imshow

Calling Sequence

imshow(Img)

imshow(Img,n)

imshow(Img,[low high])

imshow(Img,Map)

imshow(RGBImg)

imshow filename

imshow(Img, arg2 [, strf])

Parameters

filename

A string, the image filename to be created. The extension determines the type of the image.

Img

MxN matrix, a grayscale (0-1 range) or pseudo-color/indexed (1-Ncolors range) image.

n

A scalar, the number of levels of gray to display Img. 1x2 array corresponding to the grayscale range to be considered.

[low high]

1x2 array corresponding to the grayscale range to be considered.

Map

Mx3 matrix containing the image colormap (for indexed images). Entries may range from 0 to 1

RGBImg

MxNx3 hypermatrix in 0-1 range.

strf

this is used to e.g. put axes around your image. See the plot2d help page. You may use this optional parameter in the assignment style, as in

imshow(img,strf='041')  // same as imshow but draw axes

Description

imshow(Img, n): displays Img using n gray levels. Img is an MxN matrix in 0 - (n-1) range. If n is omitted, it will be assumed to be 256.
imshow(Img, [low high]): displays Img using a grayscale within the specified range. Elements <= low will map onto black, Elements >= high will map onto white, and elements in between will map as a shade of gray. If an empty matrix '[]' is used, [low,high] will be assumed to be [min(Img), max(Img)].
imshow(Img, Map): displays Img using the specified colormap.
imshow(RGBImg): displays the RGBImg MxNx3 (0-1) truecolor image.
imshow('filename'): displays the image filename in the scilab graphical window. Any raster image format is accepted (see Remarks section).

Examples

initial_dir = PWD;
chdir (SIPDIR + 'images');

a = rand(100,100);   // create random image
clf;
imshow(a);

imshow(a*255 + 1,hotcolormap(256));
imshow(a,[0.3 0.6]);
imshow(a,[]);
clf;
imshow('example.png');

chdir(initial_dir);

Remarks

In theory, imshow(filename) will work with any raster image format. In practice, it has been tested only for BMP, GIF, JPEG, PNG, PCX, TIFF, XPM, and MIFF. Displaying other file formats will probably work, but this case have not been tested by the developers of the SIP toolbox.

Bugs and Shortcomings

The display of truecolor images is somewhat inefficient.

Images are stored in double precision matrices. Hopefully, the next release will make usage of integer types.