Is graycomatrix's NumLevels and GrayLimits the same thing MATLAB












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Ive been looking at implementing GLCM within MATLAB using graycomatrix. There are two arguments that I have discovered (NumLevels and GrayLimits) but in in my research and implementation they seem to achieve the same result.



GrayLimits specified bins between a range set [low high], causing a restricted set of gray levels.



NumLevels declares the number of gray levels in an image.



Could someone please explain the difference between these two arguments, as I don't understand why there would be two arguments that achieve the same result.










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    0














    Ive been looking at implementing GLCM within MATLAB using graycomatrix. There are two arguments that I have discovered (NumLevels and GrayLimits) but in in my research and implementation they seem to achieve the same result.



    GrayLimits specified bins between a range set [low high], causing a restricted set of gray levels.



    NumLevels declares the number of gray levels in an image.



    Could someone please explain the difference between these two arguments, as I don't understand why there would be two arguments that achieve the same result.










    share|improve this question

























      0












      0








      0







      Ive been looking at implementing GLCM within MATLAB using graycomatrix. There are two arguments that I have discovered (NumLevels and GrayLimits) but in in my research and implementation they seem to achieve the same result.



      GrayLimits specified bins between a range set [low high], causing a restricted set of gray levels.



      NumLevels declares the number of gray levels in an image.



      Could someone please explain the difference between these two arguments, as I don't understand why there would be two arguments that achieve the same result.










      share|improve this question













      Ive been looking at implementing GLCM within MATLAB using graycomatrix. There are two arguments that I have discovered (NumLevels and GrayLimits) but in in my research and implementation they seem to achieve the same result.



      GrayLimits specified bins between a range set [low high], causing a restricted set of gray levels.



      NumLevels declares the number of gray levels in an image.



      Could someone please explain the difference between these two arguments, as I don't understand why there would be two arguments that achieve the same result.







      matlab image-manipulation image-segmentation glcm






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      asked Nov 22 '18 at 20:21









      user10190803

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          From the documentation:




          'GrayLimits': Range used scaling input image into gray levels, specified as a two-element vector [low high]. If N is the number of gray levels (see parameter 'NumLevels') to use for scaling, the range [low high] is divided into N equal width bins and values in a bin get mapped to a single gray level.



          'NumLevels': Number of gray levels, specified as an integer.




          Thus the first parameter sets the input gray level range to be used (defaults to the min and max values in the image), and the second parameter sets the number of unique gray levels considered (and thus the size of the output matrix, defaults to 8, or 2 for binary images).



          For example:



          >> graycomatrix(img,'NumLevels',8,'GrayLimits',[0,255])
          ans =
          17687 1587 81 31 7 0 0 0
          1498 7347 1566 399 105 8 0 0
          62 1690 3891 1546 298 38 1 0
          12 335 1645 4388 1320 145 4 0
          2 76 305 1349 4894 959 18 0
          0 16 40 135 965 7567 415 0
          0 0 0 2 15 421 2410 0
          0 0 0 0 0 0 0 0

          >> graycomatrix(img,'NumLevels',8,'GrayLimits',[0,127])
          ans =
          1 9 0 0 0 0 0 0
          7 17670 1431 156 50 31 23 15
          1 1369 3765 970 350 142 84 92
          0 128 1037 1575 750 324 169 167
          0 46 361 836 1218 747 335 260
          0 16 163 330 772 1154 741 547
          0 10 74 150 370 787 1353 1208
          0 4 67 136 294 539 1247 21199

          >> graycomatrix(img,'NumLevels',4,'GrayLimits',[0,255])
          ans =
          28119 2077 120 0
          2099 11470 1801 5
          94 1829 14385 433
          0 2 436 2410


          As you can see, these parameters modify the output in different ways:




          1. In the first case above, the range [0,255] was mapped to columns/rows 1-8, putting 32 different input grey values into each.

          2. In the second case, the smaller range [0,127] was mapped to 8 indices, putting 16 different input grey values into each, and putting the remaining grey values 128-255 into the 8th index.

          3. In the third case, the range [0,255] was mapped to 4 indices, putting 64 different input grey values into each.






          share|improve this answer





















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            From the documentation:




            'GrayLimits': Range used scaling input image into gray levels, specified as a two-element vector [low high]. If N is the number of gray levels (see parameter 'NumLevels') to use for scaling, the range [low high] is divided into N equal width bins and values in a bin get mapped to a single gray level.



