Instrumentation endoscope apparatus

A reference point-designating section 18b designates two reference points on a measurement object. A reference curve-calculating section 18c calculates a reference curve calculated by approximating an outline of the measurement object based on the reference points. A loss-composing point-calculating section 18d calculates loss-composing points constituting a loss outline formed on the measurement object based on the reference points and the reference curve. A loss size-calculating section 18f measures loss size based on the loss-composing points. Designating two reference points enables loss size measurement, thereby reducing complex operation and improving operability.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an endoscope apparatus that conducts measurement processing on a measurement object based on images picked up by an electronic endoscope.

The present application claims priority to Japanese Patent Application No. 2007-020906 filed on Jan. 31, 2007, and Japanese Patent Application No. 2007-175158 filed on Jul. 3, 2007, the details of which are incorporated herein.

2. Background Art

Sometimes, turbine blade edges or compressor blade edges of gas turbines mainly used in aircraft are subject to losses due to foreign bodies. The size of loss is a decision-making factor of blade replacement, so its inspection is very important. Under this circumstance, conventional endoscope apparatuses approximated loss edges of turbine blades or compressor blades by virtual curves and virtual points and measured loss sizes based on the approximated virtual curves and points (see, cf. Patent Document 1).Patent Document 1: Japanese Patent Application Laid-open No. 2005-204724.

However, parametric curves used to approximate loss edges in conventional methods necessitated the designating of at least three points to calculate a virtual curve and to change the edge shape by adjusting the calculated virtual curve manually, thereby requiring complex operations. Also, designation of at least four reference points due to edge losses formed on corners of measurement objects approximated by a virtual curve and virtual points formed on the curve necessitated complex operation.

SUMMARY OF THE INVENTION

The present invention was conceived in consideration of the aforementioned problems, and an object thereof is to provide an endoscope apparatus that can reduce complex operations and improve operability.

The present invention enables loss size measurement upon designating two reference points, thereby obtaining effects of reducing complex operations and improving operability.

PREFERRED EMBODIMENTS

Embodiments of the present invention are explained in detail with reference to drawings as follows. In the following embodiments, “area” indicates the extent or measurement of a surface in mathematic meaning; and “region” indicates a mere space or section free from the mathematic meaning.FIG. 1shows the configuration of an endoscope apparatus1according to an embodiment of the present invention. The endoscope apparatus1according to the present embodiment as shown inFIG. 1includes: an endoscope2; a control unit3; a LCD monitor5; a face mount display (FMD)6; an FMD adapter6a; optical adapters7a,7b, and7c; an endoscope unit8; a camera-control unit9; and a control unit10.

The endoscope2(electronic endoscope) for picking up a measurement object and generating an image signal has an elongate insertion tube20. Formed consecutively to the insertion tube20in order from the distal end are: a hard distal end section21; a bending section22that is capable of freely bending in, e.g., horizontal and vertical directions; and a flexible tube section23having flexibility. The proximal end of the insertion tube20is connected to the endoscope unit8. The distal end section21is configured to allow various optical adapters to screw therewith detachably, e.g., the stereo optical adapters7aand7bhaving two observational perspectives, or the ordinary observation optical adapter7chaving an observational perspective.

Provided in the control unit3are the endoscope unit8; an image-processing unit, i.e., the camera-control unit (hereinafter called the CCU)9; and a control unit, i.e., the control unit10. The endoscope unit8is provided with a light source apparatus that supplies illumination light necessary for observation; and a bending apparatus that bends the bending section22constituting the insertion tube20. An image signal output from a solid image-pickup device2abuilt in a distal end section21of the insertion tube20and input to the CCU9is converted into an image signal, e.g., an NTSC signal and supplied to the control unit10.

The control unit10is constituted by a voice signal-processing circuit11; an image-signal-processing circuit12; a ROM13; a RAM14; a PC card interface (hereinafter called a PC card I/F)15; a USB interface (hereinafter called a USB I/F)16; an RS-232C interface (hereinafter called an RS-232C I/F)17; and a measurement-processing section18.

Supplied to the voice signal-processing circuit11is a voice signal collected by a microphone34; a voice signal obtained by re-playing data stored in a storage medium, e.g., a memory card; or a voice signal generated by the measurement-processing section18. The image-signal-processing circuit12carries out a process of synthesizing the image signal supplied from the CCU9with a display signal for use in an operation menu generated by operating the measurement-processing section18in order to display synthesized image including an endoscopeally obtained image supplied from the CCU9and the graphic operation menu. In addition, the image-signal-processing circuit12upon providing predetermined processes to the synthesized image signal supplies the processed signal to the LCD monitor5in order to display an image on the screen of the LCD monitor5.

The PC card I/F15provides free installation and removal of memory cards (storage medium) thereto, e.g., a PCMCIA memory card32or a flash memory card33. Attaching the memory card thereto and controlling the measurement-processing section18enable capturing of control-processing information or image information stored in the memory card and storing of the control-processing information or the image information in the memory card.

The USB I/F16is an interface that provides electrical connection between the control unit3and a personal computer31. Electrical connection between the control unit3and the personal computer31via the USB I/F16allows the personal computer31to supply various commands regarding display of an endoscopeally obtained image and regarding control including image-processing during measurement. In addition, this enables input and output of various processing information and data between the control unit3and the personal computer31.

Connected to the RS-232C I/F17are the CCU9; the endoscope unit8; and a remote controller4that provides commands to control the CCU9and to move the endoscope unit8, etc. The remote controller4, upon carrying out a user's command, commences communication required to control operations of the CCU9and the endoscope unit8based on the details of the operation.

FIG. 2illustrates the configuration of the measurement-processing section18. As illustrated inFIG. 2, the measurement-processing section18is constituted by: a control section18a; a reference point-designating section18b; a reference curve-calculating section18c; a loss-composing point-calculating section18d; a loss-type-identifying section18e; a loss size-calculating section18f; and a storage section18g.

The control section18a(control unit) controls components in the measurement-processing section18. In addition, the control section18ahas a function of generating a display signal that causes the LCD monitor5or the face-mount display6(display unit) to display a measurement result or an operation menu and outputting the generated signal to the image-signal-processing circuit12.

The reference point-designating section18b(a reference point-designating unit) designates a reference point (details thereof are explained later) on a measurement object based on a signal input from the remote controller4or the PC31. The reference point-designating section18bcalculates the coordinates of two arbitrary reference points input by the user who is observing the image of the measurement object displayed on the LCD monitor5or the face-mount display6.

