Python RGB array to HSL and back [duplicate]

This question already has answers here: Detecting th开发者_运维知识库resholds in HSV color space (from RGB) using Python / PIL (4 answers) Closed 9 years ago.

well i've seen some code to convert RGB to HSL; but how to do it fast in python.

Its strange to me, that for example photoshop does this within a second on a image, while in python this often takes forever. Well at least the code i use; so think i'm using wrong code to do it

In my case my image is a simple but big raw array [r,g,b,r,g,b,r,g,b ....]

I would like this to be [h,s,l,h,s,l,h,s,l .......]

Also i would like to be able to do hsl to rgb

the image is actually 640x 480 pixels; Would it require some library or wrapper around c code (i never created a wrapper) to get it done fast ?

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For manipulating image data, many use the Python Imaging Library. However, it doesn't handle HSL colour. Luckily, Python comes with a library called colorsys. Here's an example of colorsys being used to convert between colour modes on a per-pixel level: http://effbot.org/librarybook/colorsys.htm

colorsys also provides a function to convert HSL to RGB: http://docs.python.org/library/colorsys.html

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I wrote this RGB to HSV converter a little while back. It starts with a PIL image but uses numpy to do the array operations efficently. It could very easily be modified to do HSL. Let me know if you want the modified version.

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One option is to use OpenCV. Their Python bindings are pretty good (although not amazing). The upside is that it is a very powerful library, so this would just be the tip of the iceberg.

You could probably also do this very efficiently using numpy.