1. A method of enabling touch determination based on an output signal from a touch-sensitive apparatus, the touch-sensitive apparatus comprising a panel configured to conduct light wave signals from a plurality of peripheral incoupling points to a plurality of peripheral outcoupling points, thereby defining detection lines that extend across a surface portion of the panel between pairs of incoupling and outcoupling points, at least one signal generator coupled to the incoupling points to generate the signals, and at least one signal detector coupled to the outcoupling points to generate the output signal, the method comprising: processing the output signal to generate a set of data samples, wherein each data sample is indicative of transmitted light wave energy on one of the detection lines and is defined by a signal value and first and second dimension values in a two-dimensional sample space, wherein the first and second dimension values define the location of the detection line on the surface portion, and wherein the data samples are non-uniformly arranged in the sample space; obtaining adjustment factors for the set of data samples, wherein each adjustment factor is representative of the local density of data samples in the sample space for a respective data sample; processing the set of the data samples by tomographic reconstruction, while applying the adjustment factors by scaling the signal value of each data sample in the set of data samples by its corresponding adjustment factor, to generate data indicative of a reconstructed distribution of a light wave attenuation parameter within at least part of the surface portion; wherein the reconstructed distribution includes spatial data points, each spatial data point having a unique location on the surface portion and corresponding to a curve of a sinogram in the sample space; and wherein the processing the set of data samples includes, generating filtered signal values for the data samples by scaling the signal value of each data sample by a weight given by a filter function based on the distance of the data sample from the curve in the first dimension, and evaluating each spatial data point by scaling the filtered signal value by the adjustment factor of the corresponding data sample, and summing the scaled filtered signal values.