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Merge pull request #295 from drewnoakes/flir
Add support for FLIR thermal image metadata
2 parents c7cbaef + ac4bf1c commit d79ec6d

19 files changed

+925
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‎MetadataExtractor.Samples/FlirSamples.cs

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// Copyright (c) Drew Noakes and contributors. All Rights Reserved. Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
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using System.Diagnostics.CodeAnalysis;
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using System.Drawing;
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using System.Drawing.Imaging;
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using System.IO;
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using System.Linq;
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using System.Runtime.InteropServices;
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using System.Windows.Media;
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using System.Windows.Media.Imaging;
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using MetadataExtractor.Formats.Flir;
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using MetadataExtractor.Formats.Jpeg;
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using MetadataExtractor.Util;
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namespace MetadataExtractor.Samples
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{
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public static class FlirSamples
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{
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public static void Main()
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{
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var inputFile = "my-input.jpg"; // path to a FLIR JPEG file
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var outputFile = "my-output.png"; // path to the output thermal image
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if (TryGetThermalImageBytesFromJpeg(inputFile, out byte[]? bytes, out int width, out int height))
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{
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WritePng(bytes, width, height, outputFile);
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}
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}
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public static bool TryGetThermalImageBytesFromJpeg(
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string jpegFile,
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[NotNullWhen(returnValue: true)] out byte[]? imageBytes,
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out int width,
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out int height)
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{
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var readers = JpegMetadataReader
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.AllReaders
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.Where(reader => reader is not FlirReader)
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.Concat(new[] { new FlirReader { ExtractRawThermalImage = true } })
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.ToList();
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var directories = JpegMetadataReader.ReadMetadata(jpegFile, readers);
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var flirRawDataDirectory = directories.OfType<FlirRawDataDirectory>().FirstOrDefault();
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if (flirRawDataDirectory is null)
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{
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imageBytes = null;
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width = 0;
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height = 0;
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return false;
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}
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width = flirRawDataDirectory.GetInt32(FlirRawDataDirectory.TagRawThermalImageWidth);
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height = flirRawDataDirectory.GetInt32(FlirRawDataDirectory.TagRawThermalImageHeight);
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imageBytes = flirRawDataDirectory.GetByteArray(FlirRawDataDirectory.TagRawThermalImage);
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return imageBytes != null;
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}
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public static void WritePng(byte[] thermalImageBytes, int width, int height, string outputFile)
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{
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var fileType = FileTypeDetector.DetectFileType(new MemoryStream(thermalImageBytes));
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if (fileType == FileType.Png)
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{
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// Data is already in PNG format.
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// It is likely already coloured and ready for presentation to a human.
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File.WriteAllBytes(outputFile, thermalImageBytes);
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return;
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}
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// Assume data is in uint16 grayscale.
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//
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// It is "raw" meaning uncoloured but, more importantly, the levels are unadjusted.
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// For example, if the scene did not have much temperature variation relative to the
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// range of the sensor, most values may be within a very narrow band of the 16-bit spectrum,
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// making the image appear a flat gray. Opening it in Photoshop/Gimp/etc and adjusting levels
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// will reveal the image.
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//
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// There is other metadata in the image that may inform this process (untested -- please
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// share if you find a good process here).
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var pixelFormats = PixelFormats.Gray16;
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var bitmap = new Bitmap(width, height, System.Drawing.Imaging.PixelFormat.Format16bppGrayScale);
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var data = bitmap.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.WriteOnly, bitmap.PixelFormat);
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Marshal.Copy(thermalImageBytes, 0, data.Scan0, thermalImageBytes.Length);
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var source = BitmapSource.Create(
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width,
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height,
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bitmap.HorizontalResolution,
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bitmap.VerticalResolution,
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pixelFormats,
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null,
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data.Scan0,
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data.Stride * height,
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data.Stride);
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bitmap.UnlockBits(data);
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using var stream = new FileStream(outputFile, FileMode.Create);
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var encoder = new PngBitmapEncoder();
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encoder.Frames.Add(BitmapFrame.Create(source));
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encoder.Save(stream);
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}
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}
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}

