OpenCV lower color values

I was wondering if there was a way to lower the color scheme of an image. Lets say I have an image that has 32bit color range in the RGB. I was wondering if it would be possible to scale it down to perhaps an 开发者_如何学C8 bit color scheme. This would be similar to a "cartoon" filter in applications like photoshop or if you change your screen color space from 32-bit true color to 256 colors.

Thanks

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If you want the most realistic result take a look at colour quantisation. Basically find the blocks of pixels with a similar RGB colour and replace them with a single colour, you are trying to minimize the number of pixels that are changed and the amount each new pixel is different from it's original colour - so it's a space parameterisation problem

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Well, you could do convertTo(newimg, CV_8U) to convert it to 8-bit, but that's still 16 million colors. If the image has integer pixel values you can also do val = val / reductionFactor * reductionFactor + reductionFactor / 2 (or some optimization thereof) on each pixel's R, G, and B values for arbitrary reduction factors or val = val & mask + reductionFactor >> 1 for reduction factors that are a power of two.

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Have you tried the pyramidal Mean Shift filter example program given in the samples with OpenCV? The mention of "cartoon" filter reminded me of it - the colors are flattened and subtle shades are merged and reduced resulting in a reduction in the number of colors present.

The reduction is based on a threshold and some experimentation should surely get satisfactory results.