            'NumLevels': Number of gray levels, specified as an integer.




            Thus the first parameter sets the input gray level range to be used (defaults to the min and max values in the image), and the second parameter sets the number of unique gray levels considered (and thus the size of the output matrix, defaults to 8, or 2 for binary images).



            For example:



            >> graycomatrix(img,'NumLevels',8,'GrayLimits',[0,255])
            ans =
            17687 1587 81 31 7 0 0 0
            1498 7347 1566 399 105 8 0 0
            62 1690 3891 1546 298 38 1 0
            12 335 1645 4388 1320 145 4 0
            2 76 305 1349 4894 959 18 0
            0 16 40 135 965 7567 415 0
            0 0 0 2 15 421 2410 0
            0 0 0 0 0 0 0 0

            >> graycomatrix(img,'NumLevels',8,'GrayLimits',[0,127])
            ans =
            1 9 0 0 0 0 0 0
            7 17670 1431 156 50 31 23 15
            1 1369 3765 970 350 142 84 92
            0 128 1037 1575 750 324 169 167
            0 46 361 836 1218 747 335 260
            0 16 163 330 772 1154 741 547
            0 10 74 150 370 787 1353 1208
            0 4 67 136 294 539 1247 21199

            >> graycomatrix(img,'NumLevels',4,'GrayLimits',[0,255])
            ans =
            28119 2077 120 0
            2099 11470 1801 5
            94 1829 14385 433
            0 2 436 2410


            As you can see, these parameters modify the output in different ways:




            1. In the first case above, the range [0,255] was mapped to columns/rows 1-8, putting 32 different input grey values into each.

            2. In the second case, the smaller range [0,127] was mapped to 8 indices, putting 16 different input grey values into each, and putting the remaining grey values 128-255 into the 8th index.

            3. In the third case, the range [0,255] was mapped to 4 indices, putting 64 different input grey values into each.






            share|improve this answer


























              1














              From the documentation:




              'GrayLimits': Range used scaling input image into gray levels, specified as a two-element vector [low high]. If N is the number of gray levels (see parameter 'NumLevels') to use for scaling, the range [low high] is divided into N equal width bins and values in a bin get mapped to a single gray level.



              'NumLevels': Number of gray levels, specified as an integer.




              Thus the first parameter sets the input gray level range to be used (defaults to the min and max values in the image), and the second parameter sets the number of unique gray levels considered (and thus the size of the output matrix, defaults to 8, or 2 for binary images).



              For example:



              >> graycomatrix(img,'NumLevels',8,'GrayLimits',[0,255])
              ans =
              17687 1587 81 31 7 0 0 0
              1498 7347 1566 399 105 8 0 0
              62 1690 3891 1546 298 38 1 0
              12 335 1645 4388 1320 145 4 0
              2 76 305 1349 4894 959 18 0
              0 16 40 135 965 7567 415 0
              0 0 0 2 15 421 2410 0
              0 0 0 0 0 0 0 0

              >> graycomatrix(img,'NumLevels',8,'GrayLimits',[0,127])
              ans =
              1 9 0 0 0 0 0 0
              7 17670 1431 156 50 31 23 15
              1 1369 3765 970 350 142 84 92
              0 128 1037 1575 750 324 169 167
              0 46 361 836 1218 747 335 260
              0 16 163 330 772 1154 741 547
              0 10 74 150 370 787 1353 1208
              0 4 67 136 294 539 1247 21199

              >> graycomatrix(img,'NumLevels',4,'GrayLimits',[0,255])
              ans =
              28119 2077 120 0
              2099 11470 1801 5
              94 1829 14385 433
              0 2 436 2410


              As you can see, these parameters modify the output in different ways:




              1. In the first case above, the range [0,255] was mapped to columns/rows 1-8, putting 32 different input grey values into each.

              2. In the second case, the smaller range [0,127] was mapped to 8 indices, putting 16 different input grey values into each, and putting the remaining grey values 128-255 into the 8th index.

              3. In the third case, the range [0,255] was mapped to 4 indices, putting 64 different input grey values into each.






              share|improve this answer
























                1












                1








                1






                From the documentation:




                'GrayLimits': Range used scaling input image into gray levels, specified as a two-element vector [low high]. If N is the number of gray levels (see parameter 'NumLevels') to use for scaling, the range [low high] is divided into N equal width bins and values in a bin get mapped to a single gray level.



