Patent Publication Number: US-2018033129-A1

Title: Systems and methods for indexing and detecting components

Description:
FIELD 
     This disclosure relates generally to position control used with automated defect inspection for gas turbine engines. 
     BACKGROUND 
     Video inspection systems, such as borescopes, have been widely used for capturing images or videos of difficult to-reach locations by “snaking” image sensor(s) to such locations. Applications utilizing borescope inspections include aircraft engine blade inspection, power turbine blade inspection, internal inspection of mechanical devices, and the like. 
     A variety of techniques for inspecting the images or videos provided by borescopes for determining defects therein have been proposed in the past. Most such techniques capture and display images or videos to human inspectors for defect detection and interpretation. Human inspectors then decide whether any defect within those images or videos exists. 
     Once defects are detected in a member of a device, the member must typically be manually located within the device and reinspected to confirm the presence and extent of the defect identified in the images or video. Identifying and locating the defective member within the device may be time consuming and difficult because of the size of the device, the quantity of members within the device that may need to be inspected, the location of the defective member within the device, and, in some cases, the similarity of each member to one another. 
     SUMMARY 
     Systems and methods for position control are described herein, in accordance with various embodiments. A method of performing position control on members of a device, the method comprising applying, by a deposition device, a fiducial mark to a first member of the device, and receiving, by a processing unit, from an image capture device coupled to the processing unit, an image of the first member. 
     In various embodiments, the method may further comprise detecting, by the processing unit, the fiducial mark on the first member. The method may further comprise transmitting, by the processing unit, instructions to a turning tool to move the first member to an inspection position in the device. The method may further comprise detecting, by the processing unit, a defect in a second member. The method may further comprise transmitting, by the processing unit, instructions to a turning tool to move the second member to an inspection position in the device. The applying the fiducial mark may be in response to the detecting the defect. The applying may be performed via the deposition device, the deposition device being coupled near a tip of the image capture device. The method may further comprise selecting, by the processing unit, the first member to be a reference member, wherein the selecting is in response to the detecting the fiducial mark. The method may further comprise indexing a location of the second member relative to the first member. The device may comprise an aircraft engine. The first member may comprise a blade. 
     A defect detection and position control system may comprise a processing unit, a deposition device in communication with the processing unit, the deposition device configured to deposit a fiducial mark onto a member of a device, and an image capture device in communication with the processing unit, the image capture device configured to send an image of the member to the processing unit. 
     In various embodiments, the deposition device may be attached to the image capture device. The depositing the fiducial mark and the sending the image may be simultaneous. The processing unit may be configured to detect the fiducial mark. The deposition device may be configured to deposit the fiducial mark onto the member in response to the processing unit detecting a defect on the member. The processing unit may include a non-transitory computer readable medium having instructions stored thereon that, in response to execution by the processing unit, cause the processing unit to perform operations comprising receiving, by the processing unit, from the image capture device a first image of a first member of the device, receiving, by the processing unit, from the image capture device a second image of a second member of the device, detecting, by the processing unit, a first defect in the first member, detecting, by the processing unit, a second defect in the second member, the second member being in sequence with the first member, determining, by the processing unit, that the second defect is indistinguishable from the first defect, and selecting, by the processing unit, a sequence of reference members comprising at least the first member and the second member. The member may comprise a blade. The device may comprise an aircraft engine. 
     A method of performing position control may comprise receiving, by a processing unit, from an image capture device in electronic communication with the processing unit, an image of a first member inside of a device, receiving, by the processing unit, from the image capture device an image of a second member inside of the device, detecting, by the processing unit, a first defect in the first member, detecting, by the processing unit, a second defect in the second member, determining, by the processing unit, that the second defect is indistinguishable from the first defect, and selecting, by the processing unit, a sequence of reference members comprising at least the first member and the second member. 
     In various embodiments, the method may further comprise indexing a location of each of a plurality of members within the device relative to the sequence of reference members. The method may further comprise detecting, by the processing unit, a defect in a third member of the plurality of members. The plurality of members may comprise a plurality of blades and the device may comprise an aircraft engine. 
