware component, including an FPGA module or a module with similar functions.

8. The dental x-ray imaging system according to claim 1 or 2, Included is a holding system (210) that can be secured or adapted to an x-ray emitter and / or an x-ray sensor to align the x-ray emitter (120, 115, 250) relative to the x-ray sensor (110, 105).

9. A dental x-ray imaging method for producing intraoral x-ray images with reduced motion blur, by means of an x-ray imaging system according to any one of claims 1 to 8, wherein an intraoral x-ray sensor (110, 105) is placed within the patient's mouth, in the beam path of an x-ray emitter (120, 115, 250) positioned outside the patient's mouth, and behind the patient tissue (130) to be irradiated, and wherein two or more time-sequential individual x-ray images of the patient's tissue (130) are recorded during corresponding exposure periods, and wherein an overall x-ray image is created based on the individual x-ray images or some of them in the time sequence such that, on the one hand, the results of the corresponding exposures are merged and, on the other hand, motion occurring between and / or during the sequential individual x-ray images is compensated to produce an exposed-blended intraoral x-ray image with reduced motion blur.

10. The method of claim 9, wherein the x-ray emitter (120, 115, 250) is a handheld x-ray emitter.

11. A method for generating x-ray images with reduced motion blur on an x-ray phantom, by means of an x-ray imaging system according to any one of claims 1 to 8, An x-ray phantom is provided having a phantom structure to be irradiated, which in particular simulates dental patient tissue, and wherein an intraoral x-ray sensor (110, 105) is placed behind a phantom structure to be irradiated, in the beam path of an x-ray emitter (120, 115, 250), and wherein two or more time-sequential individual x-ray images of the phantom structure are recorded during corresponding exposure periods, and wherein an overall x-ray image is created from the individual x-ray images or some of them in said chronological sequence such that, on the one hand, the results of the respective exposures are merged and, on the other hand, motion occurring between and / or during the exposures is compensated to produce an exposure-blended x-ray image with reduced motion blur.

12. The method of claim 11, wherein the x-ray emitter (120, 115, 250) is a handheld x-ray emitter.

13. A method for post-processing time-sequential intraoral individual x-ray images for producing an exposure-blended intraoral x-ray image with reduced motion blur, by means of an x-ray imaging system according to any one of claims 1 to 8, wherein two or more time-sequential intraoral individual x-ray images are read from a memory, and wherein an overall x-ray image is created from the individual x-ray images or some of them in the time sequence such that, on the one hand, the results of the corresponding exposures are merged and, on the other hand, motion occurring between and / or during the sequence of individual x-ray images is compensated to produce an exposure-blended x-ray image with reduced motion blur.

14. A computer program product for a dental x-ray imaging system according to any one of claims 1 to 8, or for a dental x-ray imaging method according to claim 9, or for a method of generating x-ray images about an x-ray phantom according to claim 11, or for a method for post-processing intraoral individual x-ray images according to claim 13, comprising: Instructions which, when executed by a computer, cause the computer to record two or more time-sequential individual x-ray images of patient tissue or phantom structures during respective exposures and / or to read said images from a memory, and / or instructions which, when executed by a computer, cause the computer to analyze the results of exposure of at least one of the sequence of individual x-ray images, and / or instructions which, when executed by a computer, cause the computer to optimize the sequence of individual x-ray images and / or the overall x-ray image, or at least one thereof, with the aid of one or more dark current images, and / or instructions which, when executed by a computer, cause the computer to select or reject particular individual x-ray images from the sequence of individual x-ray images or some of them, and / or instructions which, when executed by a computer, cause the computer to detect motion occurring between and / or during the sequence of individual x-ray images or some of them, and / or instructions which when executed by a computer cause the computer to coordinate the sequence of individual x-ray images, or some of them, with one another so that motion is compensated, and / or Instructions which when executed by a computer cause the computer to combine the sequence of coordinated individual x-ray images, or some of them, into an overall x-ray image.

15. A data carrier comprising a computer program according to a computer program product as claimed in claim 14.

Images