# Reversing the threshold filter
**URL:** https://discourse.processing.org/t/reversing-the-threshold-filter/13579
**Category:** Coding Questions
**Created:** [August 25, 2019, 3:28am UTC](https://discourse.processing.org/t/reversing-the-threshold-filter/13579 "2019-08-25T03:28:36Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@eric](https://discourse.processing.org/u/eric)
#### Post date: [August 25, 2019, 3:28am UTC](https://discourse.processing.org/t/reversing-the-threshold-filter/13579/1 "2019-08-25T03:28:36Z")
I’ll throw in only the important parts, but for an image processing application I’m making, I want to analyze the image with the rgb components (typical picture), and then change it to black and white using the threshold filter, and run a few things with black and white. It all happens when I click the mouse, but I can’t seem to get the color photo back. Ideally it would happen in mouseReleased, and I’d run the majority of the code in mousePressed. Let me know with any thoughts, thanks.
```auto
PImage crossSection;
void setup() {
size(1008, 756);
crossSection = loadImage("crossSection.jpg");
}
void draw() {
backgound(0);
image(crossSection, 0, 0);
crossSection.resize(1008, 756);
loadPixels();
crossSection.loadPixels();
updatePixels();
}
void mousePressed() {
//code that needs an RGB photo
crossSection.filter(THRESHOLD, .85);
updatePixels();
//code that needs the black and white version
}
void mouseReleased() {
//not sure what to put here in order to change the image back to RGB
}
```
---
### Author:  [@kll](https://discourse.processing.org/u/kll)
#### Post date: [August 25, 2019, 3:41am UTC](https://discourse.processing.org/t/reversing-the-threshold-filter/13579/2 "2019-08-25T03:41:46Z")
untested,
but i think that the idea is to run the
```auto
filter();
```
[https://processing.org/reference/filter\_.html](https://processing.org/reference/filter_.html) function
after the
```auto
image();
```
a temporary loading from mousePressed() might be overwritten by next draw.
so better use the mouse to change the threshold value only ( used in draw later )
OR
move the `image();` up into the `setup();` could work too.
* * *
start from:
/File/Examples/ Basics/Image/LoadDisplayImage/
for operation can try my MouseWheelPlusPlus
```auto
/**
* Load and Display
*/
PImage img;
float fset = 0.50;
boolean fenable = false;
void setup() {
size(640, 360);
img = loadImage("moonwalk.jpg"); // Load the image into the program
println("click on canvas, press \n click toggle enable filter\n key [f] and turn mousewheel");
}
void draw() {
image(img, 0, 0);
if ( fenable ) filter(THRESHOLD,fset);
}
void mouseWheel(MouseEvent event) {
float e = event.getCount(); //println(e);
if ( keyPressed && key == 'f' ) {
fset += e/10.0 ;
println(" key f: fset "+fset);
}
}
void mousePressed() {
fenable = ! fenable;
}
```
---
### Author:  [@eric](https://discourse.processing.org/u/eric)
#### Post date: [August 25, 2019, 4:53am UTC](https://discourse.processing.org/t/reversing-the-threshold-filter/13579/3 "2019-08-25T04:53:12Z")
It worked, thank you very much!