     The foregoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated otherwise. These features and elements as well as the operation thereof will become more apparent in light of the following description and the accompanying drawings. It should be understood, however, the following description and drawings are intended to be exemplary in nature and non-limiting. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a schematic view of a defect detection and position control system, in accordance with various embodiments; 
         FIGS. 2A and 2B  illustrate flowcharts of exemplary steps of position control methods used in conjunction with automated defect detection, in accordance with various embodiments; 
         FIG. 3  illustrates the image detection device and the deposition device of  FIG. 1  being located in an inspection port of an aircraft engine, in accordance with various embodiments; 
         FIG. 4  illustrates an exemplary set of images received by the processing unit of  FIG. 1 , in accordance with various embodiments; and 
         FIG. 5  illustrates a method of performing position control including sub steps of the exemplary steps of  FIG. 2A  and  FIG. 2B . 
     
    
    
     DETAILED DESCRIPTION 
     The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, it should be understood that other embodiments may be realized and that logical changes and adaptations in design and construction may be made in accordance with this disclosure and the teachings herein. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation. The scope of the disclosure is defined by the appended claims. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not necessarily limited to the order presented. Furthermore, any reference to singular includes plural embodiments, and any reference to more than one component or step may include a singular embodiment or step. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option. Additionally, any reference to without contact (or similar phrases) may also include reduced contact or minimal contact. Surface shading lines may be used throughout the figures to denote different parts but not necessarily to denote the same or different materials. In some cases, reference coordinates may be specific to each figure. 
     Gas turbine engines include various stages which include blades, some or all of which may benefit from visual inspection periodically. Such blades may be accessible during the inspection process by a relatively small inspection port. Thus, inspection is typically performed via an image capture device. The image capture device may provide a set of images of the blades which may be inspected by an automated defect detection and position control system. Indexing of the blades is especially useful so that a blade of interest may be rotated to the inspection port for visual inspection. The automated defect detection and position control system, as described herein, includes a deposition device capable of making a fiducial mark on the blades to create one or more reference blades. Such reference blades may be used during the indexing process. Fiducial marks may allow for the automated defect detection and position control system to repeatedly and accurately detect the reference blade. 
     With reference to  FIG. 1 , a schematic illustration of a defect detection and position control system (system)  2  is shown, in accordance with various embodiments. The defect detection system may include a processing unit  14 , an image capture device  10 , and a deposition device  40 . An engine  4  may have a plurality of stages  6 , each of the stages having a plurality of airfoils such as stationary airfoils (also referred to as vanes) or such as rotating airfoils (also referred to as blades) which are shown as blades  8 , some or all of which may benefit from visual inspection periodically or at predetermined intervals by an image capture device  10 . In this regard, blades  8  may comprise members of engine  4 . Furthermore, engine  4  may be referred to herein as a device. In various embodiments, the image capture device  10  may be one or more borescopes. The engine  4  may be representative of a wide variety of engines, such as, jet aircraft engines, aeroderivative industrial gas turbines, steam turbines, diesel engines, automotive and truck engines, and the like. Notwithstanding that the present disclosure has been described in relation to visual inspection of the blades  8  of an engine  4 , in other embodiments, the system  2  may be employed to inspect other parts of the engine  4 , as well as to perform inspection on the parts or members of other types of equipment and devices. Such parts/members are not limited to airfoils such as blades. For example, the system  2  may be used for medical endoscopes, or inspecting interior surfaces in machined or cast parts, and the like. 
     With combined reference to  FIG. 1  and  FIG. 4 , the image capture device  10  may be an optical device having an optical lens or other imaging device or image sensor and capable of capturing and transmitting images  434  through a communication channel  12  to a processing unit  14 . The image capture device  10  may be representative of any of a variety of flexible borescopes or fiberscopes, rigid borescopes, video borescopes or other devices, such as, endoscopes, which are capable of capturing and transmitting images  434  of difficult-to-reach areas through the communication channel  12 . The communication channel  12  in turn may be an optical channel or may be any other wired, wireless, or radio channel or any other type of channel capable of transmitting images  434  between two points, including a packet-switched network such as one using Transmission Control Protocol/Internet Protocol (TCP/IP). 
