1. A device for detecting changes in background of images using multiple binary images thereof and Hough transformation, comprising: image input module for receiving successive inputs of gray scale images; accumulated values obtaining module for separating both previous image I k-l and current image I k inputted through the image input module into same number of binary images, counting the number of pixels having pixel values within certain range of pixel values, said range of pixel values being respectively assigned to each binary image, and obtaining vertically accumulated values h j V (I k-l ), h j′ V (I k ) and horizontally accumulated values h i H (I k-l ), h i′ H (I k ), said vertically accumulated values h j V (I k-l ), h j′ V (I k ) representing the total number of the counted pixels in each column of the previous image I k-l and current image I k , said horizontally accumulated values h i H (I k-l ), h i′ H (I k ) representing the total number of the counted pixels in each row of the previous image I k-l and current image I k ; pairs obtaining module for determining effective pairs of rows (i, i′) of the previous image I k-l and current image I k and effective pairs of columns (j, j′) of the previous image I k-l and current image I k on the basis of the accumulated values obtained by the accumulated values obtaining module; and Hough transformation module for transforming the effective pairs using Hough transformation and determining peak values ρ V , θ V , ρ H , θ H , wherein changes in background of images are detected from the peak values ρ V , θ V , ρ H , θ H .