1. A method for adjusting image colors of an image projector, the method comprising the steps of: outputting by an image projector of a portable communication terminal a white signal to a projection surface; photographing by a camera unit of the portable communication terminal a background color by taking a picture of the projection surface; calculating by a controller a chromaticity of an average value of the photographed background color in order to determine if another background color and a first white background color exist; performing by the controller a color correction of the photographed background color if another background color exists; and outputting by the image projector the corrected image to the projection surface in real-time; wherein the projection surface comprises a projection screen including one of a flat surface of a certain color and a white wall, and wherein a chromaticity of an object having a second white background color differing from said first white background color is obtained without activation of a white balance function of the camera unit, wherein the step of performing the color correction comprises the sub-steps of: converting an image size into a size of an original image using the photographed background color image as a mask image; and correcting a brightness of the original image using a brightness of the mask image, thereby correcting a non-homogeneity of the brightness of the mask image with the converted size, and wherein, in the step of correcting the non-homogeneity of the brightness of the mask image with the converted size, the average value of luminance of the mask image is calculated after RGB value of the original image and the mask image is moved to a YCbCr color space coordinate in order to separate a luminance signal from a color signal, and then a difference between the luminance values corresponding to respective pixels of the mask image is obtained on the basis of the average value of the luminance of the mask image, so as to adjust the luminance value of the original image depending on the difference.