     Deposition device  40  may comprise any device capable of depositing ink  342  (see  FIG. 3 ) onto blades  8 . For example, deposition device  40  may comprise a controllable inkjet print head. A fiducial mark may be deposited onto blades  8  via deposition device  40 . A fiducial mark may comprise any unique and/or distinguishable mark capable of being detected by processing unit  14  via image capture device  10 . For example, a fiducial mark may comprise a dot, line, circle, square, polygon, numerical values, Roman numerals, alphabetical characters, or any other distinguishable marks. Ink  342  (see  FIG. 3 ) deposited by deposition device  40  may comprise a high temperature resistant marking agent. Ink  342  (see  FIG. 3 ) deposited by deposition device  40  may be blue. Blue ink may be detectable by processing unit  14  via an excess-blue algorithm. In general, Ink  342  may comprise any subsequently detectable material, e.g., the ink may be visibly detectable as described, may contain infrared fluorescent constituents, radioactive tracers, and the like. Similarly, image capture device  10  may be additionally sensitive to non-human-visible portions of the electromagnetic spectrum, radiation, and the like. The deposition device  40  may be in communication with processing unit  14  via communication channel  32 . Communication channel  32  may be similar to communication channel  12 . Processing unit  14  may be capable of sending commands or otherwise controlling deposition device  40  via communication channel  32 . 
     Processing unit  14  may be located on-site near or on the engine  4  or processing unit  14  may be located at a remote site away from the engine  4 . The system  2  may include a storage medium  20 . Storage medium  20  may be in communication with the processing unit  14 . The storage medium  20  may store data and programs used in processing images  434  of the blades  8 , and monitoring and controlling the position of the blade(s)  8  in the engine  4 . The processing unit  14  may receive and process images  434  of the blades  8  that are captured and transmitted by the image capture device  10  via the communication channel  12 . Upon receiving the images  434 , the processing unit  14  may process the images  434  to perform feature extraction and image analysis and to determine whether there are defects within any of the blades  8 . In various embodiments the defect detection may be automatic or may be semi-automated. 
     The system  2  may include an output unit  18 . Results (e.g., the defects) may be transmitted through communication channel  16  and displayed or printed by the output unit  18 . The output unit may be a visual display, a printer, auditory unit, or the like. In addition, the output unit  18  may be a combination of the aforementioned exemplary output units. For example in various embodiments, the output unit may comprise a visual display, an auditory unit, and a printer. The results may include information regarding whether any defects in any of the blades  8  were found. Information about the type of defect, the location of the defect, size of the defect, etc. may also be reported as part of the results. For example, the output unit  18  may display a map of the engine  4  or a portion of the engine  4  and may identify the location of a defective blade  8  on the map. In various embodiments, the output unit  18  may display directions to guide a user to locate a defective blade  8  in the engine  4 . The directions may be in a step-by-step format. In various embodiments, the output unit  18  may provide auditory directions or signals to guide a user to locate a defective blade  8  in the engine  4 . 
     Similar to the communication channel  12 , the communication channel  16  may be any of variety of communication links including, wired channels, optical or wireless channels, radio channels, or using a packet-switched network such as TCP/IP. It will also be understood that although the output unit  18  has been shown as being a separate device from the processing unit  14 , in various embodiments, output unit  18  and processing unit  14  are housed in the same device. Rather, in various embodiments, the output unit  18  may be part of the processing unit  14  and the results may be stored within and reported through the processing unit  14  as well. Furthermore, reporting of the results may involve storing the results in the storage medium  20  for future reference. 
     The system  2  may include an input unit  22  coupled to the processing unit  14 . The input unit  22  may be a keyboard, touch screen, or any other input device as known in the art. The input unit  22  may be coupled to the processing unit  14  by communication channel  24 . Similar to the communication channel  12 , communication channel  24  may be any of variety of communication links including, wired channels, optical or wireless channels, radio channels, or using a packet-switched network such as TCP/IP. 
