Frame Editor (IKONOS and NITF)

ERDAS IMAGINE Help

HGD_Variant
16.5.2
HGD_Product
ERDAS IMAGINE
HGD_Portfolio_Suite
Producer

This dialog allows you to specify an image and its associated rational polynomial coefficients (RPC) data to be used in the block file. Some examples of such image types include IKONOS GeoTIFF or NITF files and NITF files from other sources. This dialog opens when you have a Frame camera project open and select block_measure_io Interior Orientation on the Photogrammetry tab.

IKONOS stereo data is stored in two formats for use in IMAGINE Photogrammetry: TIF and NITF. In the case of TIF, two overlapping TIF images and additional metadata (along with the image geometry model [IGM]) files are used. Metadata files include information such as projection, image extent, rational polynomial coefficients, and correction coefficients. In the case of NITF, V2.0 files are used along with RPC information.

The use of NITF files in IMAGINE Photogrammetry assumes that you have access to the NITF module for ERDAS IMAGINE. The image files must be saved as TIF, and the IGM must be output to an ASCII file. NITF RPC data is stored in the NTF format (*.ntf). The rational polynomial coefficient information is stored in the NITF file—there is not an external file that contains the data. Projection information, however, is stored in a separate metadata text file.

The dialog has the following tabs: Sensor and Chipping.

Sensor Tab

This tab displays basic information about the current file: the one with the > indicator in the IMAGINE Photogrammetry Project Manager CellArray.

Image File Name: This field displays the name of the current file.

Attach    Click to attach or replace the current file. A file selector opens. Use the Ctrl (Control) and Shift keys on the keyboard to attach multiple files. To attach individual files not in a series, hold down the Ctrl key and click each one; to select files in a series, hold down the Shift key and click the first and last files in the series.

When attaching multiple files, the file names (not paths) must correspond to the file names in the block file. This is not true for a single file attachment.

SHARED Tip The only way to detach a file is to rename it or move it to another location.

SHARED Tip Attempting to attach the same image twice results in an error message indicating that files must be unique.

View Image Click to view the current image file. A Viewer opens displaying the file.

Block Model Type: This field displays the type of sensor used to capture the image file. In the case of a block containing IKONOS data, this field displays IKONOS. In the case of a block containing NITF data, this field displays NITF RPC.

RPC Coefficients: This field displays the RPC file associated with the image. The RPC file is an ASCII file, and contains rational function polynomial coefficients. This file is generated on the ground based on the position of the satellite at the time of image capture, and can be further refined using GCPs.

In the case of an NITF image, this field is blank since the RPC data needed to support the NITF data is in the *.ntf file and therefore, an external file is not required.

Elevation in Meters: This section of the Frame Editor is used when you change the projection of the data to something other than the default Geographic Lat/Lon projection. When you change the projection of images, the rational function coefficients must be recalculated. The calculation requires the elevation range (Min and Max values listed below) to be provided by you.

Min: Enter the minimum elevation of the scene in meters in the text field. This elevation reflects the minimum elevation on the ground for the area of interest. The default value is based on the elevation offset and scale from the external RPC file or the RPC information contained in the *.ntf file itself: minimum = offset - scale.

Max: Enter the maximum elevation of the scene in meters in the text field. This elevation reflects the maximum elevation on the ground for the area of interest. The default value is based on the elevation offset and scale from the external RPC file or the RPC information contained in the *.ntf file itself: maximum = offset + scale.

Mean: Enter the mean elevation of the scene in meters in the text field. The default value is the elevation offset from the external RPC file or the RPC information contained in the *.ntf file itself.

Apply Mean To All: Check to apply the mean elevation of the current image to all images in the block.

Chipping Tab

This tab allows calculation of RPCs for an image chip rather than the full, original image from which the chip was derived. This is made possible by specifying an affine relationship (pixel) between the chip and the full, original image.

Use of this tab is only required when the RPCs that accompany the image chip correspond to the full, original image and not the chip itself. Typically, this is not the case.

Specify Chipping Parameters as: You can select either Arbitrary Affine or Scale and Offset (the more simple of the two options).

Arbitrary Affine: The formulas for calculating an arbitrary affine are listed in the dialog:
x' = ax + by + c and y' = dx + ey + f. In the formulas, x' (x prime) and y' (y prime) correspond to pixel coordinates in the full, original image. The values x and y correspond to pixel coordinates in the chip you are currently working with.

SHARED Tip If the software determines that the arbitrary affine parameters (stored in the header of the chip file) contain information that is more detailed than simply scales and offsets, Arbitrary Affine is selected for you, and the Specify Chipping Parameters as field becomes disabled.

Values for the following variables are either obtained from the header data of the chip, or default to predetermined values:

a: This is a scale factor and is also used in rotation. In the absence of header data, this value defaults to 1.

b: This value is used in rotation. In the absence of header data, this value defaults to 0.

c: This is an offset value. In the absence of header data, this value defaults to 0.

d: This value is used in rotation. In the absence of header data, this value defaults to 0.

e: This is a scale factor and is also used in rotation. In the absence of header data, this value defaults to 1.

f: This is an offset value. In the absence of header data, this value defaults to 0.

Scale and Offset: The formulas for calculating the affine using scale and offset are listed below. As above, x' and y' correspond to the pixel coordinates for the full, original image.

scale_and_offset

Row Offset: This value corresponds to value c, as defined above.

Row Scale: This value corresponds to value a, as defined above.

Column Offset: This value corresponds to value f, as defined above.

Column Scale: This value corresponds to value e, as defined above.

The values for b and d, as defined above, are set to 0.

Full Row Count: If the chip header contains the appropriate data, this value is the row count of the full, original image. If the header data is absent, this value corresponds to the row count of the chip.

Full Column Count: If the chip header contains the appropriate data, this value is the column count of the full, original image. If the header data is absent, this value corresponds to the column count of the chip.

Buttons

OK Accept all the values entered in this dialog and close the Frame Editor.

Previous View the parameters of the previous image listed in the block file.

Next Accept the values entered for this image and view the parameters of the next image listed in the block file.

When you click the Next button, the camera or sensor information associated with an image is accepted. For example, the selected camera is the one that is listed within the Sensor Name dropdown list when you click Next.

Cancel Cancel any values entered in this dialog and close the Frame Editor.

Help Open this Online Help.