                'NumLevels': Number of gray levels, specified as an integer.




                Thus the first parameter sets the input gray level range to be used (defaults to the min and max values in the image), and the second parameter sets the number of unique gray levels considered (and thus the size of the output matrix, defaults to 8, or 2 for binary images).



                For example:



                >> graycomatrix(img,'NumLevels',8,'GrayLimits',[0,255])
                ans =
                17687 1587 81 31 7 0 0 0
                1498 7347 1566 399 105 8 0 0
                62 1690 3891 1546 298 38 1 0
                12 335 1645 4388 1320 145 4 0
                2 76 305 1349 4894 959 18 0
                0 16 40 135 965 7567 415 0
                0 0 0 2 15 421 2410 0
                0 0 0 0 0 0 0 0

                >> graycomatrix(img,'NumLevels',8,'GrayLimits',[0,127])
                ans =
                1 9 0 0 0 0 0 0
                7 17670 1431 156 50 31 23 15
                1 1369 3765 970 350 142 84 92
                0 128 1037 1575 750 324 169 167
                0 46 361 836 1218 747 335 260
                0 16 163 330 772 1154 741 547
                0 10 74 150 370 787 1353 1208
                0 4 67 136 294 539 1247 21199

                >> graycomatrix(img,'NumLevels',4,'GrayLimits',[0,255])
                ans =
                28119 2077 120 0
                2099 11470 1801 5
                94 1829 14385 433
                0 2 436 2410


                As you can see, these parameters modify the output in different ways:




                1. In the first case above, the range [0,255] was mapped to columns/rows 1-8, putting 32 different input grey values into each.

                2. In the second case, the smaller range [0,127] was mapped to 8 indices, putting 16 different input grey values into each, and putting the remaining grey values 128-255 into the 8th index.

                3. In the third case, the range [0,255] was mapped to 4 indices, putting 64 different input grey values into each.






                share|improve this answer












                From the documentation:




                'GrayLimits': Range used scaling input image into gray levels, specified as a two-element vector [low high]. If N is the number of gray levels (see parameter 'NumLevels') to use for scaling, the range [low high] is divided into N equal width bins and values in a bin get mapped to a single gray level.



                'NumLevels': Number of gray levels, specified as an integer.




                Thus the first parameter sets the input gray level range to be used (defaults to the min and max values in the image), and the second parameter sets the number of unique gray levels considered (and thus the size of the output matrix, defaults to 8, or 2 for binary images).



                For example:



                >> graycomatrix(img,'NumLevels',8,'GrayLimits',[0,255])
                ans =
                17687 1587 81 31 7 0 0 0
                1498 7347 1566 399 105 8 0 0
                62 1690 3891 1546 298 38 1 0
                12 335 1645 4388 1320 145 4 0
                2 76 305 1349 4894 959 18 0
                0 16 40 135 965 7567 415 0
                0 0 0 2 15 421 2410 0
                0 0 0 0 0 0 0 0

                >> graycomatrix(img,'NumLevels',8,'GrayLimits',[0,127])
                ans =
                1 9 0 0 0 0 0 0
                7 17670 1431 156 50 31 23 15
                1 1369 3765 970 350 142 84 92
                0 128 1037 1575 750 324 169 167
                0 46 361 836 1218 747 335 260
                0 16 163 330 772 1154 741 547
                0 10 74 150 370 787 1353 1208
                0 4 67 136 294 539 1247 21199

                >> graycomatrix(img,'NumLevels',4,'GrayLimits',[0,255])
                ans =
                28119 2077 120 0
                2099 11470 1801 5
                94 1829 14385 433
                0 2 436 2410


                As you can see, these parameters modify the output in different ways:




                1. In the first case above, the range [0,255] was mapped to columns/rows 1-8, putting 32 different input grey values into each.

                2. In the second case, the smaller range [0,127] was mapped to 8 indices, putting 16 different input grey values into each, and putting the remaining grey values 128-255 into the 8th index.

                3. In the third case, the range [0,255] was mapped to 4 indices, putting 64 different input grey values into each.







                share|improve this answer












                share|improve this answer



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                answered Nov 23 '18 at 5:35









                Cris Luengo

                18.7k51947




                18.7k51947






























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