The reference curve-calculating section18c(an approximate-outline-calculation unit) calculates a reference curve (details of the reference curve will be explained later) that corresponds to an approximate outline that approximates the outline of the measurement object based on the reference point designated by the reference point-designating section18b. The loss-composing point-calculating section18d(loss-composing points-calculating unit) calculates loss-composing points (details of the loss-composing points will be explained later) that constitute a loss outline (edge) formed on the measurement object based on the reference point and the reference curve.

The loss-type-identifying section18e(loss-type-identifying unit) calculates an angle defined by two reference curves that correspond to the two reference points designated by the reference point-designating section18b; and identifies the loss type based on the calculated angle. The loss size-calculating section18f(loss-measurement unit) measures loss size based on the loss-composing points. The storage section18gstores various type of information that will undergo processes conducted by the measurement-processing section18. The information stored in the storage section18gis read out by the control section18aand is output to appropriate components.

Terms used in the present embodiment will be explained as follows. First, a reference point, a reference curve, and a reference point region will be explained with reference toFIG. 3. Reference points301and302on the displayed screen are actually designated by the user. As illustrated inFIG. 3, these points, disposed on both sides of a loss300, are on edges that are free from losses.

Reference curves311and312approximating the outline of the measurement object (edge) are calculated based on the two reference points301and302. In particular, a reference curve calculated in the present embodiment is a distortion-corrected curve calculated by correcting distortion of an image-pickup optical system provided to the distal end of the endoscope2(in the distal end section21) and distortion of an image-pickup optical system (optical adapters7a,7b, and7c) separately provided to the distal end of the endoscope2.

Reference point regions321and322indicate image regions that extract an edge around the reference point in order to obtain the reference curves311and312. The distortion-corrected curve may be calculated based on appropriately established size of reference point regions321and322.

Subsequently, loss type, loss-start point, loss-end point, loss-apex point, and loss-composing points will be explained with reference toFIGS. 4 and 5. Two types of loss, i.e., an edge loss and a corner loss undergo the measurement according to the present embodiment.

FIG. 4illustrates an edge loss400formed on a side of a measurement object andFIG. 5illustrates a corner loss500formed on a corner defined by edge lines of a measurement object.

Loss-start points401and501displayed on a measurement screen undergo a loss calculation which will be explained later and are recognized first as constituting a loss. Loss-end points402and502are recognized last as forming the loss. A loss-apex point503is recognized as a cross-point between reference curves521and522forming a part of the corner loss500. Loss-composing points410and510each including the loss-start point, loss-end point, and loss-apex point constitute a loss edge formed on the measurement object.

Loss size will be explained next with reference toFIGS. 6 and 7. Loss size is a parameter that represents a detected loss size. Size of an edge loss undergoing calculation of the present embodiment includes width, depth, and area, and size of a corner loss includes width, depth, and area. To be more specific, a width of the loss is a spatial distance between a loss-start point and a loss-end point. A depth of the loss is a spatial distance between a predetermined loss-composing point and a line connecting the loss-start point to the loss-end point. A spatial distance between the loss-apex point and the loss-start point, and a spatial distance between the loss-apex point and the loss-end point indicate a loss side. The loss area indicates an area of a space surrounded by all of the loss-composing points.

FIG. 6describes loss size with respect to an edge loss. A loss width600, calculated by a loss calculation which will be explained later, indicates a spatial distance between a loss-start point611and a loss-end point612. A loss depth601indicates a spatial distance between a predetermined loss-composing point613and a line between the loss-start point611and the loss-end point612. The loss area indicates a spatial area620surrounded by all the loss-composing points including non-illustrated loss-composing points.

FIG. 7describes loss size with respect to a corner loss. A loss width700, calculated by a loss calculation which will be explained later, is a spatial distance between a loss-start point711and a loss-end point712. A loss side701indicates a spatial distance calculated between a loss-apex point713and the loss-start point711. A loss side702indicates a spatial distance calculated between the loss-apex point713and the loss-end point712. The loss area indicates a spatial area720surrounded by all the loss-composing points including non-illustrated loss-composing points.

A measurement point and a measurement point region will be explained next with reference toFIG. 8. Measurement points801on the edge of a measurement object on a displayed measurement screen undertake sequential search (exploration) in a direction from a first reference point802to a second reference point803in a loss calculation which will be explained later. In addition, some of the searched measurement points are recognized as loss-composing points.

A measurement point region804indicates an image region for use in searching of the measurement point801and extracting of the edge around the measurement point. The edge may be extracted based on an appropriately established size of the measurement point region804.

Characteristic points will be explained next with reference toFIGS. 9 and 10. Characteristic points901and902on an edge are extracted within a reference point region910including a reference point903. Also, characteristic points1001and1002on an edge are extracted within a measurement point region1010including a measurement point1003. The characteristic points901and902extracted within the reference point region910are used for calculating a reference curve in a loss calculation which will be explained later. Some of the characteristic points extracted within, e.g., the measurement point region1010are selected as measurement points in the loss calculation.

A procedure of loss measurement according to the present embodiment will be explained next. Loss measurement and a measurement screen will be explained as follows with reference toFIGS. 11 and 12.FIG. 11describes a procedure of the loss measurement.FIG. 12shows a measurement screen. Measurement screens, shown in e.g.,FIG. 12, may omit an operation menu. As illustrated inFIG. 12, measurement images1200,1210, and1220indicate that a measurement object is an edge loss, and measurement images1230,1240, and1250indicate that a measurement object is a corner loss.

The present embodiment implements stereoscopic loss measurement. A measurement object picked up by a stereoscopic optical adapter attached to the distal end section21of the endoscope2based on the stereoscopic measurement is viewed as a pair of images generated on a measurement screen.

First in the loss measurement, when user operates the remote controller4or the PC31and designates two reference points on a measurement screen displayed on the LCD monitor5or the face-mount display6, the information of the reference points designated is input into the measurement-processing section18(step SA). Preferably, user selects the point on both sides of the loss and on the edge which is free from the loss as reference points. Reference points1201and1202, and reference points1231and1232that are found in left-images inFIG. 12are designated.

Subsequently, the measurement-processing section18implements a loss calculation based on the coordinates of the designated reference points (step SB). The loss calculation carries out a calculation with respect to coordinates of the loss-composing points and loss size; and identification of loss type. The measurement images1210and1240indicate measurement screens during calculation. Details of the loss calculation will be explained later.

