EEDI

EEDI stands for Edge Directed Interpolation. It is an algorithm that is used for upscaling images while preserving the edges.

Introduction

Upscaling an image is a common task in image processing. However, traditional upscaling algorithms produce blurry images with less detail. The reason for this is that traditional algorithms do not consider the edges of an image. Edges are the areas in an image where the color or intensity changes sharply. These areas are important for preserving the detail in an image.

EEDI algorithm takes the edges of an image into consideration while upscaling the image. This results in a more detailed image with sharper edges.

Implementation

EEDI can be implemented in software using a variety of programming languages. There are also implementations available in some image processing software such as Avisynth and VapourSynth.

Here is an example of a Python implementation of the EEDI algorithm:

import cv2
import numpy as np

def eedi_upscale(img, ratio):
    # Convert image to YUV color space
    img_yuv = cv2.cvtColor(img, cv2.COLOR_RGB2YUV)
    # Extract Y channel
    y = img_yuv[:,:,0]
    # Create a mask of edges
    edges = cv2.Canny(y, 100, 200)
    # Upscale the image using bicubic interpolation
    y_upscaled = cv2.resize(y, None, fx=ratio, fy=ratio, interpolation=cv2.INTER_CUBIC)
    # Blur the upscaled image
    y_upscaled_blur = cv2.GaussianBlur(y_upscaled, (3, 3), 0)
    # Fill in the masked edges with the original values
    y_upscaled_edges = cv2.bitwise_and(y_upscaled_blur, y_upscaled_blur, mask=edges)
    y_upscaled_filled = cv2.addWeighted(y_upscaled, 1, y_upscaled_edges, 1, 0)
    # Combine the upscaled Y channel with the original U and V channels
    img_yuv_upscaled = img_yuv.copy()
    img_yuv_upscaled[:,:,0] = y_upscaled_filled
    img_upscaled = cv2.cvtColor(img_yuv_upscaled, cv2.COLOR_YUV2RGB)
    # Return the upscaled image
    return img_upscaled

Conclusion

EEDI is a powerful algorithm for upscaling images while preserving the edges. It produces high quality images with more detail and sharper edges. EEDI can be easily implemented in software using a variety of programming languages.