The NITF image header (sarpy.io.general.nitf_elements.image)

The image subheader definitions.

class sarpy.io.general.nitf_elements.image.ImageBand(**kwargs)

Bases: NITFElement

Single image band, part of the image bands collection

IREPBAND: str

Representation. This field shall contain a valid indicator of the processing required to display the nth band of the image with regard to the general image type as recorded in the IREP field. The significance of each band in the image can be derived from the combination of the ICAT, and ISUBCAT fields. Valid values of the IREPBAND field depend on the value of the IREP field.

Type:

str

ISUBCAT: str

Subcategory. The purpose of this field is to provide the significance of the band of the image with regard to the specific category (ICAT field) of the overall image.

Type:

str

IFC: str

Image Filter Condition. Takes values in {'N'}. Default value is N.

Type:

str

IMFLT: str

Standard Image Filter Code. This field is reserved for future use.

Type:

str

classmethod minimum_length()

The minimum size in bytes that takes to write this header element.

Return type:

int

property LUTD

The Look-up Table (LUT) data.

Return type:

None|numpy.ndarray

property NLUTS

Number of LUTS for the Image Band. This field shall contain the number of LUTs associated with the nth band of the image. LUTs are allowed only if the value of the PVTYPE field is INT or B.

Return type:

int

property NELUTS

Number of LUT Entries for the Image Band. This field shall contain the number of entries in each of the LUTs for the nth image band.

Return type:

int

classmethod from_bytes(value, start)

Parameters:

• value (bytes|str) – the header string to scrape

• start (int) – the beginning location in the string

get_bytes_length()

Get the length of the serialized bytes array

Return type:

int

to_bytes()

Write the object to a properly packed str.

Return type:

bytes

to_json()

Serialize element to a json representation. This is intended to allow a simple presentation of the element.

Return type:

dict

class sarpy.io.general.nitf_elements.image.ImageSegmentHeader(**kwargs)

Bases: NITFElement

The image segment header - see standards document Joint BIIF Profile (JBP) for more information.

IM: str

File part type. Takes values in {'IM'}. Default value is IM.

Type:

str

IID1: str

Image Identifier 1. This field shall contain a valid alphanumeric identification code associated with the image. The valid codes are determined by the application.

Type:

str

IDATIM: str

Image Date and Time. This field shall contain the time (UTC) of the image acquisition in the format YYYYMMDDhhmmss.

Type:

str

TGTID: str

Target Identifier. This field shall contain the identification of the primary target in the format, BBBBBBBBBBOOOOOCC, consisting of ten characters of Basic Encyclopedia (BE) identifier, followed by five characters of facility OSUFFIX, followed by the two character country code as specified in FIPS PUB 10-4.

Type:

str

IID2: str

Image Identifier 2. This field can contain the identification of additional information about the image.

Type:

str

Security: NITFSecurityTags

The image security tags.

Type:

NITFSecurityTags

ENCRYP: str

Encryption. Takes values in {'0'}. Default value is 0.

Type:

str

ISORCE: str

Image Source. This field shall contain a description of the source of the image. If the source of the data is classified, then the description shall be preceded by the classification, including codeword(s).

Type:

str

NROWS: int

Only the rows indexed 0 to the value of the NROWS field minus 1 of the image contain significant data. The pixel fill values are determined by the application. Default value is 0.

Type:

int

Type:

Number of Significant Rows in Image. This field shall contain the total number of rows of significant pixels in the image. When the product of the values of the NPPBV field and the NBPC field is greater than the value of the NROWS field (\(NPPBV \cdot NBPC > NROWS\)), the rows indexed with the value of the NROWS field to (\(NPPBV\cdot NBPC - 1\)) shall contain fill data. NOTE

NCOLS: int

Only the columns indexed 0 to the value of the NCOLS field minus 1 of the image contain significant data. The pixel fill values are determined by the application. Default value is 0.

