DETECTOR STRIP FOR RADIOGRAPHIC FILM

Abstract

The invention relates to a system (1) for detecting image parameters during the exposure of films (2), in particular X-ray films. It is an object of the invention to provide a system which allows a simple and fast production of optimally exposed recordings. For this purpose, the system (1) comprises a detector element (3) which can be detachably attached to a film (2) and which detects in a spatially resolved manner the radiation (4) impinging on the film (2) during exposure or the radiation (4) transmitted through the film and thereby generates a signal from which image parameters generated by the current film exposure can be derived.

Claims

1. A system (1) for acquiring image parameters during the exposure of films (2), in particular X-ray films, wherein the system (1) comprises a detector element (3) which can be detachably attached to a film (2) and which detects in a spatially resolved manner the radiation (4) impinging on the film (2) during exposure or the radiation (4) transmitted through the film and thereby generates a signal from which image parameters generated by the current film exposure can be derived.

2. The system (1) according to claim 1, characterized in that the image contrast generated by the current exposure on the film (2) can be derived from the signal generated by the detector element (3).

3. The system (1) according to claim 1, characterized in that the detector element (3) is connected to an evaluation system (5).

4. The system (1) according to claim 3, characterized in that the evaluation system (5) analyzes local exposure differences.

5. The system (1) according to claim 3, characterized in that the evaluation system (5) generates a message as soon as the image quality corresponds to predefinable criteria.

6. The system (1) according to claim 3, characterized in that the evaluation system (5) automatically interrupts the exposure of the film (2) as soon as the image quality corresponds to predefinable criteria.

7. The system (1) according to claim 3, characterized in that the evaluation system (5) is connected to a communication unit (6), which transmits results of the evaluation system (5) to external devices (7).

8. The system (1) according to claim 1, characterized in that the detector element (3) comprises a plurality of digital radiation sensors.

9. The system (1) according to claim 1, characterized in that the detector element (3) is configured as an elongate strip.

10. The system (1) according to claim 9, characterized in that the strip extends along the film.

11. The system (1) according to claim 9, characterized in that the strip is flexible.

Description

[0028] Further features, details and advantages of the invention are apparent from the following description and from the drawings. Exemplary embodiments of the invention are shown purely schematically in the following drawings and are described in more detail below. Corresponding objects or elements are provided with the same reference characters in all figures. Shown are in:

[0029] FIG. 1 a schematic representation of the system according to the invention;

[0030] FIG. 2 X-ray images with profile lines.

[0031] Designated by the reference character 1 in FIG. 1 is a system 1 for acquiring image parameters during the exposure of films 2, in particular X-ray films. The representation according to FIG. 1 shows a radiation source 10, from which radiation 4 is emitted in the direction of examination object 12 and film 2. During the exposure of the film 2, the radiation 4 of the radiation source 10 penetrates the examination object 12, wherein a part of the radiation 4 is absorbed by the examination object 12. As a result, after sufficient exposure of the film 2, the contour and also the internal structure of the examination object 12 can be recognized on the recording. This is the known principle of film-based X-ray imaging for non-destructive testing.

[0032] As mentioned above, exposure is critical for achieving optimal image quality. For this reason, the system according to the invention has a digital detector element 3 which can be attached to the film 2 (for example, by adhesion or by clamping by means of suitable holding elements) and which detects the radiation 4 impinging on the film 2 during the exposure and generates a signal therefrom, which makes it possible to deduce the image parameters achieved during the exposure. In particular, these image parameters comprise the contrast generated on the film 2 by the exposure. The detector element 3 is connected to an evaluation system 5, which evaluates the signals of the detector element 3. In this case, the evaluation system 5 analyzes in particular local differences in exposure of the radiation acquired by the detector element 3. On the basis of these evaluations, the evaluation system 5 transmits a message to an operator as soon as the image quality corresponds to the image parameters predefined by the operator. The evaluation system 5 can also automatically interrupt the exposure of the film 2 as soon as the image quality corresponds to the image parameters desired by the operator. A communication unit 6 is also connected to the evaluation system 5, which communication unit transmits the results of the evaluation system 5 to external devices 7 (for example, smart phones or laptops) via a wireless connection. In addition, the evaluation system 5 and possibly also the radiation source 10 can be remotely controlled via the external devices 7.

