GB2469436A

GB2469436A - Method and apparatus for generating and storing graph representation data

Info

Publication number: GB2469436A
Application number: GB0901992A
Authority: GB
Inventors: Mark Boyes; Mikolaj Romanowski
Original assignee: INZPIRE Ltd
Current assignee: INZPIRE LIMITED
Priority date: 2009-02-09
Filing date: 2009-02-09
Publication date: 2010-10-20
Also published as: GB0901992D0

Abstract

A method, apparatus and user interface for generating and storing graph representation data comprising receiving guide image data 402 representative of a graphical image, generating graph representation data 404,406 representative of a plurality of graph parameters and values derived from the graphical image, and storing the graph type data and graph value data as electronic graph data 408 for subsequent use in performing a function corresponding to a function illustrated by the graphical image. The step of generating the data 404,406 may be responsive to user input representing values corresponding to the graph parameters. The user may manipulate the guide image data or graph data, by stretching a sub-section of the graph, to adjust how the data is displayed. Receiving the image 402 may involve scanning a hard paper copy of the graph or downloading the graph over a network. Data for first and second graphs may be generated and stored, where the output of the first graph provides the input values for the second graph. To check the accuracy of the results, safety checks such as reverse verification calculations or a known results check, may be performed periodically or before and after a user-instigated function.

Description

METHOD AND APPARATUS FOR GENERATING AND STORING GRAPH

REPRESENTATION DATA

Technical Field

The present disclosure relates to the field of methods and apparatus for generaUng and storing graph representation data, and in particular, but not necessary to methods and apparatus that are capable of digitally simulating the application of graphical data received as an image.

Background

It is known in the aviabon industry for a human operator to manually use one or more graphs to determme safety critical information such as minimum speed for take-off.

Calculating such information takes into account a number of parameters including, for example, the weight of the aircraft, air temperature, air pressure, etc. Currently, the human operator will use a pencil and a ruler to manually draw lines on physical paper graphs to determine outputs for the known input values. In some scenarios, it may be necessary to take the output of one graph as an input to a subsequent graph in order to generate the final desired output value from the second graph.

Although some automated systems for performing such calculations have been proposed in the past, the element of risk that the calculations will not be applied properly is not considered acceptable, and therefore the only approved way of performing calculations based on such graphs is to have the user manually apply the inputs in order to read output values from the graphs, as discussed above.

In some embodiments, the data that is represented by a graph may be available as one or more mathematical formulae, and may be considered as source data. However, use of such source data is not generally accepted because it is difficult to spot any anomalies in the data, which would otherwise have been identified in graphical form. Again, the associated risks are deemed unacceptable in safety critical systems.

The listing or discussion of a prior-published document or any background in this specification should not necessarily be taken as an acknowledgement that the document or background is part of the state of the art or is common general knowledge. One or more aspects/embodiments of the present disdosure may or may not address one or

more of the background issues.

Summary

According to a first aspect, there is provided a method of generating graph representation data, corn prising: receiving guide image data representative of a graphica' image; and generating graph representation data representative of a plurality of graph parameters and values derived from the graphical image.

The method may also comprise storing the graph representation data for subsequent use in performing a function corresponding to a function illustrated by the graphical image.

The above method can enable image data to be converted into a format that can be used to perform one or more calculations that are represented by the graphical image that could not have been performed directly from the guide image data. An embodiment of the invention may be considered as digitising information encoded in a guide image for subsequent use in performing calculations electronically.

The step of generating graph representation data may be responsive to user input, for example user input may be provided that represents one or more manipulation operations that are used to set values associated with parameters for a specific type of graph. Alternatively, the values may be automatically set in accordance with an image processing operation.

The graph representation data may comprise one or more of the number of major and minor grid squares on the X and Y axis, titles/labels for X and Y axis, the scale and range of values for the X and Y axis, and also how the current graph representation is inked to any adjacent graph representations.

User input may represent one or more va'ues corresponding to a plurality of graph parameters.

The method may further comprise enabling user manipulation of the guide image data and/or graph representation data in order for a display of the guide image data and a display of the graph representation data to be adjusted, and optionally to be made coincident, or at least to be brought closer together.

Manipulation of the guide image data may comprise stretching a subsection of the graphical image. This can enable any inaccuracies in the guide image data to be accounted for so that a display of the guide image data and the graph representation data can be made coincident. This can be particularly advantageous where it is not possible to obtain accurate guide image data, for example by scanning in a page of a book, for which it is not possible to get the page of the book flat on the glass window of a flatbed scanner.

The method may further comprise: generating and storing first and second graph representation data for a first and second graphical image respectively; and associating the first graph representation data representative of the first graphical image with the second graph representation data representative of the second graphical image, such that one or more output values of the first graph representation data are provided as one or more input values to the second graph representation data.

The step of receiving guide image data may comprise scanning in a hard copy of a graphical image or downloading the guide image data from an externa' device over a network, such as the internet. These are examples of how an input file can be received that contains the guide image data in a graphical image format such as TIFF, PDF, GIF, JPG, BMP or any other suitable file format.

The method may further comprise storing an association between the guide image data and the graph representation data, and in some embodiments, more than one set of graph representation data can be associated with the same guide image data. For example, this may be appropriate if similar graph representation data is used for different overall calculations, such as in combination with other graphs in different ways.

The method may further comprise performing a function on one or more input values using the graph representation data in order to generate one or more output va'ues.

The input va'ues may correspond to one or more values for which the correct result is known, and the method may further comprise comparing the one or more output values with the correct result in order to identify any discrepancies.

One or more verfficaton checks/procedures may be performed penodically, and/or before andlor after a user-instigated calculation.

The method may further comprise providing the generated one or more output values as one or more reverse inputs to the function, performing the function in reverse in order to generate one or more reverse outputs, and comparing the one or more reverse outputs with the one or more inputs in order to identify any discrepancies.

One or more methods of identifying discrepancies may involve calculating a percentage error, and comparing it with a threshold value to determine if a required accuracy is achieved.

