C#getPixel和内存法读取灰度图信息

最新推荐文章于 2024-10-28 14:12:44 发布

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最新推荐文章于 2024-10-28 14:12:44 发布

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原文链接：http://www.cnblogs.com/zhayunjia/p/8078606.html

本文介绍了两种图像处理方法：一种是通过getPixel方法获取图像最大亮度值；另一种是使用内存法实现灰度图像的最大灰度值提取。此外，还提供了根据数组绘制图像的方法及如何将灰度图像转换为一维数组的技术细节。

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getPixel方法：

        private int getPixels(Bitmap bmpobj)
        {
            int[,] data = new int[1920, 1200];
            int max = 0;
            for (int i = 0; i < bmpobj.Height; i++)
            {
                for (int j = 0; j < bmpobj.Width; j++)
                {
                    Color b = bmpobj.GetPixel(j, i);
                    if (max < b.R)
                    {
                        max = b.R;
                    }
                }
            }
            return max;
        }

内存法：

private int GetImgInfo(Bitmap a)
        {
            Bitmap src = new Bitmap(a);
            int w = src.Width;
            int h = src.Height;
            int max = 0;
            BitmapData srcData = src.LockBits(new Rectangle(0, 0, w, h), ImageLockMode.ReadWrite, PixelFormat.Format32bppArgb);
            unsafe
            {
                byte* p = (byte*)srcData.Scan0;
                int gray = 0;
                for (int j = 1; j < h - 1; j++)
                {
                    for (int i = 1; i < w - 1; i++)
                    {
                        gray = p[0] ;//+= (p[0] + p[1] + p[2]) / 3;
                        p += 4;
                        if (max < gray)
                        {
                            max = gray;
                        }
                    }
                    p += srcData.Stride - w * 4;
                }
                src.UnlockBits(srcData);
                return  max ;
            }
        }

根据数组画图

  private Bitmap drawPic(byte[] srcdata, int width, int height)
        {
            // 8bit索引方式位图，设置灰度调色板
            var fmt = PixelFormat.Format8bppIndexed;
            var bmp = new Bitmap(width, height, fmt);
            var palette = bmp.Palette;
            for (var i = 0; i < 256; i++)
            {
                palette.Entries[i] = Color.FromArgb(i, i, i);
            }
            bmp.Palette = palette;

            // 把数据映射到256灰度，unsafe填充到位图
            var bmpData = bmp.LockBits(new Rectangle(0, 0, width, height), ImageLockMode.WriteOnly, fmt);
            unsafe
            {
                var p = (byte*)bmpData.Scan0;
                for (var i = 0; i < srcdata.Length; i++)
                {
                    *p = (byte)(srcdata[i]);
                    p++;
                }
            }
            bmp.UnlockBits(bmpData);
            return bmp;
        }

View Code

根据灰度图像读入一维数组对于8位深度图像来说

public unsafe byte[] ToArray(Bitmap b)
        {
            BitmapData data = b.LockBits(new Rectangle(0, 0, b.Width, b.Height), ImageLockMode.ReadOnly, b.PixelFormat);
            int height = data.Height;
            int stride = data.Stride;

            IntPtr ptr = data.Scan0;
            int scanBytesLength = stride * height;

            byte[] rgbValues = new byte[scanBytesLength];
            unsafe
            {
                Marshal.Copy(ptr, rgbValues, 0, scanBytesLength);
            }
            b.UnlockBits(data);
            return rgbValues;
        }