Type:

int

Type:

Number of Significant Columns in Image. This field shall contain the total number of columns of significant pixels in the image. When the product of the values of the NPPBH field and the NBPR field is greater than the NCOLS field (\(NPPBH\cdot NBPR > NCOLS\)), the columns indexed with the value of the NCOLS field to (\(NPPBH\cdot NBPR - 1\)) shall contain fill data. NOTE

PVTYPE: str

Pixel Value Type. This field shall contain an indicator of the type of computer representation used for the value for each pixel for each band in the image. Takes values in {'R', 'INT', 'SI', 'B', 'C'}.

Type:

str

IREP: str

Image Representation. This field shall contain a valid indicator of the processing required in order to display an image. Takes values in {'NODISPLY', 'RGB/LUT', 'MONO', 'NVECTOR', 'YCbCr601', 'RGB', 'POLAR', 'VPH', 'MULTI'}. Default value is NODISPLY.

Type:

str

ICAT: str

Image Category. This field shall contain a valid indicator of the specific category of image, raster or grid data. The specific category of an IS reveals its intended use or the nature of its collector. Default value is SAR.

Type:

str

ABPP: int

Actual Bits-Per-Pixel Per Band. This field shall contain the number of “significant bits” for the value in each band of each pixel without compression. Even when the image is compressed, ABPP contains the number of significant bits per pixel that were present in the image before compression. This field shall be less than or equal to Number of Bits Per Pixel (field NBPP). The number of adjacent bits within each NBPP is used to represent the value. Default value is 0.

Type:

int

PJUST: str

Pixel Justification. When ABPP is not equal to NBPP, this field indicates whether the significant bits are left justified (L) or right justified (R). Takes values in {'R', 'L'}. Default value is R.

Type:

str

ICORDS: str

Image Coordinate Representation. This field shall contain a valid code indicating the type of coordinate representation used for providing an approximate location of the image in the Image Geographic Location field (IGEOLO). Takes values in {'', 'N', 'D', 'S', 'U', 'G'}. Default value is G.

Type:

str

Comments: ImageComments

The image comments.

Type:

ImageComments

Bands: ImageBands

The image bands.

Type:

ImageBands

ISYNC: int

Image Sync code. This field is reserved for future use. Default value is 0.

Type:

int

IMODE: str

Image Mode. This field shall indicate how the Image Pixels are stored in the NITF file. Takes values in {'B', 'R', 'P', 'S'}. Default value is P.

Type:

str

NBPR: int

Number of Blocks Per Row. This field shall contain the number of image blocks in a row of blocks (paragraph 5.4.2.2) in the horizontal direction. If the image consists of only a single block, this field shall contain the value one. Default value is 1.

Type:

int

NBPC: int

Number of Blocks Per Column. This field shall contain the number of image blocks in a column of blocks (paragraph 5.4.2.2) in the vertical direction. If the image consists of only a single block, this field shall contain the value one. Default value is 1.

Type:

int

NPPBH: int

Number of Pixels Per Block Horizontal. This field shall contain the number of pixels horizontally in each block of the image. It shall be the case that the product of the values of the NBPR field and the NPPBH field is greater than or equal to the value of the NCOLS field (\(NBPR\cdot NPPBH \geq NCOLS\)). When NBPR is 1, setting the NPPBH value to 0 designates that the number of pixels horizontally is specified by the value in NCOLS. Default value is 0.

Type:

int

NPPBV: int

Number of Pixels Per Block Vertical. This field shall contain the number of pixels vertically in each block of the image. It shall be the case that the product of the values of the NBPC field and the NPPBV field is greater than or equal to the value of the NROWS field (\(NBPC\cdot NPPBV \geq NROWS\)). When NBPC is 1, setting the NPPBV value to 0 designates that the number of pixels vertically is specified by the value in NROWS. Default value is 0.

Type:

int

NBPP: int

Number of Bits Per Pixel Per Band. Default value is 0.

