Deep Learning for Computer Vision

Rajalingappaa Shanmugamani, Abdul Ghani Abdul Rahman, Stephen Maurice Moore, Nishanth Koganti

• Editore: Packt Publishing
• Anno: 2018
• ISBN:
  9781788293358
• Edizione: 1
• Argomento: Computer Science
• Categoria: Artificial Intelligence (AI) & Semantics

Learn how to model and train advanced neural networks to implement a variety of Computer Vision tasks

Key Features

• Train different kinds of deep learning model from scratch to solve specific problems in Computer Vision
• Combine the power of Python, Keras, and TensorFlow to build deep learning models for object detection, image classification, similarity learning, image captioning, and more
• Includes tips on optimizing and improving the performance of your models under various constraints

Book Description

Deep learning has shown its power in several application areas of Artificial Intelligence, especially in Computer Vision. Computer Vision is the science of understanding and manipulating images, and finds enormous applications in the areas of robotics, automation, and so on. This book will also show you, with practical examples, how to develop Computer Vision applications by leveraging the power of deep learning.

In this book, you will learn different techniques related to object classification, object detection, image segmentation, captioning, image generation, face analysis, and more. You will also explore their applications using popular Python libraries such as TensorFlow and Keras. This book will help you master state-of-the-art, deep learning algorithms and their implementation.

What you will learn

• Set up an environment for deep learning with Python, TensorFlow, and Keras
• Define and train a model for image and video classification
• Use features from a pre-trained Convolutional Neural Network model for image retrieval
• Understand and implement object detection using the real-world Pedestrian Detection scenario
• Learn about various problems in image captioning and how to overcome them by training images and text together
• Implement similarity matching and train a model for face recognition
• Understand the concept of generative models and use them for image generation
• Deploy your deep learning models and optimize them for high performance

Who this book is for

This book is targeted at data scientists and Computer Vision practitioners who wish to apply the concepts of Deep Learning to overcome any problem related to Computer Vision. A basic knowledge of programming in Python—and some understanding of machine learning concepts—is required to get the best out of this book.

Generative Models

Generative models have become an important application in computer vision. Unlike the applications discussed in previous chapters that made predictions from images, generative models can create an image for specific objectives. In this chapter, we will understand:

• The applications of generative models
• Algorithms for style transfer
• Training a model for super-resolution of images
• Implementation and training of generative models
• Drawbacks of current models

By the end of the chapter, you will be able to implement some great applications for transferring style and understand the possibilities, as well as difficulties, associated with generative models.

Applications of generative models

Let's start this chapter with the possible applications of generative models. The applications are enormous. We will see a few of these applications to understand the motivation and possibilities.

Artistic style transfer

Artistic style transfer is the process of transferring the style of art to any image. For example, an image can be created with the artistic style of an image and content of another image. An example of one image combined with several different styles is shown here illustrated by Gatys et al. (https://www.cv-foundation.org/openaccess/content_cvpr_2016/papers/Gatys_Image_Style_Transfer_CVPR_2016_paper.pdf). The image A is the photo on which the style is applied, and the results are shown in other images:

Reproduced from Gatys et al.

This application has caught the public's attention, and there are several mobile apps in the market providing this facility.

Predicting the next frame in a video

Predicting future frames from synthetic video sets is possible using generative models. In the following image proposed by Lotter et al. (https://arxiv.org/pdf/1511.06380.pdf) the images on the left side are the models from the previous frame, and on the right side, there are two algorithms compared with respect to the ground truth:

Reproduced from Lotter et al.

The frames generated by the generative models will be realistic.

Super-resolution of images

The super-resolution is the process of creating higher resolution images from a smaller image. Traditionally, interpolations were used to create such bigger images. But interpolation misses the high-frequency details by giving a smoothened effect. Generative models that are trained for this specific purpose of super-resolution create images with excellent details. The following is an example of such models as proposed by Ledig et al. (https://arxiv.org/pdf/1609.04802.pdf). The left side is generated with 4x scaling and looks indistinguishable from the original on the right:

Reproduced from Ledig et al.

Super-resolution is useful for rendering a low-resolution image on a high-quality display or print. Another application could be a reconstruction of compressed images with good quality.

Interactive image generation

Generative models can be used to create images by interaction. A user can add edits and the images can be generated, reflecting the edits as shown here as proposed by Zhu et al. (https://arxiv.org/pdf/1609.03552v2.pdf):

Reproduced from Zhu et al.

As shown, the images are generated based on the shape and color of the edits. A green color stroke at the bottom creates a grassland, a rectangle creates a skyscraper and so on. The images will be generated and fine-tuned with further inputs from the user. The generated image can also be used to retrieve the most similar real image that can be utilized. Interactiv...