function y = isrgb1(x)
%ISRGB Return true for RGB image.
% FLAG = ISRGB(A) returns 1 if A is an RGB truecolor image and
% 0 otherwise.
% ISRGB uses these criteria to determine if A is an RGB image:
% - If A is of class double, all values must be in the range
% [0,1], and A must be M-by-N-by-3.
% - If A is of class uint8 or uint16, A must be M-by-N-by-3.
% Note that a four-dimensional array that contains multiple RGB
% images returns 0, not 1.
% Class Support
% A can be of class uint8, uint16, or double. If A is of
% class logical it is considered not to be RGB.
% See also ISBW, ISGRAY, ISIND.
% Copyright 1993-2003 The MathWorks, Inc.
% $Revision: 18.104.22.168 $ $Date: 2003/08/23 05:52:55 $
wid = sprintf('Images:%s:obsoleteFunction',mfilename);
str1= sprintf('%s is obsolete and may be removed in the future.',mfilename);
str2 = 'See product release notes for more information.';
y = size(x,3)==3;
if isa(x, 'logical')
y = false;
elseif isa(x, 'double')
% At first just test a small chunk to get a possible quick negative
m = size(x,1);
n = size(x,2);
chunk = x(1:min(m,10),1:min(n,10),:);
y = (min(chunk(:))>=0 && max(chunk(:))<=1);
% If the chunk is an RGB image, test the whole image
y = (min(x(:))>=0 && max(x(:))<=1);