Class with static methods for EXIF tags.
This class defines the constants that represents the EXIF tags known to PEL. They are supposed to be used whenever one needs to specify an EXIF tag, and they will be denoted by the pseudo type PelTag throughout the documentation.
All the methods in this class are static and should be called with the EXIF tag on which they should operate.
Located in /PelTag.php (line 57)
Artist
This tag records the name of the camera owner, photographer or image creator. The detailed format is not specified, but it is recommended that the information be written as in the example below for ease of Interoperability. When the field is left blank, it is treated as unknown.
Battery Level
Bits per Sample
The number of bits per image component. In this standard each component of the image is 8 bits, so the value for this tag is 9. See also SAMPLES_PER_PIXEL. In JPEG compressed data a JPEG marker is used instead of this tag.
Brightness
The value of brightness. The unit is the APEX value. Ordinarily it is given in the range of -99.99 to 99.99.
CFA Pattern
Indicates the color filter array (CFA) geometric pattern of the image sensor when a one-chip color area sensor is used. It does not apply to all sensing methods.
CFA Repeat Pattern Dim
Color Space
The color space information tag is always recorded as the color space specifier. Normally sRGB (=1) is used to define the color space based on the PC monitor conditions and environment. If a color space other than sRGB is used, Uncalibrated (=FFFF.H) is set. Image data recorded as Uncalibrated can be treated as sRGB when it is converted to FlashPix. On sRGB see Appendix E.
Components Configuration
Information specific to compressed data. The channels of each component are arranged in order from the 1st component to the 4th. For uncompressed data the data arrangement is given in the PHOTOMETRIC_INTERPRETATION tag. However, since PHOTOMETRIC_INTERPRETATION can only express the order of Y, Cb and Cr, this tag is provided for cases when compressed data uses components other than Y, Cb, and Cr and to enable support of other sequences.
Compressed Bits per Pixel
Information specific to compressed data. The compression mode used for a compressed image is indicated in unit bits per pixel.
Compression
The compression scheme used for the image data. When a primary image is JPEG compressed, this designation is not necessary and is omitted. When thumbnails use JPEG compression, this tag value is set to 6.
Contrast
This tag indicates the direction of contrast processing applied by the camera when the image was shot.
Copyright
Copyright information. In this standard the tag is used to indicate both the photographer and editor copyrights. It is the copyright notice of the person or organization claiming rights to the image. The Interoperability copyright statement including date and rights should be written in this field; e.g., "Copyright, John Smith, 19xx. All rights reserved.". In this standard the field records both the photographer and editor copyrights, with each recorded in a separate part of the statement. When there is a clear distinction between the photographer and editor copyrights, these are to be written in the order of photographer followed by editor copyright, separated by NULL (in this case, since the statement also ends with a NULL, there are two NULL codes) (see example 1). When only the photographer is given, it is terminated by one NULL code (see example 2). When only the editor copyright is given, the photographer copyright part consists of one space followed by a terminating NULL code, then the editor copyright is given (see example 3). When the field is left blank, it is treated as unknown.
Custom Rendered
This tag indicates the use of special processing on image data, such as rendering geared to output. When special processing is performed, the reader is expected to disable or minimize any further processing.
Date and Time
The date and time of image creation. In this standard (EXIF-2.1) it is the date and time the file was changed.
Date and Time (digitized)
The date and time when the image was stored as digital data.
Date and Time (original)
The date and time when the original image data was generated. For a digital still camera the date and time the picture was taken are recorded.
Device Setting Description
This tag indicates information on the picture-taking conditions of a particular camera model. The tag is used only to indicate the picture-taking conditions in the reader.
Digital Zoom Ratio
This tag indicates the digital zoom ratio when the image was shot. If the numerator of the recorded value is 0, this indicates that digital zoom was not used.
Document Name
Exif IFD Pointer
A pointer to the Exif IFD. Interoperability, Exif IFD has the same structure as that of the IFD specified in TIFF. ordinarily, however, it does not contain image data as in the case of TIFF.
Exif Version
The version of this standard supported. Nonexistence of this field is taken to mean non-conformance to the standard.
Exposure Bias
The exposure bias. The units is the APEX value. Ordinarily it is given in the range of -99.99 to 99.99.
Exposure index
Indicates the exposure index selected on the camera or input device at the time the image is captured.
Exposure Mode
This tag indicates the exposure mode set when the image was shot. In auto-bracketing mode, the camera shoots a series of frames of the same scene at different exposure settings.