‎MetadataExtractor.Samples/MetadataExtractor.Samples.csproj

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<Project Sdk="Microsoft.NET.Sdk">
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<PropertyGroup>
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<TargetFrameworks>net5.0;net35;net45</TargetFrameworks>
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<TargetFramework>net48</TargetFramework>
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<OutputType>Exe</OutputType>
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<StartupObject>MetadataExtractor.Samples.Program</StartupObject>
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</PropertyGroup>
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<ItemGroup>
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<ProjectReference Include="..\MetadataExtractor\MetadataExtractor.csproj" />
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</ItemGroup>
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<ItemGroup Condition=" '$(TargetFramework)' == 'net35' ">
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<Reference Include="System" />
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<ItemGroup>
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<PackageReference Include="Nullable" Version="1.3.0">
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<PrivateAssets>all</PrivateAssets>
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<IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
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</PackageReference>
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</ItemGroup>
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<ItemGroup Condition=" '$(TargetFramework)' == 'net45' ">
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<Reference Include="System" />
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<Reference Include="Microsoft.CSharp" />
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<ItemGroup>
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<Reference Include="PresentationCore" />
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<Reference Include="WindowsBase" />
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</ItemGroup>
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</Project>

‎MetadataExtractor.Tools.FileProcessor/MetadataExtractor.Tools.FileProcessor.csproj

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<Project Sdk="Microsoft.NET.Sdk">
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<PropertyGroup>
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<TargetFrameworks>net5.0</TargetFrameworks>
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<TargetFramework>net5.0</TargetFramework>
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<OutputType>Exe</OutputType>
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</PropertyGroup>
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‎MetadataExtractor.sln.DotSettings

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<s:Boolean x:Key="/Default/UserDictionary/Words/=Finepix/@EntryIndexedValue">True</s:Boolean>
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<s:Boolean x:Key="/Default/UserDictionary/Words/=Fisheye/@EntryIndexedValue">True</s:Boolean>
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<s:Boolean x:Key="/Default/UserDictionary/Words/=Flashpix/@EntryIndexedValue">True</s:Boolean>
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<s:Boolean x:Key="/Default/UserDictionary/Words/=Flir/@EntryIndexedValue">True</s:Boolean>
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<s:Boolean x:Key="/Default/UserDictionary/Words/=Foveon/@EntryIndexedValue">True</s:Boolean>
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<s:Boolean x:Key="/Default/UserDictionary/Words/=ftyp/@EntryIndexedValue">True</s:Boolean>
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<s:Boolean x:Key="/Default/UserDictionary/Words/=Fujifilm/@EntryIndexedValue">True</s:Boolean>

‎MetadataExtractor/Formats/Exif/ExifTiffHandler.cs

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PushDirectory(new DjiMakernoteDirectory());
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TiffReader.ProcessIfd(this, reader, processedIfdOffsets, makernoteOffset);
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}
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else if (string.Equals("FLIR Systems", cameraMake, StringComparison.Ordinal))
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{
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PushDirectory(new FlirMakernoteDirectory());
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TiffReader.ProcessIfd(this, reader, processedIfdOffsets, makernoteOffset);
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}
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else
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{
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// The makernote is not comprehended by this library.

‎MetadataExtractor/Formats/Exif/makernotes/FlirMakernoteDescriptor.cs

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// Copyright (c) Drew Noakes and contributors. All Rights Reserved. Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
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using System.Diagnostics.CodeAnalysis;
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namespace MetadataExtractor.Formats.Exif.Makernotes
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{
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[SuppressMessage("ReSharper", "MemberCanBePrivate.Global")]
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public class FlirMakernoteDescriptor : TagDescriptor<FlirMakernoteDirectory>
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{
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public FlirMakernoteDescriptor(FlirMakernoteDirectory directory)
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: base(directory)
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{
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}
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}
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}