The method may further comprise displaying a graphical representation of the interaction between the graph representation data and the input and output values. The graphical representation may include a display of the graphical representation data in a format that is similar to the guide image on which it is based, with the input and output values identified thereon. The graphical representation may also include an identification of the location at which the one or more input values meet one or more curves, which may be contours, represented by the graph representation data The method may also comprise disp'aying the guide image and/or a representation of the graph representation data, in combination with the graphical representation of the interaction between the graph representation data and the input and output values.

According to a further aspect of the invention, there is provided an apparatus comprising: a receiver configured to receiving guide image data representative of a graphical image; a processor configured to generate graph representation data representative of a plurality of graph parameters and values derived from the graphical image; and computer memory configured to store the graph representation data for subsequent use in performing a function corresponding to a function illustrated by the graphical image.

According to a further aspect of the invention, there is provided a user interface having a display and one or more user inputs, the user interface configured to: receive guide image data representative of a graphical image; generate graph representation data representative of a pluraUty of graph parameters and values denved from the graphical image n response to user input; and store the graph representation data for subsequent use in performing a function corresponding to a function iUustrated by the graphical image.

The user interface may be configured to perform a function on one or more input values received at the user inputs using the graph representation data to generate and display one or more output values.

The user interface may be further configured to display a graphical representation of the interaction between the graph representation data and the input and output values.

According to a further aspect of the invention, there is provided a computer program configured to perform any method disclosed herein, or to configure any apparatus disc'osed herein, or to provide any user interface disclosed herein.

The computer program may be stored on a data carrier, such as a disc, or may be embodied on a transient carrier such as a signal, for example as a network down'oad, including an Internet download.

The present disclosure includes one or more corresponding aspects, embodiments or features in isolation or in various combinations whether or not specifically stated (including claims) in that combination or in isolation. Corresponding means for performing one or more of the discussed functions are also within the present disclosure.

The above summary is intended to be merely exemplary and non-limiting.

Brief Description of the Figures

A description is now given, by way of example only, with reference to the accompanying drawings, in which: Figures la and lb iUustrate example graphs that can be used with embodiments of the present invention; Figures 2a and 2b illustrate an electronic device according to an embodiment of the present invention; Figures 3a to 3i illustrate user interfaces according to embodiments of the present invention; Figure 4 ifiustrates schematicay a method according to an embodiment of the present invention; Figures 5a and 5b ifiustrate user interfaces according to embodiments of the present invention; Figure 6 illustrates a user interface according to an embodiment of the present invention; Figure 7 illustrates a user interface according to an embodiment of the present invention; Figure 8 illustrates a user interface according to an embodiment of the present invention; Figure 9 illustrates schematically a reverse verification operation according to an embodiment of the present invention; Figure 10 illustrates schematical'y a "known results check" operation according to an embodiment of the present invention; and Figures ha to hlj illustrate schematically class diagrams according to embodiments of the invention.

Description of Specific Aspects/Embodiments

One or more embodiments described herein may involve converting an image file that represents a graphical function into graph representation data, wherein the graph representation data is in a format that is usable for performing the function on one or more received input values. The image file may not be capable of being used for performing calculations/functions, and may be a jpeg or bitmap file, for example.

An embodiment described herein may provide the abiUty to electronically perform calculations represented by graphical image data with an acceptable degree of confidence, that otherwise were only possib'e by a human user physically inspecting a graph on a piece of paper, or were not possible at all. Embodiments herein can involve receiving data representative of a guide image that illustrates graphica' data, and generating/selecting graph representation data that corresponds to information that is represented by the graphical image, for examp'e graph parameters and values.

The graph representation data can be used to perform calculations/functions on input values received at a user interface, wherein the calculations/functions correspond to a function illustrated by the graphical image.

In this way, the graph representation data can be used by a computer to perform calculations represented by the image of the graph in an efficient manner. Furthermore, embodiments described herein can be particularly advantageous for safety critical systems, because elements of self-checking and verification of any calculations that are performed can be available. In addition, a user may be able to inspect visually/graphically the application of the graph representation data in order to verify that a graph has been applied properly, and it may be relatively easy to identify any errors in the application of the graph representation data.

Further advantages can be provided as it may be possible to efficiently vary one or more input values, and determine the effect on one or more outputs in real-time. This may not be possible with the current state of the art where human inspection of one or more graphs is required for each individual calculation.

Figures la and lb illustrate example graphs 100, 102 that are used in the aviation industry. Although some of the axis headings and values have been omitted from the graphs 100, 102, it can be seen that such graphs can comprise an X and a Y axis, along with one or more contour lines that represent functions of two variables (the parameters represented by the X and Y axis) along which the function has a constant value. In the example of Figure ib, a first set of contour lines 104 represent values on the X and Y axis that have the same pressure altitude, and a second set of contour lines 106 represent X and Y values that have the same temperature.

As can be seen from the graphical representation 108 in the top right-hand corner of Figure Ib, an input value on the Y axis is provided, which is manipulated in accordance with the known values representing the contour functions 104, 106 (pressure altitude and temperature) such that an output value can be read out from the X axis. The graphical representation panel 108 provides instructions on how to use the graph 102.

It will be appreciated that calculation of the output value is prone to human error in reading values from the graph 102, and also manually performing any interpolation between contour lines 104, 106 and or sub-divisions of the grid for the X and/or Y axis.

In safety critical systems, this human error may be deemed acceptable as it is considered preferable to utilising any mathematical source data, whereby any anomalies/errors can be easily overlooked.

Figure 2a illustrates an electronic device 200 according to an embodiment of the invention. The electronic device 200 comprises a processor 202, computer memory 204, a display device 208 and one or more input/output devices 206, all of which are connected to a data bus 210. The processor 202 is configured to perform one or more application programs as will be discussed in more detail below.

The electronic device 200 may be a conventional personal computer (PC), a laptop computer, or may be a handheld computing device such as a personal digital assistant (PDA), which can enable the functionality described herein to be portable. This may provide advantages in the aviation industry as it can allow calculations to be performed in light of changing circumstances, for example failure of an engine, as required. It will be appreciated that one or more of the components of the electronic device 200 may be provided locally or may be distributed over a plurality of electronic devices, such as over a network.

