I tried again with the Scripts/Picture Database demo.
To read the jpg and it decoded into an integer array of shape 2848 4288,
7!:5 <'recdat'
67108864
3!:0 recdat
4
$ recdat
2848 4288
*/4 2848 4288
48848896
I appears that this ARGB array is not "wrong" size, and requires less memory to
represent the picture. I'm able to display the picture with memory limit of 2^26
(about 67MB).
Does your equation Y = C*X + B work for pixels encoded as ARGB integers? Does
the platimg dll already provide this operation, or it still needs decomposition
into 3 channels as that in image3?
Oleg Kobchenko wrote:
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.
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regards,
bill
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