李伟
267 lines
10 KiB
C#
267 lines
10 KiB
C#
// ============================================================================
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// Copyright © 2026 Hexagon Technology Center GmbH. All Rights Reserved.
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// 文件名: HistogramOverlayProcessor.cs
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// 描述: 直方图叠加算子，计算灰度直方图并以蓝色柱状图绘制到结果图像左上角
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// 功能:
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// - 计算输入图像的灰度直方图
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// - 将直方图绘制为蓝色半透明柱状图叠加到图像左上角
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// - 输出直方图统计表格数据
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// 算法: 灰度直方图统计 + 彩色图像叠加
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// 作者: 李伟 wei.lw.li@hexagon.com
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// ============================================================================
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using Emgu.CV;
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using Emgu.CV.CvEnum;
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using Emgu.CV.Structure;
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using XP.ImageProcessing.Core;
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using Serilog;
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using System.Drawing;
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using System.Text;
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namespace XP.ImageProcessing.Processors;
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/// <summary>
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/// 直方图叠加算子，计算灰度直方图并以蓝色柱状图绘制到结果图像左上角，同时输出统计表格
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/// </summary>
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public class HistogramOverlayProcessor : ImageProcessorBase
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{
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private static readonly ILogger _logger = Log.ForContext<HistogramOverlayProcessor>();
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// 固定参数
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private const int ChartWidth = 256; // 柱状图绘图区宽度
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private const int ChartHeight = 200; // 柱状图绘图区高度
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private const int AxisMarginLeft = 50; // Y轴标签预留宽度
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private const int AxisMarginBottom = 25; // X轴标签预留高度
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private const int Padding = 8; // 背景额外内边距
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private const int PaddingRight = 25; // 右侧额外内边距（容纳X轴末尾刻度文字）
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private const int Margin = 10; // 距图像左上角边距
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private const float BgAlpha = 0.6f;
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private const double FontScale = 0.35;
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private const int FontThickness = 1;
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public HistogramOverlayProcessor()
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{
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Name = LocalizationHelper.GetString("HistogramOverlayProcessor_Name");
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Description = LocalizationHelper.GetString("HistogramOverlayProcessor_Description");
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}
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protected override void InitializeParameters()
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{
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// 无可调参数
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}
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public override Image<Gray, byte> Process(Image<Gray, byte> inputImage)
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{
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int h = inputImage.Height;
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int w = inputImage.Width;
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var srcData = inputImage.Data;
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// === 1. 计算灰度直方图 ===
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var hist = new int[256];
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for (int y = 0; y < h; y++)
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for (int x = 0; x < w; x++)
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hist[srcData[y, x, 0]]++;
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int maxCount = 0;
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long totalPixels = (long)h * w;
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for (int i = 0; i < 256; i++)
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if (hist[i] > maxCount) maxCount = hist[i];
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// === 2. 计算统计信息 ===
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double mean = 0, variance = 0;
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int minVal = 255, maxVal = 0;
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int modeVal = 0, modeCount = 0;
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long medianTarget = totalPixels / 2, cumulative = 0;
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int medianVal = 0;
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bool medianFound = false;
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for (int i = 0; i < 256; i++)
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{
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if (hist[i] > 0)
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{
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if (i < minVal) minVal = i;
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if (i > maxVal) maxVal = i;
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}
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if (hist[i] > modeCount) { modeCount = hist[i]; modeVal = i; }
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mean += (double)i * hist[i];
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cumulative += hist[i];
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if (!medianFound && cumulative >= medianTarget) { medianVal = i; medianFound = true; }
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}
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mean /= totalPixels;
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for (int i = 0; i < 256; i++)
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variance += hist[i] * (i - mean) * (i - mean);
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variance /= totalPixels;
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double stdDev = Math.Sqrt(variance);
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// === 3. 输出表格数据 ===
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var sb = new StringBuilder();
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sb.AppendLine("=== 灰度直方图统计 ===");
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sb.AppendLine($"图像尺寸: {w} x {h}");
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sb.AppendLine($"总像素数: {totalPixels}");
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sb.AppendLine($"最小灰度: {minVal}");
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sb.AppendLine($"最大灰度: {maxVal}");
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sb.AppendLine($"平均灰度: {mean:F2}");
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sb.AppendLine($"中位灰度: {medianVal}");
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sb.AppendLine($"众数灰度: {modeVal} (出现 {modeCount} 次)");
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sb.AppendLine($"标准差: {stdDev:F2}");
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sb.AppendLine();
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sb.AppendLine("灰度值\t像素数\t占比(%)");
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for (int i = 0; i < 256; i++)
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{
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if (hist[i] > 0)
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sb.AppendLine($"{i}\t{hist[i]}\t{(double)hist[i] / totalPixels * 100.0:F4}");
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}
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OutputData["HistogramTable"] = sb.ToString();
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OutputData["Histogram"] = hist;
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// === 4. 生成彩色叠加图像（蓝色柱状图 + XY轴坐标） ===
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var colorImage = inputImage.Convert<Bgr, byte>();
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var colorData = colorImage.Data;
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// 布局：背景区域包含 Padding + Y轴标签 + 绘图区 + Padding（水平）
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// Padding + 绘图区 + X轴标签 + Padding（垂直）
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int totalW = Padding + AxisMarginLeft + ChartWidth + PaddingRight;
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int totalH = Padding + ChartHeight + AxisMarginBottom + Padding;
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int bgW = Math.Min(totalW, w - Margin);
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int bgH = Math.Min(totalH, h - Margin);
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if (bgW > Padding + AxisMarginLeft && bgH > Padding + AxisMarginBottom)
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{