     The system  2  may also include a turning tool  26  coupled to the processing unit  14  by communication channel  28 . The turning tool  26  may be coupled to the engine  4  by direct mechanical coupling  30  or other means causing the movement of blades  8 . In various embodiments, the turning tool may be coupled to the engine stage  6 . The turning tool  26  is configured to move the blades  8  of the engine  4  based on instructions provided to the turning tool  26  by the processing unit  14 . In various embodiments, the turning tool  26  may be a motor configured to move a blade  8  of an engine stage  6  into an inspection position  38  based on instructions received from the processing unit  14 . The inspection position  38  may, for example, be a port or appropriately sized opening in the engine  4  through which maintenance or other personnel may visually inspect the blade  8  directly or using a borescope. Similar to the communication channel  12 , the communication channel  28  may be any of variety of communication links including, wired channels, optical or wireless channels, radio channels, or using a packet-switched network such as TCP/IP. 
     With reference to  FIG. 3 , an image capture device  310  and deposition device  340  being located in an inspection port  320  of an engine  304  is illustrated, in accordance with various embodiments. Image capture device  310  and deposition device  340  may be similar to image capture device  10  and deposition device  40  of  FIG. 1 , respectively. Engine  304  may comprise multiple stages  306  and may comprise blade(s)  308 . Engine  304  may be similar to engine  4  of  FIG. 1 . Blade(s)  306  may be similar to blade(s)  6  of  FIG. 1 . With combined reference to  FIG. 1  and  FIG. 3 , in various embodiments, deposition device  340  may be coupled to image capture device  310 . For example, deposition device  340  may be coupled near a tip  312  of image capture device  310 . Thus, image capture device  310  and deposition device  340  may be simultaneously inserted into an inspection port  320  of engine  304  for inspecting blade(s)  308 . In this regard, image capture device  310  may send images of at least a portion of blade(s)  306  at the same time that deposition device  340  is depositing a fiducial mark. Coupling deposition device  340  to image capture device  310  may aide in automated deposition of ink  342  onto blade(s)  308 . However, deposition device  340  may be a separated from image capture device  310 , in accordance with various embodiments. 
       FIG. 2A  and  FIG. 2B  are exemplary flowcharts  100  showing sample steps which may be followed in performing automated defect detection and position control using the system  2 . In other words,  FIG. 2A  and  FIG. 2B  provide methods of performing position control on defective members in a device. In  FIG. 2A , a fiducial mark is made before the images are received by the processing unit. In  FIG. 2B , a fiducial mark is made after the images are received by the processing unit and have been evaluated for defect detection. 
     With combined reference to  FIG. 1 ,  FIG. 2A ,  FIG. 2B , and  FIG. 4 , after starting at step  102 , in various embodiments as illustrated in  FIG. 2A , the process proceeds to step  103 , in which a fiducial mark is applied via deposition device  40 . The fiducial mark may be applied in an automated process or may be applied by human control. The fiducial mark may be used for indexing blades  8  via images  434 . For example, the reference blade  36  may be the blade having the fiducial mark and the blades  8  may be indexed relative to the reference blade  36 , in accordance with various embodiments. In various embodiments, applying a fiducial mark may provide an easily distinguishable mark for processing unit  14  to detect during the indexing process. 
     In various embodiments, as illustrated in  FIG. 2B , the process proceeds to step  104 , in which an initial set of images  434  of blades  8  of an engine  4  may be received by the processing unit  14  from the image capture device  10 . The set  432  of images  434  may be sequential in terms of the order in which they are captured by the image capture device (e.g., image one followed by image two, etc.). In further embodiments, the images  434  may be non-sequential with regard to the order in which the images  434  were captured by the image capture device  10 . For example, every third image captured by the image capture device  10  may be received by the processing unit  14 . 