‎MetadataExtractor/Formats/Exif/makernotes/FlirMakernoteDirectory.cs

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// Copyright (c) Drew Noakes and contributors. All Rights Reserved. Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
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using System.Collections.Generic;
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using System.Diagnostics.CodeAnalysis;
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namespace MetadataExtractor.Formats.Exif.Makernotes
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{
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[SuppressMessage("ReSharper", "MemberCanBePrivate.Global")]
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public class FlirMakernoteDirectory : Directory
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{
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public const int TagImageTemperatureMax = 0x0001;
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public const int TagImageTemperatureMin = 0x0002;
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public const int TagEmissivity = 0x0003;
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public const int TagUnknownTemperature = 0x0004;
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public const int TagCameraTemperatureRangeMin = 0x0005;
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public const int TagCameraTemperatureRangeMax = 0x0006;
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private static readonly Dictionary<int, string> _tagNameMap = new()
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{
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{ TagImageTemperatureMax, "Image Temperature Max" },
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{ TagImageTemperatureMin, "Image Temperature Min" },
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{ TagEmissivity, "Emissivity" },
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{ TagUnknownTemperature, "Unknown Temperature" },
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{ TagCameraTemperatureRangeMin, "Camera Temperature Range Max" },
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{ TagCameraTemperatureRangeMax, "Camera Temperature Range Min" }
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};
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public FlirMakernoteDirectory() : base(_tagNameMap)
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{
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SetDescriptor(new FlirMakernoteDescriptor(this));
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}
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public override string Name => "FLIR Makernote";
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}
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}

‎MetadataExtractor/Formats/Flir/FlirCameraInfoDescriptor.cs

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// Copyright (c) Drew Noakes and contributors. All Rights Reserved. Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
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using static MetadataExtractor.Formats.Flir.FlirCameraInfoDirectory;
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namespace MetadataExtractor.Formats.Flir
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{
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public sealed class FlirCameraInfoDescriptor : TagDescriptor<FlirCameraInfoDirectory>
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{
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public FlirCameraInfoDescriptor(FlirCameraInfoDirectory directory)
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: base(directory)
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{
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}
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public override string? GetDescription(int tagType)
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{
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return tagType switch
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{
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TagReflectedApparentTemperature => KelvinToCelcius(),
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TagAtmosphericTemperature => KelvinToCelcius(),
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TagIRWindowTemperature => KelvinToCelcius(),
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TagRelativeHumidity => RelativeHumidity(),
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TagCameraTemperatureRangeMax => KelvinToCelcius(),
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TagCameraTemperatureRangeMin => KelvinToCelcius(),
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TagCameraTemperatureMaxClip => KelvinToCelcius(),
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TagCameraTemperatureMinClip => KelvinToCelcius(),
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TagCameraTemperatureMaxWarn => KelvinToCelcius(),
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TagCameraTemperatureMinWarn => KelvinToCelcius(),
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TagCameraTemperatureMaxSaturated => KelvinToCelcius(),
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TagCameraTemperatureMinSaturated => KelvinToCelcius(),
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_ => base.GetDescription(tagType)
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};
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string KelvinToCelcius()
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{
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float f = Directory.GetSingle(tagType) - 273.15f;
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return $"{f:N1} C";
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}
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string RelativeHumidity()
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{
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float f = Directory.GetSingle(tagType);
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float val = (f > 2 ? f / 100 : f);
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return $"{(val * 100):N1} %";
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}
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}
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}
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}

