# \[JAVA\] Remove background and record screen through chroma key
**URL:** https://discourse.processing.org/t/java-remove-background-and-record-screen-through-chroma-key/35912
**Category:** Coding Questions
**Created:** [March 23, 2022, 4:41pm UTC](https://discourse.processing.org/t/java-remove-background-and-record-screen-through-chroma-key/35912 "2022-03-23T16:41:02Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@GWAK](https://discourse.processing.org/u/GWAK)
#### Post date: [March 23, 2022, 4:41pm UTC](https://discourse.processing.org/t/java-remove-background-and-record-screen-through-chroma-key/35912/1 "2022-03-23T16:41:02Z")
1. Is it possible to remove the picture background(ex. green color) through the chroma key technique?
(Is there a library or an easy workaround?) / (ex. Chromakey)
2. I want to record the screen after removing the background. Is there any way?
---
### Author:  [@th75](https://discourse.processing.org/u/th75)
#### Post date: [March 26, 2022, 12:32am UTC](https://discourse.processing.org/t/java-remove-background-and-record-screen-through-chroma-key/35912/2 "2022-03-26T00:32:32Z")
Hi GWAK,
i don’t know library for this, i will go for glsl filter…
but, more easily, you can process each pixels, get the color, if it is “green” replace by a color or same pixel from another image,
like [here](https://forum.processing.org/two/discussion/25647/greenscreen-effect-for-movie.html) for movie frames
i found too this in the forum: [key-out-color-from-video](https://discourse.processing.org/t/key-out-color-from-video/324)
i hope it help…
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### Author:  [@GWAK](https://discourse.processing.org/u/GWAK)
#### Post date: [March 27, 2022, 3:27am UTC](https://discourse.processing.org/t/java-remove-background-and-record-screen-through-chroma-key/35912/3 "2022-03-27T03:27:22Z")
@th75
Thanks for the quick reply and kind explanation.
I have one question.
Link: [Key out color from video](https://discourse.processing.org/t/key-out-color-from-video/324)
You can see the code on the site above.
```auto
PShader chroma;
PImage guy;
PImage beach;
void setup(){
size(1080,720,P2D);
chroma = loadShader("chroma.glsl");
chroma.set("u_res",(float)width,(float)height);
beach=loadImage("beach.jpg");
guy=loadImage("fig.jpg"); // guy.jpg
chroma.set("u_tex",guy);
}
void draw(){
resetShader();
image(beach,0,0);
shader(chroma);
float HUE, SAT, BRI,
HUE_range,SAT_range,BRI_range,
yikes;
// hsb values
// HUE=0.39; SAT=0.80; BRI=0.90;
HUE=0.427; SAT=0.098; BRI=0.256;
//hsb tolerances
HUE_range=0.10; SAT_range=0.60; BRI_range=1.80;
//experiment
yikes=0.47;
chroma.set("u_low",HUE-HUE_range,SAT-SAT_range,BRI-BRI_range);
chroma.set("u_high",HUE+HUE_range,SAT+SAT_range,BRI+BRI_range);
chroma.set("u_foo",yikes);
rect(0,0,width,height);
}
```
`HUE=0.39; SAT=0.80; BRI=0.90;`
How do I get the above values? It looks like a green background color, but I can’t figure out how it came out like that.
---
### Author:  [@th75](https://discourse.processing.org/u/th75)
#### Post date: [March 28, 2022, 12:47am UTC](https://discourse.processing.org/t/java-remove-background-and-record-screen-through-chroma-key/35912/4 "2022-03-28T00:47:51Z")
hi,
colors can be coded in many different ways, (processing [implement 2](https://processing.org/reference/colorMode_.html) methods RGB and HSB)
here its hsb for hue, saturation, brightness
in processing menu “tools”, “color selector”, you can choose a color and get the value in both RGB and HSB
i guess HSB is a good choice for chroma key, one value H will be stable for green and B will change if
there is shadows
from the picture you sent, h=108, s=23, b=73
(i’m not totally sure your question was about this, tell me…)
---
### Author:  [@GWAK](https://discourse.processing.org/u/GWAK)
#### Post date: [March 28, 2022, 1:19am UTC](https://discourse.processing.org/t/java-remove-background-and-record-screen-through-chroma-key/35912/5 "2022-03-28T01:19:13Z")
@th75
1. Information on the background value for the figure is
- RGB : r=153, g=189, b=145
- HSB: h=108, s=23, b=73
You can get it through pictures.
1. (Curious) Is there a way to convert RGB values to HSB values in Processing?
2. These are the results of actual testing.
I divided 400.0. I don’t know why. But it seems to have come out somewhat.
```auto
PShader chroma;
PImage guy;
PImage beach;
void setup(){
size(1080,720,P2D);
chroma = loadShader("chroma.glsl");
chroma.set("u_res",(float)width,(float)height);
beach=loadImage("beach.jpg");
guy=loadImage("fig.jpg"); // guy.jpg
chroma.set("u_tex",guy);
}
void draw(){
resetShader();
image(beach,0,0);
shader(chroma);
float HUE,SAT,BRI,
HUE_range,SAT_range,BRI_range,
yikes;
// hsb values
// HUE=0.39; SAT=0.80; BRI=0.90;
// HUE=0.6; SAT=0.741; BRI=0.568;
float ref_f = 400.0;
HUE=108/ref_f; SAT=23/ref_f; BRI=73/ref_f;
//hsb tolerances
HUE_range=0.10; SAT_range=0.60; BRI_range=1.80;
//experiment
yikes=0.47;
chroma.set("u_low",HUE-HUE_range,SAT-SAT_range,BRI-BRI_range);
chroma.set("u_high",HUE+HUE_range,SAT+SAT_range,BRI+BRI_range);
chroma.set("u_foo",yikes);
rect(0,0,width,height);
}
```
---
### Author:  [@th75](https://discourse.processing.org/u/th75)
#### Post date: [March 28, 2022, 9:04pm UTC](https://discourse.processing.org/t/java-remove-background-and-record-screen-through-chroma-key/35912/6 "2022-03-28T21:04:59Z")
great,
yes from processing you can get HSB value:
```auto
color c=color(153,189,145); // set a color in rgb mode
colorMode(HSB, 360, 100, 100);
println(hue(c),saturation(c),brightness(c)); //print HSB values
```
note here that we set range for each parameters: hue is 0-360 and others 0-100, and its arbitrary
on your code this is a glsl shader performing the color evaluation, so i guess there are all from 0.0 to 1.0 (it explain why you had to divide by 400)
so i will try with:
```auto
color c=color(153,189,145);
colorMode(HSB, 1, 1, 1);
println(hue(c),saturation(c),brightness(c));
```
0.3030 0.2328 0.7412
for the small artefact, i guess it s due to unnoticeable colors shift due to the image compression
for same reason (color change on a green background due to shadows, reflections…)
the code send to the shader both the reference color and a range, i will try to keep range for H low (stay green) and a bigger amount for brightness range to include this shades of green
last, it looks your pictures have 2 colors background, (this black layer around) for this you can do another pass with black as reference, black is not a color, so it will be any hue (hue=0 and hue range 1.0) any saturation but brightness 0 and brightness range 0.05 or 0.1
replacing black pixels will certainly unleash the dog 😉
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### Author:  [@GWAK](https://discourse.processing.org/u/GWAK)
#### Post date: [March 28, 2022, 10:19pm UTC](https://discourse.processing.org/t/java-remove-background-and-record-screen-through-chroma-key/35912/7 "2022-03-28T22:19:39Z")
@th75
Dear th75
I liked your explanation, so I could understand.
It’s understandable enough.
thank you.