5 Common Mistakes in Computer Vision Projects

Best Practices Tutorial

Introduction

After working on dozens of computer vision projects, I’ve seen teams make the same mistakes repeatedly. Here are the top 5 pitfalls and how to avoid them.

1. Insufficient Training Data

The Problem

Many teams start with only a few hundred images, expecting deep learning magic to happen.

The Solution

  • Minimum viable dataset: 1000+ images per class
  • Use data augmentation: Rotation, flipping, color jitter
  • Synthetic data generation: When real data is scarce
  • Active learning: Iteratively add hard examples
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from albumentations import (
    Compose, Rotate, RandomBrightnessContrast, 
    HorizontalFlip, GaussNoise
)

transform = Compose([
    Rotate(limit=30),
    HorizontalFlip(p=0.5),
    RandomBrightnessContrast(p=0.2),
    GaussNoise(p=0.1)
])

2. Ignoring Class Imbalance

The Problem

Real-world defects are rare. Your dataset might have 95% “good” images and only 5% defects.

The Solution

  • Weighted loss functions
  • Oversampling minority class
  • Focal loss for hard examples
  • Synthetic minority oversampling (SMOTE)

3. Not Testing on Production-Like Data

The Problem

Model performs great in lab conditions but fails in production due to:

  • Different lighting
  • Camera angles
  • Background noise
  • Motion blur

The Solution

  • Collect data from actual production line
  • Test with various lighting conditions
  • Simulate real-world conditions in training
  • Continuous monitoring and retraining

4. Over-Optimizing for Accuracy

The Problem

Chasing 99% accuracy when 95% is sufficient, adding complexity and computational cost.

The Solution

  • Define success metrics clearly: False positives vs false negatives
  • Consider business impact: What’s the cost of each error type?
  • Optimize for production constraints: Speed, memory, power
  • Use appropriate metrics: Precision, recall, F1, not just accuracy

5. Neglecting Model Interpretability

The Problem

Black-box models make it hard to debug failures and gain stakeholder trust.

The Solution

  • Use Grad-CAM for visualization
  • Feature importance analysis
  • Document failure cases
  • Implement confidence scores
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from pytorch_grad_cam import GradCAM

# Visualize what the model is looking at
cam = GradCAM(model=model, target_layers=[model.layer4[-1]])
grayscale_cam = cam(input_tensor=image)

Bonus Tips

Model Deployment

  • Start simple (classical CV before deep learning)
  • Version your datasets and models
  • A/B test in production
  • Build feedback loops

Data Quality

  • Manual review of edge cases
  • Regular data audits
  • Clear labeling guidelines
  • Multiple annotators for validation

Conclusion

Success in computer vision comes from:

  1. Quality data over quantity (though you need both!)
  2. Production-focused development
  3. Iterative improvement based on real feedback
  4. Clear metrics aligned with business goals

Avoid these mistakes, and you’ll save months of frustration!

What mistakes have you encountered? Share in the comments below!

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James Lions

James Lions

AI & Computer Vision enthusiast exploring the future of automated defect detection

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