MINCSTATS(1) MINC User's Guide MINCSTATS(1) NAME mincstats - calculate simple statistics across voxels of a minc file SYNOPSIS mincstats [<options>] <in1>.mnc DESCRIPTION Mincstats will calculate simple statistical measures across all voxels of a minc file. Note that these are global statistical measures and not voxel- by-voxel measures (see mincaverage for that). By default all statistics are calculated. If any statistics are requested via a command-line option, then only the requested statistics are printed. A very useful feature of this program is the ability to restrict the set of voxels included in the statistic calculation, either by restricting the range of included values, or by using a mask file with a restricted range. Multiple ranges for the input file or mask file can be specified. For each range of included volume values, and for each range of mask values, the relevant statistics are printed out (n*m values, where n is the number of volume ranges and m the number of mask ranges). These calculations are done in a single pass through the data, so specifying multiple ranges is much faster than running the program repeatedly. This is quite helpful when cal- culating many regional averages with a VOI mask volume. Special mention should be given to histograms and related statistical mea- sures. The default range of the histogram is from the smallest value in the file to the largest. In the not uncommon, but special, case when the number of histogram bins exactly matches the number of possible values in the file (e.g. 256 bins for full-range byte data), the histogram can end up with some odd features when using the default histogram range. This arises from the discretization of the data that are then rebinned into a slightly mis- matched histgram. For the example of byte data, the values that should be used are 256 bins and a histogram range that extends half a bin below the smallest value and half a bin above the largest. Use option -discrete_his- togram to work this out automatically, or use -integer_histogram to have bins of unit width if the input data are inherently integer (e.g. label data). In general, one should be careful about the rebinning of discretized data to a histogram with a bin size that is close to the level of dis- cretization. OPTIONS Note that options can be specified in abbreviated form (as long as they are unique) and can be given anywhere on the command line. The order in which the statistics are printed will be always the same irrespective or the or- der in which they are requested on the command line General options -clobber Overwrite an existing file. -noclobber Don't overwrite an existing file (default). -verbose Print out extra information (more than the default). -quiet Print out only the requested numbers -max_buffer_size_in_kb size Specify the maximum size of the internal buffers (in kbytes). De- fault is 4 MB. Invalid value options -ignore_nan Exclude invalid values (outside valid range) from statistic calcula- tions. This is the default. -include_nan Treat invalid values as zeros and include them in statistic calcula- tions. -replace_nan value Replace invalid values with the specified value and include the new value in statistic calculations. Volume range options -floor min1,min2,... Comma-separated list of lower bounds for ranges of data to include in statistic calculation. -ceil max1,max2,... Comma-separated list of upper bounds for ranges of data to include in statistic calculation. -range min1,max1,min2,max2,... Comma-separated list of lower and upper bounds for ranges of data to include in statistic calculation. -binvalue val1,val2,... Comma-separated list of integer values to include in statistic cal- culation. A range of +/- 0.5 is defined around each specified value. -mask filename.mnc Name of file to be used for masking data included in statistic cal- culation. For this to have any effect, you must specify a mask range with one of the following options. -mask_floor min1,min2,...: Like -floor, but applied to the mask file. -mask_ceil max1,max2,... Like -ceil, but applied to the mask file. -mask_range min1,max1,min2,max2,... Like -range, but applied to the mask file. -mask_binvalue val1,val2,... Like -binvalue, but applied to the mask file. Histogram options -histogram filename Specify the name of a file into which the histogram is written. If multiple ranges or mask ranges are specified, then all histograms are written in this file, separated by blank lines. Information de- scribing each histogram is written before it in lines starting with the hash (pound) character. These files can be loaded into gnuplot. -hist_bins number-of-bins Specify the number of bins in the histogram. -bins number-of-bins Synonym for -hist_bins. -hist_floor min Specify lower bound for histogram. -hist_ceil max Specify upper bound for histogram. -hist_range min max Specify a range for the histogram -integer_histogram Create bins of unit width, centred around integer values. This is useful for integer data such as labels. The histogram range is rounded to the nearest integer, then the min is lowered and the