The response of the central neuron in the primary visual cortex (V1) is not only affected by the stimulus inside the classical receptive field but also modulated by the surrounding stimulus (NCRF). Contextual modulation is mediated by horizontal connections across the visual cortex. This study proposes a contour detection method based on the visual mechanism in V1. First

the response of every visual neuron in V1 is computed by local energy. Second

facilitation and suppression (contextual influence) on a neuron through horizontal interactions are obtained by constructing a spatially unified modulating function. Finally

the total output response of one neuron to complex visual stimuli is acquired by combining the influence of local visual context on the neuron and energy response. Unlike previous studies

the present work unified the facilitation and suppression modulated by surrounding elements in the image without separating the regions of excitatory and inhibitory lateral connections. The proposed method was tested on synthetic and natural images; encouraging results were obtained. The proposed model is expected to improve contour detection performance when images contain objects of interest on a cluttered background.