When the loss calculation is completed, the detected loss region is displayed on the measurement screen based on an instruction by the measurement-processing section18(step SC), and simultaneously the loss type and the loss size are displayed (steps SD to SE). As illustrated inFIG. 12, the loss region is displayed on a left-image1221of the measurement image1220and on a left-image1251of the measurement image1250. To be more specific, the calculated loss-composing points that are connected by lines are displayed. In addition, a loss-start point, a loss-end point, and a loss-apex point are each displayed as cursors “∘”, “*”, and “□” among the loss-composing points.

In addition, images of the detected loss type are displayed in upper sections of result windows1223and1253of right-images1222and1252in the measurement images1220and1250. In addition, letters indicating the detected loss size are displayed in lower sections of the result windows1223and1253of the right-images1222and1252in the measurement images1220and1250.

A procedure of loss calculation in step SB2described inFIG. 11will be explained next with reference toFIG. 13.

When positions of the two reference points designated by the user in the left-image are input into the measurement-processing section18, the reference point-designating section18bcalculates image coordinates of the two reference points (two-dimensional coordinates on an image displayed on the LCD monitor5or the face-mount display6) (step SB1). Subsequently, the reference curve-calculating section18ccalculates two reference curves based on the image coordinates of the two reference points (step SB2).

Subsequently, the loss-type-identifying section18ecalculates the angle defined by the two reference curves and identifies the loss type corresponding to the calculated angle (step SB3). Subsequently, the loss-composing point-calculating section18dcalculates the image coordinates of the loss-composing points based on the image coordinates of the two reference points (and using reference curves in the case of a corner loss) (step SB4).

Subsequently, the loss-composing point-calculating section18dcalculates the image coordinates of matching points in the right-image corresponding to the calculated loss-composing points in the left-images and further calculates the spatial coordinates of the loss-composing points (real-space three-dimensional coordinates) based on the calculated loss-composing points and the image coordinates of the matching points of the calculated loss-composing points (step SB6).

A method for calculating spatial coordinates is the same as that disclosed in Japanese Unexamined Patent Application, First Publication No. 2004-49638. The loss size-calculating section18ffinally calculates the loss size corresponding to the loss type based on the spatial coordinates of the calculated loss-composing points (step SB7).

A procedure of calculating a reference curve in the step SB2ofFIG. 13will be explained next with reference toFIG. 14. When the image coordinates of the two reference points calculated by the reference point-designating section18bare input into the reference curve-calculating section18c(step SB21), the reference curve-calculating section18ccalculates by two characteristic points with one reference point based on the image coordinate of the input reference point (step SB22).

Subsequently, the reference curve-calculating section18ccalculates a distortion-corrected curve, that the distortion of the objective optical system is corrected, based on the two characteristic points (step SB23). Accordingly, two distortion-corrected curves are calculated corresponding to the two reference points. The reference curve-calculating section18cfinally outputs the details of the reference curves, i.e., details of the distortion-corrected curve (indicated by the image coordinates of points that compose the curve, or a formula of the curve), to the control section18a(step SB24).

A procedure of calculating characteristic points in the step SB22will be explained with reference toFIG. 15as follows. The calculation of characteristic points is carried out not only when a reference curve is calculated but also when loss-composing points are calculated. The calculation of characteristic points will be explained in summary here while the calculation of the loss-composing points will be explained later.

FIGS. 16 and 17illustrating the calculation of characteristic points schematically are also referred to if necessary.FIG. 16illustrates a procedure of calculating characteristic points around a reference point, andFIG. 17illustrates a procedure of calculating characteristic points around a measurement point.

When the image coordinate of the reference point or the measurement point is input (step SF1), a region image within a reference point region or the measurement point region is extracted based on the input image coordinate of the reference point or the measurement point (step SF2). Accordingly, a region image1601within the reference point region including a reference point1600, or a region image1701within the measurement point region including a measurement point1700is extracted.

Subsequently, the extracted region image is converted to grayscale (step SF3), and the edge is extracted from the grayscale image (step SF4). Subsequently, an approximated outline of the extracted edge is calculated (step SF5), and then two cross-points between the calculated edge approximation line and the region border line are calculated (step SF6). Accordingly, an edge approximation line1602or an edge approximation line1702is calculated. Cross-points1603and1604formed by the edge approximation line1602and the region border line, or cross-points1703and1704formed by the edge approximation line1702and the region border line are calculated.

Finally, nearest points on the extracted edge by the calculated cross-points are calculated (step SF7), and the two calculated nearest points are output into the control section18aas characteristic points (step SF8). Accordingly, the characteristic point, i.e., nearest points1605and1606corresponding to the cross-points1603and1604, or the nearest points1705and1706corresponding to the cross-points1703and1704are output.

Preferably, edge extraction should adapt a method that can minimize noise in an extracted image since an edge approximation line is calculated after the edge extraction of the step SF4. A usable first-differential filter may be e.g., a Sobel filter, a Prewitt filter, or a gradient filter, and a usable second-differential filter may be e.g. a Laplacian filter.

Alternatively, edge extraction may be conducted by combining filters corresponding to processes, e.g., dilation, erosion, subtraction, and noise-reduction. A method that is necessary to binarize this grayscale image state may use a fixed threshold value. Also, a method for changing a threshold based on brightness of the grayscale image may be a P-tile method, mode method, or discriminant analysis method.

Also, the edge approximation line is calculated in the step SF5by using, e.g., a simple least squares method that is based on details of the edge extracted in the step SF4. It should be noted that curve approximation using quadratic function may be conducted in contrast to linear approximation conducted with respect to edge shape as explained above. Curve approximation may provide more accurate calculation of characteristic points if the edge shape is curved rather than straightened.

A procedure of calculating distortion-corrected curves in step SB23ofFIG. 14will be explained next. The endoscope2adapted to the endoscope apparatus1according to the present embodiment measures optical data of the image-pickup optical system that is unique to each endoscope2. The measured optical data is stored in, e.g., the flash memory card33. The use of optical data allows a measurement image to be converted into a distortion-corrected image with respect to the image-pickup optical system.

A method for calculating a distortion-corrected curve will be explained as follows with reference toFIG. 18. An original image1800is the image of a measurement object. Points P1and P2are two characteristic points calculated in step SB22ofFIG. 14. Converting the original image1800by using the optical data obtains a distortion-corrected image1801. Points P1′ and P2′ are post-conversion points of P1and P2, respectively.

