Patent Application
20090086914
The invention relates generally to inspection systems and more specifically to an inspection planning tool for a radiographic inspection system.
Radiographic inspection of industrial parts is desirable. However, composite parts comprising multiple materials present certain challenges for radiographic inspection. Conventionally, in radiographic inspection systems, a beam of high-energy radiation, such as X-rays, is transmitted through a test object to be inspected, and a corresponding image of the test object is formed using various image processing techniques. A flaw, defect or structural inhomogeneity in the test object is detected by examining the image generated.
For accurate examination of the generated image, it is often required to generate the image with a desired gray level. To obtain the desired gray level in the image, the radiation source needs to be initialized with suitable exposure parameters. In existing radiographic inspection systems, the desired exposure parameters are obtained after performing several trial experiments.
One problem with using the trial and error method is the corresponding increase in time required to obtain accurate parameters. Also, to inspect composite parts with multiple regions having different material properties, it would be desirable to inspect the different regions in a short period of time and with the minimum number of exposures (or shots). Since the exposure parameters may be different for the different regions, the increased time for accurately determining the exposure parameters leads to loss in productivity.
In addition, many inspection systems have various types of radiation sources that are adapted for inspecting specific types of objects. Using a trial and error method to calculate the exposure parameters for each type of source and for the different regions within a composite article could be a cumbersome task.
Therefore, it is desirable to implement a technique that is capable of automatically determining exposure parameters for various radiation sources based on the object being inspected. Further, it would be desirable for the technique to be capable of automatically determining the exposure parameters for a composite article having multiple regions with different material properties.
Briefly, in accordance with one embodiment, a system is provided for radiographic inspection of an object comprising multiple regions having different material properties. The system comprises a radiation source configured to generate radiation, and a display unit for displaying a graphical user interface comprising a plurality of fields. A user enters input data related to one or more material properties for each region of the object into the fields. The system further includes a processor configured to compute a plurality of exposure parameters based on the input data.
In another embodiment, a method is provided for radiographic inspection of an object comprising multiple regions having different material properties. The method comprises irradiating the object with radiation, generating a graphical user interface comprising a plurality of fields, providing a thickness of each region of the object being inspected in respective ones of the fields, entering one or more material properties for each region into respective ones of the fields, and computing a plurality of exposure parameters based on the thicknesses and the material properties of multiple regions within the object.
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
As used herein, “adapted to”, “configured” and the like refer to mechanical or structural connections between elements to allow the elements to cooperate to provide a described effect; these terms also refer to operation capabilities of electrical elements such as analog or digital computers or application specific devices (such as an application specific integrated circuit (ASIC)) that are programmed to perform a sequel to provide an output in response to given input signals.
Radiation source 12 is configured to generate high energy radiation to irradiate an object 14. In one embodiment, the radiation source is an X-ray source. The exposures parameters of the radiation source are initialized based on the object being inspected. In particular for a composite article comprising multiple regions having different material properties, the exposure parameters of the radiation source are determined for the different regions 15.
Detector 16 is configured to receive the radiation energy passing through the object. The detector is configured to convert the received radiation into corresponding electrical signals. In one embodiment, the detector is a small area detector, such as a charge-coupled device. In one example, the small area detector has an area of less than about 10.2 centimeters (cm)×10.2 centimeters (cm), with a weight that is less than about 2.27 kg.
Computer system 18 comprises a processor 20 and a display unit 22. The processor is configured to implement a radiographic inspection tool that is adapted to receive the electrical signals from the detector and generate a corresponding image of the object. The display unit is used to display an image of the object.
The display unit is further adapted to display a graphical user interface (GUI) comprising a plurality of fields. The fields are adapted to accept input data provided by a user. Input data comprises information related to the object being inspected and/or to the radiation source and detector. For example, the user can provide information related to the thickness of different materials of the object, the type of radiation source being used, the material of the regions 15, the distance between the radiation source and a radiation detector, the magnification factor, etc. According to a particular embodiment, the input data includes data related to one or more material properties for each region of the composite article 14. The processor 20 is configured to calculate the exposure parameters for the radiation source based on the input data, which will result in generating an image with a desired gray level. An example GUI is discussed below with reference to
According to a more particular embodiment, the processor is configured to compute the exposure parameters for each region of the composite article 14. In a more particular embodiment, the processor is further configured to determine an overlap between the exposure parameters for the regions and to select a plurality of exposure parameter values within the overlap for use in inspecting the object. Beneficially, by selecting exposure parameter values within the overlap, the different regions of the composite article can be inspected in single exposure, thereby reducing both the inspection time and the radiation exposure. For example, if one region requires 20-35 kV and a second region requires 30-40 kV, the optimum technique would be 30-35 kV to image both areas.