The memory 204 has electronic data stored thereon, including guide image data 212 and graph representation data 214. The guide image data 212 is representative of a guide image that contains graphical image data such as that illustrated in Figures la and lb. The guide image data 212 may be received by the electronic device 200 when a graph is scanned in using a conventional flatbed scanner, or may otherwise be obtained from a computer network, such as downloading from the internet. It will be appreciated that the guide image data 212 does not represent any mathematical calculations illustrated by the graphical data and in some embodiments can be a jpeg or bitmap data file, for example.

The graph representation data 214 can be generated according to an embodiment of the invention, and is discussed in detail in relation to Figure 3 below. The graph representation data 214 represents one or more parameters that provide a model of the image represented by the guide image data 212, and the parameters can be used by the electronic device 200 to apply a function represented by the graph illustrated in the guide image data 212 as is described in more detail below in relation to Figures 5 to 8.

Example data structures of the guide image data 212 and graph representation data 214 are illustrated in Figure 2b. In this example, the guide image data 212 comprises a plurality of pixel values that can be used to display the guide image on the display 208. It wlI be appreciated that the pxeI values cannot be used duectly for performmg one or more functions represented by the graphical images.

In contrast, the graph representation data 214 comprises a plurality of parameters that can have values attributed to them, and that together define a function/operation defined by the graph that is illustrated in the guide image. In this embodiment, values for the plurality of parameters are stored in such a way that the graphical representation can be conveniently illustrated on the display 208. A non-limiting example of the plurality of parameters includes: graph type, X axis range, Y axis range, X axis resolution, Y axis resolution, number of contours, coordinates of contours, input parameters, output parameters, title, X axis heading, Y axis heading, inks to associated graphs, etc. In this embodiment, the contours are stored as a set of coordinates, and appropriate mathematical formulae are created dynamically based on the set of contour coordinates as and when required to perform a calculation. In other embodiments, one or more mathematical formulae may be stored instead of, or as well as, the coordinates of contours parameter. It will be appreciated that one or more of the parameters may not have values associated with them depending upon the type of graph being used, and that the type of graph" parameter may define further parameters still, such as the number of sets of contour lines and their orientation, number and orientation of baselines, etc. It will be appreciated that the data structure of the guide image data 212 does not enable any calculations to be performed with that data, whereas the data structure of the graph representation data 214 enables calculations to be performed and can also be in a format that is easy for a user to interact with when manually setting the values of the graph representation data 214, an example of which is illustrated in Figure 3. The graph representation data 214 can also be easy to display to a user.

Embodiments of the invention can include converting the guide image data 212 into the graph representation data 214, and/or using the graph representation data 214 to perform the one or more functions, and/or using the guide image data 212 and graph representation data 214 in combination to automatically or manually verify the results when performing the one or more functions.

According to this embodiment of the invention, the processor 202 is configured to generate graph representation data 214 representative of the image represented by the guide image data 212. User nput is provided to ensure that the generated graph representation data 214 correctly represents the graph of the guide image data 212, although in other embodiments the generation of the graph representation data 214 may be automated or semi-automated as will be discussed below.

In this example, the processor 202 is configured to run a "graph representation data generation" application program in order to provide a user with the capability to interact with the input/output devices 206 and display 208 in order for the electronic graph data representative of the graphical image to be generated. An example of one or more user interfaces that can be displayed to a user when the "graph representation data generation" application is run is illustrated as Figure 3, and can be activated by a user selecting an "Edit Graph.. ." or "Graph Type..." option, as will be discussed in relation to Figure 3a.

After the electronic graph data has been generated by the electronic graph generation application program, a user can interact with a user interface to provide input values for one or more parameters that correspond to input values for the one or more graphs represented by the electronic graph data. Once the input values have been provided, a user can cause output values to be generated by activating a "calculate application program" for example by clicking the "calculate" button 506 in Figure 5a. Such example user interfaces are illustrated as Figures 5, 7 and 8.

It will be appreciated that different users may have different privileges for using one or more user interfaces described herein. For example, every user may have access to the "calculation application program" in order to perform calculations, whereas only administrators may have access to the "graph representation data generation" application program. In addition, only administrators may be able to set constant values or limits that are associated with the system. Examples of limits that can be set include threshold values, which if exceeded cause error message to be displayed to a user. This can be particularly advantageous in embodiments where safety critical parameters are exceeded. An example of a safety critical parameter is a tyre temperature of an aircraft.

An embodiment of a user interface that can be used for generation of the graph representation data 214 is shown as Figures 3a to 3i. The user interface may be used to perform the "graph representation data generation" application program described above.

Figure 3a illustrates a user interface 300 that a user can interact with to add one or more graphs, and build relationships between the graphs so that the output values from one graph can be fed into a subsequent graph as input values as appropriate. Initially, three boxes 302, 302'. 302" are il'ustrated, each of which can be configured with graph representation data representing a calculation illustrated by guide image data. As can be seen from Figure 3a, a user can click on one of the boxes 302, 302'. 302" to display a number of options, that can provide the functionality to add an additional graph in any orientation to the s&ected graph!square 302, 302'. 302", for example, above, to the right or to the eft; delete a graph; edit graph data; and adjust the graph type. Some of these options are described in more detail below.

If a user selects the "Graph Type option, then the user interlace illustrated by Figure 3b is displayed to the user. Figure 3b shows a non-limiting example of different graph types that can be seected according to embodiments of the invention. The different graph types can have no base lines, vertical base lines, horizontal base lines or be single contour graphs. In addition, the graphs may have vertical contours, horizontal contours, two sets of vertical contours, two sets of horizontal contours, or both vertical and horizonta contours. It will be appreciated that any number of contours in any direction, any number of base lines in any orientation, and any number of inputs and outputs in any orientation could be provided according to an embodiment of the invention.

In this embodiment, the user selects the graph type that corresponds to the guide image data that they are attempting to simulate. It will be appreciated that in other embodiments, image processing software may be used to process the image data and determine which of the graph types is appropriate. This may be considered as an automatic or semi-automatic selection as no, or limited, user input may be required.

Selecting the graph type may cause a tempate of graph representation data that corresponds to the selected graph type to be stored in memory as a new data file that can be manipulated in order to provide the required parameters and values in order to fully represent a function illustrated by the guide image data. Exampe manipulation operations are described in relation to Figures 3c to 3i.

