Imaging device magnification measuring method and system, storage medium and instruction
Through two imaging calculations of the true height and magnification of the scanning target in the CBCT system, the dimensional error problem caused by the change in the distance between the target and the X-ray source is solved, accurate dimensional measurement without reference samples is achieved, and the application scope of the imaging equipment is expanded.
Patent Information
- Application Number
- CN202411163684.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-23
- Publication Date
- 2024-12-13
AI Technical Summary
In CBCT imaging systems, the change in the distance between the target and the X-ray source leads to a size error in the projected image. The prior art relies on reference samples or empirical value estimation, and there are errors.
The projected images of different angles are obtained through two imaging times, the true height and magnification of the scanning target are calculated, and the true size and magnification of the scanning target are calculated using the change relationship between the distance from the ray source to the detector and the distance from the scanning target to the detector.
Without reference to samples and implants, the true dimensions of any position can be measured by two imaging, avoiding errors caused by distance changes, and expanding the scope of application of imaging equipment.
Smart Images
Figure CN119124051A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of medical equipment, and in particular, to a magnification measurement method, system, storage medium and instruction of an imaging device. Background Art
[0002] The CBCT imaging system uses cone-shaped rays emitted by an X-ray source to image the target. After passing through the target, these rays are received by a flat-panel detector to form a projection image. Therefore, there is a certain difference between the size of the object displayed in the projection image and its size in the actual position. This difference is mainly caused by the relative position of the target and the ray source during the imaging process. Specifically, the part closer to the ray source will appear larger in the projection image, while the part farther away will appear smaller. Since the magnification of CBCT is affected by the distance between the real object and the ray source. Therefore, when using the projection image to estimate the actual size of the object, the distance between the object and the X-ray source must be taken into account. However, in the actual operation process, the distance between the photographed target and the ray source is not fixed. Therefore, in the prior art, a reference sample or implant of known size is generally used to infer the proportion of the target object by the length of the reference sample or implant on the scanned image. In practical applications, if there is no implant, the empirical value of the length of human bones is generally used to estimate. For reference samples or implants, the distance between the scanned target and the radiation source in the human body and the distance between the reference object and the radiation source are not always equal during each scan, which may cause errors in the size of the target object on the scanned image. Summary of the invention
[0003] In order to solve the above technical problems, the present application provides a magnification measurement method, system, storage medium and instructions for an imaging device, which can measure the actual size and magnification of a scanning target at any position in the imaging area through two imaging operations.
[0004] Specifically, the technical solution of this application is as follows:
[0005] In a first aspect, the present application discloses a method for measuring magnification of an imaging device, comprising:
[0006] When performing a first scan on a scanning target placed between a ray source and a detector on an imaging device, a first distance between the ray source and the detector and a first projection image obtained by scanning are acquired;
[0007] Based on the scanning angle of the first scanning, when the imaging device rotates 180 degrees along the scanning center to perform a second scanning, the second distance between the ray source and the detector during the second scanning is obtained, and a second projection image is obtained;
[0008] Acquire a first height of the scanning target on the first projection image, and a second height of the scanning target on the second projection image;
[0009] The magnification of the scanning target is calculated based on the first distance, the first height, the second distance, and the second height.
[0010] In some implementations, the step of calculating the magnification of the scanned target based on the first distance, the first height, the second distance, and the second height includes:
[0011] Calculating a true height of the scanned object based on the first distance, the first height, the second distance, and the second height;
[0012] The magnification of the scanning target is calculated according to the real height of the scanning target.
[0013] In some embodiments, when the first distance and the second distance are not equal, the true height H of the scanned target is calculated by the following formula:
[0014]
[0015] Wherein, H1 is the first height of the scanning target on the first projection image; SDD1 is the first distance between the ray source and the detector during the first scan;
[0016] L1 is the detection distance between the scanning target and the detector during the first scanning, which can be obtained by the following formula:
[0017]
[0018] Among them, H2 is the second height of the scanning target on the second projection image; SDD2 is the second distance between the ray source and the detector during the second scan; L1 is the detection distance between the scanning target and the detector during the first scan; L is the change distance of the position of the detector between two scans.
[0019] In other embodiments, when the first distance is equal to the second distance, the true height H of the scanned target is calculated by the following formula:
[0020]
[0021] Wherein, H1 is the first height of the scanning target on the first projection image; SDD is the fixed distance between the ray source and the detector;
[0022] L1 is the detection distance between the scanning target and the detector during the first scan, which is obtained by the following formula:
[0023]
[0024] Wherein, H2 is the second height of the scan target on the second projection image; and L is the change distance of the position of the detector during two scans.