‎MetadataExtractor/Formats/Flir/FlirCameraInfoDirectory.cs

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// Copyright (c) Drew Noakes and contributors. All Rights Reserved. Licensed under the Apache License, Version 2.0. See LICENSE in the project root for license information.
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using System.Collections.Generic;
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namespace MetadataExtractor.Formats.Flir
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{
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public sealed class FlirCameraInfoDirectory : Directory
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{
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public const int TagEmissivity = 32;
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public const int TagObjectDistance = 36;
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public const int TagReflectedApparentTemperature = 40;
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public const int TagAtmosphericTemperature = 44;
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public const int TagIRWindowTemperature = 48;
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public const int TagIRWindowTransmission = 52;
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public const int TagRelativeHumidity = 60;
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public const int TagPlanckR1 = 88;
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public const int TagPlanckB = 92;
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public const int TagPlanckF = 96;
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public const int TagAtmosphericTransAlpha1 = 112;
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public const int TagAtmosphericTransAlpha2 = 116;
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public const int TagAtmosphericTransBeta1 = 120;
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public const int TagAtmosphericTransBeta2 = 124;
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public const int TagAtmosphericTransX = 128;
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public const int TagCameraTemperatureRangeMax = 144;
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public const int TagCameraTemperatureRangeMin = 148;
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public const int TagCameraTemperatureMaxClip = 152;
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public const int TagCameraTemperatureMinClip = 156;
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public const int TagCameraTemperatureMaxWarn = 160;
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public const int TagCameraTemperatureMinWarn = 164;
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public const int TagCameraTemperatureMaxSaturated = 168;
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public const int TagCameraTemperatureMinSaturated = 172;
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public const int TagCameraModel = 212;
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public const int TagCameraPartNumber = 244;
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public const int TagCameraSerialNumber = 260;
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public const int TagCameraSoftware = 276;
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public const int TagLensModel = 368;
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public const int TagLensPartNumber = 400;
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public const int TagLensSerialNumber = 416;
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public const int TagFieldOfView = 436;
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public const int TagFilterModel = 492;
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public const int TagFilterPartNumber = 508;
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public const int TagFilterSerialNumber = 540;
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public const int TagPlanckO = 776;
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public const int TagPlanckR2 = 780;
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public const int TagRawValueRangeMin = 784;
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public const int TagRawValueRangeMax = 786;
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public const int TagRawValueMedian = 824;
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public const int TagRawValueRange = 828;
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public const int TagDateTimeOriginal = 900;
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public const int TagFocusStepCount = 912;
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public const int TagFocusDistance = 1116;
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public const int TagFrameRate = 1124;
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public override string Name => "FLIR Camera Info";
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private static readonly Dictionary<int, string> _nameByTag = new()
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{
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{ TagEmissivity, "Emissivity" },
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{ TagObjectDistance, "Object Distance" },
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{ TagReflectedApparentTemperature, "Reflected Apparent Temperature" },
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{ TagAtmosphericTemperature, "Atmospheric Temperature" },
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{ TagIRWindowTemperature, "IR Window Temperature" },
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{ TagIRWindowTransmission, "IR Window Transmission" },
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{ TagRelativeHumidity, "Relative Humidity" },
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{ TagPlanckR1, "Planck R1" },
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{ TagPlanckB, "Planck B" },
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{ TagPlanckF, "Planck F" },
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{ TagAtmosphericTransAlpha1, "Atmospheric Trans Alpha1" },
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{ TagAtmosphericTransAlpha2, "Atmospheric Trans Alpha2" },
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{ TagAtmosphericTransBeta1, "Atmospheric Trans Beta1" },
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{ TagAtmosphericTransBeta2, "Atmospheric Trans Beta2" },
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{ TagAtmosphericTransX, "Atmospheric Trans X" },
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{ TagCameraTemperatureRangeMax, "Camera Temperature Range Max" },
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{ TagCameraTemperatureRangeMin, "Camera Temperature Range Min" },
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{ TagCameraTemperatureMaxClip, "Camera Temperature Max Clip" },
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{ TagCameraTemperatureMinClip, "Camera Temperature Min Clip" },
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{ TagCameraTemperatureMaxWarn, "Camera Temperature Max Warn" },
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{ TagCameraTemperatureMinWarn, "Camera Temperature Min Warn" },
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{ TagCameraTemperatureMaxSaturated, "Camera Temperature Max Saturated" },
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{ TagCameraTemperatureMinSaturated, "Camera Temperature Min Saturated" },
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{ TagCameraModel, "Camera Model" },
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{ TagCameraPartNumber, "Camera Part Number" },
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{ TagCameraSerialNumber, "Camera Serial Number" },
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{ TagCameraSoftware, "Camera Software" },
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{ TagLensModel, "Lens Model" },
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{ TagLensPartNumber, "Lens Part Number" },
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{ TagLensSerialNumber, "Lens Serial Number" },
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{ TagFieldOfView, "Field Of View" },
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{ TagFilterModel, "Filter Model" },
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{ TagFilterPartNumber, "Filter Part Number" },
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{ TagFilterSerialNumber, "Filter Serial Number" },
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{ TagPlanckO, "Planck O" },
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{ TagPlanckR2, "Planck R2" },
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{ TagRawValueRangeMin, "Raw Value Range Min" },
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{ TagRawValueRangeMax, "Raw Value Range Max" },
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{ TagRawValueMedian, "Raw Value Median" },
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{ TagRawValueRange, "Raw Value Range" },
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{ TagDateTimeOriginal, "Date Time Original" },
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{ TagFocusStepCount, "Focus Step Count" },
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{ TagFocusDistance, "Focus Distance" },
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{ TagFrameRate, "Frame Rate" }
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};
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public FlirCameraInfoDirectory() : base(_nameByTag)
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{
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SetDescriptor(new FlirCameraInfoDescriptor(this));
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}
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}
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}

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