Exposure Program
The class of the program used by the camera to set exposure when the picture is taken.
File Source
Indicates the image source. If a DSC recorded the image, this tag value of this tag always be set to 3, indicating that the image was recorded on a DSC.
Fill Order
Flash
This tag is recorded when an image is taken using a strobe light (flash).
Flash Energy
Indicates the strobe energy at the time the image is captured, as measured in Beam Candle Power Seconds (BCPS).
FlashPix Version
The FlashPix format version supported by a FPXR file.
Focal Length
The actual focal length of the lens, in mm. Conversion is not made to the focal length of a 35 mm film camera, see the FOCAL_LENGTH_IN_35MM_FILM tag for this information.
Focal Length In 35mm Film
This tag indicates the equivalent focal length assuming a 35mm film camera, in mm. A value of 0 means the focal length is unknown. Note that this tag differs from the FOCAL_LENGTH tag.
Focal Plane Resolution Unit
Indicates the unit for measuring FOCAL_PLANE_X_RESOLUTION and FOCAL_PLANE_Y_RESOLUTION. This value is the same as the RESOLUTION_UNIT.
Focal Plane x-Resolution
Indicates the number of pixels in the image width (X) direction per FOCAL_PLANE_RESOLUTION_UNIT on the camera focal plane.
Focal Plane y-Resolution
Indicates the number of pixels in the image height (V) direction per FOCAL_PLANE_RESOLUTION_UNIT on the camera focal plane.
Gain Control
This tag indicates the degree of overall image gain adjustment.
GPS Info IFD Pointer
A pointer to the GPS Info IFD. The Interoperability structure of the GPS Info IFD, like that of Exif IFD, has no image data.
Image Description
A character string giving the title of the image. It may be a comment such as "1988 company picnic" or the like. Two-bytes character codes cannot be used. When a 2-bytes code is necessary, the Exif Private tag USER_COMMENT is to be used.
Image Length
The number of rows of image data. In JPEG compressed data a JPEG marker is used instead of this tag.
Image Unique ID
This tag indicates an identifier assigned uniquely to each image. It is recorded as an ASCII string equivalent to hexadecimal notation and 128-bit fixed length.
Image Width
The number of columns of image data, equal to the number of pixels per row. In JPEG compressed data a JPEG marker is used instead of this tag.
Interoperability IFD Pointer
Interoperability IFD is composed of tags which stores the information to ensure the Interoperability and pointed by the following tag located in Exif IFD. The Interoperability structure of Interoperability IFD is the same as TIFF defined IFD structure but does not contain the image data characteristically compared with normal TIFF IFD.
Interoperability Index
Indicates the identification of the Interoperability rule. Use "R98" for stating ExifR98 Rules. Four bytes used including the termination code (NULL). see the separate volume of Recommended Exif Interoperability Rules (ExifR98) for other tags used for ExifR98.
Interoperability Version
Inter Color Profile
IPTC/NAA
ISO Speed Ratings
Indicates the ISO Speed and ISO Latitude of the camera or input device as specified in ISO 12232.
JPEG Interchange Format
The offset to the start byte (SOI) of JPEG compressed thumbnail data. This is not used for primary image JPEG data.
JPEG Interchange Format Length
The number of bytes of JPEG compressed thumbnail data. This is not used for primary image JPEG data. JPEG thumbnails are not divided but are recorded as a continuous JPEG bitstream from SOI to EOI. Appn and COM markers should not be recorded. Compressed thumbnails must be recorded in no more than 64 Kbytes, including all other data to be recorded in APP1.
JPEGProc
Manufacturer
The manufacturer of the recording equipment. This is the manufacturer of the DSC, scanner, video digitizer or other equipment that generated the image. When the field is left blank, it is treated as unknown.
Maker Note
A tag for manufacturers of Exif writers to record any desired information. The contents are up to the manufacturer.
Max Aperture Value
The smallest F number of the lens. The unit is the APEX value. Ordinarily it is given in the range of 00.00 to 99.99, but it is not limited to this range.
Model
The model name or model number of the equipment. This is the model name or number of the DSC, scanner, video digitizer or other equipment that generated the image. When the field is left blank, it is treated as unknown.
CFA Pattern
Indicates the color filter array (CFA) geometric pattern of the image sensor when a one-chip color area sensor is used. It does not apply to all sensing methods.