[0025] In some embodiments, the method for measuring magnification of an imaging device further includes:
[0026] Acquiring a first position of the detector during a first scan;
[0027] acquiring a second position of the detector during a second scan;
[0028] Based on the first position and the second position, a change distance L of the position of the detector during two scans is calculated.
[0029] In a second aspect, the present application also discloses a magnification measurement system for an imaging device, comprising a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of a magnification measurement method for an imaging device described in any one of the above embodiments.
[0030] In a third aspect, the present application further discloses a computer-readable storage medium having a computer program / instruction stored thereon, which, when executed by a processor, implements the steps of a method for measuring the magnification of an imaging device as described in any of the above-mentioned embodiments.
[0031] In a fourth aspect, the present application further discloses a computer program product including a computer program / instructions, which, when executed by a processor, implements the steps of a method for measuring the magnification of an imaging device described in any of the above embodiments.
[0032] Compared with the prior art, the present invention has at least one of the following beneficial effects:
[0033] 1. This application does not require reference samples and implants, and only requires two imagings to measure the true size of the scanned target at any position in the imaging area. Compared with the existing technology, this application can avoid the error problem caused by the reference object and the measured object being at different distances.
[0034] 2. In this application, non-isocentric imaging can be performed, that is, the imaging center position of the first imaging and the second imaging is set to be inconsistent with the imaging range size. Through non-isocentric imaging, not only can the imaging field of view be adjusted, but also the actual size of the scanning target can be calculated when the distance between the scanning target and the ray source changes, thereby calculating the magnification. The magnification measurement method of the imaging device provided in this application can make the application scope of the imaging device wider. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] The preferred implementation scheme will be described below in a clear and understandable manner with reference to the accompanying drawings to further illustrate the above-mentioned characteristics, technical features, advantages and implementation methods of the present application.
[0036] Figure 1 A flowchart of the steps of an embodiment of a method for measuring magnification of an imaging device of the present application;
[0037] Figure 2 A schematic diagram of a scanning scene in an embodiment provided in the present application;
[0038] Figure 3 for Figure 2 Schematic diagram of the imaging range in the corresponding scene;
[0039] Figure 4 A schematic diagram of a scanning scene in another embodiment provided by the present application;
[0040] Figure 5 for Figure 4 Schematic diagram of the imaging range in the corresponding scene. DETAILED DESCRIPTION
[0041] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.
[0042] It should be understood that when used in this specification and the appended claims, the term "comprising" indicates the presence of the described features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections.
[0043] In order to simplify the drawings, only the parts related to the invention are schematically shown in each figure, and they do not represent the actual structure of the product. In addition, in order to simplify the drawings and facilitate understanding, in some figures, only one of the parts with the same structure or function is schematically drawn or marked. In this article, "one" not only means "only one", but also means "more than one".
[0044] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.
[0045] In this document, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0046] In a specific implementation, the terminal device described in the embodiments of the present application includes, but is not limited to, other portable devices such as mobile phones, laptop computers, tutoring machines, or tablet computers with touch-sensitive surfaces (e.g., touch screen displays and / or touch pads). It should also be understood that in some embodiments, the terminal device is not a portable communication device, but a desktop computer with a touch-sensitive surface (e.g., touch screen displays and / or touch pads).
[0047] In addition, in the description of the present application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.
[0048] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the specific implementation methods of the present application will be described below with reference to the accompanying drawings. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings and other implementation methods can be obtained based on these drawings without creative work.
[0049] The CBCT imaging system uses cone-shaped rays emitted by an X-ray source to image the target. After passing through the target, these rays are received by the flat-panel detector to form a projection image. Therefore, there is a certain difference between the size of the object displayed in the projection image and its size in the actual position. This difference is mainly caused by the relative position of the target and the X-ray source during the imaging process. Specifically, the part closer to the X-ray source will appear larger in the projection image, while the part farther away will appear smaller.
[0050] Since the magnification of CBCT is affected by the distance between the real object and the X-ray source, when using the projection image to estimate the actual size of the object, the distance between the object and the X-ray source must be taken into account. However, in actual operation, the distance between the object being photographed and the X-ray source is not fixed, so there is a need for a method to calculate the magnification at different distances.
[0051] In some prior art solutions, generally, an implant of known size is used to perform X-ray projection imaging at the same distance. Through this process, the magnification of the distance where the implant is located can be determined, and the actual size of the target object can be inferred from this.
[0052] The technique relies on implants of known size, but not all implants are at the same distance from the target, which can lead to errors. In addition, when there are no implants in the patient, empirical estimates of bone size are often used, but this method still has errors.