Type:

int

IDLVL: int

Image Display Level. This field shall contain a valid value that indicates the display level of the image relative to other displayed file components in a composite display. The valid values are 1-999. The display level of each displayable segment (image or graphic) within a file shall be unique. Default value is 0.

Type:

int

IALVL: int

Attachment Level. This field shall contain a valid value that indicates the attachment level of the image. Default value is 0.

Type:

int

ILOC: str

Image Location. The image location is the location of the first pixel of the first line of the image. This field shall contain the image location offset from the ILOC or SLOC value of the segment to which the image is attached or from the origin of the CCS when the image is unattached (IALVL contains 0). A row or column value of 0 indicates no offset. Positive row and column values indicate offsets down and to the right while negative row and column values indicate offsets up and to the left.

Type:

str

IMAG: str

Image Magnification. This field shall contain the magnification (or reduction) factor of the image relative to the original source image. Decimal values are used to indicate magnification, and decimal fraction values indicate reduction. For example, 2.30 indicates the original image has been magnified by a factor of 2.30, while 0.5 indicates the original image has been reduced by a factor of 2. Default value is 1.0.

Type:

str

UserHeader: UserHeaderType

User defined header.

Type:

UserHeaderType

ExtendedHeader: UserHeaderType

Extended subheader - TRE list.

Type:

UserHeaderType

property is_masked

Does this image segment contain a mask?

Type:

bool

property is_compressed

Is this image segment compressed?

Type:

bool

property IC

Image Compression. This field shall contain a valid code indicating the form of compression used in representing the image data.

Valid values for this field are, C1 to represent bi-level, C3 to represent JPEG, C4 to represent Vector Quantization, C5 to represent lossless JPEG, I1 to represent down sampled JPEG, and NC to represent the image is not compressed. Also valid are M1, M3, M4, and M5 for compressed images, and NM for uncompressed images indicating an image that contains a block mask and/or a pad pixel mask. C6 and M6 are reserved values that will represent a future correlated multicomponent compression algorithm. C7 and M7 are reserved values that will represent a future complex SAR compression. C8 and M8 are the values for ISO standard compression JPEG 2000.

The format of a mask image is identical to the format of its corresponding non-masked image except for the presence of an Image Data Mask at the beginning of the image data area. The format of the Image Data Mask is described in paragraph 5.4.3.2 and is shown in table A-3(A). The definitions of the compression schemes associated with codes C1/M1, C3/M3, C4/M4, C5/M5 are given, respectively, in ITU- T T.4, AMD2, MIL-STD-188-198A, MIL-STD- 188-199, and NGA N0106-97. C1 is found in ITU- T T.4 AMD2, C3 is found in MIL-STD-188-198A, C4 is found in MIL-STD-188-199, and C5 and I1 are found in NGA N0106-97. (NOTE: C2 (ARIDPCM) is not valid in NITF 2.1.) The definition of the compression scheme associated with codes C8/M8 is found in ISO/IEC 15444- 1:2000 (with amendments 1 and 2).

Type:

str

property COMRAT

Compression Rate Code. If the IC field contains one of C1, C3, C4, C5, C8, M1, M3, M4, M5, M8, I1, this field shall be contain a code indicating the compression rate for the image.

If IC is NC or NM, then this will be set to None.

Type:

None|str

property IGEOLO

Image Geographic Location. This field, when present, shall contain an approximate geographic location which is not intended for analytical purposes (e.g., targeting, mensuration, distance calculation); it is intended to support general user appreciation for the image location (e.g., cataloguing). The representation of the image corner locations is specified in the ICORDS field. The locations of the four corners of the (significant) image data shall be given in image coordinate order: (0,0), (0, MaxCol), (MaxRow, MaxCol), (MaxRow, 0). MaxCol and MaxRow shall be determined from the values contained, respectively, in the NCOLS field and the NROWS field.

Type:

None|str

property mask_subheader: None | MaskSubheader

The mask subheader, if it has been appended.

