Color GF-HoG

This repo contains Matlab implementation for Color Gradient Field Histogram of Oriented Gradient (Color GF-HoG) as described in the ICCV ws 2015 paper Scalable Sketch-based Image Retrieval using Color Gradient Features .

GF-HoG implementation

Original	GF-HoG

If you work on black-white sketches only, please check example.m under the BW folder:

des = ComputeGF('circle.png',0);

will compute local GF-HoG descriptors for a sketch. If you input an image, change the second argument to 1.

This implementation follows the original C code by Rui Hu and Stuart James (project page here and here) with several improvements that achieves 16.6% mAP on the Flickr15K benchmark (18.2% mAP with Inverted Index), as reported in Fig. 5 in our paper.

Color GF-HoG implementation

Original	Color GF-HoG visualisation

If you work on colour sketches, please check example.m under the color folder:

[des_shape, des_color] = ComputeGF_colour('underground_sketch.png',0);

will compute local shape and color descriptors for a sketch. For image, change the second argument to 1.

Difference from the paper In the paper, the luminance channel (L*) is passed through a double sigmoid function to separate black and white from the rest. Our implementation currently employs L* directly. We will implement this functionality in the next update.

Demo

Reference

@inproceedings{bui2015scalable,
  title={Scalable sketch-based image retrieval using color gradient features},
  author={Bui, Tu and Collomosse, John},
  booktitle={Proceedings of the IEEE International Conference on Computer Vision Workshops},
  pages={1--8},
  year={2015}
}