In other embodiments, the template of the graph representation data for the selected graph type may be usabe in combination with a separate data file that contains value and parameter information, such that together they can be considered as graph representation data that can be used to perform one or more calculations in accordance with the one or more functions represented by the guide image data.

Once a graph type has been set, the user can edit the graph by selecting the "edit graph..." option illustrated in Figure 3a. When this option is se'ected, the edit graph user interface 303 illustrated in Figure 3c is displayed to the user, and in this embodiment is provided to a user in order to receive graph value data that wilt be associated with the parameters that are appropriate for the selected graph type, and stored as graph representation data.

When the edit graph user interface 303 is first opened, it displays a representation 304 of the generic graph type that has been selected -the representation 304 is a graphical i'lustration of the current graph representation data. In order for the user to be able to modify the representation 304 such that it corresponds to a guide image, they can select "guide image" option 308 such that the guide image 306 is overlaid on the representation 304. It is then possible for the user to move and re-size the guide image 306 such that its region of interest, which may be the entire guide image 306, corresponds with the limits of the graph representation 304. A number of options relating to the guide image are shown in panel 310 of the user interface 303, and include the ability for a user to control whether or not the guide image is displayed, the brightness of the guide image, which elements of the graph representation 304 are shown, for example the grid/base line, contours, and input/output. In addition, the user is a'so presented with the option of opening a new guide image or clearing the current guide image 306.

A panel 311 in the user interface 303 is provided so that a user can select whether to edit properties of the guide image, or properties of the representation 304 such as contour lines can be edited by interacting with the guide image 306 and/or the graph representation 304.

A further panel 312 in the user interface 303 is provided for manipu'ating properties of the graph representation 304. Examples of parameters that can be adjusted include the number of major and minor grid squares on the X and Y axis, titles/labels for X and Y axis, the scale and range of values for the X and Y axis, and also how the current graph representation 304 is linked to any adjacent graph representations. An examp'e of the layout of adjacent graph representations is illustrated in Figure 3a with reference to boxes 302, 302'. 302" that show three vertically arranged adjacent graphs.

It will be appreciated that an association between the graphical representation data 304 and the guide image data 306 can be stored in computer memory. For example, the association between graphical representation data 304 and the guide image data 306 can be stored in a database or a look-up-table, for example. In this way, it can be possible to display information representative of both sets of data at the same time, such as by selecting the "0DM Graph.. ." button 516, 566 in Figure 5a and 5b.

Figure 3d illustrates the "edit graph" user interface of Figure 3c, but with the guide image 316 re-sized to be coincident with the graph representation 314.

As can be seen from the panel 311' in the top right-hand side of the user interface 303', the user has selected to edit the blue contours of the graph representation 304, as opposed to editing the guide image as was selected in the example of the user interface 303 shown in Figure 3c.

The contours of the graph representation 314 are shown as unbroken lines 318, and the corresponding contour lines of the guide image 316 are shown as dashed lines 320. As can be seen from Figure 3d, initially the contour lines 318 of the graph representation 314 do not exactly correspond with the guide image contour lines 320. The user can use well-known graphical editing techniques to move and/or re-size and/or re-shape one or more of the graph representation contour lines 318 such that they correspond with the guide image contour lines 320.

An example of how a contour line 320' can be edited is shown in Figure 3e. In this example, a contour line 320' can be selected for editing, and the editing can include adding points along the contour line 320', editing points, deleting points, changing a point from a smooth to a corner point and vice versa, and/or setting the exact coordinates of a point on the contour line 320' in terms of the X and Y axis. The location of the points along the contour line may be stored as the contour coordinates in the graph representation data. It will be appreciated that this is a non-limiting example of how one or more parameters of the digital graphical image 314 can be amended.

In this example, the user can choose to adjust all digital graphical image contour lines 320 at the same time with the same manipulation operation, such as dragging a point on a contour line 320' in order to provide a curve in the contour line 320', or adjust only a subset of the contour lines 320 with the same manipulation operation, and can also manipulate a single contour line 320 as appropriate.

In some embothments, a user may be ab'e to initiate a "snap-to nearest contour line" application, in order for the electronic device to automaticaHy manipulate the contour lines 320 of the graph representation to the nearest contour lines of the guide image.

The application may use one or more known image processing operations to perform this operation.

In further embodiments still, image processing operations may be used to determine a graph type illustrated in the guide image, automatically attribute an appropriate graph type and thereby generate the template graph representation data for the appropriate graph type. In addition, image processing operations may be used to determine the scale and resolution of the axes of the graph, how many contour lines are present, the relative location of the contour lines, and any further parameters of the graph represented by the guide image that are required in order to reproduce the graph represented by the guide image. In such embodiments, complete graph representation data representative of a graph illustrated in the guide image may be automatically generated.

Figure 3f illustrates the edit graph user interface wherein the graph representation contour lines have been adjusted so that they exactly correspond with the underlying contour lines of the guide image. n some embodiments, it may be possible for a user to move a cursor over the graph representation in order for the undedying coordinates to be displayed to a user as a check that they have composed the graph representation correctly. An example of this functionality is iUustrated in Figure 6.

Figure 3g illustrates a user interface that is similar to that illustrated in Figure 3a, but wherein a first graph 330 has now been set up, for example through use of the user interfaces iUustrated in Figures 3b to 3f. The user can then move on to a second graph 332 if required, which has a relationship with the first graph 330 in order to perform the desired overall calculation. It will be appreciated that any number of graphs 330, 332 can be associated in any configuration, and with any suitable r&ationship between each other.

Figure 3h illustrates additional functionality that can be provided by an "edit graph" user interface 340 according to an embodiment of the invention. This embodiment can enable inaccuracies in the guide image 342 to be accounted for, such that an accurate graph representation can be constructed and hence accurate graph representation data can be generated.

The guide image 342 iUustrated in Figure 3h is distorted as it was scanned in from a page in a book, and it was not possible to place the page flat on the flatbed glass window of a scanner when generating the electronic guide image data. Because of this, the left-hand side and the bottom of the guide image 342 are distorted.

In order for a user to account for this distortion, they can add one or more horizontal or vertical stretch lines to the guide image 342. In the example of Figure 3h, four vertical stretch lines 346 and one horizontal stretch line 348 are illustrated. The user can locate the stretch lines using the interface illustrated as reference 344 in Figure 3h.

