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DADiSP Worksheet Functions > Function Categories > Image Processing > RGBIMAGE
Creates a 24 bit image from red, green and blue components.
RGBIMAGE(r, g, b)
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r |
- |
An array, the red values. |
|
g |
- |
An array, the green values. |
|
b |
- |
An array, the blue values. |
An array, a 24 bit color image.
RGBIMAGE(a, val) sets or resets the interpretation of the data values as composite RGB values.
val = RGBIMAGE(a) returns 1 if the image is a 24 bit RGB image, else 0.
W1: density(spline2(ravel(gnorm(100,1),10), 8));rainbow()
(r, g, b) = getrgb(W1)
W2: rgbimage(r, g*1.1, b);
W1 contains an image of a random surface shaded with the colors of the spectrum ranging from red to blue. W2 converts the image into a 24 bit color image with the green intensities increased by 10%.
W1: readimage(".\data\mandrill.bmp")
W2: W1;gray
W3: W2;rgbimage(1)
W1 contains a 24 bit RGB color image. W2 copies the image and re-shades it with a black to white colormap. Although the data values are not changed, the color shading is altered and the data is no longer marked as a 24 bit image. However, because the data values are unchanged, rgbimage(1) restores the original 24 bit color scheme for the image.
Unlike standard images, a 24 bit image does not reference a separate colormap. Instead, each pixel of the image is comprised of a composite 24 bit RED, GREEN, BLUE value packed into a long integer (4 bytes). Use
(r, g, b) = getrgb(image)
to retrieve the separate red, green and blue values from a composite 24 bit image.
image = rgbimage(r, g, b)
to construct a 24 bit composite image from separate RGB values.
Because 24 bit color images do not require a colormap (the colors are implicit), the image can be saved and restored automatically with the correct colors.
isrgb = rgbimage(image)
returns 1 if the image is 24 bit, else 0.
See GETRGB to return the red, green and blue components of an image as separate arrays.
See RGBTOCOLOR to convert RGB values into a color index.