Block artifacts detection

A method of detecting block artifacts in a video signal, the method comprising:

• computing a gradient signal on basis of the video signal;
• establishing a list of samples corresponding to respective local maximum values of the gradient signal;
• determining a histogram of inter-sample distances, a first one of the inter-sample distances corresponding to a first distance between a first one of the samples and a second one of the samples succeeding the first one of the samples, and a second one of the inter-sample distances corresponding to a second distance between the first one of the samples and a third one of the samples succeeding the second one of the samples;
• and
• analyzing the histogram of inter-sample distances and producing a block artifact indicator on basis of the histogram.

A computer program product to be loaded by a computer arrangement, comprising instructions to detect block artifacts in a video signal, the computer arrangement comprising processing means and a memory, the computer program product, after being loaded, providing said processing means with the capability to carry out:

• computing a gradient signal on basis of the video signal;
• establishing a list of samples corresponding to respective local maximum values of the gradient signal;
• determining a histogram of inter-sample distances, a first one of the inter-sample distances corresponding to a first distance between a first one of the samples and a second one of the samples succeeding the first one of the samples, and a second one of the inter-sample distances corresponding to a second distance between the first one of the samples and a third one of the samples succeeding the second one of the samples;
• and
• analyzing the histogram of inter-sample distances and producing a block artifact indicator on basis of the histogram.