     The blades  8  may be rotating in the engine  4  at the time the images  434  are captured. For example, the blades  8  may rotate toward or away from the image capture device  10  when the images  434  are being captured. The images  434  captured may be of the same blade  8  in different positions in the field of view of the image capture device  10  and/or may be of a plurality of blades  8  in different positions in the field of view of the image capture device  10 . Thus, there may be periodic or semi-periodic motion in the capturing of images  434  of such inspected engine blades  8 . 
     In step  106  the processing unit  14  may extract the features from each blade  8  from the set  432  of images  434  and may detect defects in one or more blades  8  of the engine  4 . Various techniques of feature extraction and defect detection may be utilized by the processing unit  14 . For example, defects may be determined by comparing received image data from the image capture device  10  with a normal model of an undamaged blade  8 . The normal model may be created or otherwise learned automatically from data transmitted by the image capture device  10 , or the normal model may be received by input from a user. 
     In various embodiments, Robust Principal Component Analysis (RPCA) may be utilized to determine the normal model and/or detect defects. RPCA may be applied to the set  432  of images  434  to decompose the set  432  of images  434  received by the processing unit  14  from the image capture device  10  into a first series of low rank component images (low rank matrix) and a second series of sparse component anomaly images (sparse matrix). Typically blades  8  of an engine  4  are of the same size in a given engine stage  6 . When a second blade  8  rotates to the same position as that which the first blade  8  had been in previously, the two images  434  taken at the two different instances are generally almost the same. The repetitive, nearly identical images  434  are captured in the low rank matrix and may be utilized to create a normal blade model. The damaged areas, for example nicks or dents, which tend to occupy a small percentage of the entire image, are captured in the sparse matrix and may, in various embodiments, be further processed for defect detection. An example of such additional processing done on image data in the sparse matrix may include statistical techniques such as polynomial fitting, blob extraction and size filtering, and morphological filtering and the like to detect non-smooth edges, to filter out small regions and sporadic pixels etc. 
     In various embodiments, a feature based approach for extracting features, such as, corner-like features and intensity gradient features, to determine any common features between images  434  may be utilized. In various embodiments, an image based approach may be utilized where the entire image is used when comparing a current image with prior images  434 . In various embodiments, a combination of feature based and image based approaches, or other commonly employed technique for aligning and comparing the current and the prior images  434  may be employed as well. 
     Techniques like SURF (Speeded Up Robust Features), SIFT (Scale Invariant Feature Transform), or ASIFT (Affine SIFT) may be employed for feature correspondence extraction or techniques, such as, FFT (Fast Fourier Transform) and NCC (Normalized Cross Co-relation) may be employed for image based comparison. All the aforementioned techniques are well known in the art and, accordingly, for conciseness of expression, they have not been described here. Notwithstanding in the present disclosure, only the SURF, SIFT, ASIFT, FFT, and NCC techniques for image comparison have been mentioned, in at least various embodiments, other types of techniques that are commonly employed for comparing images  434  or for detecting differences or defects in images  434  may be used. 
     The automated defect detection analysis performed by the processing unit  14  may also implement a classifier that confirms and verifies potential defects as either defects or non-defects. Defects identified through automatic detection may include, but are not limited to, types of defects such as leading edge defects, erosions, nicks, dents, cracks or cuts, the location of the defects, the size of the defects and other defect parameters. 
     In various embodiments, as illustrated in  FIG. 2A , where the fiducial mark has already been deposited, feature extraction may include detection of the fiducial mark. 
     In various embodiments as illustrated in  FIG. 2B , the process proceeds to step  107 , in which a fiducial mark is applied via deposition device  40 . The fiducial mark may be applied to a blade  8  in response to a defect being detected. 
     As illustrated in  FIG. 2A  and  FIG. 2B , the position of each blade  8  in the engine  4  or engine stage  6  may be indexed in step  108 . In various embodiments, a reference blade  36  is selected from the plurality of blades  8 . The selection of the reference blade  36  may be done by the processing unit  14  or may be selected by a user of the system  2  and input via the input unit  22  into the processing unit  14  for use in indexing. The position of reference blade  36  is retained in storage medium  20  during the subsequent movement of blades  8  by continuously counting subsequent blades  8  and their direction of motion as they are seen by the image capture device  10 . The reference blade  36  may be the blade having been marked with the fiducial mark. 
