deleteAnnotations

Delete annotations from EDF or EDF+ file

Since R2021a

Syntax

edfw = deleteAnnotations(edfw,annotationindices)

edfw = deleteAnnotations(edfw)

Description

edfw = deleteAnnotations(edfw,annotationindices) deletes the annotations at the indices specified in annotationindices from the European Data Format (EDF) or EDF+ file.

edfw = deleteAnnotations(edfw) deletes all the annotations present in edfw.

Examples

Delete Annotations from EDF+ File

Load an edfwrite object into the workspace that contains a timetable with 28 annotations. Each annotation corresponds to the onset of one of six arm motions or a rest period:

• Hand open – "1"

• Hand close – "2"

• Wrist flexion – "3"

• Wrist extension – "4"

• Supination – "5"

• Pronation – "6"

• Rest – "7"

load edfw

Delete the rest periods ("7") from edfw and view the annotations timetable. There are 22 annotations remaining and no instances of rest.

idx = find(edfw.Annotations.Annotations == "7");
edfw = deleteAnnotations(edfw,idx);
edfw.Annotations

ans=22×2 timetable
      Onset       Annotations    Duration
    __________    ___________    ________

    12.257 sec        "3"         3 sec  
    32.32 sec         "6"         3 sec  
    40.449 sec        "1"         3 sec  
    51.202 sec        "2"         3 sec  
    70.404 sec        "4"         3 sec  
    79.84 sec         "1"         3 sec  
    89.327 sec        "4"         3 sec  
    109.26 sec        "2"         3 sec  
    118.8 sec         "1"         3 sec  
    128.8 sec         "6"         3 sec  
    138.42 sec        "5"         3 sec  
    157.55 sec        "4"         3 sec  
    166.78 sec        "3"         3 sec  
    176.71 sec        "5"         3 sec  
    196.42 sec        "1"         3 sec  
    206.31 sec        "3"         3 sec  
      ⋮

Create a region-of-interest (ROI) table that contains the remaining annotations. Convert the duration arrays to double arrays.

anns = edfw.Annotations;
region = seconds([anns.Onset anns.Onset+anns.Duration]);
label = anns.Annotations;
roi = table(region,label)

roi=22×2 table
         region         label
    ________________    _____

    12.257    15.257     "3" 
     32.32     35.32     "6" 
    40.449    43.449     "1" 
    51.202    54.202     "2" 
    70.404    73.404     "4" 
     79.84     82.84     "1" 
    89.327    92.327     "4" 
    109.25    112.25     "2" 
    118.81    121.81     "1" 
     128.8     131.8     "6" 
    138.42    141.42     "5" 
    157.55    160.55     "4" 
    166.78    169.78     "3" 
    176.71    179.71     "5" 
    196.43    199.43     "1" 
    206.31    209.31     "3" 
      ⋮

Load the electromyography (EMG) data [1] related to the annotations. The data is available at www.sce.carleton.ca/faculty/chan/index.php?page=matlab. The sample rate is 1000 Hz. Create a signal variable that contains only the first channel of data.

load EMGdata
fs = 1000;
x = data(:,1);

Create a signal mask for the regions of interest and motion labels. Plot the EMG signal along with the annotation regions.

msk = signalMask(roi,"SampleRate",fs);
plotsigroi(msk,x)

Input Arguments

edfw — EDF or EDF+ file

edfwrite object

EDF or EDF+ file, specified as an edfwrite object.

annotationindices — Annotation indices

numeric vector

Annotation indices, specified as a numeric vector. The values in annotationindices must be row indices of the Annotations property.

Data Types: double

Output Arguments

edfw — EDF or EDF+ file

edfwrite object

EDF or EDF+ file, returned as an edfwrite object.

References

[1] Chan, Adrian D.C., and Geoffrey C. Green. 2007. "Myoelectric Control Development Toolbox". Paper presented at 30th Conference of the Canadian Medical & Biological Engineering Society, Toronto, Canada, 2007.

[2] Kemp, Bob, Alpo Värri, Agostinho C. Rosa, Kim D. Nielsen, and John Gade. “A Simple Format for Exchange of Digitized Polygraphic Recordings.” Electroencephalography and Clinical Neurophysiology 82, no. 5 (May 1992): 391–93. https://doi.org/10.1016/0013-4694(92)90009-7.

[3] Kemp, Bob, and Jesus Olivan. "European Data Format 'plus' (EDF+), an EDF Alike Standard Format for the Exchange of Physiological Data." Clinical Neurophysiology 114, no. 9 (2003): 1755–1761. https://doi.org/10.1016/S1388-2457(03)00123-8.

Version History

Introduced in R2021a