[0053] In other existing technology solutions, the Laser Fusion Research Center of the China Academy of Engineering Physics provides an X-ray projection measurement image size calibration method. This method places a standard sample at a certain distance, and through two scans, the projection size of the standard sample is obtained to determine the magnification of the distance, thereby measuring the size of the sample to be measured at the distance.
[0054] Although the method is similar in nature to conventional techniques, it takes a new approach. By using a standard sample to determine the magnification at a fixed position, it no longer relies on implants. However, in the medical field, the distance to the target to be measured is not fixed due to the different location of the lesion in the patient and the change in the height of the bed. In addition, the scanning distance may also change for devices with non-isocentric scanning trajectories, so conventional techniques still dominate in the medical field.
[0055] In order to solve the above problem, the distance between the scanning target and the radiation source in the human body and the distance between the reference object and the radiation source are not always equal during each scan, which may cause errors in the size of the target object on the scanned image. Figure 1The present application provides a method for measuring the magnification of an imaging device, comprising the following steps:
[0056] S1, when performing a first scan on a scanning target placed between a ray source and a detector on an imaging device, obtaining a first distance between the ray source and the detector, and a first projection image obtained by scanning;
[0057] S2, based on the scanning angle of the first scan, the imaging device rotates 180 degrees along the scanning center and performs a second scan, obtains the second distance between the ray source and the detector during the second scan, and obtains a second projection image;
[0058] S3, acquiring a first height of the scanning target on the first projection image, and a second height of the scanning target on the second projection image;
[0059] S4, calculating the magnification of the scanned target based on the first distance, the first height, the second distance, and the second height. Specifically, calculating the real height of the scanned target based on the first distance, the first height, the second distance, and the second height. Calculating the magnification of the scanned target by the real height of the scanned target.
[0060] The present application provides an embodiment of a method for measuring magnification of an imaging device, comprising the following steps:
[0061] The scanning target is placed between the ray source and the detector of the imaging device to perform a first scan to obtain a first projection image; and a first height H1 of the scanning target on the first projection image is obtained.
[0062] Based on the current angle, the imaging device is rotated 180 degrees along the scanning center and then a second scan is performed to obtain a second projection image; and a second height H2 of the scanning target on the second projection image is obtained.
[0063] The true height H of the scan target is calculated by the following formula:
[0064]
[0065] Wherein, H1 is the first height of the scanning target on the first projection image; SDD1 is the first distance between the ray source and the detector during the first scan.
[0066] Wherein, L1 is the detection distance between the scanning target and the detector during the first scanning; it is calculated by the following formula:
[0067]
[0068] Among them, H2 is the second height of the scanning target on the second projection image; SDD2 is the second distance between the ray source and the detector during the second scan; and L is the change distance of the position of the detector during two scans.
[0069] In this embodiment, before calculating the true height of the scanning target, the following steps are further included:
[0070] The first distance SDD1 between the ray source and the detector during the first scan is acquired.
[0071] The second distance SDD2 between the ray source and the detector during the second scan is acquired.
[0072] The change distance L of the position of the detector during two scans is acquired.
[0073] Specifically, before the imaging device works, an imaging scheme is preset through the control system, and the imaging scheme includes an imaging radius and an imaging trajectory, etc. During calculation, the values of SDD1, SDD2 and L are directly retrieved from the control system of the imaging device.
[0074] In some implementations of this embodiment, the first position of the detector during the first scan and the second position of the detector during the second scan can be measured; based on the first position and the second position, the change distance L of the position of the detector during the two scans can be calculated.
[0075] In some other implementations of this embodiment, the distance L between the detectors during two scans cannot be directly obtained in some imaging devices. Then the change distance L of the position of the detectors during two scans can be calculated by the following formula:
[0076] L=SDD1+SDD2-L0.
[0077] Among them, SDD1 is the first distance from the ray source to the detector; SDD2 is the second distance from the ray source to the detector; L0 is the distance between the ray sources during two scans, which can be obtained from the operating system of the imaging device or measured manually. Specifically, the position of the ray source during the first scan is obtained; the position of the ray source during the second scan is obtained; and the change distance L0 of the position of the ray source during the two scans is obtained by calculating the difference.
[0078] In this embodiment, the actual height of the scanned target is calculated based on the principle of similar triangles. The specific concept is as follows. Figure 2 ,exist Figure 2 In the scan scene shown, based on similar triangles, we can get:
[0079]
[0080] It is inferred that: or, Among them, (SDD1-L1) is the distance between the scanning target and the radiation source during the first scan; (SDD2-L+L1) is the distance between the scanning target and the radiation source during the second scan. For example, when it is necessary to measure the length of the human bone without performing a tomographic scan on the human bone, since the scanning target is inside the human body, the actual distance between the scanning target and the detector cannot be intuitively obtained. Therefore, the actual distance L1 between the scanning target and the detector is calculated in the following way.