     In various embodiments, with reference to  FIG. 2A , a fiducial mark is deposited onto a blade  8  to mark said blade  8  as the reference blade  36 . The location of each blade  8  may be indexed in the engine stage  6  according to its relative position to the reference blade  36 . This relative position may be determined by the processing unit  14  by analysis of the set  432  of images  434  received from the image capture device  10  to determine the number of blades  8 , away from the specific blade  8  to be indexed, is from the reference blade  36 . In various embodiments, the relative position of the blade to be indexed from the reference blade  36  may be determined by analysis of the images  434  captured by the image capture device  10  while the blade  8  moves or rotates in the engine  4 . 
     In various embodiments, with reference to  FIG. 2B , the location of each blade  8  within the engine stage  6  may be indexed by each blade&#39;s  8  unique appearance. The processing unit  14  determines each blade&#39;s  8  unique appearance by analysis of the images  434  received from the image capture device  10 . The processing unit  14  may utilize two dimensional images  434  or three-dimensional images  434 . The three-dimensional images  434  may be synthesized from successive 2D images  434  captured while the blade  8  moves or rotates in the engine  4  or may be a depth map from a 3D sensor. Such a 3D sensor can be operable in the electromagnetic or acoustic spectrum capable of producing a depth map (which are also known as a point cloud and in this context are called an image only by analogy to 2D images). Various depth sensing sensor technologies and devices include, but are not limited to, structured light measurement, phase shift measurement, time of flight measurement, a stereo triangulation device, a sheet of light triangulation device, light field cameras, coded aperture cameras, focal stack cameras, computational imaging techniques, simultaneous localization and mapping (SLAM), imaging radar, imaging sonar, echolocation, laser radar (LIDAR), scanning LIDAR, flash LIDAR, or a combination comprising at least one of the foregoing. Different technologies can include active (transmitting and receiving a signal) or passive (only receiving a signal) and may operate in a band of the electromagnetic or acoustic spectrum such as visual, infrared, ultrasonic, etc. 
     The unique appearance of a blade includes one or more of its visual appearance, 2D or 3D shape, defects (regardless of size or operational significance), color, etc. After determining each blade&#39;s  8  unique appearances a fiducial mark may be applied to a blade  8  in response to damage being detected on the blade  8 . In various embodiments, the fiducial mark may be applied to one blade  8 . In various embodiments, the fiducial mark may be applied to a plurality of blades  8 . For example, each damaged blade may receive a fiducial mark. The fiducial mark may number each damaged blade by, for example, numbering each blade using reference numerals. In various embodiments, only one blade  8  may receive the fiducial mark to create a reference blade  36  and each successive blade may be indexed relative to the reference blade  36 . For example, fiducial mark  425  may be applied to blade  408 . 
     In various embodiments, where the blades  8  are highly similar, the blades may be indexed by their offset from a sequence of reference blades  436 . For example, with reference to  FIG. 1  and  FIG. 4 , a first blade  401  may be very similar to second blade  402  such that processing unit  14  cannot definitively define a difference between the two blades using their respective images. In this regard, with reference to  FIG. 5 , step  106  may comprise additional sub steps  502 ,  504 ,  506 ,  508 , and  510 . Sub step  502  may include receiving a set of images. Sub step  504  may include detecting a first defect. Sub step  506  may include detecting a second defect. Sub step  508  may include determining that the second defect is indistinguishable from the first defect. Sub step  506  may include selecting a sequence of reference members. 
