1. A method for evaluating a color picture tube comprising: displaying on a display surface of a color picture tube a measurement pattern including a plurality of first patterns arranged at different positions relative to fluophor dots of said color picture tube and a plurality of second patterns near said first patterns and sufficiently large relative to said fluophor dots; obtaining a first image using an imaging element to image said displayed measurement pattern; obtaining a second image using said imaging element to image while controlling light intake to allow brightness components of no more than about 1% of maximum luminance from said first image to be separated from noise and imaged; creating a third image by combining said first image and said second image while adjusting scales according to a light intake ratio; calculating, from said third image, display center positions of said plurality of first patterns using said second pattern positions; measuring discrete fluophor emission intensity distributions for each of said plurality of first patterns; and obtaining an electron beam intensity distribution by matching display center positions of said plurality of first patterns and combining said plurality of first patterns.