Reverse conversion conducted with respect to each pixel point on a line L causes the line L to be converted to a curve L′ on the original image1802where the line L indicates a line calculated by connecting the point P1′ to P2′ on the distortion-corrected image1801. Details of the curve L′, i.e., distorted line passing through the points P1and P2is output to the control section18a. Details of optical data, the method of producing thereof, and a distortion-correcting Method are the same as those disclosed in Japanese Unexamined Patent Application, First Publication No. 2004-49638.

A procedure of calculating a reference curve in the step SB2ofFIG. 13will be explained next with reference toFIG. 19. The loss-type-identifying section18eupon undertaking the input of details of the two reference curves from the control section18a(step SB31) causes the loss-type-identifying section18eto calculate the angle defined by the two reference curves (step SB32).

Subsequently, the loss-type-identifying section18edetermines as to whether or not the angle defined by the two reference curves is within a predetermined range (step SB33).

In a case where the angle defined by the two reference curves is in the predetermined range (e.g., the angle is close to 180°), the loss-type-identifying section18eupon determining that a loss is of edge-type outputs the loss identification result to the control section18a. The control section18astores the loss identification result in the storage section18g(step SB34). In a case where the angle defined by the two reference curves is not in the predetermined range (e.g., the angle is close to 90°), the loss-type-identifying section18eupon determining that a loss is of corner-type outputs the loss identification result to the control section18a. The control section18astores the loss identification result in the storage section18g(step SB34).

A procedure of calculating loss-composing points in step SB24ofFIG. 13will be explained next. Calculation of the loss-composing points includes processes of loss-apex-calculation, loss-start-point calculation, two-types-of-measurement-points-calculation, and loss-end-point-calculation. The loss-apex-calculation will be explained first with reference toFIG. 20.

The loss-composing point-calculating section18dupon undertaking the input of the loss identification result from the control section18a(step SB411a) identifies the loss type based on the identification result (step SB411b). If the loss is of corner type, the details of the two reference curves are input by the control section18a(step SB411c).

The loss-composing point-calculating section18dcalculates the cross-point between the two reference curves based on the input details (step SB411d) and outputs the image coordinate of the calculated cross-point. The control section18astores the image coordinate of the cross-point between the two reference curves, i.e., the image coordinate of the loss-composing points (loss-apex point) in the storage section18g(step SB411e). Subsequently, the procedure moves to a first-measurement-point-calculation described inFIG. 21. Also, if the loss is of edge-type, the procedure subsequent to the step SB411bmoves to the first-measurement-point-calculation described inFIG. 21.

A procedure of the first-measurement-point-calculation will be explained next with reference toFIG. 21.FIG. 22schematically showing a procedure of the first-measurement-point-calculation will be referred to if necessary. The loss-composing point-calculating section18dupon carrying out the input of an image coordinate of a first one of two reference points that have been designated first (step SB412a) by the user executes the calculation of the characteristic point as shown inFIG. 15and calculates the two characteristic points (step SB412b). This results in calculating two characteristic points2201and2202corresponding to a first reference point2200.

Subsequently, the image coordinates of a second reference point are input by the control section18a(step SB412c). The loss-composing point-calculating section18dcalculates a two-dimensional distance between the two characteristic points and the second reference point. The characteristic point closer to the second reference point are a next measurement point (step SB412d).

In a case where a direction of the second reference point is a direction T22inFIG. 22, one of the two characteristic points2201and2202, i.e., the characteristic point2202is a next measurement point2203.

Subsequently, the loss-composing point-calculating section18doutputs the image coordinate of the calculated cross-point to the control section18a. The control section18astores the image coordinate of the measurement point in the storage section18g(step SB412e). Subsequently, the procedure moves to a loss-start-point-calculation described inFIG. 23.

The loss-start-point-calculation will be explained next with reference toFIG. 23.FIG. 24schematically showing a procedure of the loss-start-point-calculation will be referred if necessary. First, the image coordinate of the previously obtained measurement point is input by the control section18a(step SB413a). Details of the first reference curve calculated based on the first reference point are input by the control section18a(step SB413b).

Subsequently, the loss-composing point-calculating section18dupon calculating the two-dimensional distance between the first reference curve and the measurement point (step SB413c) determines as to whether or not the calculated two-dimensional distance is a predetermined value or greater (step SB413d). In a case where the calculated two-dimensional distance is greater than the predetermined value, the loss-composing point-calculating section18dcalculates an edge approximation line that is calculated by approximating the edge of the measurement object (step SB413e). An edge approximation line2411is calculated in a case of, e.g.,FIG. 24where the two-dimensional distance D24between a first reference curve2410and a measurement point2402calculated based on the first reference point2401is the predetermined value or greater.

Subsequently, the loss-composing point-calculating section18dcalculates the cross-point between the first reference curve and the edge approximation line (step SB413f). Accordingly, the cross-point2403between the first reference curve2410and the edge approximation line2411is calculated.

Subsequently, the loss-composing point-calculating section18doutputs the image coordinate of the calculated cross-point to the control section18a. The control section18astores the image coordinate of the cross-point, i.e., the image coordinate of the loss-composing points (loss-start point) in the storage section18g(step SB413g). Subsequently, the procedure moves to a first-measurement-point-calculation described inFIG. 25. Also, the procedure subsequent to the step SB413dmoves to the second-measurement-point-calculation as shown inFIG. 25in a case where the two-dimensional distance calculated in the step SB413cis smaller than the predetermined value.

A procedure of the first-measurement-point-calculation will be explained next with reference toFIG. 25.FIG. 26schematically showing a procedure of the first-measurement-point-calculation will be referred to if necessary. The loss-composing point-calculating section18d, upon carrying out the input of the image coordinate of the previously obtained measurement point by the control section18a(step SB414a), executes a calculation of the characteristic point as shown inFIG. 15and calculates two characteristic points (step SB414b). Accordingly, two characteristic points2601and2602corresponding to the measurement point2600are calculated.

Subsequently, the loss-composing point-calculating section18dcalculates two-dimensional distances between the characteristic point and the two previously obtained measurement points. The characteristic point that is farther from the previously obtained measurement is a next measurement point (step SB414c). The characteristic point2602of the characteristic points2601and2602is a next measurement point2603in a case where the direction indicating the previously obtained measurement point is a direction T22ofFIG. 26.

