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SPOT |
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SPOT |
Overview
The SPOT object is very similar to the photo object, however, its geometric model is not the same. Unlike a traditional aerial photo, which is basically a single shot frame-image, SPOT is an image consisting of a number of shot of a linear array stringed together to form a frame-look-like image.
Noobeed models a SPOT image without using any orbital parameters, yet results are very accurate as long as there are enough well-distributed ground control points. The model describes trajectory and orientation of each individual array by a first degree of polynomial of a time-dependent variable. Thus apart from the 6 conventional EOP, there are another 6 parameters which used to model rate of change of them. Consequently, a minimum of 6 ground control points are required to solve for the 12 unknowns parameters.
SPOT object is not supposed to be used for only SPOT image. In fact any sensor that is of linear array type can also utilize the SPOT object as well, e.g. IKONOS image. However, the default values of IOP (Interior Orientation Parameter - focal length, xp, array length and scan time), given by Noobeed is valid only for SPOT, and they must be set correctly.
For more details in linear coordinate system, please see understanding coordinate system.
Member data
| Name | Data type | Meaning |
| id | int | ID of photo |
| name | String | name of photo |
| matrix | Matrix_uch | a Matrix_uch object |
| focal | double | focal length of sensor (default value is for SPOT) |
| ppx | double | x coordinate of principal point of the sensor (default value is for SPOT) |
| arrlen | double | length of linear array sensor (default value is for SPOT) |
| arrtime | double | total image capturing time (default value is for SPOT) |
| EO_para | Vector | a vector contains exterior orientation parameters |
| flag_earth | bool | flag controls computation of earth curvature correction |
| flag_refract | bool | flag controls computation of atmospheric correction |
Operator
no operator provided
Construction function
{SPOT} ret = SPOT([{int} argm1, {int} argm2])
argm1 = no of row (default = 0)
argm2 = no of column (default = 0)
Example:
| ->scene_1 = SPOT() | an empty SPOT image |
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->scene_1 = SPOT(6000,6000) |
a SPOT image size 6000 x 6000 pixels |
Lfunction
object({int} argm1, {int} argm2) = {uchar} left-value
argm1 = row index
argm2 = column index
object.ID() = {int} left-value
object.NAME() = {String} left-value
object.MATRIX() = {Matrix_uch} left-value
object.FOCAL() = {double} left-value
object.PPX() = {double} left-value
object.ARRLEN() = {double} left-value
object.ARRTIME() = {double} left-value
object.EO_PARA() = {Vector} left-value
object.FLAG_EARTH() = {bool} left-value
object.FLAG_REFRACT() = {bool} left-value
Example:
| ->scene_1(10,20) = 35 | set value of element at row 10, column 20 |
| ->scene_1.flag_earth() = 1 | turn on the earth curvature correction flag |
Class function