A method of processing light field images of a three-dimensional scene captured by a plenoptic imaging system, the method implemented on a computer system and comprising: accessing an (image,view) domain representation of the light field images of the three-dimensional scene captured by the plenoptic imaging system; characterised by: applying a scale-depth transform to transform the (image,view) domain representation to an (image,scale,depth) domain representation; and processing the (image,scale,depth) domain representation of the three-dimensional scene, wherein the processing comprises estimating depth in the three-dimensional scene based on processing the (image,scale,depth) domain representation, the scale-depth transform is a normalized second derivative Ray-Gaussian transform, and estimating depth in the three-dimensional scene comprises finding extrema of the normalized second derivative Ray-Gaussian transform and estimating depth based on said extrema; wherein a Ray-Gaussian transform kernel is defined as wherein x is an (image) coordinate, u is a (view) coordinate, σ is a (scale) coordinate, and φ is a (depth) coordinate wherein applying a scale-depth transform comprises: convolving the (image,view) domain representation with the Ray-Gaussian kernel or one among its first and second derivatives for σ ∈ { σ 1,..., σ n} and for φ ∈ { φ 1,..., φ m}; and repeating at least once the step of downsampling the (image,view) domain representation, or an image portion thereof, by p and convolving with the Ray-Gaussian kernel or its corresponding derivative for σ ' E { σ ' 1,..., σ' n} and for { φ' 1,..., φ' m}; where σ' = pσ and φ ' = arctan( p tan φ), n is the number of samples per downsampling range of scale, m is the number of samples in the depth domain, and p is the downsampling factor. accessing an (image,view) domain representation of the light field images of the three-dimensional scene captured by the plenoptic imaging system; characterised by: applying a scale-depth transform to transform the (image,view) domain representation to an (image,scale,depth) domain representation; and processing the (image,scale,depth) domain representation of the three-dimensional scene, wherein the processing comprises estimating depth in the three-dimensional scene based on processing the (image,scale,depth) domain representation, the scale-depth transform is a normalized second derivative Ray-Gaussian transform, and estimating depth in the three-dimensional scene comprises finding extrema of the normalized second derivative Ray-Gaussian transform and estimating depth based on said extrema; applying a scale-depth transform to transform the (image,view) domain representation to an (image,scale,depth) domain representation; and processing the (image,scale,depth) domain representation of the three-dimensional scene, wherein the processing comprises estimating depth in the three-dimensional scene based on processing the (image,scale,depth) domain representation, the scale-depth transform is a normalized second derivative Ray-Gaussian transform, and estimating depth in the three-dimensional scene comprises finding extrema of the normalized second derivative Ray-Gaussian transform and estimating depth based on said extrema;