[0081] When SDD1, SDD2 (SDD1 is not equal to SDD2) and L are known, we can get:
[0082]
[0083] H2*SDD1*SDD2-H2*SDD1*L+H2*SDD1*L1=H1*SDD2*SDD1-H1*SDD2*L1;
[0084] H2*SDD1*SDD2-H2*SDD1*L+H2*SDD1*L1=H1*SDD2*SDD1-H1*SDD2*L1;
[0085] L1*(H2*SDD1+H1*SDD2)=SDD1*(H2*L+H1*SDD2-H2*SDD2);
[0086]
[0087] Substitute the above solution formula for L1 into the solution formula for the true height H to obtain the true height H.
[0088] Reference Manual Attached Figure 3 , where the shaded part is Figure 2 Regarding the imaging range in the corresponding scene, the method disclosed in the present application can calculate the actual size of the scanning target as long as the scanning target is within the imaging range, even if the distance between the scanning target and the radiation source changes after the imaging device is rotated by a set angle.
[0089] Another embodiment of the magnification measurement method of an imaging device of the present application is as shown in the attached specification. Figure 4 As shown, based on an embodiment of the magnification measurement method of the above-mentioned imaging device, assuming that the imaging range of the first scan is the same as that of the second scan, and assuming that the first distance and the second distance are equal, the true height H of the scanned target is calculated by the following formula:
[0090]
[0091] Among them, H1 is the first height of the scanning target on the first projection image; SDD is the fixed distance between the ray source and the detector, SDD1=SDD2=SDD; L1 is the detection distance between the scanning target and the detector during the first scan.
[0092] The detection distance L1 between the scanning target and the detector during the first scanning is calculated by the following formula:
[0093]
[0094] Among them, H1 is the first height of the scanning target on the first projection image; H2 is the second height of the scanning target on the second projection image; SDD is the fixed distance between the ray source and the detector; L1 is the detection distance between the scanning target and the detector during the first scan; L is the change distance of the position of the detector between two scans.
[0095] The specific idea is as follows: Substituting SDD1=SDD2=SDD into the calculation formula of L1, we can get:
[0096]
[0097] Substituting SDD1=SDD2=SDD into the calculation formula for H, we can infer that:
[0098] or,
[0099] The true height H can be calculated by combining the above formula.
[0100] Reference Manual Attached Figure 5 As shown, the shaded part is Figure 4 Imaging range in corresponding scenes. The present application provides a magnification measurement method for an imaging device, which can indirectly adjust the imaging range of the device by adjusting the distances SDD1 and SDD2 between the ray source and the receiver during two imaging operations, thereby making the imaging device more applicable.
[0101] Another embodiment of a magnification measurement method for an imaging device of the present application is shown, based on any one of the above embodiments of the magnification measurement method for an imaging device, further comprising:
[0102] The magnification of the scanned object is calculated by the real height H of the scanned object. Specifically, the magnification is the ratio of the height of the photographed object on the projection image to the height of the real object. More preferably, a first magnification of the real height of the scanned object relative to the first projection image and a second magnification of the real height of the scanned object relative to the second projection image can be calculated respectively.
[0103] Based on the same technical concept, the present application also discloses a magnification measurement system for an imaging device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement any of the above-mentioned magnification measurement methods for the imaging device.
[0104] In one embodiment, a magnification measurement system for an imaging device specifically includes:
[0105] The image acquisition module is used to place the scanning target between the ray source and the detector of the imaging device for the first scanning to acquire the first projection image and acquire the first height H1 of the scanning target on the first projection image.
[0106] The image acquisition module is further used to rotate the imaging device 180 degrees along the scanning center based on the current angle and then perform a second scan to acquire a second projection image, and acquire a second height H2 of the scanning target on the second projection image.
[0107] The height calculation module is used to calculate the real height H of the scanning target by the following formula:
[0108]
[0109] Wherein, H1 is the first height of the scanning target on the first projection image; SDD1 is the first distance between the ray source and the detector during the first scan.
[0110] The distance calculation module is used to calculate the detection distance L1 between the scanning target and the detector during the first scanning by the following formula:
[0111]
[0112] Among them, H2 is the second height of the scanning target on the second projection image; SDD1 is the first distance between the ray source and the detector during the first scan; and L is the change distance of the position of the detector during two scans.
