splat1.m

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% Created by Jonathan T Barron and Jitendra Malik, Electrical Engineering
% and Computer Science, University of California, Berkeley.
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function X_splat = splat1(X, bin_range_low, bin_range_high)

assert(~any(any(any(isnan(X)))))

N_BINS = 254;

X_splat.valid = bsxfun(@gt, X, bin_range_low + 10*eps) & bsxfun(@lt, X, bin_range_high - 10*eps);

X = bsxfun(@max, bin_range_low + 10*eps, X);
X = bsxfun(@min, bin_range_high - 10*eps, X);

X_splat.span = bin_range_high - bin_range_low;
X_splat.n_bins = N_BINS;
X_splat.bin_width = X_splat.span / (X_splat.n_bins+1);

X_splat.bin_area = X_splat.bin_width;

X_splat.dims = 1+ceil((bin_range_high - bin_range_low)/X_splat.bin_width);

X_splat.bin_range_low = bin_range_low;
X_splat.bin_range_high = bin_range_high;

dX = bsxfun(@minus, X, bin_range_low) / X_splat.bin_width + 1;
before = min(floor(dX), X_splat.n_bins+1);

X_splat.f2 = dX - before;
X_splat.f1 = 1 - X_splat.f2;

X_splat.idx1 = uint32(before);
X_splat.idx2 = X_splat.idx1 + 1;

X_splat.N = accumarray(X_splat.idx1, X_splat.f1, [X_splat.dims,1]) + accumarray(X_splat.idx2, X_splat.f2, [X_splat.dims,1]);