Method transform1D

ij/src/main/java/ij/process/FHT.java:172–180

Performs an optimized 1D Fast Hartley Transform (FHT) of an array. Array size must be a power of 2. Note that all amplitudes in the output 'x' are multiplied by the array length. Therefore, to get the power spectrum, for 1 <=i < N/2, use ps[i] = (x[i] x[i]+x[maxN-i] x[maxN-i])/(maxN maxN), where

(float[] x)

	 *  but you have to divide by maxN instead of 2*maxN.
	 */
	public void transform1D(float[] x) {
		int n = x.length;
		if (S==null || n!=maxN) {
			if (!isPowerOf2(n))
				throw new IllegalArgumentException("Not power of 2 length: "+n);
			initializeTables(n);
		}
		dfht3(x, 0, false, n);
	}

    /** Performs an inverse 1D Fast Hartley Transform (FHT) of an array */
	public void inverseTransform1D(float[] fht) {