Subsequently, the loss-composing point-calculating section18ddetermines as to whether or not the image coordinate of the loss-start point is previously stored in the storage section18g(step SB414d). The loss-composing point-calculating section18doutputs the image coordinate of the calculated measurement point to the control section18ain a case where the image coordinate of the loss-start point has been previously stored in the storage section18g. The control section18astores the image coordinate of the measurement point, i.e., the image coordinate of the loss-composing points in the storage section18g(step SB414e). Subsequently, the procedure moves to a loss-end-point-calculation described inFIG. 27. The procedure moves again to the loss-start-point-calculation as shown inFIG. 23in a case where the image coordinate of the loss-start point has not been stored in the storage section18gyet.

The procedure of the loss-end-point-calculation will be explained with reference toFIG. 27. Also,FIG. 28schematically showing the procedure of the loss-end-point-calculation will be referred to if necessary. First, the image coordinate of the previously obtained measurement point is input by the control section18a(step SB415a). Details of the second reference curve calculated based on the second reference point are input by the control section18a(step SB415b).

Subsequently, the loss-composing point-calculating section18dupon calculating the two-dimensional distance between the second reference curve and the measurement point (step SB415c) determines as to whether or not the calculated two-dimensional distance is a predetermined value or smaller (step SB415d). In a case where the calculated two-dimensional distance is the predetermined value or smaller, the loss-composing point-calculating section18dcalculates an edge approximation line that is calculated by approximating the edge of the measurement object (step SB415e). An edge approximation line2811is calculated in a case of, e.g.,FIG. 28where a two-dimensional distance D28between a second reference curve2800and the calculated second measurement point2810calculated based on the second reference point2800is the predetermined value or smaller.

Subsequently, the loss-composing point-calculating section18dcalculates the cross-point between the first reference curve and the edge approximation line (step SB413f). Accordingly, the cross-point2810between the first reference curve2811and the edge approximation line2803is calculated.

Subsequently, the loss-composing point-calculating section18doutputs the image coordinate of the calculated cross-point to the control section18a. The control section18astores the image coordinate of the cross-point, i.e., the image coordinate of the loss-composing points (loss-end point) in the storage section18g(step SB415g). This process finishes the whole procedure of calculating the aforementioned loss-composing points. Also, the procedure moves to the second-measurement-point-calculation again as shown inFIG. 25in a case where the two-dimensional distance calculated in the step SB415cexceeds the predetermined value.

A procedure of calculating the edge approximation line in the step SB413eofFIG. 23and in the step SB415eofFIG. 27will be explained with reference toFIG. 29. The loss-composing point-calculating section18d, upon carrying out an input of the image coordinate of a measurement point (step SG1), extracts a region image in a measurement point region based on the image coordinate of the input measurement point (step SG2).

Subsequently, the loss-composing point-calculating section18dconverts the extracted region image to grayscale (step SG3) and implements edge extraction to the grayscale image (step SG4). Subsequently, the loss-composing point-calculating section18dcalculates the approximation line of the extracted edge (step SG5) and outputs details of the calculated edge approximation line to the control section18a(step SG6).

The processes of the aforementioned steps SG1to SG5are the same as those of the steps SF1to SF5ofFIG. 15.

A method for calculating a matching point in the step SB5ofFIG. 13will be explained next. The loss-composing point-calculating section18dexecutes a process of pattern-matching based on the loss-composing points calculated by the aforementioned loss calculation and calculates the matching point that corresponds to the left-image and right-images. The pattern-matching method is the same as that is disclosed in Japanese Unexamined Patent Application, First Publication No. 2004-49638.

However, sometimes the pattern-matching process does not work and a matching point cannot be calculated in a case where the loss is of corner-type, since the loss-apex point positioned in the background of the measurement object does not have a characteristic pattern, e.g., the edge on the image. Therefore, the present embodiment implements the calculation of the matching point of the loss-apex point as follows in a case where the loss is of corner-type.

As shown inFIG. 30A, first calculated are matching points3021and3022in a right-image3020that correspond to reference points3001and3002in a left-image3000. Subsequently, calculated are reference curves3010and3011passing through the reference points3001and3002respectively and reference curves3030and3031passing through the matching points3021and3022respectively.

Subsequently calculated as a loss-apex point as shown inFIG. 30Bis a cross-point3003between the reference curves3010and3011in the left-image3000. A cross-point3023between the reference curves3030and3031in the right-image3020is calculated and assumed as the matching point of the loss-apex point.

A procedure of calculating loss size in the step SB7ofFIG. 13will be explained next with reference toFIG. 31. The spatial coordinates (three-dimensional coordinates) of the loss-composing points and a loss-identification result are input into the loss size-calculating section18f(step SB71), calculates a loss width (the spatial distance between the loss-start point and the loss-end point) (step SB72).

Subsequently, the loss size-calculating section18fidentifies the loss type based on the loss identification result (step SB73). The loss size-calculating section18fcalculates a loss depth, i.e., a spatial distance between a predetermined loss-composing points and a line connecting the loss-start point to the loss-end point (step SB74) when the loss is of edge type. The loss size-calculating section18ffurthermore calculates a loss area, i.e., a spatial area of a region surrounded by all of the loss-composing points (step SB75).

Subsequently, the loss size-calculating section18foutputs the calculated loss size to the control section18a.

The control section18astores the loss size in the storage section18g(step SB76). Alternatively, the loss size-calculating section18fcalculates a loss side, i.e., a spatial distance between the loss-apex point and the loss-start point and a spatial distance between the loss-apex point and the loss-end point (step SB77) in a case where the loss is of corner type. Subsequently, the procedure moves to step SB75.

A method of displaying a measurement result according to the present embodiment will be explained in next.FIG. 32illustrates a measurement screen prior to starting of a loss measurement. A left-object image is displayed as measurement information in a left-image3200and a right-object image of the measurement object is displayed in a right-image3210. Other details, i.e., except the left-image3200and the right-image3210, of measurement displayed in an upper section of the measurement screen are an optical adapter name information3220; a date and time information3221; icons3223a,3223b,3223c,3223d, and3223e; and a zoom window3224.

Both the optical adapter name information3220and the date and time information3221indicate measurement conditions.

The optical adapter name information3220literally indicates a name of a current used optical adapter. The date and time information3221indicates current date and time literally. The message information3222includes literal information that indicates operational instructions to the user; and literal information that indicates the coordinate of a measurement condition, i.e., reference point.