After the stretch lines 346, 348 have been placed, either a stretch line 346, 348 or a boundary of the guide image 342 can be dragged either side-to-side or up-and-down by a user in order to "stretch" the image between adjacent stretch lines, or between a stretch line and the boundary of the guide image 342.

Image stretch processing is performed by effectively dividing the original image into rectangles by a user placing one or more stretch lines 346, 348 over the image, such that the stretch lines 346, 348, and a boundary of the image where appropriate, form the borders of the rectangles. In the example of Figure 3h, the guide image 342 has been effectively divided into ten rectangles by the placement of four vertical stretch lines 346 and one horizontal stretch line 348. The two left-most rectangles are beyond the edge of the graph and therefore contain mostly white pixels.

The stretch function works by comparing the original placement of a rectangle (for example rectangle 352 in Figure 3h) to the stretched placement of the rectangle (for example rectangle 352' in Figure 3i), and linearly interpolating the pixel values for pixels contained in the original rectangle 352 to generate pixel values that can be applied to the pixels of the new rectangle 352'. In this example, the top right rectangle 352, 352' in guide image 342 has been shrunk in the horizontal dimension and expanded in the vertical dimension.

Figure 3i illustrates the guide image data 342 of Figure 3h after a stretching operation. In this example, the vertical stretch lines 346 have been dragged to the left to stretch the areas of the left-hand side of the guide image and remove the associated distortions.

Also, the bottom boundary 350 of the guide image 342' has been dragged downwards in order to stretch the region of the image bounded by the horizontal stretch line 348, the bottom boundary 350 and the sides of the image, thereby removing the distortion at the bottom of the guide image 342'.

Figure 4 illustrates schematically a method of generating graph representation data according to an embodiment of the invention.

The method begins at step 402 by receiving guide image data. The guide image data may be in a known image format such as jpeg or bitmap, and may be received by scanning a paper copy of a graph or by downloading an image from the internet. The guide image data represents a graphical image.

At step 404, graph type data is generated, and may comprise default values for a plurality of parameters associated with the graph type. The graph type data may be generated automatically or semi-automatically by performing image processing on the received guide image. Alternatively, user input may be received in relation to which of a plurality of graph types is appropriate for the guide image.

At step 406, graph value data is generated. Again, the graph value data may be generated automatically, semi-automatically or in direct response to user input. In any case, the graph value data defines the values for the parameters of the specific graph type that has been generated at step 404. For example, the resolution and scale of the axes of the graph; and one or more functions that are illustrated on the graph, which may include one or more sets of contour lines; may be represented by the graph value data.

In addition, one or more optional parameters associated with the graph type may also be generated as part of the graph value data, and can include axes labels/headings, titles, legends, etc. The optional parameters may not be essential for performing the function defined by the graph, although may render the graph value data more understandable to a user, particularly during a verification operation.

The graph value data may be generated in response to a user manipulating one or more characteristics of a "standard' graph type, for example by manipulating any functions that are provided for the graph type that has been generated, and in some embodiments this manipulation may be made through use of a user interface such as that illustrated as Figure 3.

The graph type data and graph value data may be considered together as graph representation data.

At step 408, the graph type data and graph value data are stored together as graph representation data. The graph representation data can be used for subsequent calculations. In some embodiments, the graph representation data may represent one or more mathematical formulae that represent functions for the generated graph type.

Alternatively, or additionally, the graph representation data can represent a sequence of coordinates that correspond to the function/equation lines that have been generated as part of the graph value data, without necessarily calculating a corresponding mathematical function for the line. Either way, the electronic graph representation data can be interpolated for any specific subsequent calculations that are required.

In embodiments where the electronic graph representation data represents both mathematical formulae and coordinate data, the mathematical formulae can be used to efficiently and economically perform the subsequent calculations, and the coordinate data can be used to graphically illustrate the results of the subsequent calculation in a way that is readily understandable by an end user. This can take advantage of the fact that any anomalies may be more readily apparent in the graphical data than in a mathematical formula, and the benefits of performing calculations directly using the mathematical formulae can still be retained.

In one embodiment, "graph representation data" consists of one or more of Graph Type, X-Axis Range and Resolution, Y-Axis Range and Resolution, Input Parameters, Output Parameters, X-Axis Heading, Y-Axis Heading and Links to associated graphs.

Additionally, the data can contain contour information that is stored in a hierarchy:

Control Point! Contour / Contour Field.

"Control Points" are stored as X/Y coordinates and can be either Smooth or Corner points.

Contours" consist of two or more "Control Points". The "Contours" can be represented to a user by using mathematical best fit polynomial formulas based on the "Control Point" coordinates to generate a line that can be displayed on a graph. The mathematical best fit polynomial formulas can also be used for a subsequent calculation. These formulas may not be stored as part of the graph representation data, but rather can be calculated from the "Control Points" of a "Contour" whenever they are required for performing a calculation.

"Contour Fields" consist of two or more "Contours". "Contour Fields' may relate to more contours than are actually defined by child Contours, that is, Contours that are initially set up by a user when defining the graph representation data. For example, a Contour Field" may contain ten Contours, but may be defined solely by the two Contours marking the eft-most and right-most edges of the "Contour Field". The remaining eight contours can be known as "interpolated contours" and are not stored as part of the graph representation data, but are calculated whenever they are required for example, displaying the graph representation data to a user.

An example application that can use a method or apparatus for generating graph representation data as described herein is in the aviation industry. An example application for calculating take-off data, tyre cooling data and landing data for a Tornado combat aircraft is now described. It will be appreciated that embodiments of the invention can be equally applicable for different aircraft and different industries altogether. For example, embodiments of the invention may be particularly advantageous in safety-critical systems, and can be utilised in any situation that requires use of a graph to calculate information.

A non-limiting list of alternative applications for embodiments of the present invention include electricity generation, electricity transmission and distribution, including systems related to nuclear power plants, systems associated with the emergency services, nuclear reactor control systems, scuba diving pressure calculations and other transport systems, including railways, aviation and space flight. It will be appreciated that although embodiments of the invention offer particular advantages for safety-critical systems, the same advantages can be equally applicable to any system that utilises graphical data.

