Josphat (Githuka) G.

Data Annotation Lead

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Berlin, Germany

Experience

Jan 2018 - Mar 2025
7 years 3 months

Data Annotation Lead

Sigma AI

  • Lead a team of 15 annotators on large-scale computer vision projects for autonomous vehicle systems
  • Developed comprehensive annotation guidelines that improved inter-annotator agreement by 35 percent
  • Implemented quality control processes that reduced error rates by 42% across all projects
  • Collaborated with ML engineers to identify edge cases and improve dataset quality
  • Managed annotation projects for Fortune 500 clients, delivering 100% on time
Jan 2015 - Dec 2017
3 years

Data Annotation Specialist

DataWorks Inc

  • Performed high-volume image segmentation and bounding box annotation for ecommerce AI systems
  • Annotated text data for NLP projects including sentiment analysis and named entity recognition
  • Trained new team members on annotation tools and quality standards
  • Participated in guideline development and process improvement initiatives
  • Maintained consistent annotation accuracy of 98.5 percent across all projects
Jan 2015 - Dec 2016
2 years

Junior Data Annotator

Lionbridge

  • Conducted image classification and tagging for facial recognition datasets
  • Performed data validation and quality checks on annotated datasets
  • Assisted in audio transcription and labeling for speech recognition projects
  • Met daily annotation targets while maintaining high quality standards

Summary

Data Annotation Specialist with a decade of experience in preparing, labeling, and quality-checking diverse datasets for machine learning applications. Expertise in image, text, audio, and video annotation with proven ability to develop annotation guidelines, train teams, and implement efficient workflows. Strong background in computer vision and natural language processing projects with meticulous attention to detail and deep understanding of AI/ML data requirements.

Skills

  • Image, Text, Audio & Video Annotation
  • Data Labeling Quality Assurance
  • Annotation Guideline Development
  • Team Training & Supervision
  • Project Management & Workflow Optimization
  • Data Analysis & Validation
  • Tool: Labelbox, Cvat, Prodigy, Vgg Image Annotator, Amazon Sagemaker Ground Truth
  • Technical Skills: Python, Sql, Basic Data Analysis, Microsoft Office Suite

Languages

English
Advanced
German
Intermediate

Education

Oct 2013 - Jun 2017

Karlsruhe University

Bachelor of Science, Computer Science · Computer Science · Karlsruhe, Germany

Certifications & licenses

Certified Data Annotation Professional (CDAP)

AWS Machine Learning Foundations

Google Cloud AI Platform Fundamentals

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