JSL- get values of pixels in 0-255

Question

Hi all, I am trying to get pixel values in 0-255 using Get Pixels().

{r, g, b} = img << Get Pixels("rgb");

This gives me normalized values (0-1). How can I get the pixel values in 0-255?

Thanks!

ian_jmp · Answer

I think there's more than one way to do this. But here's a reference and a JMP implementation:

Names Default To Here( 1 );

Web("https://web.stanford.edu/class/cs101/image-6-grayscale.html", JMP Window);

img = Open( "$SAMPLE_IMAGES/tile.jpg", jpg );
win = New Window( "tile(40,40)", img );
{r, g, b} = img << Get Pixels( "rgb" );

// Average the rgb values of each pixel and scale from [0, 1] to [0, 255]
nr = NRow(r);
nc = NCol(r);
r2 = Shape(r, 1, nr*nc);
g2 = Shape(g, 1, nr*nc);
b2 = Shape(b, 1, nr*nc);
g2 = VMean(VConcat(r2, g2, b2));
g = Shape(g2, nr, nc);
g = Round(g*255, 0);
dt = AsTable(g);
dt << setName("Greyscale");

jthi · Answer

Just guessing here, but maybe it would be enough to just multiply by 255?

This link could also give ideas (and has additional links) What do the numbers returned by << Get Pixels(); correspond to?