Figure 5a illustrates a user interface 500 for processing take off data for a Tornado aircraft. The user interface 500 includes an input section 502 and an output section 504.

In this example, the input section 502 includes four panels that represent different types of input data. In this embodiment, the input sections are atmospherics, runway, aircraft and technique. A number of parameters can be set by a user in order to provide input data that defines a situation/scenario that is to be modelled. Once a user has entered values for each of the parameters in the input section 502, the user can press a "calculate" button 506 in order to generate output data. The output data is illustrated in the output section 504 of the user interface 500.

In this embodiment, when a user presses the "calculate" button 506, a processor processes the associated graph representation data, and uses the input values that have been provided in the input section 502 of the user interface 500 to generate the output value/data.

As described above in relation to the contour data that is stored as "Control Point / Contour I Contour Field", the contour data is processed to identify the appropriate contours that should be applied, and one or more mathematical best fit polynomial formulae are applied to generate a mathematical function that represents the contour between the two points either side of the input value that has been provided. Any interpolation that is required to provide the correct contour is performed, and the generated mathematical function is then applied to the input value in order to generate the output value.

In this example, the output section 504 includes a speed graph section 510 which has a vertical axis that represents speed in knots, and consists of a single bar with key speeds identified thereon that are output values for graphical calculations that have been performed on input values that have been provided in the input section 502 of the user interface 500. For example, an emergency braking speed (EMBS) indicator is shown at 122 knots on the speed graph 510, a "vStop" indicator is provided at 123 knots and indicates the speed at which the brakes will stop the aircraft before reaching the end of the runway, "vStop (R)" is shown at 181 knots and indicates the maximum speed at which the aircraft can be stopped using a cable, and "vGo" at 190 knots indicates the minimum speed that the aircraft can still take off if it loses one engine. In this example, "vGo" is at 190 knots, which is greater than "vStop (R)" at 181 knots. Such an arrangement may be deemed unacceptable because there is a range of speeds at which the aircraft could neither stop nor take off, and this is why a region of the bar chart illustrated by reference 508 is shown in red to indicate danger. In this example, the vGo" indicator is crossed out, and this indicates that a problem has occurred when referencing the graph representation data, for example, an integral self check has failed, and/or one or more of the inputs are outside an acceptable range.

It will be appreciated that any limits that are considered to be unacceptable and/or dangerous may be user-defined, and preferably administrator only-defined. Such limits can be entered by a user using a suitable user interface (not shown).

The output section 504 of the user interface 500 also includes a graphical representation of the runway 512 that illustrates the output values in terms of distances/lengths.

In this example, when a user presses the calculate button 506, a safety check application is run to check that each of the input parameters has been adjusted/set since the last calculation was performed. If any of the input parameters have not been adjusted/set, and are left as a default/previous value, then a red warning indicator is provided next to those parameters that have not been set. An example red warning indicator is shown next to the wind bearing parameter 514 (amongst others) in the atmospherics section of the input section 502. In this example, a user prompt is provided after the user presses the calculate button 506 identifying those input parameters that have not been adjusted/set, and gives the user the opportunity to go back and adjust those parameters, or accept the default values. This process is provided to ensure that calculations are not inadvertently performed using data that the user has not made a conscious decision to set, or accept as a default value. This can be particularly advantageous for safety critical systems where making calculations using incorrect input values can have catastrophic consequences.

In an alternative embodiment illustrated in Figure 5b, the user interface 550 may run in a "what-if mode of operation. The user interface 550 of Figure 5b is very similar to the user interface 500 of Figure 5a, but does not include the calculate button 506. In effect, the user interface 550 is always configured to calculate output values in accordance with the current input values of the input section 552. This enables a user to adjust various parameters in the input section 552 and observe the effect in the output section 554 as that parameter is changed. This can provide advantages when a user would like to explore how different input parameters affect the output and determine any critical values at which, for example, the aircraft will not be able to reach take off speed by the time it reaches the end of the runway.

As can be seen in both Figure 5a and Sb, an "0DM graph button 516, 566 is available in the output section 504,554 of interface 500,550. 0DM stands for Operating Data Manual and relates to the graph representations that have been generated, and have been described in relation to Figures 2, 3 and 4.

An example of a user interlace that is displayed after clicking the "0DM graph button 516, 566 is shown as Figure 6. The graph 600 in this example is the first in a plurality of graphs that are used with at least some of the input values that have been provided, and illustrates graphically how the graph representation data has been applied to generate the required output values.

The graph 600 in this example receives as a horizontal input 602 a temperature value of 26°C, and utilises contour lines 606 representative of pressure altitude to generate a vertical output 604. A summary of the variable values for the graph can be found in display box 608 in the top left hand corner of the user interface. The display box 608 also illustrates a self check error of 0.000006%, and the generation of self check errors will be discussed later in relation to Figures 9 and 10 for example.

It will be appreciated that the input values for temperature and pressure altitude are obtained from the input section 502, 552 of the user interlace shown in Figures 5a and 5b.

The 0DM graph functionality may enable the guide image and associated graph representation data to be displayed to a user in combination with a representation of the specific input and output values relating to a calculation, and can include a representation of the interaction with the input output values with the graph representation data.

The functionality of a user being able to view the graphical data that was used to generate the output values can be very powerful, as it enables a user to verify visually whether or not the calculations appear to have been performed correctly. It may be considered easier to spot any anomalies or mistakes in calculations by viewing the workings in this way as opposed to the results of mathematical equations. A further advantage can be provided by the user selecting an option to display the guide image (for example the originally scanned-in graph) at the same time as the generated graph representation to satisfy themselves that the correct graphical data is being used.

A further advantage can be that a user is able to position a cursor/crosshair anywhere over the graph 600 such that the user interlace displays the variable values for that cursor location. Such a cursor location is illustrated as reference 610 in Figure 6.

It can be seen from the graph 600 in Figure 6 that the vertical output 604 extends off the bottom of the visible area in Figure 6. In this examp'e, the vertical output 604 is provided as a vertical input to a second graph (not shown). It will be recalled from the description of Figure 3g, that a plurality of graphs can be configured in any suitable arrangement, and for the embodiment of Figure 6, a second graph is configured to receive at least a vertical input.

