This book constitutes the proceedings of the 13th Mexican Conference on Pattern Recognition, MCPR 2021, which was planned to be held in Mexico City, Mexico, in June 2021. They are organized in the following topical sections: artificial intelligence techniques and recognition; pattern recognition techniques;

Artificial Intelligence Techniques and Recognition.- A Straightforward Framework For Video Retrieval Using CLIP.- Inferential Rules for Identifying Answers in TOEFL Texts.- Automatic Detection of Injection Attacks by Machine Learning in NoSQL Databases.- Automatic Recognition of Learning-Centered Emotions.- Pattern Recognition Techniques.- Unsupervised Feature Selection Methodology for Analysis of Bacterial Taxonomy Profiles.- A Comparative Study of Two Algorithms for Computing the Shortest Reducts: MiLIT and MinReduct.- Extremal Topologies for the Merrifield-Simmons Index on Dynamic Trees.- Experimental Comparison of Oversampling Methods for Mixed Datasets.- Shortening the Candidate List for Similarity Searching using Inverted Index.- Neural Networks and Deep Learning.- Neuroevolution for Sentiment Analysis in Tweets Written in Mexican Spanish.- Neovascularization Detection on Optic Disc Region using Deep Learning.- Metric Localisation for the NAO Robot.- Multi-Source Transfer Learning for Deep Reinforcement Learning.- Efficient Training of Deep Learning Models through Improved Adaptive Sampling.- Graph Representation for Learning the Traveling Salesman Problem.- Satellite Imagery Classification using Shallow and Deep Learning Approaches.- Skeletal Age Estimation from Hand Radiographs using Ensemble Deep Learning.- Computer Vision.- Quantifying Visual Similarity for Artistic Styles.- Automatic Classification of Zingiberales from RGB Images.- Classification of Rail Welding Defects based on the Bag of Visual Words Approach.- Fast Background Subtraction and Graph Cut for Thermal Pedestrian Detection.- Image Processing and Analysis.- Development of a Method for Identifying People by Processing Digital Images from Handprint.- Finding the Optimum Bit-quad Patterns for Computing the Euler Number of 2D Binary Images using Simulated Annealing.- Perceptual and Pixel-Wise Information for Visual Novelty Detection.- Multi-core Median Redescending M-Estimator for Impulsive Denoising in Color Images.- A Comparative Study of 3D Plant Modeling Systems based on Low-cost 2D LiDAR and Kinect.- Evaluation of Denoising Algorithms for Source Camera Linking.- Texture based Supervised Learning for Crater-like Structures Recognition using ALOS / PALSAR Images.- Medical Applications of Pattern Recognition.- A Comparison Study of EEG Signals Classifiers for Inter-subject Generalization.- COVID-19 Related Pneumonia Detection in Lung Ultrasound.- Breastfeeding and Caries. A Relationship Analysis to Develop a Computer-Assisted Diagnosis using Random Forest.- Lung-nodule Segmentation using a Convolutional Neural Network with the U-Net Architecture.- Multi-target Attachment for Surgical Instrument Tracking.- W-net: a Convolutional Neural Network for Retinal Vessel Segmentation.- Novel Features for Glaucoma Detection in Fundus Images.