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int plotW = Math.Min(ChartWidth, bgW - Padding - AxisMarginLeft - PaddingRight);
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int plotH = Math.Min(ChartHeight, bgH - Padding - AxisMarginBottom - Padding);
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if (plotW <= 0 || plotH <= 0) goto SkipOverlay;
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// 绘图区左上角在图像中的坐标
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int plotX0 = Margin + Padding + AxisMarginLeft;
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int plotY0 = Margin + Padding;
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// 计算每列柱高
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double binWidth = (double)plotW / 256.0;
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var barHeights = new int[plotW];
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for (int px = 0; px < plotW; px++)
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{
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int bin = Math.Min((int)(px / binWidth), 255);
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barHeights[px] = maxCount > 0 ? (int)((long)hist[bin] * (plotH - 1) / maxCount) : 0;
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}
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float alpha = BgAlpha;
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float inv = 1.0f - alpha;
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// 绘制半透明黑色背景（覆盖整个区域含坐标轴和内边距）
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Parallel.For(0, bgH, dy =>
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{
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int imgY = Margin + dy;
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if (imgY >= h) return;
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for (int dx = 0; dx < bgW; dx++)
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{
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int imgX = Margin + dx;
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if (imgX >= w) break;
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colorData[imgY, imgX, 0] = (byte)(int)(colorData[imgY, imgX, 0] * inv);
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colorData[imgY, imgX, 1] = (byte)(int)(colorData[imgY, imgX, 1] * inv);
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colorData[imgY, imgX, 2] = (byte)(int)(colorData[imgY, imgX, 2] * inv);
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}
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});
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// 绘制蓝色柱状图
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Parallel.For(0, plotH, dy =>
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{
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int imgY = plotY0 + dy;
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if (imgY >= h) return;
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int rowFromBottom = plotH - 1 - dy;
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for (int dx = 0; dx < plotW; dx++)
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{
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int imgX = plotX0 + dx;
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if (imgX >= w) break;
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if (rowFromBottom < barHeights[dx])
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{
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byte curB = colorData[imgY, imgX, 0];
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byte curG = colorData[imgY, imgX, 1];
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byte curR = colorData[imgY, imgX, 2];
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colorData[imgY, imgX, 0] = (byte)Math.Clamp(curB + (int)(255 * alpha), 0, 255);
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colorData[imgY, imgX, 1] = (byte)Math.Clamp(curG + (int)(50 * alpha), 0, 255);
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colorData[imgY, imgX, 2] = (byte)Math.Clamp(curR + (int)(50 * alpha), 0, 255);
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}
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}
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});
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// === 5. 绘制坐标轴线和刻度标注 ===
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var white = new MCvScalar(255, 255, 255);
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var gray = new MCvScalar(180, 180, 180);
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// Y轴线
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CvInvoke.Line(colorImage,
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new Point(plotX0, plotY0),
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new Point(plotX0, plotY0 + plotH),
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white, 1);
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// X轴线
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CvInvoke.Line(colorImage,
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new Point(plotX0, plotY0 + plotH),
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new Point(plotX0 + plotW, plotY0 + plotH),
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white, 1);
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// X轴刻度: 0, 64, 128, 192, 255
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int[] xTicks = { 0, 64, 128, 192, 255 };
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foreach (int tick in xTicks)
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{
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int tx = plotX0 + (int)(tick * binWidth);
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if (tx >= w) break;
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CvInvoke.Line(colorImage,
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new Point(tx, plotY0 + plotH),
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new Point(tx, plotY0 + plotH + 4),
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white, 1);
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string label = tick.ToString();
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CvInvoke.PutText(colorImage, label,
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new Point(tx - 8, plotY0 + plotH + 18),
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FontFace.HersheySimplex, FontScale, white, FontThickness);
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}
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// Y轴刻度: 0%, 25%, 50%, 75%, 100%
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for (int i = 0; i <= 4; i++)
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{
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int val = maxCount * i / 4;
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int ty = plotY0 + plotH - (int)((long)plotH * i / 4);
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CvInvoke.Line(colorImage,
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new Point(plotX0 - 4, ty),
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new Point(plotX0, ty),
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white, 1);
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// 网格虚线
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if (i > 0 && i < 4)
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{
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for (int gx = plotX0 + 2; gx < plotX0 + plotW; gx += 6)
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{
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int gxEnd = Math.Min(gx + 2, plotX0 + plotW);
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CvInvoke.Line(colorImage,
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new Point(gx, ty),
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new Point(gxEnd, ty),
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gray, 1);
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}
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}
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string label = FormatCount(val);
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CvInvoke.PutText(colorImage, label,
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new Point(Margin + Padding, ty + 4),
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FontFace.HersheySimplex, FontScale, white, FontThickness);
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}
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}
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SkipOverlay:
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OutputData["PseudoColorImage"] = colorImage;
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_logger.Debug("Process completed: histogram overlay, mean={Mean:F2}, stdDev={Std:F2}", mean, stdDev);
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return inputImage.Clone();
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}
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/// <summary>
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/// 格式化像素计数为紧凑字符串（如 12345 → "12.3K"）
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/// </summary>
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private static string FormatCount(int count)
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{
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if (count >= 1_000_000) return $"{count / 1_000_000.0:F1}M";
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if (count >= 1_000) return $"{count / 1_000.0:F1}K";
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return count.ToString();
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}
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}
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