Archive | Image Processing

Long exposure with OpenCV and Python

One of my favorite photography techniques is long exposure, the process of creating a photo that shows the effect of passing time, something that traditional photography does not capture. When applying this technique, water becomes silky smooth, stars in a night sky leave light trails as the earth rotates, and car headlights/taillights illuminate highways in […]

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Text skew correction with OpenCV and Python

Today’s tutorial is a Python implementation of my favorite blog post by Félix Abecassis on the process of text skew correction (i.e., “deskewing text”) using OpenCV and image processing functions. Given an image containing a rotated block of text at an unknown angle, we need to correct the text skew by: Detecting the block of text in the […]

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Seam carving with OpenCV, Python, and scikit-image

Easily one of my all-time favorite papers in computer vision literature is Seam Carving for Content-Aware Image Resizing by Avidan and Shamir from Mitsubishi Electric Research Labs (MERL). Originally published in the SIGGRAPH 2007 proceedings, I read this paper for the first time during my computational photography class as an undergraduate student. This paper, along with […]

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Bubble sheet multiple choice scanner and test grader using OMR, Python and OpenCV

Over the past few months I’ve gotten quite the number of requests landing in my inbox to build a bubble sheet/Scantron-like test reader using computer vision and image processing techniques. And while I’ve been having a lot of fun doing this series on machine learning and deep learning, I’d be lying if I said this little […]

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