max is raised by 0.5. The number of bins is taken as the difference of these two values. Note that 0.01 is added to the minimum and sub- tracted from the maximum prior to the rounding in order to ensure that a correctly specified range (e.g. [0.5,255.5]) is preserved. If you want to have integer bins that are wider than one, you will have to work out the histogram range and number of bins yourself and not use this option. -discrete_histogram Attempt to match the histogram to the discretization of the input data. This is appropriate for continuous data that are stored in an integer representation and when a bin width close to the discretiza- tion is desired. This is similar to -integer_histogram, except that the the histogram range is first converted to voxel values which are rounded and extended by half a bin on either side. This new voxel range is then converted back to real values. The number of bins is taken as the difference in the voxel value range. Note that this does not account for variations in slice-to-slice scaling, so odd histogram effects may still occur. This option is intended to give behaviour similar to that of volume_stats. -int_max_bins number-of-bins Specify the largest histogram that can be automatically sized with the above options. The limit prevents accidental creation of huge histograms. This option replaced the old -max_bins option in MINC 1.1. Basic statistics -all Compute all statistical measures. This is the default. -none Synonym for -count (for similarity to volume_stats). Note that al- though this was necessary for volume_stats, it is not needed here, since specifying any of these options automatically turns off -all -count Count the number of voxels that are within the range and mask. -percent Print the percentage of voxels within the range and mask -volume Print the volume of the voxels within the range and mask (in mm- cubed). -min Print the minimum value. -max Print the maximum value. -sum Print the sum of all values. -sum2 Print the sum of the squares of all values. -mean Print the mean. -variance Print the variance. -stddev Print the standard deviation. -skewness Print the sample skewness (3rd moment) . -kurtosis Print the sample kurtosis (4th moment) . -CoM Print the centre of mass. Both the voxel coordinate and the world coordinates are printed. The voxel coordinates are printed in file order, whilst the world coordinates are printed in x,y,z order. -com Synonym for -CoM. -world_only Print the centre of mass in world coordinates only. Histogram statistics Note that histogram statistics are derived solely from the histogram counts and bin centres, so results such as the median will not be exactly the same as the true value for all included voxels. For example, the error on the median can be as large as a half bin width. Furthermore, if the histogram range is less than that of included voxels, then the result applies only to voxels included in the histogram. -hist_count Print number of voxels in histogram. This may be different from the number of included and masked voxels if the histogram range is less than the range of the included data. -hist_percent Print percentage of voxels included in histogram. -median Print the histogram median. -majority Print the bin centre (intensity value) for the bin with the most counts. -biModalT Print the bi-modal threshold separating the volume into two classes The default is to use the otsu method (see options below) -otsu Use the method described in Otsu N, "A Threshold Selection Method from Grey-level Histograms", IEEE Trans on Systems, Man and Cyber- netics. 1979, 9:1; 62-66 to calculate the threshold -kittler Use the Kittler&Illingworth '86 algorithm to calculate the for bi- modal threshold. Kittler, J. & Illingworth J., "Minimum error thresholding", Pattern Recognition, vol 19, pp 41-47, 1986. -kapur Use the Kapur et al. '85 algorithm to calculate the bimodal thresh- old. Kapur, Sahoo & Wong "A new method for Gray-level picture thresholding using the entropy of the histogram", Computer Vision, Graphics, and Image Processing, vol 29, pp 273-285, 1985. -simple Use simple mean-of-means algorithm to calculate the bimodal thresh- old This is more computationally expensive than some of the alterna- tives, and doesn't seem to do a great job. But it does seem more ro- bust than some of the other methods. -pctT Print the threshold needed for a particular critical percentage of the histogram. -entropy Print the Shannon entropy. H(x) = - Sum(P(i) * log2(P(i)) where P(i) is the bin probability Generic options for all commands: -help Print summary of command-line options and exit. -version Print the program's version number and exit. AUTHOR Andrew Janke COPYRIGHTS Program: Copyright (C) 2000 by Andrew Janke Man page: Copyright (C) 2001 by Peter Neelin $Date: 2004-05-20 21:52:09 $ MINCSTATS(1)
NAME | SYNOPSIS | DESCRIPTION | OPTIONS | General options | Invalid value options | Volume range options | Histogram options | Basic statistics | Histogram statistics | Generic options for all commands: | AUTHOR | COPYRIGHTS
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