davisking/dlib

Support for reading images in correct orientation using EXIF data.

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#1,706 opened on Mar 28, 2019

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enhancementhelp wanted

Description

Current Behavior

I'm working on image processing with some images I collected myself. Dlib's dlib.load_rgb_image('image_path') method swaps the rows and columns on some images while OpenCV's cv2.imread('image_path') method does not.

Check out the results below

img = dlib.load_rgb_image("myimg.jpg")
print(img.shape)

--------------------
OUTPUT: (1944, 2592, 3)
(the resultant image is rotated 90 degrees clockwise)

while OpenCV's method returns the correct shape:

img = cv2.imread("myimg.jpg")
print(img.shape)

--------------------
OUTPUT: (2592, 1944, 3)

dlib.load_rgb_image() does not take into account the EXIF orientation metadata, so some images are read incorrectly.

I don't want to go in and rotate some of these offending images myself manually because I'm creating an app.

Is there a way in Dlib to read images using orientation information?

Note: I asked this question of stackoverflow, one of the comments told me to create an issue here

  • Version: 19.17.0
  • Where did you get dlib: pip
  • Platform: Windows 10 - 64bit
  • Compiler: python 3.6

Contributor guide

Tech stack
cpppython
Domain
data
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
3-5 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
C++ programmingEXIF metadatadlib image loading
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
45
Research direction
Investigate dlib's image loading implementation, likely in the dlib/image processing directory. The load rgb image function should be modified to read and apply EXIF orientation metadata. Consider using a library like libexif to parse EXIF data. Refer to the stackoverflow discussion linked in the issue for more context.