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Image Translation with OpenCV

This section explains how to translate (shift) an image using OpenCV with an affine transformation.

Image translation is commonly used for: - Data augmentation - Alignment correction - Preprocessing for vision algorithms

1. Implementation Principle​

OpenCV uses the cv2.warpAffine() function to perform affine transformations, including:

  • Translation
  • Rotation
  • Scaling
  • Shearing

For translation, a 2×3 transformation matrix is defined as:

[ 1  0  tx ]
[ 0  1  ty ]

Where: - tx is the horizontal shift - ty is the vertical shift

2. Implementation Effect​

Navigate to the OpenCV working directory:

cd ~/opencv

Run the image translation script:

python3 06.image_translate.py
note

Select the image window and press q to exit the program.

Image Translation Result

3. Implementation Code​

import cv2
import numpy as np

def translate_image(input_path, output_path, tx, ty):
    image = cv2.imread(input_path)

    if image is None:
        print("Error: Unable to open image file.")
        return

    # Affine transformation matrix
    M = np.float32([
        [1, 0, tx],
        [0, 1, ty]
    ])

    translated_image = cv2.warpAffine(
        image,
        M,
        (image.shape[1], image.shape[0])
    )

    if cv2.imwrite(output_path, translated_image):
        print(f"Image saved to {output_path}")
        cv2.imshow('Image Preview', cv2.imread(output_path))
        cv2.waitKey(0)
        cv2.destroyAllWindows()
    else:
        print("Error: Unable to save image file.")

translate_image(
    '/home/jetson/opencv/images/hemihex_logo.png',
    '/home/jetson/opencv/images/hemihex_logo_translate.png',
    50,
    50
)

4. Code Explanation​

  • cv2.imread() loads the image into memory\
  • np.float32() defines the affine transformation matrix\
  • cv2.warpAffine() applies the translation\
  • cv2.imwrite() saves the translated image\
  • Display functions preview the result

Summary​

  • Image translation shifts an image in X and Y directions
  • Implemented using affine transformation
  • Useful for augmentation and preprocessing
  • Requires explicit transformation matrix

Maintained by HemiHex for OpenCV-based image processing workflows.