在java中如何从图像中提取相机相关信息？

Question

I am looking to extract the camera related information from a jpg using Java. I have looked around but have not been able to find a solution to my problem. I am exporting my photos from Aperture on my mac (OS X 10.7) and want to use the data from Aperture that is available in the file info.

Any ideas?

I am looking to have Dimensions and Key Words extracted from photos like this one: 80.167.88.49/masters/test.html. Currently i get an exception when trying to use the Metadata Extractor. I don't know if Aperture is adding information that cannot be handled but it throws an exception on all photos from Aperture.

Exception in thread "main" java.lang.NoClassDefFoundError: com/adobe/xmp/XMPException
    at com.drew.imaging.jpeg.JpegMetadataReader.extractMetadataFromJpegSegmentReader(Unknown Source)
    at com.drew.imaging.jpeg.JpegMetadataReader.readMetadata(Unknown Source)
    at com.drew.imaging.ImageMetadataReader.readMetadata(Unknown Source)
    at com.drew.imaging.ImageMetadataReader.readMetadata(Unknown Source)
    at ImageScaler.main(ImageScaler.java:141)
Caused by: java.lang.ClassNotFoundException: com.adobe.xmp.XMPException
    at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:306)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:247)
    ... 5 more

Code:

public static void main (String[] args){

    File image = new File("/Users/peterla/Desktop/P8214462.jpg");

    Metadata metadata = null;
    try {
    metadata = ImageMetadataReader.readMetadata(image);
    } catch (ImageProcessingException e) {
    e.printStackTrace();
    } catch (IOException e) {
    e.printStackTrace();
    }

    Directory directory;

    // Keywords
    directory = metadata.getDirectory(IptcDirectory.class);
    String keywords[] = directory.getStringArray(IptcDirectory.TAG_KEYWORDS);

    // Dimensions
    directory = metadata.getDirectory(JpegDirectory.class);     
    String height = directory.getString(JpegDirectory.TAG_JPEG_IMAGE_HEIGHT);
    String width = directory.getString(JpegDirectory.TAG_JPEG_IMAGE_WIDTH);     
}

Answer 1

You need a library to read the EXIF metadata. There's an example of how to do it with ImageIO on this blog post .

There are other libraries that you might also want to consider depending on your needs. For example MetadataExtractor or Sanselan .

Answer 2

Metadata Extractor has a simple interface for reading several types of metadata from many digital image formats. This includes the EXIF metadata format used in jpeg images. The library has good Javadoc style documentation .

The primary entry point into the library is the ImageMetadataReader object.

The Getting Started page has a nice intro, including a nice example of how to get a value for a specific tag from EXIF format metadata.

Update: Example for Extracting Keywords and Dimensions

Directory directory;
// Keywords
directory = metadata.getDirectory(IptcDirectory.class);
String keywords[] = directory.getStringArray(IptcDirectory.TAG_KEYWORDS);

// Dimensions
directory = metadata.getDirectory(JpegDirectory.class);     
String height = directory.getString(JpegDirectory.TAG_JPEG_IMAGE_HEIGHT);
String width = directory.getString(JpegDirectory.TAG_JPEG_IMAGE_WIDTH);

Alternatives

Alternatives include the builtin java ImageIO library and Sanselan .

Answer 3

jhead是一个JPEG EXIF标题操作工具，是另一种选择。