公开(公告)号：CA2039028C

公开(公告)日：1995-04-18

申请号：CA2039028

申请日：1991-03-25

Applicant: IBM

Inventor： TODD STEPHEN J P

IPC: G03F3/08 ,  G06T5/00 ,  G06T5/40 ,  G09G5/02 ,  G09G5/36 ,  H04N1/407 ,  H04N1/46 ,  G09G5/00

Abstract: Saturation problems are alleviated, when displaying image data on a device capable only of displaying pixel intensity values between a minimum value (Imin) and a maximum value (Imax), by smoothly mapping source intensity values greater than a threshold value (T), which is intermediate the minimum and maximum values, to output intensity values (Io) in a range between the threshold value (T) and the maximum value (Imax). Intensity values darker than the threshold value are not altered by the image generator with the result that image detail in the lower range of values is not lost. In order to maintain the correct colour balance where separate colour component intensities are defined in the source image data, each colour component is mapped in accordance with a mapping determined for the largest colour component value.

公开(公告)号：CA1289675C

公开(公告)日：1991-09-24

申请号：CA545962

申请日：1987-09-02

Applicant: IBM

Inventor： QUARENDON PETER ,  TODD STEPHEN J P

IPC: G06T11/00 ,  G06T15/20 ,  G06T17/00 ,  G06F15/72

Abstract: UK9-85-004 A method of generating a two-dimensional (2-D) image of a transform of a three-dimensional (3-D) solid object comprises sub-dividing a 3-D box defining viewing space into sub-boxes, generating test-cells in object space by performing an inverse transform on the sub-boxes and determining which of the test-cells intersect the object. Thus, the need to transform the object itself is avoided. A particular application of the method is the generation of 2-D perspective images of a 3-D solid object. A graphics processing system comprising means for performing the method is defined.