Image Scaling Device and Method for Large Displays

Large Display Upscaler Based on Local Covariance Least Squares Interpolation and Unsharp Masking

This technology is an image scaling device that upscales low-resolution video to large display resolutions. A parameter calculation unit derives upscaling parameters using local covariance of high-resolution originals and standard least squares, while an upscaling unit expands the image and an unsharp masking unit enhances sharpness.

Conventional scaling methods such as nearest-neighbor, bilinear, bicubic, and Lanczos interpolation have limitations in fully preserving image details during expansion. Consequently, enlarging images on large screens often results in blurred edges and loss of texture.

This technology restores detail by applying low-pass filter-based unsharp masking to images expanded with adaptive interpolation coefficients derived from local covariance, adjusting enhancement levels with a control weight of 0.5 and a filter weight of 2. Applicable to scaler chips in large TVs, digital signage, and medical imaging monitors, it allows low-resolution content to be played with sharp edges and textures on large screens.

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Key Features:

• A parameter calculation unit that derives upscaling parameters using local covariance of high-resolution original images and standard least squares when height and width are doubled
• An upscaling unit that calculates vector-form upscaling parameters using the inverse of the local covariance matrix and performs upscaling based on grid-variable formulas
• An unsharp masking unit that performs unsharp masking by adding the difference between the upscaled input image and the low-pass filtering result using a control weight
• A large display image scaling method that sequentially performs parameter calculation, upscaling, and unsharp masking, applying a control weight of 0.5 and a filter weight of 2

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This invention was developed with support from the Small and Medium Business Administration for resolving technical difficulties in large-capacity image analysis for film inspection equipment.

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