Abstract:
A method of improving Ericsson Texture Compression image quality includes providing an original image in the RGB color space, performing an image dithering process on the original image to produce a dithered image, and performing an Ericsson Texture Compression process on the dithered image to produce a compressed image.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to Ericsson Texture Compression, and more particularly to a method of performing a dithering process on images before performing an Ericsson Texture Compression 1 process for improving the quality of resulting images. 
         [0003]    2. Description of the Prior Art 
         [0004]    The original version of the Ericsson Texture Compression (ETC) compression scheme is referred to as Ericsson Texture Compression 1 (ETC1), and was first developed in 2005. The ETC1 compression scheme compresses 24-bit RGB data by a factor of six. In 24-bit RGB data, eight bits of data are allocated for each of the red, green, and blue colors, which adds up to 24 bits in total. 
         [0005]    The ETC1 compression scheme takes 4×4 groups of 24-bit pixel data and compresses each group into a single 64-bit word, thereby compressing the pixel data to be one-sixth of its original size. 
         [0006]    However, the quality resulting from ETC1 compression is not good enough for images in many applications. There exists a need for an improved method of using ETC1 compression which produces higher quality images. 
       SUMMARY OF THE INVENTION 
       [0007]    It is therefore one of the primary objectives of the claimed invention to provide an improved method for performing Ericsson Texture Compression. 
         [0008]    According to an exemplary embodiment of the claimed invention, a method of improving Ericsson Texture Compression image quality is disclosed. The method includes providing an original image in the RGB color space, performing an image dithering process on the original image to produce a dithered image, and performing an Ericsson Texture Compression process on the dithered image to produce a compressed image. 
         [0009]    These and other objectives of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a functional block diagram of an image compressing device according to the present invention. 
           [0011]      FIG. 2  is a flowchart describing the method of compressing the original image file to become the resulting compressed image according to the present invention. 
           [0012]      FIG. 3  shows a comparison of the original image file, a compressed image according to the prior art method of using ETC1 encoding, and the resulting compressed image according to the present invention method of using ETC1 encoding. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    Please refer to  FIG. 1 .  FIG. 1  is a functional block diagram of an image compressing device  10  according to the present invention. The image compressing device  10  contains a processor  12  for executing software commands and controlling operation of the image compressing device  10 . A memory  20  stores an original image file  22 , dithering software  24 , ETC1 compression software  26 , as well as a resulting compressed image  28 . The image compressing device  10  also may contain an optional display  14  for showing the original image file  22  or the resulting compressed image  28 , and an input device  16  for allowing a user to control the image compressing device  10 . The original image file  22  will be operated on by the dithering software  24  for performing a dithering process. The dithered image will then be operated on by the ETC1 compression software  26  for performing an ETC1 process on the dithered image to produce the resulting compressed image  28 . 
         [0014]    Please refer to  FIG. 2 .  FIG. 2  is a flowchart describing the method of compressing the original image file  22  to become the resulting compressed image  28  according to the present invention. Steps in the flowchart will be explained as follows. 
         [0015]    Step  100 : Start. 
         [0016]    Step  102 : The original image file  22  is provided to the image compressing device  10  by the user of the image compressing device  10 . The original image file  22  is an RGB image. In a preferred embodiment, the original image file  22  is a 24-bit RGB image. 
         [0017]    Step  104 : A dithering process is performed on the original image file  22  by the dithering software  24  to produce a dithered image. 
         [0018]    Step  106 : An ETC1 encoding process is performed on the dithered image to produce the resulting compressed image  28 . 
         [0019]    Step  108 : The resulting compressed image  28  is produced and output by the image compressing device  10 . 
         [0020]    Step  110 : End. 
         [0021]    Differing from the conventional method of performing ETC1 encoding on an image, the present invention first performs the dithering process, which is used to create the illusion of color depth in the dithered image. By first performing the dithering process on the original image file  22  before the dithered image is compressed using the ETC1 encoding process, the resulting compressed image  28  much more closely resembles the original image file  22  than would be the case if the dithering process was not used. 
         [0022]    Please refer to  FIG. 3 .  FIG. 3  shows a comparison of the original image file  22 , a compressed image  200  according to the prior art method of using ETC1 encoding, and the resulting compressed image  28  according to the present invention method of using ETC1 encoding. As can be seen, the resulting compressed image  28  more closely resembles the original image file  22  than does the compressed image  200  according to the prior art method of using ETC1 encoding. Thus, the additional dithering process performed by the dithering software  24  before the ETC1 encoding process is performed by the ETC1 compression software  26  produces better end results for the resulting compressed image  28 . 
         [0023]    Those skilled in the art will readily observe that numerous modifications and alterations of the device and method may be made while retaining the teachings of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.