Abstract: A method of inspecting a liquid crystal panel and determining the type of defect. Each part of the liquid crystal panel is extracted and inspected by comparison with an extracted reference part. The parts to be inspected may be found based on the location of previously found parts or by examining a plot of the density in the image. Vector data from a part that is known to be defectless is used to extract the reference part. Alternatively, the contour of a reference part may be determined by analyzing the vector data which was obtained for the parts to be inspected. The type of defect is determined by classifying the defective part according to characteristics of the part's image (e.g., brightness of the pixels) as compared with parts having known defects.

Abstract: The present invention makes it possible for unskilled to inspect the total surface of a liquid crystal panel accurately in short time. It is defined that a liquid crystal panel can be divided into a single part which is a constituent, isolable, and an inspectable area, and that the single part to be "unit area of image" which is defined as a pattern to be inspected. Before the inspection, a unit area of an image without defect is selected from a liquid crystal panel to be inspected. The upper limit reference pattern and the lower limit reference pattern are generated by giving the maximal brightness in a convolution and adding the predetermined brightness and by giving the minimal brightness in the convolution and subtracting the predetermined brightness, respectively, to each pixel of the convolution.