A method of planar curve classification, which is invariant to rotation, scaling and translation using the zerocrossings representation of wavelet transform was introduced. The description of the object is represented by taking a ratio between its two adjacent boundary points so it is invariant to object rotation, translation and size. Transforming this signal to zero-crossings representation using wavelet transform, the minimum distance between the object and model while shifting the signals each other, can be used as classification parameter.