| ... | ... | @@ -194,7 +194,7 @@ The coefficients $a_i$ have been calculated as presented in the previous section |
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The method for constructing orthoimages is as follows:
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- Define the area to be imaged in the real-world coordinate system, that is, provide the (X,Y) coordinates of the 4 corners of the orthoimage (done in the [Orthorectification](User-Manual/Orthorectification-of-Images#transformation-parameters) menu).
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- Define the area to be imaged in the real-world coordinate system, that is, provide the (X,Y) coordinates of the 4 corners of the orthoimage (done in the [Orthorectification](User-Manual/Image-Orthorectification#transformation-parameters) menu).
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- Sample this area with a given resolution to create a grid, where each node of this grid will be the center of a pixel in the orthorectified image.
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- For each grid node, with coordinates $(X_i,Y_i)$, calculate the corresponding coordinates in the source image $(i_i,j_i)$ using equation (2). The coordinates $(i_i,j_i)$ calculated this way are real numbers rather than integers.
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- Assign to each pixel centered at $(X_i,Y_i)$ a grayscale intensity corresponding to the pixel $(i_i,j_i)$ in the source image. Since the coordinates $(i_i,j_i)$ are real numbers, interpolation on neighboring pixels is used to determine the grayscale intensity, with cubic convolution:
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