Icons3223ato3223econstitute an operation menu that allows the user to input operational instructions, e.g., switching of measurement modes, or clearing measurement results. When user operates the remote controller4or the PC31and moves a cursor (not shown) on any one of the icons3223ato3223eand e.g., clicking a cursor, signals that correspond to the operations is input into the measurement-processing section18. The control section18arecognizes the operational instructions input by the user based on the signals and controls the measurement processing. Also, an enlarged image of the measurement object is displayed on the zoom window3224.

FIG. 33illustrates a measurement screen when the loss measurement result is displayed. Picked up image and literal information, etc. in the right-image are hidden behind an result window3300since the result window3300that carries out displaying of measurement result overlaps on the picked up image and various information with respect to the measurement object as illustrated inFIG. 32. This state (first displaying state) is suitable for obtaining a space necessary to display measurement result and to improve visibility of the measurement result.

Operations e.g., clicking of a cursor, not shown in the drawings, and moving the cursor onto the result window3300conducted by the user who maneuvers the remote controller4or the PC31cause the control section18ato control the measurement screen to change to a measurement screen as illustrated inFIG. 34. Transparent state of the result window3400and a hidden state of the measurement result visualize the picked up image and literal information in the right-image that is hidden by the result window3300shown inFIG. 33. Only a frame of the result window3400is displayed.

This state (second displaying state) is suitable for obtaining a space necessary to display measurement result, e.g., a picked-up image and to improve visibility of the measurement result. This allows observing of matching state of the loss-composing points in, e.g., the left-image and the right-images. Operations e.g., clicks conducted by the user who maneuvers the remote controller4or the PC31as illustrated inFIG. 34cause the control section18ato control the measurement screen to change to a measurement screen as shown inFIG. 33.

The measurement screen may be changed to the measurement screen as illustrated inFIG. 35in a case where the user instructs to switch a displayed state of measurement screen as illustrated inFIG. 33. An result window3500as illustrated inFIG. 35is obtained by minimizing an result window and moving a displayed position thereof so as not to prevent from displaying of other information.FIG. 35shows a suitable state of a displayed image having a space necessary to display a measurement result, e.g., a picked-up image with improved visibility of the measurement result. Only one of the result window size and the display position may be changed, i.e., both of them may not have to be changed together unless for preventing from displaying of other information.

The present embodiment that enables measurement of loss size upon designating two reference points can reduce complex operations and improve operability more significantly than in a conventional case where three reference points, or four or more reference points are designated. Also, measurement accuracy in loss size can be improved by calculating a reference curve that is assumed to be a distortion-corrected curve that underwent distortion correction of an image-pickup optical system provided to the distal end of the electronic endoscope.

Determining of loss type based on an angle defined by two reference curves that correspond to two reference points enables automatic measurement according to the determined loss type, thereby reducing complex operations and improving operability. Parameter calculation that indicates loss size based on automatic selection of parameters corresponding to loss type allows the user who is unaware of loss type to conduct optimal automatic measurement, thereby reducing complex operations and improving operability.

Also, a problem that occurs in a conventional endoscope apparatus was lower measurement accuracy in loss size since an edge of an corner loss formed at a corner of a measurement object including an apex of an angle is approximated by a virtual curve and virtual points formed on the curve; and since selecting of the above virtual points that correspond to apices of the corner losses are conducted manually. In contrast, the present embodiment can improve measurement accuracy in loss size since a calculated cross-point between two reference curves that correspond to two reference points is assumed to be a loss-composing point (loss-apex point).

Loss size can be calculated in detail by calculating at least two types of parameters that indicate loss size.

In addition, calculating of at least two characteristic points on an edge of the measurement object and calculating a reference curve based on the calculated characteristic point can improve not only calculation accuracy in reference curve but also measurement accuracy in loss size.

In addition, the present embodiment can obtain the following effect. Conventional endoscope apparatuses had limits in size with respect to display apparatuses and monitors of the display apparatuses since movement of the apparatus must be facilitated in a site which undergoes measurement. Therefore, conventional endoscope apparatuses may be subject to lower visibility since a significant space cannot be obtained to display a picked-up image and measurement result of a measurement object.

In contrast, the present embodiment can obtain a necessary space in view of measurement information and measurement result by switching display states, between the first display state and the second display state, where the first display state displays a measurement result that overlaps on at least a part of measurement information including a picked-up image of a measurement object; the second display state visualizes the measurement information that is overlapped by the measurement result in the first display state. This can improve visibility of the measurement information and the measurement result. In addition to improved visibility, the screen of the display apparatus has a space to display not only a picked-up image of the measurement object but also literal information that indicates measurement conditions, literal information that indicates operational instructions for the user, and an operation menu for use in inputting details of operations.

First Modified Example

Modified examples of the present embodiment will be explained next. First, a first modified example will be explained. A method for calculating a reference curve based on three characteristic points will be explained as follows in contrast to calculating of a reference curve based on two characteristic points as explained above.

As illustrated inFIG. 36, two characteristic points P1and P2in an original image3600are calculated based on positions of a reference point3601and a reference point region3602. Furthermore, a third characteristic point P3is calculated by calculating the nearest point with respect to the reference point3601and the edge of the measurement object. It should be noted that the characteristic point P3in the original image3600is omitted in the drawings.

Converting the original image3600by using the optical data obtains a distortion-corrected image3610. Points P1′P2′ and P3′ are post-conversion points of P1, P2, and P3respectively. Obtaining an approximation line L by calculating a line based on e.g., a least squares method based on the points P1′, P2′, and P3′ and reverse conversion of pixel points on the approximation line L based on optical data causes the approximation line L to be converted into a curve L′ on an original image3620. The curve L′ indicates a distortion-corrected curve that passes through the points P1, P2, and P3.

Calculating a reference curve based on three characteristic points as explained above can improve calculation accuracy in the reference curve. Calculation of a reference curve may be conducted by calculating four or more characteristic points in place of the above case using three characteristic points.

It should be noted that curve approximation using quadratic function may be conducted in contrast to linear approximation conducted with respect to a distortion-corrected characteristic point as explained above. Curve approximation may provide more accurate calculation of characteristic points if the distortion-corrected edge shape is curved rather than straightened.

Second Modified Example

Next, a second modified example will be explained. As previously explained with reference toFIG. 30, a matching point of two reference points is calculated on a right-image when a spatial coordinate of a loss-apex point (three-dimensional coordinate) is calculated; the two reference curves on the right-image are calculated based on the matching point; their cross-points are assumed to be matching points of loss-apex points; and then, a spatial coordinate of the loss-apex point is calculated based on the image coordinate of the matching point. Explained as follows is a method for calculating two three-dimensional lines based on characteristic points calculated based on two reference points, and obtaining a spatial coordinate of the loss-apex point by calculating the cross-point between the two three-dimensional lines.

