Bao Ngo - 2022-12-15T11:55:29+00:00
Question: Output argument (and possibly others) not assigned
Output argument (and possibly others) not assigned a value in the execution with function I have a function script as follows: function [h]=getColorHist(im, color_table, opt) im = rgb2hsv(im); [ht,wid,~]=size(im); if opt == 'euc' % euclidean distance D = pdist2(color_table, reshape(im, [ht*wid, 3])); end end I call this function from a different script HW3.m from the command line and get the following error: HW3 Output argument "h" (and possibly others) not assigned a value in the execution with "getColorHist" function. Error in HW3 (line 23) f_hist(f_cnt, :) = getColorHist(hsv_im, color_table,'euc') where HW3.m is: im_path='/MATLAB Drive/Published/NWPU-RESISC45_1'; ids = {'airplane', 'airport', 'baseball_diamond', 'baseball_court', 'beach','bridge','chaparral', 'church', 'circular_farmland', 'cloud','commercial_area','dense_residental', 'desert', 'forest', 'freeway'}; kColor = 64; color_table = getHSVColorTable_2(im_path, ids, kColor); nClass = length(ids); nImg = 40; f_hist = zeros(nImg*nClass, kColor); labels = zeros(nImg*nClass, 1); f_cnt = 0; for k=1:nClass % list of files class_path = sprintf('%s/%s', im_path, ids{k}); f_list = dir(sprintf('%s/*.jpg', class_path)); offs = randperm(length(f_list)); % load random 256 pixels from each images if isempty(offs) == 0 for j=1:nImg f_cnt = f_cnt + 1; % read in a random image from the class im = imread(sprintf('%s/%s', class_path, f_list(offs(j)).name)); hsv_im = rgb2hsv(im); f_hist(f_cnt, :) = getColorHist(hsv_im, color_table,'euc'); labels(f_cnt) = k; % plot if (1) figure(3); subplot(nClass, nImg, f_cnt); plot(f_hist(f_cnt, :)); grid on; end end end end Can anyone check whether my code has any errors to let this problem occur? This is mind-boggling to me, appreciate any help! Here this the script for function getHSVColorTable_2 in HW3.m: function [color_table]=getHSVColorTable_2(im_path, ids, kColor) dbg=1; if dbg im_path='/MATLAB Drive/Published/NWPU-RESISC45_1'; ids = {'airplane', 'airport', 'baseball_diamond', 'baseball_court', 'beach','bridge','chaparral', 'church', 'circular_farmland', 'cloud','commercial_area','dense_residental', 'desert', 'forest', 'freeway'}; kColor = 64; end nClass = length(ids); nImg = 40; nPixelPerImage = 256; % sample images from the repository to train a global HSV color table % training pixels x = zeros(nImg*nPixelPerImage*nClass, 3); cnt = 0; for k=1:nClass % list of files class_path = sprintf('%s/%s', im_path, ids{k}); f_list = dir(sprintf('%s/*.jpg', class_path)); offs = randperm(length(f_list)); % load random 256 pixels from each images if isempty(offs) == 0 for j=1:nImg % read in a random image from the class im = imread(sprintf('%s/%s', class_path, f_list(offs(j)).name)); hsv_im = rgb2hsv(im); [ht,wid,~] = size(im); hsv_im = reshape(hsv_im, [ht*wid, 3]); pix_offs = randperm(ht*wid); x(cnt+1:cnt+nPixelPerImage, :) = hsv_im(pix_offs(1:nPixelPerImage), :); cnt = cnt + nPixelPerImage; end % plot if dbg figure(1); subplot(1, nClass, k); subplot(1, nClass, k); imshow(im); title(ids{k}); end end end
Expert Answer
Prashant Kumar answered .
2025-11-20
The error is simple. In the given function:
function [h]=getColorHist(im, color_table, opt)
im = rgb2hsv(im);
[ht,wid,~]=size(im);
if opt == 'euc' % euclidean distance
D = pdist2(color_table, reshape(im, [ht*wid, 3]));
end
end
The output seeked is h. Did you see any variable calculated in the function on the name h? No, the variable is not ther ein the function and you are trying to take it as output, so the error pops out.
I think the output should not be h, it shoudle be D. Change the function to:
function D=getColorHist(im, color_table, opt)
im = rgb2hsv(im);
[ht,wid,~]=size(im);
if opt == 'euc' % euclidean distance
D = pdist2(color_table, reshape(im, [ht*wid, 3]));
end
end
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