Read scale from metadata

[swharden]

using Tiff image = Tiff.Open("demo.tif", "r");

StringBuilder sb = new();

foreach (TiffTag tag in Enum.GetValues(typeof(TiffTag)))
{
    FieldValue[] values = image.GetField(tag);

    if (values is null)
        continue;

    foreach (FieldValue value in values)
        sb.AppendLine($"{tag} = {value}");
}

Console.WriteLine(sb);

SUBFILETYPE = 0
IMAGEWIDTH = 256
IMAGELENGTH = 256
BITSPERSAMPLE = 16
COMPRESSION = NONE
PHOTOMETRIC = MINISBLACK
IMAGEDESCRIPTION = ImageJ=1.53q
images=48
channels=2
frames=24
hyperstack=true
mode=composite
unit=micron
finterval=1
loop=false
min=169.0
max=8191.0
STRIPOFFSETS = System.UInt64[]
SAMPLESPERPIXEL = 1
ROWSPERSTRIP = 16
STRIPBYTECOUNTS = System.UInt64[]
XRESOLUTION = 0.848324
YRESOLUTION = 0.848324
PLANARCONFIG = CONTIG
RESOLUTIONUNIT = NONE
TILEOFFSETS = System.UInt64[]
TILEBYTECOUNTS = System.UInt64[]

public static double GetMicronsPerPixel(string tifFilePath)
{
    using Tiff image = Tiff.Open(tifFilePath, "r");
    return 1.0 / (float)image.GetField(TiffTag.XRESOLUTION).First().Value;
}

metrics of interest:

unit=micron
XRESOLUTION = 0.848324
YRESOLUTION = 0.848324