ImageMD Extension Schema
ImageMD contains technical metadata that describe a digital image.
ImageMD:
The ImageMD schema has the following top-level elements:
1. format: information about the segmentation (tile/strip) and orientation of the image;
2. spatial_metrics: information about the digital dimensions of the image; and
3. energetics: information about the pixel characteristics e.g. chromaticities, color map, response curve, etc....
ImageMDType: Complex Type for encapsulating within a single
parent element the individual technical metadata elements that describe an image or portion of an
image. But note that the top-level technical metadata elements that comprise the
ImageMD schema can be used directly under a METS mdSec.dmWrap element.
The individual elements are documented under their corresponding types.
ImageMDType has a single attribute, ID (XML ID).
formatType:
The formatType complex type contains technical metadata about the format of an image.
It has the following elements:
1. segment: information about the segmentation of the image;
2. planar_configuration: designates how the components of each pixel are stored;
3. orientation: information about the orientation of the image on disk and display.
segmentType: Complex Type for recording information about image segments of
an item or portion of an item. segmentType has 2 attributes,
ID: (XML ID)
FIELDTYPE: qualifier of the type of metadata contained in the element.
- segment_form: specifies whether the image is stored in tiles or strips;
- strip_offsets: the byte offset of a strip;
- strip_rows: the number of rows per strip;
- strip_byte_counts: the number of image data bytes stored within each strip after compression;
- tile_width: the tile width in pixels;
- tile_height: the tile height in pixels;
- tile_offsets: the byte offset of a tile;
- tile_byte_counts: the number of image data bytes stored within each tile after compression.
planar_configurationType: Complex Type for recording how the components of a pixel in
an item or portion of an item are stored. planar_configurationType has a single attribute, ID (XML ID).
orientationType: Complex Type for recording orientation information about
an item or portion of an item. orientationType has 2 attributes,
ID: (XML ID)
FIELDTYPE: qualifier of the type of metadata contained in the element.
- orientation_disk: orientation of the image on disk;
- orientation_display: orientation of the image on display.
spatial_metricsType:
The spatial_metricsType complex type provides technical metadata about the spatial metrics of an image.
It has the following elements:
1. dimensions: information about the dimensions of the image in pixels;
2. sampling_frequency: information about the sampling frequency of the image;
dimensionsType: Complex Type for recording pixel dimension information about
an item or portion of an item. dimensionsType has 2 attributes,
ID: (XML ID)
FIELDTYPE: qualifier of the type of metadata contained in the element.
- pixels_horizontal: the width of the image in pixels;
- pixels_vertical: the height of the image in pixels;
sampling_frequencyType: Complex Type for recording sampling frequency information about
an item or portion of an item. sampling_frequencyType has 2 attributes,
ID: (XML ID)
FIELDTYPE: qualifier of the type of metadata contained in the element.
- sampling_frequency_horizontal: the number of pixels per sampling frequency unit by width;
- sampling_frequency_vertical: the number of pixels per sampling frequency unit by height;
- sampling_frequency_unit: the unit of measure for horizontal and vertical sampling frequency;
- sampling_frequency_plane: the reference plane location for horizontal and vertical sampling frequency.
energeticsType:
The energetics complex type provides technical metadata about the pixel characteristics of an image.
It has the following attributes:
1. sample: information about sample and pixel size;
4. color_map: information about the red-green-blue color map (color lookup table);
5. gray_response: information about the gray response curve;
8. chromaticities: information about chromaticities.
sampleType: Complex Type for recording sample sizing information for
an item or portion of an item. sampleType has 2 attributes,
ID: (XML ID)
FIELDTYPE: qualifier of the type of metadata contained in the element.
- bits_per_sample: the number of bits per component for each pixel;
- samples_per_pixel: the number of color components per pixel;
- extra_samples: specifies that each pixel has extra components i.e. Yes or No.
color_mapType: Complex Type for recording color map information for
an item or portion of an item. color_mapType has 2 attributes,
ID: (XML ID)
FIELDTYPE: qualifier of the type of metadata contained in the element.
- color_map_location: the location of the color map i.e. Image File, Auxiliary File, Associated File, Embedded Text;
- color_map_value: the color map embedded in schema as text.
gray_responseType: Complex Type for recording gray response information for
an item or portion of an item. gray_responseType has 2 attributes,
ID: (XML ID)
FIELDTYPE: qualifier of the type of metadata contained in the element.
- gray_response_location: the location of the gray response curve i.e. Image File, Aux File, Associated File, Metadata;
- gray_response_value: the optical density of each possible pixel value embedded in schema as text;
- gray_response_unit: the unit of measure for the gray_response_curve.
chromaticitiesType: Complex Type for recording chromaticities information for
an item or portion of an item. chromaticitiesType has 2 attributes,
ID: (XML ID)
FIELDTYPE: qualifier of the type of metadata contained in the element.
- chromaticities_white_point: the white point chromaticity of the effective illumination source;
- chromaticities_primary: the chromaticities of the primary colors of the image;