Axis-aligned interaction type sampling soft shadow generation method

An axis-aligned and interactive technology, applied in the field of image processing, which can solve the problems of difficulty in smooth real-time presentation, slow filtering speed, and large filtering size, and achieve the effect of speeding up filtering speed, reducing waste, and small filtering size.

Active Publication Date: 2017-02-08
SHANGHAI JIAO TONG UNIV
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Problems solved by technology

In the axis-aligned filtering method, the problem of filter size is not considered. No matter how wide the shadow frequency band after Fourier transform is, this method will always use the axis-aligned method for processing. In this way, although the processing method becomes simple, it is also convenient The filter decoupling between the x-axis and the y-axis becomes simple, which makes it easier to expand from 2D to 4D in the later stage, but the problem is that the filter size is too large, which slows down the filter speed
In special cases, when the shadow spectrum is very narrow, it will be a great waste of resources to filter a large area
Through the implementation of its source code, it is found that this soft shadow generation algorithm is still difficult to display smoothly in real time on ordinary computers

Method used

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  • Axis-aligned interaction type sampling soft shadow generation method

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Embodiment Construction

[0030] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is carried out on the premise of the technical solution of the present invention, and detailed implementation and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

[0031] Such as figure 1 As shown, this embodiment provides an axis-aligned interactive sampling soft shadow generation method for locating the optic disk area of ​​the fundus image, and the method includes the following steps:

[0032] 1) Construct a masking function;

[0033] 2) Perform Fourier transform on the masking function to obtain the masking function in the frequency domain;

[0034] 3) Perform axis-aligned interactive filtering on the masking function in the frequency domain to obtain the main masking function;

[0035] 4) According to the main masking function and combin...

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Abstract

The invention relates to an axis-aligned interaction type sampling soft shadow generation method, and planar light is processed, according to a known function, to generate a soft shadow. The method comprises the following steps that a shielding function is constructed; Fourier transform is carried out on the shielding function to obtain a shielding function in the frequency domain; axis-aligned interaction type filtering is carried out on the shielding function in the frequency domain to obtain a major shielding function; and according to the major shielding function, the known function is combined to carry out calculation, and a soft shadow area is obtained. Compared with the prior art, the method of the invention has the advantages including high filtering speed, good soft shadow generation effect, low computational complexity and smooth realization.

Description

technical field [0001] The invention relates to the technical field of image processing, in particular to an axis-aligned interactive sampling soft shadow generation method. Background technique [0002] Soft shadows are the semi-dark parts of the shadow area produced by flat or dim light. In order to generate this effect, there are two main directions, one is to calculate the real situation of light irradiation through ray tracing, and the other is to simulate the soft shadow area effect through algorithms. [0003] Nowadays, the shadow effect has been well realized in various games, and the most popular algorithm is ShadowMapping, which was proposed by Lance Williams in 1978. The basic principle of the algorithm is that if there is no object blocking the line between the light source and the target point, the target point is not in the shadow, and if there is an object blocking, the target point is in the shadow. From this, a ShadowMap can be created, which is a texture ...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06T15/60G06T15/06
CPCG06T15/06G06T15/60
Inventor 盛斌伍明利
Owner SHANGHAI JIAO TONG UNIV
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