US 7502518

As of April 26, 2026, searches of the USPTO database and CAFC 2026 dockets for US patent 7502518 did not reveal any active litigation or specific mentions in the CAFC's scheduled cases for June 2026.

Here is a concise summary of US Patent 7502518:

• Title: Apparatus and method for coding image based on level of visual attention and level of perceivable image quality distortion, and computer program product therefor
• Assignee: Toshiba Corp
• Inventor: Reiko Noda
• Filing Date: June 15, 2005
• Issue Date: March 10, 2009
• Abstract: An apparatus for coding an image includes a setting unit that sets quantization width for each coded block of an image frame of image data. The apparatus also includes a visual attention calculating unit that calculates a level of visual attention to a first element for each coded block of the image frame; and a perceptual distortion calculating unit that calculates a level of perceptual distortion of a second element whose distorted image quality is easily visually perceived, for each coded block of the image frame. The apparatus also includes a correcting unit that corrects the quantization width based on the level of visual attention and the level of perceptual distortion; and a quantizing unit that quantizes the image data based on the corrected quantization width.

Plain-Language Overview of Independent Claims:

• Claim 1 (Apparatus - Multiplication-based Correction): This claim describes an image coding apparatus. It comprises a setting unit to define a quantization width for each image block, a visual attention calculating unit to determine a level of visual attention for a specific image characteristic within each block, and a perceptual distortion calculating unit to ascertain how easily distortions are perceived in another image characteristic for each block. A correcting unit then adjusts the initial quantization width by multiplying it with a factor derived from the calculated visual attention and a "level of distorted precision" (likely a typo for "level of perceptual distortion" as used in the abstract and description). Finally, a quantizing unit processes the image data using this corrected quantization width.
• Claim 2 (Apparatus - Addition-based Logarithmic Correction): This claim describes an image coding apparatus similar to Claim 1 in its initial steps of setting quantization width and calculating levels of visual attention and perceptual distortion. However, the correcting unit here adjusts the quantization width by adding to it a value. This added value is a product of a predetermined positive real number and a logarithm (with a base of one or greater) of the product of the visual attention level and the perceptual distortion level. A quantizing unit then uses this logarithmically-corrected quantization width.
• Claim 3 (Method - Multiplication-based Correction): This claim outlines a method for image coding, which mirrors the functionality of the apparatus described in Claim 1. It involves setting a quantization width for each coded block, calculating a level of visual attention and a level of perceptual distortion for respective elements, correcting the quantization width by multiplying it with the product of the visual attention level and the "level of distorted precision" (again, likely "perceptual distortion"), and then quantizing the image data based on this corrected width.
• Claim 4 (Method - Addition-based Logarithmic Correction): This claim describes an image coding method that corresponds to the apparatus of Claim 2. The method includes setting a quantization width, calculating levels of visual attention and perceptual distortion, and then correcting the quantization width by adding to it a value that is a product of a positive real number and a logarithm of the combined visual attention and perceptual distortion levels. The image data is subsequently quantized using this corrected width.
• Claim 5 (Apparatus - Specific Visual Attention and Perceptual Distortion Details, Multiplication-based Correction): This claim details an image coding apparatus, building upon the principles of Claim 1 with more specific definitions for calculating visual attention and perceptual distortion. The visual attention calculation assigns values based on elements like average pixel color's value, saturation, and hue, where higher attention areas get smaller values (less than one) and lower attention areas get larger values (greater than one). The perceptual distortion calculation assigns values based on the variance of the input image within a block, with flatter areas (less than average variance) receiving smaller values (less than one) and more complex areas (more than average variance) receiving larger values (greater than one). The quantization width is then corrected by multiplying it by the product of these specifically calculated visual attention and "level of distorted precision" (likely "perceptual distortion") values, followed by quantization of the image data.