symek Posted November 14, 2005 Share Posted November 14, 2005 hallo! I wonder if there is a way in VEX to find brightest or darkest pixel in image without coding some fansy loop... I would like to know the range in pixel value from input before I apply some filter designed in VEX. I don't need t6o know the positon - just info, that white point is at 17.4 and black at -3.6 (in floating point image for example) thanks for help. PS Mplay have a buttom which normalize the image range to 0 and 1. To do this it must know "bri" and "dark" to clamp or shift data. Quote Link to comment Share on other sites More sharing options...
Jason Posted November 14, 2005 Share Posted November 14, 2005 Hey there, You can slurp the image into CHOPs and find the value there - probably with icmin() and icmax() or such. (type exhelp icmax in a Houdini textport). You might want to run it though the Mono COP first (if you want Luminance or Max Component) and just suck in the single resultant channel into CHOPs. There might be other tricks too- I was kinda hoping that the new "minmax" filter that we see in Mantra 8.0 would have snuck into the Scale (downscale) filter menu then you could've scaled the image down to a single pixel and a "minmax max" would've sorted it out for you. Hope this helps, Jason Quote Link to comment Share on other sites More sharing options...
sibarrick Posted November 14, 2005 Share Posted November 14, 2005 I think you can do that sort of thing in chops, so you might need to route things through chops first. Quote Link to comment Share on other sites More sharing options...
symek Posted November 15, 2005 Author Share Posted November 15, 2005 thanks a lot, chops won't be right solution a suppose, but I will try, thanks a lot again! PS On the other hand there should be some ways to manage arrays or get some basic info from plates, shouldn't be? Quote Link to comment Share on other sites More sharing options...
edward Posted November 15, 2005 Share Posted November 15, 2005 PS On the other hand there should be some ways to manage arrays or get some basic info from plates, shouldn't be? 22595[/snapback] Do you mean using the histogram view of the COPs Viewer ? Or the inspect toolbar? Quote Link to comment Share on other sites More sharing options...
symek Posted November 16, 2005 Author Share Posted November 16, 2005 no, no, I meant that function which gives you back a max or min value in some data, set, array (plate!) it is so common need that it should be implemented in VEX. Houdini must use such function all the time, for example in MPlay to automatic shift pixel for 0 to 1... I'm sure there is a way to get it . Quote Link to comment Share on other sites More sharing options...
Jason Posted November 16, 2005 Share Posted November 16, 2005 no, no, I meant that function which gives you back a max or min value in some data, set, array (plate!) it is so common need that it should be implemented in VEX. Houdini must use such function all the time, for example in MPlay to automatic shift pixel for 0 to 1... I'm sure there is a way to get it . 22627[/snapback] Probably some nice access to the histogram would be able to provide a lot of this, no? Quote Link to comment Share on other sites More sharing options...
symek Posted November 18, 2005 Author Share Posted November 18, 2005 yes, you're right! Quote Link to comment Share on other sites More sharing options...
3__ Posted December 23, 2005 Share Posted December 23, 2005 heh, all for want of arrays... -cpb Quote Link to comment Share on other sites More sharing options...
hoknamahn Posted March 17, 2006 Share Posted March 17, 2006 Huh, I have the same problem. The basic idea is clear - Image COP and icmin/icmax expression functions. But I wonder how we can use ic* for "export" values from CHOPs to COPs. I'm asking because ic* work in the sand-box of the _current_ CHOP. And I can't use them as expression in my COPs. So what can I do? Quote Link to comment Share on other sites More sharing options...
sibarrick Posted March 17, 2006 Share Posted March 17, 2006 Can you modify a channel in chops land to the be the value of icmin/icmax and then use the chop expression in cops to reference that channel? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.