Control system 24 receives the computed exposure parameters from the computer system and is configured to automatically set the exposure parameters of the radiation source based on the input data provided by the user. For a particular embodiment, control system 24 initializes the radiation source 12 based on the selected exposure parameter values to inspect the regions of the composite article 14 with a single exposure, thereby reducing both the inspection time and the radiation exposure. The manner in which the processor computes the exposure parameters of the radiation source is described in further detail below.
In step 26, a user enters input data via a graphical user interface. The input data comprises information related to the object being inspected and/or to the radiation source and detector. In a specific embodiment, the user provides the thickness and the material properties of each region of the object being inspected.
In step 27, exposure parameters are computed using the input data provided by the user. According to a particular embodiment, the exposure parameters are computed for each region in the composite article based on the thickness and material property data for each of the regions. Exposure parameters include a current input parameter and a voltage input parameter. Another example exposure parameter is the exposure time. The exposure parameters are computed such that the resulting image generated by the processor is of a desired gray level. In order to arrive at the accurate exposure parameters, the interaction of the radiation energy with the object being inspected is modeled using an x-ray spectral model. As is well known to those skilled in the art, a number of different x-ray spectral models have been developed for various medical and industrial inspection techniques.
In step 28, an overlap is determined between the exposure parameters for the different regions. In step 29, a plurality of exposure parameter values are selected within the overlap for use in inspecting the multiple region composite article.
In step 30, the radiation source is initialized with the selected exposure parameter values using a control system to inspect the multiple regions of the object 14 with a single exposure that is appropriate for each of the regions. In step 31, the object is irradiated with radiation generated by the radiation source. The selected exposure parameter values are also displayed on the graphical user interface. An exemplary graphical user interface is described in further detail below.
GUI 36 comprises a plurality of fields configured to accept input data related to the radiation source, the detector and the object. For example, field 38 is configured to accept input data related to the type of radiation source being used. In one embodiment, field 38 comprises a drop down menu that includes the various types of X-ray sources that are used in industrial applications.
As noted above, the example GUI shown in
Additionally, the GUI also enables a user to provide input data related to the detector. For example, the user may provide source to detector distance in field 46 and source to object distance in field 47. Also, the GUI accepts data in field 45, related to any external filters, if employed by the inspection tool.
On entering the input data, the exposure parameters are displayed in fields 48 and 49. The exposure parameters include a current input parameter and a voltage input parameter. In a specific embodiment, the radiographic inspection tool is adapted to generate multiple sets of exposure parameters for composite object comprising multiple regions with different material properties. For example, for a composite article comprising two regions with different material properties, the radiographic inspection tool generates two sets of exposure parameters, with each of the sets being optimized for a respective one of the regions. As discussed above, an overlap between the sets of exposure parameters is then determined, and exposure parameter values with the overlap are then selected for inspection of the composite article with a single exposure that is appropriate for each of the regions.
The exposure parameters are calculated as described in the flow chart of
In step 50, a feasibility analysis is performed to determine if the desired gray level for the image can be achieved with input data provided by the user. In one embodiment, the input data comprises data related to the radiation source. The feasibility analysis is performed by calculating the gray value using the input data.
If the calculated gray value exceeds the desired gray level, the algorithm generates optimum exposure parameters for the given input data as shown in step 52. If the calculated gray value is less than the desired gray value, then the current is scaled for the desired gray scale as shown in step 54.
In step 56, the scaled current is then compared to a maximum current rating of the radiation source. If the scaled current exceeds the maximum current rating, the algorithm specifies to the user that the input data provided cannot be allowed on the inspection system as shown in step 58. If the scaled current does not exceed the maximum current, then the optimization algorithm calculates the exposure parameters for the given input data as shown in step 52.
The above described invention provides several advantages including accurate determination of exposure parameters and a substantial reduction in inspection time. In particular, the invention facilitates radiographic inspection of a composite article in a single exposure that is appropriate for each of the different regions within the article.
While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.