OECF
Indicates the Opto-Electoric Conversion Function (OECF) specified in ISO 14524. OECF is the relationship between the camera optical input and the image values.
Orientation
The image orientation viewed in terms of rows and columns.
Photometric Interpretation
The pixel composition. In JPEG compressed data a JPEG marker is used instead of this tag.
Pixel x-Dimension
Information specific to compressed data. When a compressed file is recorded, the valid width of the meaningful image must be recorded in this tag, whether or not there is padding data or a restart marker. This tag should not exist in an uncompressed file. For details see section 2.8.1 and Appendix F.
Pixel y-Dimension
Information specific to compressed data. When a compressed file is recorded, the valid height of the meaningful image must be recorded in this tag, whether or not there is padding data or a restart marker. This tag should not exist in an uncompressed file. For details see section 2.8.1 and Appendix F. Since data padding is unnecessary in the vertical direction, the number of lines recorded in this valid image height tag will in fact be the same as that recorded in the SOF.
Planar Configuration
Indicates whether pixel components are recorded in a chunky or planar format. In JPEG compressed files a JPEG marker is used instead of this tag. If this field does not exist, the TIFF default of 1 (chunky) is assumed.
Primary Chromaticities
The chromaticity of the three primary colors of the image. Normally this tag is not necessary, since colorspace is specified in the colorspace information tag (COLOR_SPACE).
Reference Black/White
The reference black point value and reference white point value. No defaults are given in TIFF, but the values below are given as defaults here. The color space is declared in a color space information tag, with the default being the value that gives the optimal image characteristics Interoperability these conditions.
Related Image File Format
Related Image Length
Related Image Width
Related Sound File
This tag is used to record the name of an audio file related to the image data. The only relational information recorded here is the Exif audio file name and extension (an ASCII string consisting of 8 characters + '.' + 3 characters). The path is not recorded. Stipulations on audio are given in section 3.6.3. File naming conventions are given in section 3.7.1. When using this tag, audio files must be recorded in conformance to the Exif audio format. Writers are also allowed to store the data such as Audio within APP2 as FlashPix extension stream data. Audio files must be recorded in conformance to the Exif audio format. The mapping of Exif image files and audio files is done in any of the three ways shown in Table 8. If multiple files are mapped to one file as in [2] or [3] of this table, the above format is used to record just one audio file name. If there are multiple audio files, the first recorded file is given. In the case of [3] in Table 8, for example, for the Exif image file "DSC00001.JPG" only "SND00001.WAV" is given as the related Exif audio file. When there are three Exif audio files "SND00001.WAV", "SND00002.WAV" and "SND00003.WAV", the Exif image file name for each of them, "DSC00001.JPG", is indicated. By combining multiple relational information, a variety of playback possibilities can be supported. The method of using relational information is left to the implementation on the playback side. Since this information is an ASCII character string, it is terminated by NULL. When this tag is used to map audio files, the relation of the audio file to image data must also be indicated on the audio file end.
Resolution Unit
The unit for measuring X_RESOLUTION and Y_RESOLUTION. The same unit is used for both X_RESOLUTION and Y_RESOLUTION. If the image resolution is unknown, 2 (inches) is designated.
Rows per Strip
The number of rows per strip. This is the number of rows in the image of one strip when an image is divided into strips. With JPEG compressed data this designation is not needed and is omitted. See also ROWS_PER_STRIP and STRIP_BYTE_COUNTS.
Samples per Pixel
The number of components per pixel. Since this standard applies to RGB and YCbCr images, the value set for this tag is 3. In JPEG compressed data a JPEG marker is used instead of this tag.
Saturation
This tag indicates the direction of saturation processing applied by the camera when the image was shot.
Scene Capture Type
This tag indicates the type of scene that was shot. It can also be used to record the mode in which the image was shot. Note that this differs from the SCENE_TYPE tag.
Scene Type
Indicates the type of scene. If a DSC recorded the image, this tag value must always be set to 1, indicating that the image was directly photographed.
Sensing Method
Indicates the image sensor type on the camera or input device.
Sharpness
This tag indicates the direction of sharpness processing applied by the camera when the image was shot.
Shutter speed
Shutter speed. The unit is the APEX (Additive System of Photographic Exposure) setting (see Appendix C).
Software
This tag records the name and version of the software or firmware of the camera or image input device used to generate the image. The detailed format is not specified, but it is recommended that the example shown below be followed. When the field is left blank, it is treated as unknown.