[0033] It can be clearly seen in FIG. 1 that the detector element 3 is configured as a strip that extends in a direction over the entire exposed film region. The detector element 3 has a plurality of spatially distributed digital radiation sensors 8, which for reasons of clarity are only individually provided with reference characters. The radiation sensors 8 are, for example, scintillator crystals having these respectively associated photodetectors or X-ray-sensitive semiconductor elements of a known type, as used, for example, in medical X-ray imaging. The system 1 has a self-sufficient power supply 9, so that the non-destructive testing of arbitrary objects (for example, building or machine parts) is flexibly possible on site. The detector element 3, the evaluation system 5 and the communication unit 6 are to be designed as small and compact as possible for optimal attachment to the film. These components then require only a very low power requirement with low voltages (<50V).

[0034] FIG. 2 shows by way of example two image recordings (left and right) to which the image parameters are acquired by means of the system 1 according to the invention (FIG. 1). The strip-shaped detector element 3 is arranged in these recordings in the center of the image for acquiring an image line, as indicated by the black line in the recordings. By acquiring the radiation 4 (FIG. 1) impinging on the film 2 (FIG. 1), a signal is generated which is visualized by the line profile 13 shown under the recordings. The data obtained by the detector element 3 are considered as a line profile signal 13 from the image for examining local differences. The recordings monitored by the system 1 (FIG. 1) show a digital X-ray image of a plastic tube. The strip-shaped detector element 3 provided (one-dimensional) spatially resolved information for exposure. The original digital radiograph with associated line profile 13 is shown below on the left side of FIG. 2. An undersampled version of the digital image is shown at 2% of the original image size on the right side of FIG. 2. A corresponding acquired line profile 13 is located below this recording. As can be clearly seen from the line profiles 13, the radiation 4 (FIG. 1) is absorbed more strongly in the region of the examination object 12, so that locally less incident radiation is measured by the detector element 3. Various indicators can be taken into account in order to quantify whether the image quality corresponds to the specifications based on the signals acquired by the detector element 3. Possible indicators arise from the slope and the curvature of the line profile 13. On the basis of these two indicators, the evaluation system 5 (FIG. 1) can decide whether there are sufficient intensity changes of the signal measured along the strip, from which it is possible to make conclusions about the image contrast. In addition, the line profile 13 can be automatically segmented to determine different segments which are to be associated with the image content of interest or the background. For example, abrupt intensity changes in the image can be identified by applying the known CUSUM test to the data series given by the line profile 13. This allows the image quality to be quantified. This evaluation allows the evaluation system 5 (FIG. 1) to generate a message or to automatically interrupt the exposure as soon as the image quality corresponds to predetermined target values.

[0035] The comparison of the two differently spatially resolved line profiles 13 shows that for the detector element 3, a sensor array of low resolution (by a multiple lower than the resolution of the film recording), is sufficient to assess the image quality with sufficient reliability, that is, with only a few discrete sensor elements 8.

[0036] The system described herein provides a predictive capability to predict the exposure at a later time based on the progress of the exposure at the current time in a comparison. This makes it possible to deduce when the exposure is not only good and sufficient, but optimal.

LIST OF REFERENCE CHARACTERS

[0037] 1 system [0038] 2 film [0039] 3 detector element [0040] 4 radiation [0041] 5 evaluation system [0042] 6 communication unit [0043] 7 external device [0044] 8 radiation sensors [0045] 9 power supply [0046] 10 radiation source [0047] 11 operator [0048] 12 examination object [0049] 13 profile line