Characteristic points are first calculated based on two reference points that are designated by the user with respect to an corner loss as illustrated inFIG. 37. The characteristic points P1and P2are calculated based on a reference point3700; and the points P3and P4are calculated based on a reference point3701. Subsequently, matching points P1′ to P4′ of the points P1to P4are calculated, and then, spatial coordinates of the characteristic points P1to P4and the characteristic points P1′ to P4′ are calculated. In the following, a formula (1) obtains a three-dimensional line L that passes through the characteristic points P1and P2where (Plx, Ply) and (Clx, Cly) indicate spatial coordinates of the characteristic points P1and P2. Similarly, a formula (2) obtains a three-dimensional line R that passes through the characteristic points P3and P4where (Prx, Pry) and (Crx, Cry) indicate spatial coordinates of the characteristic points P3and P4.

Subsequently, the cross-point between the two three-dimensional lines L and R is calculated. The present modified example assumes that a most approaching position of the two lines is the cross-point between the two lines since the three-dimensional lines L and R seldom cross each other in fact. Searching of the most approaching point of the two lines is the same as searching of a position where normals of the two lines coincide. That is, a line N that connects a most approaching point Ql on the line L to a most approaching point Qr on the line R is orthogonal to the lines L and R as illustrated inFIG. 38. Therefore, an inner product calculated based on the directional vectors of the lines L and R and the directional vector of the line N is zero. The following formulae (3) and (4) indicate these vectors.
(Plx−Clx,Ply−Cly,Plz−Clz)·(Qlx−Qrx,Qly−Qry,Qlz−Qrz)=0  (3)
(Prx−Crx,Pry−Cry,Prz−Crz)·(Qlx−Qrx,Qly−Qry,Qlz−Qrz)=0  (4)

The following formulae (5) and (6) using the formula (1), the formula (2), and constants s and t, stand effective since the most approaching points Ql and Qr are on the lines L and R respectively.

Subsequently, the spatial coordinates of the most approaching points Ql and Qr are calculated by using the above formulae (1) to (6). First, the formulae (7) and (8) define constants tmp1, tmp2, tmp3, tmp4, tmp5, and tmp6 as follows.
tmp1=Plx−Clx, tmp2=Ply−Cly, tmp3=Plz−Clz,(7)
tmp4=Prx−Crx, tmp5=Pry−Cry, tmp6=Prz−Crz,(8)

Converting the formulae (3) and (4) by using the constants tmp1 to tmp6 obtains formula (3a) and formula (4a) as follows.
(tmp1,tmp2,tmp3)·(Qlx−Qrx,Qly−Qry,Qlz−Qrz)=0  (3a)
(tmp4,tmp5,tmp6)·(Qlx−Qrx,Qly−Qry,Qlz−Qrz)=0  (4a)

Subsequently, converting the formula (3a) and (4a) by using the formulae (5a) and (6a) obtains formula (3b) and (4b) as follows.
(tmp1,tmp2,tmp3)·(tmp1*s−tmp4*t+Clx−Crx,tmp2*s−tmp5*t+Cly−Cry,tmp3*s−tmp6*t+Clz−Crz)=0  (3b)
(tmp4,tmp5,tmp6)·(tmp1*s−tmp4*t+Clx−Crx,tmp2*s−tmp5*t+Cly−Cry,tmp3*s−tmp6*t+Clz−Crz)=0  (4b)

Furthermore, formulae (3c) and (4c) are obtained by rearranging the formulae (3b) and (4b) as follows.

Organizing the formulae (3c) and (4c) by using the formulae (9) to (14) obtains the following formulae (3d) and (4d).
al*s−bl*t+cl=0  (3d)
ar*s−br*t+cr=0  (4d)

The following formulae (15) and (16) stand effective based on the formulae (3d) and (4d).

On the other hand, coordinates of the most approaching points Ql and Qr are indicated by using the formulae (5) to (8) with the following formulae (17) and (18). Substituting the formulae (7) to (18) into the formulae (17) and (18) obtains the coordinates of the most approaching points Ql and Qr.
Qlx=tmp1*s+Clx, Qly=tmp2*s+Cly, Qlz=tmp1*s+Clz,(17)
Qrx=tmp4*t+Crx, Qry=tmp5*t+Cry, Qrz=tmp6*t+Crz,(18)

Finally, the following formula (19) indicates the spatial coordinate of the loss-apex point by assuming that the midpoint between the most approaching points Ql and Qr is the cross-point between the lines L and R. Similarly to the above method, the spatial coordinate of the loss-apex point in the right-image can be calculated based on the spatial coordinates of the characteristic points P1′ to P4′.

Third Modified Example

Next, a third modified example will be explained. The previous explanations are based on assumption that the selected reference points free of a loss are positioned across a loss. However, sometimes the points on the edge free from a loss are difficult to be selected as reference points in a case where the loss is disposed near an end of the picked up image. A method for implementing loss measurement based on a loss end point as a reference point will be explained as follows.

As illustrated inFIG. 39, reference points3900and3901designated by the user are two end points of the loss. The reference point3900is located at the cross-point between an edge3910of the measurement object near the loss and an edge3911of the loss. Also, the reference point3901is located at the cross-point between an edge3912of the measurement object near the loss and an edge3913of the loss.

The characteristic points for use in calculating the reference curves in the loss calculation are searched from the reference point3900in a direction T39aand from the reference point3901in a direction T39a. The characteristic points for use in calculating the loss-composing points are searched from the reference point3900in a direction T39cand from the reference point3901in a direction T39d. The directions T39a, T39b, T39c, and T39dcan be distinguished based on correlation of the reference points3900and3901with characteristic points or measurement points.

Calculation of the characteristic points finishes when the necessary number of characteristic points are calculated. In addition, as far as calculation of the measurement points is concerned, the calculation of the measurement points finishes when the two-dimensional distance between a measurement point searched from the reference point3900and a measurement point searched from the reference point3901is a predetermined value or smaller after starting search of measurement points from the reference point3900and the reference point3901.

As previously explained, loss measurement can be conducted regardless of the position of a loss in a picked up image as long as the full image of the loss is picked up since the end point of the loss can be designated as a reference point. In addition, complex operations can be reduced and operability can be improved since it is not necessary to change an image-pickup position to pick up another image to designate a reference point.

