Scale-invariant template matching using histogram of dominant gradients

• We presented a scale-invariant template matching method using histogram of dominant gradients.
• We defined the concept of dominant gradient for scaling-tolerant gradient map.
• We enhanced the dominant gradient components and suppressed the other components.
• We extracted a scaling-tolerant histogram vector from an image.
• We carried out a scaling-invariant template matching using the extracted histogram vector.

This paper presents a histogram-based template matching method that copes with the large scale difference between target and template images. Most of the previous template matching methods are sensitive to the scale difference between target and template images because the features extracted from the images are changed according to the scale of the images. To overcome this limitation, we introduce the concept of dominant gradients and describe an image as the feature that is tolerant to scale changes. To this end, we first extract the dominant gradients of a template image and represent the template image as the grids of histograms of the dominant gradients. Then, the arbitrary regions of a target image with various locations and scales are matched with the template image via histogram matching. Experimental results show that the proposed method is more robust to scale difference than previous template matching techniques.