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Line Tracer/Digitizer

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  • mrjjM mrjj

    Hi and welcome to the forums

    Since you have the manual part working click on the image and so on, what
    part do you want help on ?
    The math in the "automatically give a vector of position" or saving to
    csv or where lies the dog ? ( not sure its the right expression :)

    P Offline
    P Offline
    ParanoidAndroid
    wrote on last edited by
    #3

    @mrjj

    I need it to automatically detect the line and plot the points so instead of the user clicking several points on the line they instead click a couple and the program autofills the other points according to the line

    mrjjM 1 Reply Last reply
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    • P ParanoidAndroid

      @mrjj

      I need it to automatically detect the line and plot the points so instead of the user clicking several points on the line they instead click a couple and the program autofills the other points according to the line

      mrjjM Offline
      mrjjM Offline
      mrjj
      Lifetime Qt Champion
      wrote on last edited by mrjj
      #4

      @ParanoidAndroid
      Ok and are those lines straight or more like a spline / curve ?
      if just a line then
      https://www.geeksforgeeks.org/program-find-line-passing-2-points/

      but since you asked for help i assume its something more complicated ?

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      • mrjjM mrjj

        @ParanoidAndroid
        Ok and are those lines straight or more like a spline / curve ?
        if just a line then
        https://www.geeksforgeeks.org/program-find-line-passing-2-points/

        but since you asked for help i assume its something more complicated ?

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        ParanoidAndroid
        wrote on last edited by
        #5

        @mrjj They can be any 2D line graph splines, straight, lines curves

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        • P ParanoidAndroid

          @mrjj They can be any 2D line graph splines, straight, lines curves

          mrjjM Offline
          mrjjM Offline
          mrjj
          Lifetime Qt Champion
          wrote on last edited by
          #6

          @ParanoidAndroid
          Ok. so we need the data these
          2D line graph splines, straight, lines curves are based on if we are to calculate its
          function based on a few points.

          Can i see one images with the drawn curves you wish to calculate ?

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          • P Offline
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            ParanoidAndroid
            wrote on last edited by
            #7

            Here is an example of the splineGraph3.png

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            • kshegunovK Offline
              kshegunovK Offline
              kshegunov
              Moderators
              wrote on last edited by
              #8

              You need to read math, I'm afraid. Rational B-splines, normal cubic splines or polyharmonic splines could work in your case, however I leave the wikipedia-ing to you. ;)

              Read and abide by the Qt Code of Conduct

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              • kshegunovK kshegunov

                You need to read math, I'm afraid. Rational B-splines, normal cubic splines or polyharmonic splines could work in your case, however I leave the wikipedia-ing to you. ;)

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                ParanoidAndroid
                wrote on last edited by
                #9

                @kshegunov
                Is there no way to say track the colour of the spline and give pixel coordinates

                kshegunovK 1 Reply Last reply
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                • P ParanoidAndroid

                  @kshegunov
                  Is there no way to say track the colour of the spline and give pixel coordinates

                  kshegunovK Offline
                  kshegunovK Offline
                  kshegunov
                  Moderators
                  wrote on last edited by
                  #10

                  Sorry, I don't understand the question. Please rephrase.

                  Read and abide by the Qt Code of Conduct

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                  • kshegunovK kshegunov

                    Sorry, I don't understand the question. Please rephrase.

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                    ParanoidAndroid
                    wrote on last edited by
                    #11

                    @kshegunov instead of using mathematics could you say click to select the colour of the line and then have the application give the coordinates of every pixel connected with that colour

                    mrjjM 1 Reply Last reply
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                    • P ParanoidAndroid

                      @kshegunov instead of using mathematics could you say click to select the colour of the line and then have the application give the coordinates of every pixel connected with that colour

                      mrjjM Offline
                      mrjjM Offline
                      mrjj
                      Lifetime Qt Champion
                      wrote on last edited by
                      #12

                      @ParanoidAndroid
                      Hi
                      If all images are as clean as this, you can easily scan to find the blue color and hence the Y coordinate.
                      https://doc.qt.io/qt-5/qimage.html#pixel-1
                      or the faster way
                      https://doc.qt.io/qt-5/qimage.html#scanLine

                      But it wont be fast as such but unless
                      tiny mini board it should be fine:)

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                      • mrjjM mrjj

                        @ParanoidAndroid
                        Hi
                        If all images are as clean as this, you can easily scan to find the blue color and hence the Y coordinate.
                        https://doc.qt.io/qt-5/qimage.html#pixel-1
                        or the faster way
                        https://doc.qt.io/qt-5/qimage.html#scanLine

                        But it wont be fast as such but unless
                        tiny mini board it should be fine:)

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                        P Offline
                        ParanoidAndroid
                        wrote on last edited by
                        #13

                        @mrjj thankyou for your help. Will this give an x coordinate aswell

                        jsulmJ 1 Reply Last reply
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                        • P ParanoidAndroid

                          @mrjj thankyou for your help. Will this give an x coordinate aswell

                          jsulmJ Offline
                          jsulmJ Offline
                          jsulm
                          Lifetime Qt Champion
                          wrote on last edited by
                          #14

                          @ParanoidAndroid said in Line Tracer/Digitizer:

                          Will this give an x coordinate aswell

                          Just iterate over all x coordinates and search for y like @mrjj suggested. Or iterate over y and get x...

                          https://forum.qt.io/topic/113070/qt-code-of-conduct

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