技术求助：如何在同一图中绘制两个2D直方图（寿命成像相量图）

Hey there! I get that you're working on lifetime imaging and need to overlay two 2D histograms using the phasor plot method without them covering each other—let's fix this up with DIPimage's ndhist function.

Core Approach #

The main issue here is that MATLAB (and DIPimage) clears the current axes by default when you plot a new histogram. The fix relies on holding the axes to keep the first plot, plus adjusting transparency or color maps so both datasets are visible.

Step-by-Step Solution #

• Prepare your phasor data: Make sure you have two sets of phasor coordinates (e.g., (g1, s1) for sample 1 and (g2, s2) for sample 2).
• Plot the first histogram: Use ndhist as you normally would, then enable hold on to lock the axes.
• Plot the second histogram: Add it with transparency (critical for visibility) or a distinct color map. Match the bin count to the first histogram for proper alignment.
• Tweak visual details: Add legends, color bars, or adjust background settings to match your desired outcome.

Example Code #

% Assume you have your phasor data ready: g1,s1 (sample 1) and g2,s2 (sample 2)
bin_count = [64 64]; % Match bins for both histograms to ensure alignment

% Plot first 2D histogram
h1 = ndhist([g1, s1], 'nBins', bin_count);
colormap jet; % Pick your preferred colormap for the first dataset
colorbar;
hold on; % Keep the current axes active so the next plot doesn't overwrite

% Plot second 2D histogram with transparency
h2 = ndhist([g2, s2], 'nBins', bin_count, 'Alpha', 0.6); % Alpha 0.5-0.7 balances visibility
colormap hsv; % Optional: Use a distinct colormap for clear dataset separation

% Add legend and refine background
legend([h1, h2], 'Sample 1', 'Sample 2');
set(gca, 'Color', 'white'); % Set background to white if you need a clean base
hold off;

Troubleshooting Tips #

• If your DIPimage version doesn't support the 'Alpha' parameter directly, use the alpha function after creating the histogram object: alpha(h2, 0.6).
• Double-check that both histograms use identical bin dimensions—this ensures they align perfectly on the phasor plot.
• Avoid overly opaque histograms; transparency lets you clearly see overlapping regions, which is often key for phasor plot analysis.

内容的提问来源于stack exchange，提问作者Yurema Teijeiro