Here are a few question-based titles that fit the content of your provided text: * **Why Does My OpenCV Image Look Different When Plotted with Matplotlib?** * **Why Is There a Color Discrepancy When

OpenCV Color Conversion Discrepancy in Image Loading

When attempting to load and display a color image using Python OpenCV, users may encounter unexpected color deviations in the resulting image. This issue arises due to a difference in the default color ordering schemes between OpenCV and the Matplotlib library.

Problem Description

The code provided by the user involves loading a color image using OpenCV's cv2.imread() function and converting it to grayscale using cv2.cvtColor(). Subsequently, both the original image and the grayscale image are plotted using Matplotlib's plt.imshow() function. Despite using the IMREAD_COLOR flag, the plotted image exhibits distorted colors.

Underlying Issue

By default, OpenCV utilizes the Blue-Green-Red (BGR) color ordering for images, while Matplotlib uses Red-Green-Blue (RGB). When the image loaded by OpenCV is displayed in Matplotlib, the channels are inverted, leading to the color discrepancy.

Solution

To resolve this issue, the user can explicitly convert the BGR image loaded from OpenCV to RGB using the cv2.cvtColor() function. The converted RGB image can then be used for plotting in Matplotlib.

<code class="python">import cv2
import matplotlib.pyplot as plt

# Load image in BGR
img = cv2.imread('lena_caption.png', cv2.IMREAD_COLOR)

# Convert BGR to RGB
RGB_img = cv2.cvtColor(img, cv2.COLOR_BGR2RGB)

# Plot RGB image in Matplotlib
plt.imshow(RGB_img)
plt.title('Original Image in RGB')
plt.xticks([]), plt.yticks([])
plt.show()</code>

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