Figure 7 illustrates an embodiment of a user interface 700 in relation to tyre cooling of a Tornado aircraft. Again, the interface 700 consists of an input section 702 and an output section 704.

The input section 702 enables the duration and properties of one or more sorties/flights to be configured. For example, the weight of the aircraft at the start and end of the sortie can be defined, the length of the taxi from and to the runway can be entered, along with other physical parameters associated with the sortie.

In the example illustrated in Figure 7, the time line which is displayed in the output section 704 is configured to be automatically calculated with a minimum turnaround duration of 15 minutes. In other embodiments, specific take off times can be provided and/or mandatory turnaround times can a'so be provided.

For the example of Figure 7, three sorties have been defined, and an automatically calculated time line is displayed in output section 704. The output section 704 includes a time line which indicates when the aircraft is taxiing, waiting pre-take off, flying, and when the aircraft is being turned around or the tyres are otherwise cooling. In addition, the tyre temperature is illustrated on the same time line as graphical display 708. The tyre temperature output values are displayed in relation to one or more threshold values on the graphical display 708. For example, a maximum tyre temperature of 120°C is shown on the graphical display 708, and it can be seen that after the taxiing the end of the second sortie the maximum temperature of the tyres is exceeded at reference 712.

When such a thresho'd value is exceeded, an error message can be displayed such as error message 706 which states that "max temperature exceeded".

It wiU be appreciated that the underlying functionality provided by one or more of the user interfaces described herein can be easily adjusted by changing and/or adding additional graph representation data. This can be incorporated into the system in a similar manner to that described in relation to Figures 2, 3 and 4. For example, in the tyre cooling appcation, it may be possible for tyre cooling covers to be applied to the aircraft wheels when it is stationary, and this additional cooling of the tyres can be incorporated into the calculations relatively easily by modification or addition of one or more graph representations.

Figure 8 illustrates a user interface 800 for a landing appUcation of a Tornado aircraft.

The user interface 800 includes an input section 802 and an output section 804, and the input section 802 is similar to the input section 502 of Figure 5. In this example, the output section 804 illustrates the stopping distance for the aircraft based upon the provided input values/parameters. In a similar way to the embodiments illustrated in Figures 5 and 7, an "0DM graph button 806 is available for a user to view the graphical data that was used to calculate the output values.

In embodiments where the accuracy of any calculations is particularly important, one or more reverse verification operations can be performed. In safety critical situations, reverse verification operations can be performed for each calculation that is executed.

An example reverse verification is illustrated schematically as Figure 9. The normal/forward calculation is illustrated as 900, and the reverse verification is illustrated as 901.

The normal calculation 900 receives three inputs 910 into a calculation module 902 representative of a function provided by one or more graphical operations, which generates a single output 912. The calculation module 902 consists of three functions 904, 906, 908 that together process the input signals 910 to generate the output signal 912.

The reverse verification calculation 901 consists of providing two of the original three inputs 914 as well as re-entering the calculated output as an additional input 916. In this way, a reverse engineered input 918 can be calculated and compared with the corresponding original input to check the validity of the calculation. This verification may be performed every time a calculation is made, for example when a "calculate" button of one of the user interfaces described herein is pressed, and the "reverse engineered" input value 918 can be compared with the corresponding original input value to generate a self-check error percentage such as that illustrated in panel 608 of Figure 6.

Any discrepancies between the reverse engineered input and the original input can indicate a problem with the computer processor and/or with the software algorithms. In some embodiments, a self check error that is determined to be above a threshold value may cause an error message to be displayed to the user indicating that the output values may not be sufficiently accurate.

In addition, or alternatively, a "known results check" may be performed periodically andlor upon the occurrence of certain events to confirm that the calculations are being performed correctly. For example, as shown in Figure 10, three input values 1004, can be provided to a calculation module 1002, for which the correct output value is known.

The known output value can be compared with the generated output value 1006, and any discrepancies can again indicate a problem with the computer processor and/or the software algorithms. Any such errors can be identified to a user in any suitable way.

Figures ha to hhj illustrate schematically class diagrams according to embodiments of the invention. The class diagrams may correspond to sub-routines that can be run by an application program according to an embodiment of the invention.

Figure ha illustrates an "EPPA.Generic.dll / cBacklmage" class diagram. This class diagram relates to an image underlaid below a cGraph rendering. This image will usually be a scan from a paper version of the cGraph, allowing the digital cGraph object to accurately reproduce the paper version.

Figure 11 b illustrates an "EPPA.Generic.dlI / cBaseline" class diagram. This class diagram relates to a baseline within a performance graph, as shown in the diagram at right.

Figure lIc illustrates an "EPPA.Generic.dll / cContour" class diagram. This class diagram represents a single user defined editable contour line within a cContourField. In this embodiment cContour objects are used to represent editable contours, and that interpolated contours (between editable contours) are not stored as objects but rather created dynamically as the need arises.

A cContour is represented by an expression Y F(X), and an associated "ContourValue". The ContourValue has no meaning in the context of the cContour itself, but is used when performing calculations on a cContourField, as it relates the value of contours relative to each other.

Contours are defined by entering a series of "Edit Points", and a best fit line is drawn between those points. Edit Points can be specified as either "smooth" or "corner".

Figures lid and lie illustrate "EPPAGeneric.dll / cContourField" class diagrams.

These class diagrams relate to a CoUection of cContours within a cGraph. Each cGraph may contain a number of cContourFeIds.

cContourFields can either be "Single Contour" or "Multiple Contour". A "Multiple Contour" cContourFied is illustrated as Figure lid and a "Single Contour' cContourField is illustrated as Figure lie.

The contours within a "Multip'e Contour" cContourField can either be user defined, or can be automatically interpolated. At minimum, a "Multip'e Contour" cContourField must contain at least 2 user defined cContours -one at each end of the cContourField.

ContourFieds are represented mathematically by X, Y and Z coordinates. Each contour is represented by an expression Y F(X), and each contour has an associated Z value, expressed as a raw percentage (0 to 1, where 0 is the first contour and 1 is the last contour).

A "Sing'e Contour" cContourField will always contain one user defined cContour object, with a Z Value of 0.