Type:

None|MaskSubheader

classmethod minimum_length()

The minimum size in bytes that takes to write this header element.

Return type:

int

get_uncompressed_block_size() → int

Gets the size of an uncompressed block.

Note that if IMODE == ‘S’, then each block consists of a single band. Otherwise, a block consists of all bands.

Return type:

int

get_full_uncompressed_image_size() → int

Gets the full size in bytes of the uncompressed image including any padding in the blocks.

Return type:

int

get_clevel() → int

Gets the CLEVEL value for this image segment.

Return type:

int

classmethod from_bytes(value, start)

Parameters:

• value (bytes|str) – the header string to scrape

• start (int) – the beginning location in the string

get_bytes_length()

Get the length of the serialized bytes array

Return type:

int

to_bytes()

Write the object to a properly packed str.

Return type:

bytes

to_json()

Serialize element to a json representation. This is intended to allow a simple presentation of the element.

Return type:

dict

class sarpy.io.general.nitf_elements.image.ImageSegmentHeader0(**kwargs)

Bases: NITFElement

The image segment header for NITF version 2.0 - see standards document MIL-STD-2500A for more information.

IM: str

File part type. Takes values in {'IM'}. Default value is IM.

Type:

str

IID: str

Image Identifier 1. This field shall contain a valid alphanumeric identification code associated with the image. The valid codes are determined by the application.

Type:

str

IDATIM: str

Image Date and Time. This field shall contain the time (UTC) of the image acquisition in the format YYYYMMDDhhmmss.

Type:

str

TGTID: str

Target Identifier. This field shall contain the identification of the primary target in the format, BBBBBBBBBBOOOOOCC, consisting of ten characters of Basic Encyclopedia (BE) identifier, followed by five characters of facility OSUFFIX, followed by the two character country code as specified in FIPS PUB 10-4.

Type:

str

ITITLE: str

Image Identifier 2. This field can contain the identification of additional information about the image.

Type:

str

Security: NITFSecurityTags0

The image security tags.

Type:

NITFSecurityTags0

ENCRYP: str

Encryption. Takes values in {'0'}. Default value is 0.

Type:

str

ISORCE: str

Image Source. This field shall contain a description of the source of the image. If the source of the data is classified, then the description shall be preceded by the classification, including codeword(s).

Type:

str

NROWS: int

Only the rows indexed 0 to the value of the NROWS field minus 1 of the image contain significant data. The pixel fill values are determined by the application. Default value is 0.

Type:

int

Type:

Number of Significant Rows in Image. This field shall contain the total number of rows of significant pixels in the image. When the product of the values of the NPPBV field and the NBPC field is greater than the value of the NROWS field (\(NPPBV \cdot NBPC > NROWS\)), the rows indexed with the value of the NROWS field to (\(NPPBV\cdot NBPC - 1\)) shall contain fill data. NOTE

NCOLS: int

Only the columns indexed 0 to the value of the NCOLS field minus 1 of the image contain significant data. The pixel fill values are determined by the application. Default value is 0.

Type:

int

Type:

Number of Significant Columns in Image. This field shall contain the total number of columns of significant pixels in the image. When the product of the values of the NPPBH field and the NBPR field is greater than the NCOLS field (\(NPPBH\cdot NBPR > NCOLS\)), the columns indexed with the value of the NCOLS field to (\(NPPBH\cdot NBPR - 1\)) shall contain fill data. NOTE

PVTYPE: str

Pixel Value Type. This field shall contain an indicator of the type of computer representation used for the value for each pixel for each band in the image. Takes values in {'R', 'INT', 'SI', 'B', 'C'}.

Type:

str

IREP: str

Image Representation. This field shall contain a valid indicator of the processing required in order to display an image. Takes values in {'NODISPLY', 'RGB/LUT', 'MONO', 'NVECTOR', 'YCbCr601', 'RGB', 'POLAR', 'VPH', 'MULTI'}. Default value is NODISPLY.

