Visual Plane
every picture states the point it is correct from
Concept

Pre-warp — where it appears

The distortion applied to an image before display so that it arrives correct at a stated seat. It is exact for that one seat and for no other, and what it leaves behind elsewhere measures how far a viewer has moved from the position the correction assumed.

Named by 2 essays across 2 fields — each of them below, with the objects they name alongside it.

Also named here as seat — the same set of essays touches all of them, so they are one junction rather than several.

025507505001e+31.5e+3how far along the sofa the viewer sits, in millimetreshow far a mark is from where it was drawn to be seen, in arcminutesthe matched picturean ordinary flat picturethey crosscurved television, along the sofacrossing at 400 mm

Matching buys one seat

Feeding a curved screen its own picture surface makes the picture exact at one point and worse everywhere else than the flat picture it replaced. Forty centimetres along the sofa the two cross, and past that the matched picture is the worse of the pair — because a flat picture is mediocre everywhere and a matched one is perfect at a point and falls away from it faster.

screen · Matched projectorthe seatcorrect from 19 cm, at 160 mm wide23.6° worst

A projector that is not at the dome's centre

A projector 0.40 of a dome's radius off centre puts its own picture up to 23.6 degrees from where it belongs, and the pre-warp that corrects it is exact for one seat and only one. Two metres from that seat costs 11.5 degrees of the same displacement, wherever the projector itself stands — because the correction never knew where the projector was in the first place.

curved · Dome

Named alongside it

The objects these essays reach for when they reach for this one.

HomographySeatAngular sizeArcminuteAudienceCentre of curvaturecentre of projectionCylindrical projectionfield of viewKeystoneMatched surfacePicture surface

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