Fourth Modified Example

Next, a fourth modified example will be explained. Measurement objects in the fourth modified example are, burning (scorching) formed on a blade surface, peeling of paint, or rust in a pipe, etc., in contrast to the aforementioned explanations concerning the primary object of specifying losses formed on a turbine blade edge or a compressor blade edge.

For example, a compressor blade4000shown inFIG. 40Ahas a loss4010formed on an edge and a burning4020on the surface thereof.FIG. 40Bshows an enlarged view of the loss4010, andFIG. 40Cshows an enlarged view of the burning4020. The loss4010has an edge on a single side relative to a line4013connecting the end points4011and4012. In contrast, the burning4020has two edges relative to a line4023connecting arbitrary points4021, and4022on an outline (edge) around the burning4020.

A method for conducting loss measurement will be explained with reference toFIGS. 41A to 41Eas follows with respect to a measurement object that has edges on both sides of a line connecting two arbitrary points on the measurement object. First, the user designates two arbitrary reference points4110and4111on an edge of the burning4100as illustrated inFIG. 41A. Sequential search subsequently conducted to the points between the two designated reference points positioned on the edge provides loss-composing points (measurement points) as aforementioned in the first embodiment. Subsequently, the loss-composing points are searched in two directions indicated by arrows4120and4121from the reference point4110to the reference point4111as illustrated inFIG. 41B. The reference points4110and4111are just registered for a loss-start point and a loss-end point respectively in the present modified example, which does not calculate a reference curve.

The searching of the loss-composing points is completed upon obtaining the predetermined or shorter two-dimensional distance between the loss-composing points and the reference point4111that have undergone the searching.FIG. 41Cillustrates the search of loss-composing points is completed. Subsequently, matching points corresponding to the extracted loss-composing points are calculated, and a spatial coordinate of each point is calculated. The size of the burning4100is calculated based on the spatial coordinate of each calculated point. The size of the calculated burning4100is indicated by an area and widths4130and4131and circumferential length4132of the burning4100as illustrated inFIG. 41D.

The width4130is a spatial distance between the reference points4110and4111. The width4131is a spatial distance between the loss-composing points4112and4113that are the most distant in a lateral direction from a line that joins the reference points4110and4111. The circumferential length4132is a sum of spatial distances between the two adjoining loss-composing points. The area indicates a spatial area of a region surrounded by all of the loss-composing points. The measurement screen, upon obtaining the calculated size of the burning4100, displays the result window4140that indicates the measurement result as illustrated inFIG. 41E. Loss measurement is practicable to burning as explained previously.

Another Modified Example

Another modified example of the present embodiment will be explained next. Measurement objects in an modified example of the present invention are, burning (scorching) formed on a blade surface, peeling of paint, or rust in a pipe etc., in contrast to the aforementioned explanations concerning the primary object of specifying losses formed on a turbine blade edge or a compressor blade edge.

For example, a compressor blade4000shown inFIG. 40Ahas a loss4010formed on an edge and a burning4020on the surface thereof.FIG. 40Bshows an enlarged view of the loss4010, andFIG. 40Cshows an enlarged view of the burning4020. The loss4010has an edge on a single side relative to a line4013connecting the end points4011and4012. In contrast, the burning4020has two edges relative to a line4023connecting arbitrary points4021, and4022on an outline (edge) around the burning4020.

A method for conducting loss measurement will be explained with reference toFIGS. 41A to 41Eas follows with respect to a measurement object that has edges on both sides of a line connecting two arbitrary points on the measurement object. First, the user designates two arbitrary reference points4110and4111on an edge of the burning4100as illustrated inFIG. 41A. Sequential search subsequently conducted to the points between the two designated reference points positioned on the edge obtains loss-composing points (measurement points) as explained in the aforementioned embodiments. Subsequently, the loss-composing points undergo the searching in two directions indicated by arrows4120and4121from the reference point4110to the reference point4111as illustrated inFIG. 41B. The reference points4110and4111are just stored as a loss-start point and a loss-end point respectively in the fourth modified example, which does not calculate a reference curve.

The searching of the loss-composing points finishes upon obtaining the predetermined or shorter two-dimensional distance between the loss-composing points and the reference point4111that have undergone the searching.FIG. 41Cillustrates the search of loss-composing points are completed. Subsequently, matching points corresponding to the extracted loss-composing points are calculated, and a spatial coordinate of each point is calculated. The size of the burning4100is calculated based on the spatial coordinate of each calculated point. The size of the calculated burning4100is indicated by an area based on the product of widths4130and4131and circumferential length4132of the burning4100as illustrated inFIG. 41D.

The width4130is a spatial distance between the reference points4110and4111. The width4131is a spatial distance between the loss-composing points4112and4113that are the most distant in a lateral direction from a line that joins the reference points4110and4111. The circumferential length4132is a sum of the spatial distances between the two adjoining loss-composing points. The area indicates a spatial area of a region surrounded by all of the loss-composing points. The measurement screen, upon obtaining the calculated size of the burning4100, displays the result window4140that indicates the measurement result as illustrated inFIG. 41E. Loss measurement is practicable to burning as explained previously.

Designating a point on an edge in the present embodiment enables detection and measurement of a burning.

A method for measuring a burning in the present embodiment will be explained as follows.

First, a reference point is designated on an edge of a burning as illustrated inFIG. 42A.

Subsequently, the loss-composing points are searched in a clockwise direction from the reference point as illustrated inFIG. 42B. The sequential search may be conducted in a counter-clockwise direction in this case.

The searching terminates upon obtaining a predetermined two-dimensional distance or shorter between the searched loss-composing point and the reference point as illustrated inFIG. 42C.

A process of pattern-matching is based on the extracted loss-composing points as illustrated inFIG. 42D, and then three-dimensional width7001, width7002, circumferential length4132, and area of the burning are calculated.

This state of width7001indicates the three-dimensional distance between the reference point and the loss-composing point P7001having the longest two-dimensional distance from the reference point.

In addition, the width7002indicates the three-dimensional distance between the loss-composing points P7002and P7003that are the most distant in a lateral direction from a line that joins the reference point and the aforementioned loss-composing points P7001.

The process terminates upon displaying the calculated measurement result on the measurement screen as illustrated inFIG. 42E.

The embodiments and modified examples of the present invention have been explained above in detail with reference to the drawings. However, it should be understood that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed; thus, the invention disclosed herein is capable of having various modifications and alternative forms, i.e., design changes.