Type:

str

ICAT: str

Image Category. This field shall contain a valid indicator of the specific category of image, raster or grid data. The specific category of an IS reveals its intended use or the nature of its collector. Default value is SAR.

Type:

str

ABPP: int

Actual Bits-Per-Pixel Per Band. This field shall contain the number of “significant bits” for the value in each band of each pixel without compression. Even when the image is compressed, ABPP contains the number of significant bits per pixel that were present in the image before compression. This field shall be less than or equal to Number of Bits Per Pixel (field NBPP). The number of adjacent bits within each NBPP is used to represent the value. Default value is 0.

Type:

int

PJUST: str

Pixel Justification. When ABPP is not equal to NBPP, this field indicates whether the significant bits are left justified (L) or right justified (R). Takes values in {'R', 'L'}. Default value is R.

Type:

str

ICORDS: str

Image Coordinate Representation. This field shall contain a valid code indicating the type of coordinate representation used for providing an approximate location of the image in the Image Geographic Location field (IGEOLO). Takes values in {'U', 'N', 'G', 'C'}. Default value is G.

Type:

str

Comments: ImageComments

The image comments.

Type:

ImageComments

Bands: ImageBands

The image bands.

Type:

ImageBands

ISYNC: int

Image Sync code. This field is reserved for future use. Default value is 0.

Type:

int

IMODE: str

Image Mode. This field shall indicate how the Image Pixels are stored in the NITF file. Takes values in {'B', 'R', 'P', 'S'}. Default value is P.

Type:

str

NBPR: int

Number of Blocks Per Row. This field shall contain the number of image blocks in a row of blocks (paragraph 5.4.2.2) in the horizontal direction. If the image consists of only a single block, this field shall contain the value one. Default value is 1.

Type:

int

NBPC: int

Number of Blocks Per Column. This field shall contain the number of image blocks in a column of blocks (paragraph 5.4.2.2) in the vertical direction. If the image consists of only a single block, this field shall contain the value one. Default value is 1.

Type:

int

NPPBH: int

Number of Pixels Per Block Horizontal. This field shall contain the number of pixels horizontally in each block of the image. It shall be the case that the product of the values of the NBPR field and the NPPBH field is greater than or equal to the value of the NCOLS field (\(NBPR\cdot NPPBH \geq NCOLS\)). When NBPR is 1, setting the NPPBH value to 0 designates that the number of pixels horizontally is specified by the value in NCOLS. Default value is 0.

Type:

int

NPPBV: int

Number of Pixels Per Block Vertical. This field shall contain the number of pixels vertically in each block of the image. It shall be the case that the product of the values of the NBPC field and the NPPBV field is greater than or equal to the value of the NROWS field (\(NBPC\cdot NPPBV \geq NROWS\)). When NBPC is 1, setting the NPPBV value to 0 designates that the number of pixels vertically is specified by the value in NROWS. Default value is 0.

Type:

int

NBPP: int

Number of Bits Per Pixel Per Band. Default value is 0.

Type:

int

IDLVL: int

Image Display Level. This field shall contain a valid value that indicates the display level of the image relative to other displayed file components in a composite display. The valid values are 1-999. The display level of each displayable segment (image or graphic) within a file shall be unique. Default value is 0.

Type:

int

IALVL: int

Attachment Level. This field shall contain a valid value that indicates the attachment level of the image. Default value is 0.

Type:

int

ILOC: str

Image Location. The image location is the location of the first pixel of the first line of the image. This field shall contain the image location offset from the ILOC or SLOC value of the segment to which the image is attached or from the origin of the CCS when the image is unattached (IALVL contains 0). A row or column value of 0 indicates no offset. Positive row and column values indicate offsets down and to the right while negative row and column values indicate offsets up and to the left.

Type:

str

IMAG: str

Image Magnification. This field shall contain the magnification (or reduction) factor of the image relative to the original source image. Decimal values are used to indicate magnification, and decimal fraction values indicate reduction. For example, 2.30 indicates the original image has been magnified by a factor of 2.30, while 0.5 indicates the original image has been reduced by a factor of 2. Default value is 1.0.

