A simple color space transformation could be done by J expressions. For example, color/brightness could be as simple as
Y = C*X + B where C is contracts and B is brightness. Earlier it was discussed that it would be good to optimize integral valued division <[EMAIL PROTECTED] But it also makes sense to optimize integral valued multiplication <[EMAIL PROTECTED] or even maybe integral valued polynomial <[EMAIL PROTECTED] For the above example it would be Y = C*X + B Y = (B,C) <[EMAIL PROTECTED] X --- bill lam <[EMAIL PROTECTED]> wrote: > I'll try tomorrow. > > Actually I need some image processing function (eg. lightening) in image3. My > original post is not well written because the large space overhead is not > directly related to image3, but rather to J interpreter itself. > > Oleg Kobchenko wrote: > > --- bill lam <[EMAIL PROTECTED]> wrote: > > > >> When I use image3 addon to read a large jpeg, it raise a memory limit > >> error, (I > >> lower the memory limit to avoid swap). So I use 7!:5 to measure the space > >> in > >> bytes used by the named objects, > >> > >> B=: 100 200 3$2 > >> 7!:5 <'B' > >> 262144 > >> */4 100 200 3 > >> 240000 > >> B=: 1000 2000 3$2 > >> 7!:5 <'B' > >> 33554432 > >> */4 1000 2000 3 > >> 24000000 > >> B=: 2848 4288 3$2 > >> 7!:5 <'B' > >> 268435456 > >> */4 2848 4288 3 > >> 146546688 > >> > >> It requires nearly double amount of space for large object. Can this be > >> improved? > > > > Could you try for comparison the platimg addon to > > see if it can handle the large jpegs that you have. > > > > Thanks. ____________________________________________________________________________________ Don't pick lemons. See all the new 2007 cars at Yahoo! Autos. http://autos.yahoo.com/new_cars.html ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