[0113] In another embodiment of a magnification measurement system for an imaging device provided by the present application, based on the above system embodiment, when the first distance and the second distance are equal, the height calculation module is further used to calculate the true height H of the scanning target by the following formula:
[0114]
[0115] Wherein, H1 is the first height of the scanning target on the first projection image; SDD is the fixed distance between the ray source and the detector, SDD1=SDD2=SDD; L1 is the detection distance between the scanning target and the detector during the first scan;
[0116] The distance calculation module is further used to calculate L1 using the following formula:
[0117]
[0118] Among them, H2 is the second height of the scanning target on the second projection image; SDD is the fixed distance between the ray source and the detector; and L is the change distance of the position of the detector during two scans.
[0119] Based on the same concept, the present application also discloses a computer-readable storage medium having a computer program / instruction stored thereon. When the computer program / instruction is executed by a processor, the steps of a method for measuring the magnification of an imaging device described in any of the above embodiments are implemented.
[0120] Based on the same concept, the present application also discloses a computer program product including a computer program / instruction, which, when executed by a processor, implements the steps of a method for measuring the magnification of an imaging device described in any of the above embodiments.
[0121] The magnification measurement method, system, storage medium and instructions of an imaging device of the present application have the same technical concept, and the technical details of the four embodiments are applicable to each other. In order to reduce repetition, they will not be repeated here.
[0122] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the division of the above-mentioned program modules is used as an example for illustration. In actual applications, the above-mentioned functions can be assigned to different program modules as needed, that is, the internal structure of the device can be divided into different program units or modules to complete all or part of the functions described above. The program modules in the embodiment can be integrated into a processing unit, or each unit can exist physically separately, or two or more units can be integrated into a processing unit, and the above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software program unit. In addition, the specific names of the program modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application.
[0123] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.
[0124] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above integrated unit may be implemented in the form of hardware or in the form of software functional units.
[0125] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.
[0126] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.
Claims
1. A method for measuring magnification of an imaging device, characterized in that: The steps include: When performing a first scan on a scanning target placed between a ray source and a detector on an imaging device, a first distance between the ray source and the detector and a first projection image obtained by scanning are acquired; Based on the scanning angle of the first scanning, when the imaging device rotates 180 degrees along the scanning center to perform a second scanning, a second distance between the ray source and the detector during the second scanning is obtained, and a second projection image is obtained; Acquire a first height of the scanning target on the first projection image, and a second height of the scanning target on the second projection image; The magnification of the scanning target is calculated based on the first distance, the first height, the second distance, and the second height.
2. A method for measuring magnification of an imaging device as claimed in claim 1, characterized in that: The calculating the magnification of the scanning target based on the first distance, the first height, the second distance, and the second height includes: Calculating a true height of the scanned object based on the first distance, the first height, the second distance, and the second height; The magnification of the scanning target is calculated according to the real height of the scanning target.
3. A method for measuring magnification of an imaging device as claimed in claim 2, characterized in that: When the first distance and the second distance are not equal, the true height H of the scanned target is calculated by the following formula: Wherein, H1 is the first height of the scanning target on the first projection image; SDD1 is the first distance between the ray source and the detector during the first scan; L1 is the detection distance between the scanning target and the detector during the first scanning, which is obtained by the following formula: Among them, H2 is the second height of the scanning target on the second projection image; SDD2 is the second distance between the ray source and the detector during the second scan; and L is the change distance of the position of the detector during two scans.
4. A method for measuring magnification of an imaging device as claimed in claim 2, characterized in that: When the first distance is equal to the second distance, the true height H of the scanned target is calculated by the following formula: Wherein, H1 is the first height of the scanning target on the first projection image; SDD is a fixed distance between the ray source and the detector; L1 is the detection distance between the scanning target and the detector during the first scan, which is obtained by the following formula: Wherein, H2 is the second height of the scanning target on the second projection image; and L is the change distance of the position of the detector during two scans.
5. A method for measuring magnification of an imaging device as claimed in claim 3 or 4, characterized in that: Also includes: Acquiring a first position of the detector during a first scan; acquiring a second position of the detector during a second scan; Based on the first position and the second position, a change distance L of the position of the detector during two scans is calculated.
6. A magnification measurement system for an imaging device, comprising a memory, a processor, and a computer program stored in the memory, characterized in that: The processor executes the computer program to implement the steps of the method for measuring magnification of an imaging device according to any one of claims 1 to 5.
7. A computer-readable storage medium having a computer program / instruction stored thereon, characterized in that: When the computer program / instructions are executed by a processor, the steps of a method for measuring magnification of an imaging device as described in any one of claims 1 to 6 are implemented.
8. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of a method for measuring magnification of an imaging device as described in any one of claims 1 to 6 are implemented.