Spatial Frequency Response
This tag records the camera or input device spatial frequency table and SFR values in the direction of image width, image height, and diagonal direction, as specified in ISO 12233.
Spectral Sensitivity
Indicates the spectral sensitivity of each channel of the camera used. The tag value is an ASCII string compatible with the standard developed by the ASTM Technical committee.
Strip Byte Count
The total number of bytes in each strip. With JPEG compressed data this designation is not needed and is omitted.
Strip Offsets
For each strip, the byte offset of that strip. It is recommended that this be selected so the number of strip bytes does not exceed 64 Kbytes. With JPEG compressed data this designation is not needed and is omitted. See also ROWS_PER_STRIP and STRIP_BYTE_COUNTS.
Subject Area
This tag indicates the location and area of the main subject in the overall scene.
Subject Distance Range
This tag indicates the distance to the subject.
Subject Location
Indicates the location of the main subject in the scene. The value of this tag represents the pixel at the center of the main subject relative to the left edge, prior to rotation processing as per the ROTATION tag. The first value indicates the X column number and second indicates the Y row number.
Subsec Time
A tag used to record fractions of seconds for the DATE_TIME tag.
SubSec Time Digitized
A tag used to record fractions of seconds for the DATE_TIME_DIGITIZED tag.
SubSec Time Original
A tag used to record fractions of seconds for the DATE_TIME_ORIGINAL tag.
Transfer Function
A transfer function for the image, described in tabular style. Normally this tag is not necessary, since color space is specified in the color space information tag (COLOR_SPACE).
Transfer Range
User Comment
A tag for Exif users to write keywords or comments on the image besides those in IMAGE_DESCRIPTION, and without the character code limitations of the IMAGE_DESCRIPTION tag. The character code used in the USER_COMMENT tag is identified based on an ID code in a fixed 8-byte area at the start of the tag data area. The unused portion of the area is padded with NULL ("00.h"). ID codes are assigned by means of registration. The designation method and references for each character code are given in Table 6. The value of CountN is determined based on the 8 bytes in the character code area and the number of bytes in the user comment part. Since the TYPE is not ASCII, NULL termination is not necessary (see Fig. 9). The ID code for the USER_COMMENT area may be a Defined code such as JIS or ASCII, or may be Undefined. The Undefined name is UndefinedText, and the ID code is filled with 8 bytes of all "NULL" ("00.H"). An Exif reader that reads the USER_COMMENT tag must have a function for determining the ID code. This function is not required in Exif readers that do not use the USER_COMMENT tag (see Table 7). When a USER_COMMENT area is set aside, it is recommended that the ID code be ASCII and that the following user comment part be filled with blank characters [20.H].
White Balance
This tag indicates the white balance mode set when the image was shot.
White Point
The chromaticity of the white point of the image. Normally this tag is not necessary, since color space is specified in the colorspace information tag (COLOR_SPACE).
x-Resolution
The number of pixels per RESOLUTION_UNIT in the IMAGE_WIDTH direction. When the image resolution is unknown, 72 [dpi] is designated.
YCbCr Coefficients
The matrix coefficients for transformation from RGB to YCbCr image data. No default is given in TIFF; but here the value given in Appendix E, "Color Space Guidelines", is used as the default. The color space is declared in a color space information tag, with the default being the value that gives the optimal image characteristics Interoperability this condition.
YCbCr Positioning
The position of chrominance components in relation to the luminance component. This field is designated only for JPEG compressed data or uncompressed YCbCr data. The TIFF default is 1 (centered); but when Y:Cb:Cr = 4:2:2 it is recommended in this standard that 2 (co-sited) be used to record data, in order to improve the image quality when viewed on TV systems. When this field does not exist, the reader shall assume the TIFF default. In the case of Y:Cb:Cr = 4:2:0, the TIFF default (centered) is recommended. If the reader does not have the capability of supporting both kinds of YCB_CR_POSITIONING, it shall follow the TIFF default regardless of the value in this field. It is preferable that readers be able to support both centered and co-sited positioning.
YCbCr Sub-Sampling
The sampling ratio of chrominance components in relation to the luminance component. In JPEG compressed data a JPEG marker is used instead of this tag.
y-Resolution
The number of pixels per RESOLUTION_UNIT in the IMAGE_LENGTH direction. The same value as X_RESOLUTION is designated.
Documentation generated on Wed, 21 Jul 2004 19:13:24 +0200 by phpDocumentor 1.3.0RC3