A system model based on slantlet transform to estimate optical flow

Abstract EN

The estimation of optical flow is the basic step for many engineering applications that exploit the image processing field as a part of their models.

In this paper a model called Slantlet Based Optical Flow Estimation (SLT_OFE) is proposed to estimate the optical flow.

Slantlet Transform (SLT) used as an effective tool, 2D and 3D- SLT-Level 2 (SLT2) are computed and employed in the proposed model to provide high accuracy estimation of the optical flow.

By its definition, optical flow is a velocity field, so the velocities in this paper are computed using the widely used Differential Technique.

Two methods from this technique are adopted ; Horn-Schunck Method and Lucas-Kanade Method.

The optical flow is estimated for two types of image sequences ; synthetic sequences and real sequences.

Unlike the real sequences, the synthetic sequences have known true velocities which are used for evaluating the proposed model by calculating mean error (Mean Err.), angular error (Ang.

Err.) and Standard Deviation (STD).

For extreme study of its performance, the proposed SLT_OFE is compared with three other models that are based on level two (Discrete Wavelet Transform (DWT), Discrete Multi Wavelet Transform (DMWT) and Framelet Transform (FT) ) which are implemented in this paper and employed in the conventional models, 2D-DWT2_OFE, 2D-DMWT2_OFE and 2D-FT2_OFE.

The results show that the proposed model offers minimum values in errors and STD when 2D-SLT2 is used, and these results are improved by using 3D-SLT2.

This leads to the fact that the proposed model SLT_OFE through both of 2D and 3D approaches possesses an improvement in the optical flow estimation process with higher accuracy, than the other models produced in the same circumstances.

MATLAB Version 7.12 (R2011a) is used to implement the proposed model and the conventional models.