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title: "Image Sampler"
canonical: "https://documentation.chaos.com/space/VRAYHOUDINI/113279287/Image%20Sampler"
format: markdown
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This page provides information on the Anti-Aliasing options in the Sampler tab of the V-Ray Renderer.


## **Overview**

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**What is Anti-Aliasing?**


One of the functions of image sampling is *anti-aliasing*, which is the reduction of jagged edges in a rendering. The following example shows the basic difference between an image with anti-aliasing, and one without. 

If only one sample is taken for each of the pixels around the edge of the sphere, the choice of pixel color is limited to the dark gray at the edge of the object, or the (white) background. Using one of these colors (i.e. taking only one sample) makes the image look jagged. This is the equivalent of no anti-aliasing at all.

If two or more samples are taken in each pixel, the colors are averaged, and pixels at the edge of the object end up being a color in between the dark gray of the sphere and the background. These in-between colors make the object appear smoother in the final rendering.



## **Anti-Aliasing**

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### **Example: Anti-aliasing Filters**


Here is an example briefly demonstrating the effect of different anti-aliasing filters on the final result.

Note that rendering with a particular filter is **not** the same as rendering without a filter and then blurring the image in a post-processing program like Adobe Photoshop. Filters are applied on a sub-pixel level, over the individual sub-pixel samples. Therefore, applying the filter at render time produces a much more accurate and subtle result than applying it as a post effect. The zoomed in images below have been zoomed in and cropped 300%.



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### **Example: Anti-aliasing Filters and Moire Effects**

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This example demonstrates the effect anti-aliasing filters have on moire effects in your images. Sharpening filters may enhance moire effects, even if your image sampling rate is very high. Blurring filters reduce moire effects.

Note that moire effects are not necessarily a result of poor image sampling. In general, moire effects appear simply because the image is discretized into square pixels. As such, they are inherent to digital images. The effect can be reduced through the usage of different anti-aliasing filters, but is not completely avoidable.

The scene is very simple: a sphere with a very fine checker map applied. The images were rendered with a very high sampling rate (15 subdivs, or 225 rays/pixel). This is enough to produce quite an accurate approximation to the pixel values. Note that the image looks quite different depending on the filter:

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### **Example: Render Mask**





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## **Progressive Sampler**

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### **Example: Stages of Rendering with the Progressive Sampler**

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![image](media://e410822d-1ac5-441e-9749-e0b3976aa9ed)

Image after 256 passes

  
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## **Bucket Sampler**

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## **Textures**

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## **Post Effects**

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## **Notes**

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- A note on RAM usage: image samplers require substantial amount of RAM to store information about each bucket. Using large bucket sizes may take a lot of RAM.