//#define DEBUGFEATUREDETECTION

/** Harris corner detector
 
 First pass: reduce to luminance and take the derivative of the luminance texture (GPUImageXYDerivativeFilter)
 
 Second pass: blur the derivative (GPUImageGaussianBlurFilter)
 
 Third pass: apply the Harris corner detection calculation
 
 This is the Harris corner detector, as described in 

import numpy as np
import cv2

"""
Harris Corner Detector
https://en.wikipedia.org/wiki/Harris_Corner_Detector
"""


class Harris_Corner:
    def __init__(self, k: float, window_size: int):

        """
        k : is an empirically determined constant in [0.04,0.06]
        window_size : neighbourhoods considered
        """

        if k in (0.04, 0.06):
            self.k = k
            self.window_size = window_size

---
title: The easiest way to get started with Svelte
description: This'll only take a minute.
author: Rich Harris
authorURL: https://twitter.com/Rich_Harris
---

     mediump float cornerness = (derivativeElements.x * derivativeElements.y - (zElement * zElement)) / (derivativeSum);
     
     // Original Harris detector
     // R = Ix^2 * Iy^2 - Ixy * Ixy - k * (Ix^2 + Iy^2)^2

---
title: Using CSS-in-JS with Svelte
description: You don't need to, but you can
author: Rich Harris
authorURL: https://twitter.com/Rich_Harris
---

CSS is a core part of any web app. By extension, a UI framework that doesn't have a built-in way to add styles to your components is unfinished.

Keno Fischer <******@****.***> <******@****.***>
Keno Fischer <******@****.***> <******@****.***>

Harlan Harris <harlan@harris.name> <harlan@harris.name>
Harlan Harris <harlan@harris.name> <harlan.harris@kaplan.com>

Douglas Bates <******@****.***> <******@****.***>

Andreas Noack Jensen <******@****.***> <******@****.***>

---
title: Setting up your editor
description: Instructions for configuring linting and syntax highlighting
author: Rich Harris
authorURL: https://twitter.com/Rich_Harris
draft: true
---

*__Coming soon__*

This post will walk you through setting up your editor so that recognises Svelte files:

* eslint-plugin-svelte3
* svelte-vscode
* associating .svelte files with HTML in VSCode, Sublime, etc.

## Atom

#import "GPUImageGaussianBlurFilter.h"

@interface GPUImageHarrisCornerDetectionFilter()

- (void)extractCornerLocationsFromImageAtFrameTime:(CMTime)frameTime;

@end

// This is the Harris corner detector, as described in 
// C. Harris and M. Stephens. A Combined Corner and Edge Detector. Proc. Alvey Vision Conf., Univ. Manchester, pp. 147-151, 1988.

@implementation GPUImageHarrisCornerDetectionFilter

---
title: Svelte on The Changelog
description: Listen to the interview here
author: Rich Harris
authorURL: https://twitter.com/Rich_Harris
---

Earlier this month, I had the privilege of appearing on [The Changelog](https://changelog.com/podcast), a podcast about software development. We had a fun (for me) and wide-ranging conversation:

* life as a coder inside a newsroom
* the big compilers-as-frameworks trend
* scalability

#import "GPUImageHarrisCornerDetectionFilter.h"

/** Noble corner detector
 
 This is the Noble variant on the Harris detector, from 
 Alison Noble, "Descriptions of Image Surfaces", PhD thesis, Department of Engineering Science, Oxford University 1989, p45.  
*/


@interface GPUImageNobleCornerDetectionFilter : GPUImageHarrisCornerDetectionFilter