Image metadata structure consists of three sections, which are represented by sub-trees.
Common Section
The Common sub-tree contains values that are common or useful for all raw files.
All values in the Common sub-tree have Type = VALUE_ITEM and are Read Only.
| Name | Id | Native Type | Value count | Description |
|---|---|---|---|---|
| ImageWidth | ImGearDCRAWTagIDs.IMAGEWIDTH | UINT32 | 1 | Image width after that masked pixels were trimmed out |
| ImageHeight | ImGearDCRAWTagIDs.IMAGEHEIGHT | UINT32 | 1 | Image height after that masked pixels were trimmed out |
| BitsPerSample | ImGearDCRAWTagIDs.BITSPERSAMPLE | UINT32 | 1..3 | Bits per sample in the original raw image (before reconstruction) |
| PhotometricInterpretation | ImGearDCRAWTagIDs.PHOTOMETRICINTERPRETATION | UINT32 | 1 | Photometric interpretation of the original raw image |
| RawLeft | ImGearDCRAWTagIDs.RAWLEFT | UINT32 | 1 | X coordinate of first column of non-masked pixels |
| RawTop | ImGearDCRAWTagIDs.RAWTOP | UINT32 | 1 | Y coordinate of first row of non-masked pixels |
| RawWidth | ImGearDCRAWTagIDs.RAWWIDTH | UINT32 | 1 | Raw Image Width, including masked pixels |
| RawHeight | ImGearDCRAWTagIDs.RAWHEIGHT | UINT32 | 1 | Raw Image Height, including masked pixels |
| ColorPlanes | ImGearDCRAWTagIDs.COLORPLANES | UINT32 | 1 | Number of colors in the CFA pattern |
| SamplesPerPixel | ImGearDCRAWTagIDs.SAMPLESPERPIXEL | UINT32 | 1 | Number of samples per pixel in the original image, before reconstruction |
| Make | ImGearDCRAWTagIDs.MAKE | STRING | 1 | Name of the camera manufacturer |
| Model | ImGearDCRAWTagIDs.MODEL | STRING | 1 | Name of the camera model |
| UniqueCameraModel | ImGearDCRAWTagIDs.UNIQUECAMERAMODEL | STRING | 1 | Unique, non-localized name for the camera model that created the image in the raw file. |
| TimeStamp | ImGearDCRAWTagIDs.TIMESTAMP | STRING | 1 | Time stamp |
| CFARepeatPatternDim | ImGearDCRAWTagIDs.CFAREPEATPATTERNDIM | UINT16 | 2 | This tag encodes the number of pixels horizontally and vertically that are needed to uniquely define the repeat pattern of the color filter array. |
| CFAPattern | ImGearDCRAWTagIDs.CFAPATTERN | INT8 | CFARepeatPatternDim[0] * CFARepeatPatternDim[1] | This tag encodes the actual color filter array geometric pattern of the image sensor used to capture the single sensor color image. |
| AsShotNeutral | ImGearDCRAWTagIDs.ASSHOTNEUTRAL | RATIONAL_INT32 | ColorPlanes | Specifies the selected white balance at time of capture, encoded as the coordinates of a perfectly neutral color in linear reference space values. |
| WhiteLevel | ImGearDCRAWTagIDs.WHITELEVEL | RATIONAL_INT32 | 1 | Image pixel value that corresponds to fully saturated encoding level. |
| CalibrationIlluminant1 | ImGearDCRAWTagIDs.CALIBRATIONILLUMINANT1 | UINT16 | 1 | The illuminant used for ColorMatrix1 color conversion matrix. Allowed values are the same as allowed values for LightSource EXIF tag (see Exif specification). |
| CalibrationIlluminant2 | ImGearDCRAWTagIDs.CALIBRATIONILLUMINANT1 | UINT16 | 1 | The illuminant used for ColorMatrix2 color conversion matrix. Allowed values are the same as allowed values for LightSource EXIF tag (see Exif specification). |
| ColorMatrix1 | ImGearDCRAWTagIDs.COLORMATRIX1 | RATIONAL_INT32 | ColorPlanes * 3 | Conversion matrix from XYZ to camera color space, for illuminant specified by CalibrationIlluminant1 tag. Matrix is stored in row scan order. |
| ColorMatrix2 | ImGearDCRAWTagIDs.COLORMATRIX2 | RATIONAL_INT32 | ColorPlanes * 3 | Conversion matrix from XYZ to camera color space, for illuminant specified by CalibrationIlluminant2 tag. Matrix is stored in row scan order. |
| BaselineExposure | ImGearDCRAWTagIDs.BASELINEEXPOSURE | RATIONAL_INT32 | 1 | Specifies baseline exposure of the camera, in EV units. Application may use this value to adjust exposure compensation for particular camera model. |
Format-Specific Level
This level includes format-specific metadata that is found in the image (CIFF, EXIF, or TIFF). See corresponding sections for structure of metadata for these formats:
Statistics
This section contains data that is collected during image loading, rather than obtained from image's header or metadata. ImGearFileFormats.LoadPage creates this section, but ImGearFileFormats.LoadPageHeader does not, because it does not load pixel data.
Currently, the Statistics section contains image Black Level information.
Black Level specifies pixel intensity, caused by heat rather than by light. Even in absolute darkness, camera sensors report non-zero pixel intensities. Black Level should be subtracted from raw image pixel intensities in the beginning of the processing cycle. If this is not done, the image may look pale or have an unwanted tint.
In order to collect Black Level information, many digital cameras expose only the central part of the sensor to the light, and leave edges of the sensor obscured. Intensities obtained from this obscured area can be averaged to calculate Black Level.
BlackLevel information is represented as a two dimensional array, containing averaged black level values for each element of a color filter array cell.
The following tags can be present in the Statistics section:
| Name | ID | Native Type | Value Count | Description |
|---|---|---|---|---|
| BlackLevelRepeatDim | ImGearDCRAWTagIDs.BLACKLEVELREPEATDIM | UINT16 | 2 | This tag specifies repeat pattern size for the "BlackLevel" tag. |
| BlackLevel | ImGearDCRAWTagIDs.BLACKLEVEL | UINT32 | BlackLevelRepeatDim[0] * BlackLevelRepeatDim[1] | This tag specifies the image Black Level. |