OpenCV Android 绿色检测 [英] OpenCV Android Green Color Detection

问题描述

目前我正在制作一个应用程序，用户可以在其中检测绿色.我使用这张照片进行测试:

currently I'm making an app where user will detect green colors. I use this photo for testing:

我的问题是我无法检测到任何绿色像素.在我使用蓝色之前，一切正常.现在虽然我尝试了 RGB 的不同组合，但我什么也检测不到.我想知道是绿色问题还是我的检测范围有问题，所以我使用 (0, 255, 0) 在油漆中制作了一个图像并且它起作用了.为什么它看不到这个圆圈呢?我使用此代码进行检测:

My problem is that I can not detect any green pixel. Before I worked with blue color and everything worked fine. Now I can't detect anything though I tried different combinations of RGB. I wanted to know whether it's problem with green or my detection range, so I made an image in paint using (0, 255, 0) and it worked. Why it can't see this circle then? I use this code for detection:

Core.inRange(hsv_image, new Scalar([I change this value]), new Scalar(60, 255, 255), ultimate_blue);

可能是我设置了错误的范围，但我使用 Photoshop 获取绿色像素之一的颜色并将其 RGB 值转换为 HSV.然而它不起作用.它甚至没有检测到我采样的像素.怎么了?提前致谢.

It could have been that I set wrong Range, but I use Photoshop to get color of one of green pixels and convert RGB value of it into HSV. Yet it doesn't work. It don't detect even pixel that I've sampled. What's wrong? Thanks in advance.

使用 Miki 的回答:

Using Miki's answer:

推荐答案

绿色是 HSV 空间的 H = 120 并且在 [0, 360] 范围内.

Green color is HSV space has H = 120 and it's in range [0, 360].

OpenCV 将 H 值减半以适应范围 [0,255]，因此 H 值不在 [0, 360] 范围内，而是在 [0, 180] 范围内.S 和 V 仍在 [0, 255] 范围内.

OpenCV halves the H values to fit the range [0,255], so H value instead of being in range [0, 360], is in range [0, 180]. S and V are still in range [0, 255].

因此，绿色的 H 值为 60 = 120/2.

As a consequence, the value of H for green is 60 = 120 / 2.

你的上下限应该是:

// sensitivity is a int, typically set to 15 - 20 
[60 - sensitivity, 100, 100]
[60 + sensitivity, 255, 255]

<小时>

更新

由于您的图像很暗，您需要使用 V 的下限.使用这些值:

Since your image is quite dark, you need to use a lower bound for V. With these values:

sensitivity = 15;
[60 - sensitivity, 100, 50]  // lower bound
[60 + sensitivity, 255, 255] // upper bound

生成的掩码如下:

您可以参考这个答案了解详情.

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