[C#] 画像ファイルからExif情報を読み出す

C#でExif情報を読み出すプログラムを書けないか調べたところ、System.Drawing.Image.PropertyItems プロパティを使って画像に格納されたメタデータを取得できることがわかった。

Image.PropertyItems プロパティ (System.Drawing)
http://msdn.microsoft.com/ja-jp/library/system.drawing.image.propertyitems(v=vs.90).aspx

Exif情報をテキストファイルにダンプするサンプルを書いてみた。

string fileName = @"C:\Temp\Exif test\ff_x_e1_001.JPG";
string dumpName = @"C:\Temp\Exif test\ff_x_e1_001.txt";
StreamWriter sw = new StreamWriter(dumpName);
Bitmap bitmap = new Bitmap(fileName);
foreach (PropertyItem item in bitmap.PropertyItems)
{
    sw.Write("Id: {0:X4}, Len: {1}, Type: {2}, Value: ", item.Id, item.Len, item.Type);
 
    switch (item.Type)
    {
    case 1: // BYTE: array of bytes
        for (int i = 0; i < item.Len; i++)
            sw.Write("{0} ", item.Value[i].ToString("X2"));
        break;
    case 2: // ASCII: null-terminated ASCII string
        sw.Write(Encoding.ASCII.GetString(item.Value));
        break;
    case 3: // SHORT: array of unsigned short (16bit)
        for (int i = 0; i < item.Len; i += 2)
            sw.Write("{0} ", BitConverter.ToUInt16(item.Value, i));
        break;
    case 4: // LONG: array of unsigned long (32bit)
        for (int i = 0; i < item.Len; i += 4)
            sw.Write("{0} ", BitConverter.ToUInt32(item.Value, i));
        break;
    case 5: // RATIONAL: array of pairs of unsigned long
        for (int i = 0; i < item.Len; i += 8)
            sw.Write("{0}/{1} ",
                BitConverter.ToUInt32(item.Value, i),
                BitConverter.ToUInt32(item.Value, i + 4));
        break;
    case 7: // UNDEFINED: array of bytes
        for (int i = 0; i < item.Len; i++)
            sw.Write("{0} ", item.Value[i].ToString("X2"));
        break;
    case 9: // SLONG: array of singed long
        for (int i = 0; i < item.Len; i += 4)
            sw.Write("{0} ", BitConverter.ToInt32(item.Value, i));
        break;
    case 10: // SRATIONAL: array of pairs of singed long
        for (int i = 0; i < item.Len; i += 8)
            sw.Write("{0}/{1} ",
                BitConverter.ToInt32(item.Value, i),
                BitConverter.ToInt32(item.Value, i + 4));
        break;
    }
    sw.WriteLine("");
}
bitmap.Dispose();
sw.Close();

Id: 010F, Len: 9, Type: 2, Value: FUJIFILM 
Id: 0110, Len: 5, Type: 2, Value: X-E1 
Id: 0112, Len: 2, Type: 3, Value: 1 
Id: 011A, Len: 8, Type: 5, Value: 72/1 
Id: 011B, Len: 8, Type: 5, Value: 72/1 
Id: 0128, Len: 2, Type: 3, Value: 2 
Id: 0131, Len: 28, Type: 2, Value: Digital Camera X-E1 Ver1.01 
Id: 0132, Len: 20, Type: 2, Value: 2012:09:29 10:16:13 
Id: 0213, Len: 2, Type: 3, Value: 2 
Id: 8298, Len: 5, Type: 2, Value: 
Id: 829A, Len: 8, Type: 5, Value: 10/1700 
Id: 829D, Len: 8, Type: 5, Value: 400/100 
Id: 8822, Len: 2, Type: 3, Value: 3 
Id: 8827, Len: 2, Type: 3, Value: 200 
Id: 8830, Len: 2, Type: 3, Value: 1 
Id: 9000, Len: 4, Type: 7, Value: 30 32 33 30 
Id: 9003, Len: 20, Type: 2, Value: 2012:09:29 10:16:13 
Id: 9004, Len: 20, Type: 2, Value: 2012:09:29 10:16:13 
Id: 9101, Len: 4, Type: 7, Value: 01 02 03 00 
Id: 9102, Len: 8, Type: 5, Value: 32/10 
Id: 9201, Len: 8, Type: 10, Value: 749/100 
Id: 9202, Len: 8, Type: 5, Value: 400/100 
Id: 9203, Len: 8, Type: 10, Value: 597/100 
Id: 9204, Len: 8, Type: 10, Value: -33/100 
Id: 9205, Len: 8, Type: 5, Value: 300/100 
Id: 9207, Len: 2, Type: 3, Value: 5 
Id: 9208, Len: 2, Type: 3, Value: 0 
Id: 9209, Len: 2, Type: 3, Value: 16 
Id: 920A, Len: 8, Type: 5, Value: 1800/100 
 (以下略)

Exifデータの意味については仕様書を参照。

JEITA / JEITA規格・AV電子機器部門（デジタルカメラ<電子カメラ一般>関係）
http://www.jeita.or.jp/cgi-bin/standard/list.cgi?cateid=1&subcateid=4

Exchangeable image file format for digital still cameras: Exif Version 2.3
http://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf