nn::camera::CTR::GetStereoCameraCalibrationMatrixEx Function

void GetStereoCameraCalibrationMatrixEx(
     nn::math::MTX34 * pDstR,
     nn::math::MTX34 * pDst,
     f32 * pDstScale,
     const StereoCameraCalibrationData & cal,
     const f32 translationByPixel,
     const f32 parallax,
     const s32 colorBufferWidth,
     const s16 orgHeight,
     const s16 dstWidth,
     const s16 dstHeight
);

	Name	Description
out	pDstR	Specifies the location where the correction matrix for the right camera image is stored.
out	pDstL	Specifies the location where the correction matrix for the left camera image is stored.
out	pDstScale	Specifies the location where the scale is stored. This is necessary to render in the area where the left and right images overlap, in the size specified by dstWidth and dstHeight.
in	cal	Specifies the calibration data.
in	translationByPixel	Specifies the required translation in 3D space to move the camera image by one pixel.
in	parallax	Specifies the parallax in the VGA image. Specify a value that expresses the movement of the left-camera image, with the right-camera image as the reference. This is measured in pixels.
in	orgWidth	Specifies the width of the camera image. If trimming, specify (in pixels) the desired width of the trimmed image. This is measured in pixels.
in	orgHeight	Specifies the height of the camera image. If trimming, specify (in pixels) the desired height of the trimmed image. This is measured in pixels.
in	dstWidth	Specifies the width necessary to render in the size of the area where the left and right images overlap.
in	dstHeight	Specifies the height necessary to render in the size of the area where the left and right images overlap.

None.

Calculates a correction matrix used to make the left camera image match the right camera image in 3D space.

The nn::camera::CTR::GetStereoCameraCalibrationMatrix function returns a matrix for correcting errors in the placement of the stereo camera. Using this matrix, however, will prevent a 3D view on the edges of the screen if the position offset of the system's stereo camera is near the limit, because the edges of the area where the left and right images overlap (for convenience, we will call this the "overlapping area") will be cut off (see figure below). Although the position offset in the figure below is extreme for purposes of illustration, the actual limit of positional offset is smaller than in this figure.

This function returns a correction matrix that will not cut off the edges of the overlapping area, even if the placement error is at the limit. It does this by enlarging the image if the overlapping area is too small.

Unless you have a specific reason, we recommend using this function instead of the nn::camera::CTR::GetStereoCameraCalibrationMatrix function.

The internal processing of this function is as follows.

(1) Finds the rectangle where the left and right images overlap, based on the calibration data and orgWidth/orgHeight (see figure below). Here, the width : height ratio of the rectangle is dstWidth : dstHeight.

(2) If the screen is configured so that the image will appear in the center, it moves the horizontal correction matrix so that the center of the rectangle is in the center of the screen (see figure below).

(3) On some systems, the size of the rectangle may be smaller than dstWidth x dstHeight. On other systems, the size of the rectangle may be larger than dstWidth x dstHeight. Here, we scale the horizontal correction matrix so that the clipped rectangle is the same size as dstWidth x dstHeight (see figure below). For example, if the specification to the function is dstWidth = 400, dstHeight = 240, and the size of the rectangle is 320 x 192, then the correction matrix will scale to 400/320 = 1.25x.

Specify in dstWidth/dstHeight the size of the overlapping rectangle to display; in other words, specify the size of image that you want the rectangle to appear as.

The correction matrix calculated by the above process is stored in pDstR and pDstL. The scale calculated in step (3), above is stored in pDstScale.

The output correction matrix is used to move the camera image horizontally. This matrix is simply a three-dimensional extension of a two-dimensional matrix that expands and shrinks images, rotates around the light axis, and performs horizontal and vertical translations; it does not include three-dimensional transformations, such as rotations about the horizontal and vertical axes.

2011/03/24

Added figures.

2011/03/22

Initial version.