[MINC-users] my student needs help with a scaling issue

[Audette, Michel A.]

Dear Minc users,

my student Tanweer Rashid seems to be having a scaling issue related to reading a minc image.

We are trying to read a digital deep-brain atlas graciously supplied by Mallar Chakravarty, and the voxel values that we get with minc routines are not quite consistent with the values that we get with the print_all_labels command run offline.

See below, which features the output of print_all_labels (which looks reasonable), calls to miget_voxel_value() within Tanweer's program, and the source code of his that calls it.

Can anyone spot something that we are doing wrong, and offer guidance on correcting Tanweer's bug?

Thanks for your kind support.

Michel

Michel Audette, Ph.D.
Assistant Professor,
Department of Modeling, Simulation and Visualization Engineering,
Old Dominion University,
Norfolk, VA.

________________________________
From: Tanweer Rashid [trash001 at odu.edu]
Sent: Friday, October 19, 2012 11:49 AM
To: Audette, Michel A.
Subject: Code and results

Results from print_all_labels():
trash001 at LCARS:/usr/local/bin$ print_all_labels ~/Desktop/labels_on_colin_Nov2010_minc2.mnc
Label: 1 933459
Label: 2 1433227
Label: 3 50946
Label: 4 893200
Label: 5 37056
Label: 6 38333
Label: 7 47522
Label: 8 11922
Label: 9 9238
Label: 10 7369
Label: 11 39738
Label: 12 53097
Label: 13 10502
Label: 14 5301
Label: 15 147
Label: 16 33782
Label: 17 918
Label: 18 296
Label: 19 504
Label: 20 5060
Label: 21 9438
Label: 22 1739
Label: 23 574
Label: 24 138283
Label: 25 16869
Label: 26 22419
Label: 27 5337
Label: 28 10464
Label: 29 9293
Label: 30 1191
Label: 31 201
Label: 32 190
Label: 33 513
Label: 34 166
Label: 35 71684
Label: 36 11454
Label: 37 72714
Label: 38 153


Results from using miget_voxel_value():
Label 0: 26653169
Label 1: 0
Label 2: 933459
Label 3: 0
Label 4: 1433227
Label 5: 0
Label 6: 50946
Label 7: 0
Label 8: 670661
Label 9: 222539
Label 10: 20739
Label 11: 16317
Label 12: 3187
Label 13: 35146
Label 14: 25484
Label 15: 22038
Label 16: 4324
Label 17: 7598
Label 18: 1261
Label 19: 7977
Label 20: 0
Label 21: 7369
Label 22: 3099
Label 23: 36639
Label 24: 0
Label 25: 53097
Label 26: 0
Label 27: 10502
Label 28: 0
Label 29: 5192
Label 30: 109
Label 31: 147
Label 32: 0
Label 33: 32633
Label 34: 1149
Label 35: 918
Label 36: 0
Label 37: 258
Label 38: 38
Label 39: 244
Label 40: 260
Label 41: 4869

Code:
    mihandle_t volume;
    int result;

    result = miopen_volume("/home/trash001/Desktop/labels_on_colin_Nov2010_minc2.mnc", MI2_OPEN_READ, &volume);
    if (result == MI_ERROR) cout << "Error in opening MINC file. " << endl;

    int labels[125];
    for (int q = 0; q < 125; q++) labels[q] = 0;

    unsigned long location[3];
    double voxel;
    for (int i = 0; i < 334; i++) {
        for (int j = 0; j < 334; j++) {
            for (int k = 0; k < 334; k++) {
                location[0] = i;
                location[1] = j;
                location[2] = k;

                result = miget_voxel_value(volume, location, 3, &voxel);
                if (result == MI_ERROR) cout << "Error in reading voxels" << endl;
                else {
                    if (voxel >= 0 && voxel <= 123) {
                        labels[(int)voxel] = labels[(int)voxel] + 1;
                    }
                    else if (voxel > 123) {
                        labels[124] = labels[124] + 1;
                    }
                }
            }
        }
    }

--
Tanweer Rashid
MSVE Dept.
Old Dominion University

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