Square root will give you a non-linear translation into the destination
space. Also, adding 32768 will mean that 32767 or 0x7fff will map to
full intensity, 0 will map to half intensity, and -32768 will map to
blackness - is that the mapping you want? If you want to convert a
signed short directly to its "unsigned short" equivalent value then
the way to do this is by using:
short s = /* some number */;
int si = s;
int ui = s & 0xffff;
In that case ui will represent the bits of s interpreted as an unsigned
value and si will represent the same numeric value as s. If you want to
reduce this value then to 8 bits in a linear way, a simple shift would
work best:
int ui = (s & 0xffff) >> 8;
Is that the conversion you wanted?
...jim
--On Wednesday, November 6, 2002 5:09 AM +0900 Kevin Kim <[EMAIL PROTECTED]> wrote:
Hi, all.
I have 224 matrixes each of which is consisted of h by w Short, 16 Signed bit pixel loaded into memory. Among these 224 matrix, I am selecting three matrixes to map into RGB value.
My understanding was that since I have a range from -32767 to 32767 for each R, G, B, I presumed, I would have to sqaure root to fit into 8 bit red representation ranging 0 to 255, green, and blue. This is shown below.
I created the bufferedImage class and am using the defaultToolKit. I ran into some odd problems.
The image is supposed to vary in color, depending on what I have selected for red, green, and blue. However, the rendered image always seems dim.
Was I supposed to normalize each three matrix instead of just algebraicly square root?
Or is is possible to create ColorModel and SampleModel in 48 bit representation for RGB? (=16 bit Short * 3 for RGB)
Here is code snipet.
/***********************************************************
* Create dataBuffer for BufferedImage before invoke paint()
*/
public void createDataForBufferedImage(SingleBandDataMatrix[] sbdm)
{
//This defindes the image size
int width = this.getPassedHeader().getSamples();
int height = this.getPassedHeader().getLines();
// This is the band index I choosed to load among 224 different matrix
int redBandMatrixIndex = this.getPassedSelectedRedBandNumber();
int greenBandMatrixIndex= this.getPassedSelectedGreenBandNumber();
int blueBandMatrixIndex = this.getPassedSelectedBlueBandNumber();
//Declare temporary matrix to copy the original matrixs selected for Red, green, and blue
int[][] redTempMatrix = new int[width][height];
int[][] blueTempMatrix = new int[width][height];
int[][] greenTempMatrix = new int[width][height];
//Copy over the selected matrix to temporary matrix for red, green, and blue
redTempMatrix = (int[][])sbdm[redBandMatrixIndex-1].getMatrix();
greenTempMatrix = (int[][])sbdm[greenBandMatrixIndex-1].getMatrix();
blueTempMatrix = (int[][])sbdm[blueBandMatrixIndex-1].getMatrix();
//Below is the actual DataBuffer going into BufferedImage
int[] data = new int[width*height];
//Pack the ARGB into 32 bit(4 byte)
int i=0;
int z=0;
//int[] red= new int[height*width];
for (int y=0; y<height ;y++ )
{
for (int x=0; x<width ;x++ )
{
/*******************************************************
* Need to pack the 2 byte of signed integer into 1 byte
*******************************************************/
// I am just adding 32768 to convert from Signed Short to UnSigned Short
// And squre root to convert current 0-65536 to 0-255 value for integer.
int red = (int)Math.sqrt((double) redTempMatrix[x][y] +32768 ) ;
int green = (int)Math.sqrt((double) greenTempMatrix[x][y]+32768 ) ;
int blue = (int)Math.sqrt((double) blueTempMatrix[x][y]+32768 ) ;
//Then pack into one RGB integer type pixel
data[i++] = (red<<16)|(green<<8)|(blue);
}
}
image = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);
image.setRGB(0,0,width, height,data,0,width);
}
public void paint(Graphics g)
{
g.drawImage(image,0,0,this);
}
Thanks in advance..
Kevin
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