1. A method for judging in a three-dimensional (3D) imaging environment that uses a display unit to display a predetermined 3D image, the predetermined 3D image including a left-eye image and a right-eye image, each of the left-eye image and the right-eye image containing a pattern that defines a preset number of enclosed areas of a respective one of the left-eye image and the right-eye image, the method to be implemented by a processor and comprising the steps of: (A) receiving, by the processor, a first image and a second image of the predetermined 3D image displayed by the display unit, the first image being captured by an image capturing unit without the aid of 3D glasses, the second image being captured by the image capturing unit with the 3D glasses arranged in front of the image capturing unit; (B) processing, by the processor, each of the first image and the second image so as to obtain a respective one of a processed first image and a processed second image; (C) obtaining, by the processor, a number of enclosed areas contained in the processed first image, and a number of enclosed areas contained in the processed second image; and (D) determining, by the processor, whether the number of the enclosed areas contained in the processed first image is equal to a predetermined number of enclosed areas associated with a standard first image, and whether the number of the enclosed areas contained in the processed second image is equal to a predetermined number of enclosed areas associated with a standard second image; wherein the 3D imaging environment is functioning normally when results of determinations made by the processor in step (D) are affirmative.