Type:

str

UserHeader: UserHeaderType

User defined header.

Type:

UserHeaderType

ExtendedHeader: UserHeaderType

Extended subheader - TRE list.

Type:

UserHeaderType

property is_masked

Does this image segment contain a mask?

Type:

bool

property is_compressed

Is this image segment compressed?

Type:

bool

property IC

Image Compression. This field shall contain a valid code indicating the form of compression used in representing the image data.

Valid values for this field are, C1 to represent bi-level, C3 to represent JPEG, C4 to represent Vector Quantization, C5 to represent lossless JPEG, I1 to represent down sampled JPEG, and NC to represent the image is not compressed. Also valid are M1, M3, M4, and M5 for compressed images, and NM for uncompressed images indicating an image that contains a block mask and/or a pad pixel mask. C6 and M6 are reserved values that will represent a future correlated multicomponent compression algorithm. C7 and M7 are reserved values that will represent a future complex SAR compression. C8 and M8 are the values for ISO standard compression JPEG 2000.

The format of a mask image is identical to the format of its corresponding non-masked image except for the presence of an Image Data Mask at the beginning of the image data area. The format of the Image Data Mask is described in paragraph 5.4.3.2 and is shown in table A-3(A). The definitions of the compression schemes associated with codes C1/M1, C3/M3, C4/M4, C5/M5 are given, respectively, in ITU- T T.4, AMD2, MIL-STD-188-198A, MIL-STD- 188-199, and NGA N0106-97. C1 is found in ITU- T T.4 AMD2, C3 is found in MIL-STD-188-198A, C4 is found in MIL-STD-188-199, and C5 and I1 are found in NGA N0106-97. (NOTE: C2 (ARIDPCM) is not valid in NITF 2.1.) The definition of the compression scheme associated with codes C8/M8 is found in ISO/IEC 15444- 1:2000 (with amendments 1 and 2).

Type:

str

classmethod from_bytes(value, start)

Parameters:

• value (bytes|str) – the header string to scrape

• start (int) – the beginning location in the string

get_bytes_length()

Get the length of the serialized bytes array

Return type:

int

to_bytes()

Write the object to a properly packed str.

Return type:

bytes

to_json()

Serialize element to a json representation. This is intended to allow a simple presentation of the element.

Return type:

dict

property COMRAT

Compression Rate Code. If the IC field contains one of C1, C3, C4, C5, C8, M1, M3, M4, M5, M8, I1, this field shall be contain a code indicating the compression rate for the image.

If IC is NC or NM, then this will be set to None.

Type:

None|str

property IGEOLO

Image Geographic Location. This field, when present, shall contain an approximate geographic location which is not intended for analytical purposes (e.g., targeting, mensuration, distance calculation); it is intended to support general user appreciation for the image location (e.g., cataloguing). The representation of the image corner locations is specified in the ICORDS field. The locations of the four corners of the (significant) image data shall be given in image coordinate order: (0,0), (0, MaxCol), (MaxRow, MaxCol), (MaxRow, 0). MaxCol and MaxRow shall be determined from the values contained, respectively, in the NCOLS field and the NROWS field.

Type:

None|str

property mask_subheader: None | MaskSubheader

The mask subheader, if it has been appended.

Type:

None|MaskSubheader

classmethod minimum_length()

The minimum size in bytes that takes to write this header element.

Return type:

int

get_uncompressed_block_size() → int

Gets the size of an uncompressed block.

Note that if IMODE == ‘S’, then each block consists of a single band. Otherwise, a block consists of all bands.

Return type:

int

get_full_uncompressed_image_size() → int

Gets the full size in bytes of the uncompressed image including any padding in the blocks.

Return type:

int

get_clevel() → int

Gets the CLEVEL value for this image segment.

Return type:

int