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https://github.com/abdelaziz18003/ndarray-imhist
📊 A package to plot images' histograms using node.js and Gnuplot inspired by Matlab `imhist` command..
https://github.com/abdelaziz18003/ndarray-imhist
histogram image-processing matlab ndarray
Last synced: 3 months ago
JSON representation
📊 A package to plot images' histograms using node.js and Gnuplot inspired by Matlab `imhist` command..
- Host: GitHub
- URL: https://github.com/abdelaziz18003/ndarray-imhist
- Owner: Abdelaziz18003
- License: mit
- Created: 2019-06-09T18:14:29.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2022-12-10T05:34:40.000Z (about 2 years ago)
- Last Synced: 2024-11-14T09:31:52.888Z (3 months ago)
- Topics: histogram, image-processing, matlab, ndarray
- Language: JavaScript
- Homepage: https://www.npmjs.com/package/ndarray-imhist
- Size: 114 KB
- Stars: 4
- Watchers: 2
- Forks: 0
- Open Issues: 5
-
Metadata Files:
- Readme: readme.md
- License: LICENSE
Awesome Lists containing this project
README
# ndarray-imhist
A package to plot grayscale images' histograms using node.js and Gnuplot, inspired by Matlab `imhist` command.
## Installation
```bash
npm install ndarray-imhist
```
[Gnuplot](http://www.gnuplot.info/) is required for this package to work. Make sure that it is installed and added to the path correctly by typing:
```bash
gnuplot --version
```
## Usage
### Syntax
```js
imhist(img [, options]);
// or
let [x, y] = imhist(img [, options]);
```
displays the histogram of a grayscale image `img` (should be an [ndarray](https://github.com/scijs/ndarray)) and return the historgram data as an array of two arrays containing `x` and `y` values respectively.
### Options
Option | required | default | description
------- | -------- | ------- | -----------
channel | no | 0 | Select the RGB channel to get the historgram for. `0` for the red channel, `1` for the green and `2` for the blue one. If `img` is a 2D array, this option has no effect.
color | no | "blue" | Set the impulses color, must be a valid Gnuplot "rgbcolor". Otherwise, plotting will fail silently
plot | no | true | If true, plot the histogram using Gnuplot. Otherwise, return just the histogram data.
### Examples
```js
const getPixels = require("get-pixels");
const imhist = require("ndarray-imhist");
getPixels("lena.png", function(err, pixels) {
if(!err && pixels) {
// show the image histogram
imhist(pixels);
// return the image histogram data without plotting it.
let [x, y] = imhist(pixels, {plot: false});
console.log(x, y);
}
})
```
Here is how the histogram will look like:
