A Novel Multi-focus Image Capture and Fusion System for Macro Photography - Advances in Image and Graphics Technologies - page 19

A Novel Multi-focus Image Capture and Fusion System
for Macro Photography
Yili Zhao 1,3 , Yi Zhou 2,3 , and Dan Xu 3
1 Southwest Forestry University, Kunming Yunnan 650224
2 Yunnan Normal University, Kunming Yunnan 650091
3 Yunnan University, Kunming Yunnan 650091
[e-mail], [e-mail], [e-mail]
Abstract. This paper proposes a novel multi-focus image capture and fusion
system for macro photography. The system consists of three components. The
first component is a novel multi-focus image capture device which can capture
multiple macro images taken at different focus distances from a photographic
subject, with high precision. The second component is a feature based method
which can align multiple in-focus images automatically. The third component is
a new multi-focus image fusion method which can combine multiple macro im-
ages to a fused image with a greater depth of field. The proposed image fusion
method is based on Gaussian and Laplacian pyramids with a novel weight map
selection strategy. Several data sets are captured and fused by the proposed
system to verify the hardware and software design. Subjective and objective
methods are also used to evaluate the proposed system. By analyzing the expe-
rimental results, it shows that this system is flexible and efficient, and the quali-
ty of the fused image is comparable to the results of other methods.
Keywords: Macro photography, multi-focus image, image alignment, Lapla-
cian pyramid, image fusion.
1 Introduction
Macro photography is gaining popularity and has been used in more and more fields
like zoology, botany and film production [1]. It is suitable for human visual percep-
tion and computer-processing tasks such as segmentation, feature extraction and
object recognition. Traditionally, professional macro lens are used in macro photo-
graphy. However, due to the limited depth-of-field of optical lenses in the CCD
devices, it is often not possible to get an image that contains all relevant objects in
focus. Consequently, the obtained image will not be in focus everywhere, i.e., if one
object in the scene is in focus, another one will be out of focus. In order to obtain all
objects in focus, multiple photos with different focus region are necessary and multi-
focus fusion is used to blend these images to a fused image.
In general, users can set the initial distance between the lens and the object, and ad-
just the lens focal length manually. However, this is tedious and error-prone. The
paper proposes a novel macro photography capture device which can capture a serial