     In this regard, with combined reference to  FIG. 1 ,  FIG. 4 , and  FIG. 5 , sub step  502  may include receiving, by processing unit  14 , set  432  of images  434 . Sub step  504  may include detecting, by processing unit  14 , a first defect (illustrated by lines  440 ) in first blade  401 . The first defect  440  may be detected via any of the feature/defect detection methods described herein or known in the art. Sub step  506  may include detecting, by processing unit  14 , a second defect (illustrated by lines  442 ) in second blade  402 . The second blade  402  may be in sequence with the first blade  401 . The second defect  442  may be detected via any of the feature/defect detection methods described herein or known in the art. Sub step  508  may include determining, by processing unit  14 , that the second defect  442  is indistinguishable from the first defect  440 . Sub step  510  may include selecting a sequence of reference blades  436  (i.e., first blade  401  and second blade  402 ) from the plurality of blades (i.e., blades  8 ). Although illustrated as comprising two blades, the sequence of reference blades  436  may comprise any number of damaged blades with any number of undamaged intervening blades. The sequence of reference blades  436  may then be utilized similar to reference blade  36 . In various embodiments, a fiducial mark may be applied to at least one of the blades in sequence of reference blades  436 . For example, a first fiducial mark  421  may be applied to first blade  401  and a second fiducial mark  422  may be applied to second blade  402 . 
     In various embodiments, a fiducial mark may be configured to remain on blades  8  until the next inspection period. In this regard, a fiducial mark may aide in inspection of similar blades over successive inspection periods. Stated another way, a fiducial mark may allow system  2  to index the blades  8  in the same manner each inspection period. In this regard, a time-series of data regarding each blade position may be generated. Indexing the blades  8  in the same manner each inspection period may allow for a user to accurately determine parameters such as wear/damage rate and wear/damage locations. In this regard, the feature detection process may include detecting an existing fiducial mark. 
     With reference again to  FIG. 2A  and  FIG. 2B , in step  110  the user may be provided with the option whether to investigate detected defects further. In some embodiments, the user may choose to dismiss further investigation, in which case the process to step  118  and ends. In various embodiments, the user may choose to investigate the defects further. 
     If the user chooses to investigate the defects further, the process, in various embodiments, proceeds to step  112 . In step  112 , the processing unit  14  transmits to a turning tool  26  instructions to move the defective blade  8  to an inspection position  38 . In various embodiments the turning tool  26  may be a motor. The turning tool  26  may be coupled, directly or indirectly, to the engine  4  or engine stage  6 . The turning tool  26  may be configured to move or rotate the defective blade  8  from its current position to an inspection position  38  based on the instructions transmitted to the turning tool  26  by the processing unit  14 . 
     After receiving the instructions from the processing unit  14 , the turning tool  26  moves the defective blade  8  from its current position to the inspection position  38  where the blade  8  can undergo further inspection and analysis by a user. 
     In various embodiments, the process may proceed from step  110  to step  114 , where the processing unit  14  may transmit or provide directions or guidance for locating the defective blade  8  in its current position and/or moving the defective blade  8  to an inspection position  38  without the assistance of the automated turning tool  26 . The directions or guidance may be written, pictorial, auditory or a combination of some or all the aforementioned. For example, in various embodiments, the output unit  18  may display written directions advising a user to turn or rotate the engine stage a certain amount, to stop at a certain point, and the like. In various embodiments, the output unit  18  may display a map of the engine  4  and may identify on the map the location of the defective blade  8 . In yet another embodiment, the processing unit  14  may provide auditory directions for locating and/or moving the defective blade  8  to an inspection position  38 . Such auditory directions may include, but are not limited to, auditory spoken instructions, alarms, or beeps to guide the user. 
     Once a defective blade  8  is located and moved from its current position to the inspection position  38  in step  116 , the process may proceed back to step  110  until all defective blades have been moved to an inspection position  38  for inspection or the user selects an option via the input unit  22  to discontinue or delay the inspection. At the point that there are no more defective blades  8  to inspect or the user selects to discontinue or delay inspection, the process ends at step  118 . 
     Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical system. However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the disclosure. The scope of the disclosure is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, where a phrase similar to “at least one of A, B, or C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C. Systems, methods and apparatus are provided herein. In the detailed description herein, references to “one embodiment”, “an embodiment”, “various embodiments”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it may be within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments. 
     Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element is intended to invoke 35 U.S.C. 112(f) unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprises”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.