Figures lit and 1 ig illustrate "EPPA.Generic.dll I cFlow" class diagrams. These class diagrams inherit cLibltem (Overriden Members are not Shown), and represent a performance page (calculation) within a source Operating Data ManuaL The class diagram can consist of one or more component cGraph objects that together calculate an output from a set of inputs.

The cGraph objects are "linked" to each other, the link determining the flow of inputs/output through the cFlow object.

cFlow calculations can be self-checked using three methods: (1) "Known Results" -cFlow objects may contain one or more saved collections of inputs with a corresponding output. The cFlow can self-check itseff by running a calculation based on these inputs and comparing the calculated output to the saved output.

(2) "Reverse Verification" -Any cFlow calculation that produces an output is automatically run in reverse (from output to first input). If the "reverse engineered" first input does not match the original first input, the calculation is labeled as nvalid. See Figure 1 ig (3) "Graph Validity" -Each cGraph will check if its Inputs or Outputs are within its graphical bounds. If they are not, the result is labeled as Invalid.

Figure 1 lh illustrates an "EPPA.Generic.dll I cGraph" class diagram. This class diagram represents a graph used within a cFLow performance calculation, and will consist of one or two cContourFields, an optional cbaseline, 2 Inputs (one or both of the inputs may be

in the form of contour field values) and 1 Output.

Figure lii illustrates an EPPA.Generic.dll I cPoly" class diagram. This class diagram forms the core mathematical description from which the cContour object inherits. cPoly is composed of a number of tPoySeg segments, each of which is a different Polynomial Equation. The tPolySegs are joined to each other at "Edit Points", which are shown as squares in Figure lii. Figure 1 lj (tPolySeg) shows for more information on the nature of these Polynomial Equations.

Figure llj i'lustrates an "EPPA.Generic.dll / cPoly I tPolySeg" class digram, and represents a Polynomial segment of a cPoly contour line. tPolySeg consists of a cubic equation, which is calculated from 4 inputs: The start point (Ptl), the end point (Pt2), the start slope and the end slope. The start and end points wiU always be known, but there may be occasions when the start and/or end slopes are not specified -in these cases the cubic equation can be simplified to a quadratic or linear equation.

It will be appreciated that embodiments described herein can enable image data to be converted into data that can be used to electronically perform one or more calculations in line with graphical information that is represented in the original image. Furthermore, a number of verification procedures may be performed in order to provide a high level of confidence in any output values that are generated, and this can be particularly important in safety-critical systems. Examples of verification procedures that can be performed include displaying the graphical information that has been used to generate the output values to a user for inspection, performing self checking routines such as reverse verification and "known results" checks.

Embodiments described herein can provide a high evel of flexibIfty and usabty for an end user to be able to perform calculations and simulations that were not previously possible. Furthermore, the accuracy of output values that can be obtained can be 9reatly improved when compared with prior art methods of a human user manually using a pencil and a ruler to calculate extremely important safety-critical information.

Claims

Claims I A method of generating and storing graph representation data, comprising: receiving guide image data representative of a graphica' image; generating graph representation data representative of a plurality of graph parameters and values derived from the graphical image; and storing the graph representation data for subsequent use in performing a function corresponding to a function iustrated by the graphical image.
2. The method of claim 1, wherein the step of generating graph representation data is responsive to user input.
3. The method of claim 2, wherein the user input represents one or more values corresponding to one or more graph parameters.
4. The method of any preceding claim, further comprising enabling user manipulation of the guide image data and/or graph representation data in order for a display of the guide image data and a display of the graph representation data to be adjusted.
5. The method of claim 4, wherein manipulation of the guide image data comprises stretching a subsection of the graphical image.
6. The method of any preceding claim, further comprising: generating and storing first and second graph representation data for a first and second graphical image respectively; and associating the first graph representation data representative of the first graphical image with the second graph representation data representative of the second graphical image, such that output values of the first graph representation data are provided as input values to the second graph representation data.
7. The method of any preceding claim, wherein the step of receiving guide image data comprises scanning in a hard copy of a graphical image or downloading the guide image data from an external device over a network.
8. The method of any preceding claim, further comprising storing an association between the guide image data and the graph representation data.
9. The method of any preceding claim, further compnsng performing a function on one or more input values using the graph representation data in order to generate one or more output values.
10. The method of claim 9, further comprising: providing the generated one or more output values as one or more reverse inputs to the function; performing the function in reverse in order to generate one or more reverse outputs; and comparing the one or more reverse outputs with the one or more inputs in order to identify any discrepancies.
11. The method of claim 9, wherein the nput values correspond to one or more values for which the correct result is known, and the method comprises comparing the one or more output values with the correct result in order to identify any discrepancies.
12. The method of claim 10 or claim 11, wherein the step of identifying any discrepancies is performed periodically and/or before and/or after a user-instigated function.
13. The method of any one of claims 9 to 12, further comprising: displaying a graphical representation of the interaction between the graph representation data and the input and output values.
14. The method of claim 13, further comprising displaying the guide image with the graphical representation of the interaction between the graph representation data and the input and output values.
15. An apparatus comprising: a receiver configured to receiving guide image data representative of a graphical image; a processor configured to generate graph representation data representative of a plurality of graph parameters and values derived from the graphical image; and computer memory configured to store the graph representation data for subsequent use in performing a function corresponding to a function illustrated by the graphical image.
16. A user interface having a display and one or more user inputs, the user interface configured to: receive guide image data representative of a graphical image; generate graph representation data representative of a plura'ity of graph parameters and values derived from the graphical image in response to user input; and store the graph representation data for subsequent use in performing a function corresponding to a function il'ustrated by the graphical image.
17. The user interface of claim 16, configured to perform a function on one or more input values received at the user inputs using the graph representation data to generate and display one or more output values.
18. The user interface of claim 17, further configured to display a graphical representation of the interaction between the graph representation data and the input and output values.
19. A computer program configured to perform the method of any one of claims 1 to 14, or to configure the apparatus of claim 15, or to provide the user interface of any one claims l6to 18.
20. A method substantially as hereinbefore described and as illustrated in the accompanying drawings.
21. An apparatus substantia'ly as hereinbefore described and as illustrated in the accompanying drawings.
22. A user interface substantially as hereinbefore described and as illustrated in the accompanying drawings.