Y Coordinates Center Pixel View Angle Attribute
| Tag | (0022,1529) |
|---|---|
| Type | Required (1) |
| Keyword | YCoordinatesCenterPixelViewAngle |
| Value Multiplicity | 1 |
| Value Representation | Single (FL) |
The vertical angle covered on the sphere by the center pixel of the projected image, as measured from the center of the sphere, in degrees. See Section C.8.17.11.1.1 for further explanation.
Section C.8.17.11.1.1
C.8.17.11.1.1 Center Pixel View Angle
The Center Pixel View Angle (0022,1528) comprises two real numbers XCENTERPIXELVIEWANGLE and YCENTERPIXELVIEWANGLE that represent in degrees the angle along the horizontal axis and the vertical axis respectively covered by the center pixel in the image, where this angle is measured from the center of the sphere. These are used to convert pixel locations in the image to their corresponding locations on a sphere. x and y are pixel locations (may be sub pixels) in the image, x running from 0 to XPIXELS from the left-hand side of the image to the right-hand side, and y running from 0 to YPIXELS from top to bottom, and if λ denotes the azimuth or longitude on the sphere and ϕ the elevation or latitude on the sphere, both in degrees, then,
where
tan2-1 used to define λ represents the two-argument inverse tangent function:
and
and
The above equations assume the use of degrees throughout. Radians can be used, if XCENTERPIXELVIEWANGLE and YCENTERPIXELVIEWANGLE are given in radians, if all trigonometric functions are switched to their radian-equivalent, and if the factor π/180 is removed from the definition of c.