Method of Improving Ericsson Texture Compression 1 Image Quality

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.

BACKGROUND OF THE INVENTION

1. Field of the Invention

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.

2. Description of the Prior Art

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.

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.

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

It is therefore one of the primary objectives of the claimed invention to provide an improved method for performing Ericsson Texture Compression.

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.

DETAILED DESCRIPTION

Please refer toFIG. 1.FIG. 1is a functional block diagram of an image compressing device10according to the present invention. The image compressing device10contains a processor12for executing software commands and controlling operation of the image compressing device10. A memory20stores an original image file22, dithering software24, ETC1 compression software26, as well as a resulting compressed image28. The image compressing device10also may contain an optional display14for showing the original image file22or the resulting compressed image28, and an input device16for allowing a user to control the image compressing device10. The original image file22will be operated on by the dithering software24for performing a dithering process. The dithered image will then be operated on by the ETC1 compression software26for performing an ETC1 process on the dithered image to produce the resulting compressed image28.

Please refer toFIG. 2.FIG. 2is a flowchart describing the method of compressing the original image file22to become the resulting compressed image28according to the present invention. Steps in the flowchart will be explained as follows.

Step102: The original image file22is provided to the image compressing device10by the user of the image compressing device10. The original image file22is an RGB image. In a preferred embodiment, the original image file22is a 24-bit RGB image.

Step104: A dithering process is performed on the original image file22by the dithering software24to produce a dithered image.

Step106: An ETC1 encoding process is performed on the dithered image to produce the resulting compressed image28.

Step108: The resulting compressed image28is produced and output by the image compressing device10.

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 file22before the dithered image is compressed using the ETC1 encoding process, the resulting compressed image28much more closely resembles the original image file22than would be the case if the dithering process was not used.

Please refer toFIG. 3.FIG. 3shows a comparison of the original image file22, a compressed image200according to the prior art method of using ETC1 encoding, and the resulting compressed image28according to the present invention method of using ETC1 encoding. As can be seen, the resulting compressed image28more closely resembles the original image file22than does the compressed image200according to the prior art method of using ETC1 encoding. Thus, the additional dithering process performed by the dithering software24before the ETC1 encoding process is performed by the ETC1 compression software26produces better end results for the resulting compressed image28.