Gamma correction
Gamma correction, or often simply gamma, is the name of a nonlinear operation used to code and decode luminance or tristimulus values in video or still image systems. It is very useful if you want to set the dark regions of a picture lighter or even darker. In this tutorial you will be shown how to create a gamma filter using Ozeki Camera SDK.
Important: you should study this article in order to find out how to setup your Windows Forms Application correctly.
Properties
Gamma: we can set the value of the contrast which is between 0.10 and 5 If you choose a low amount, the effect makes the difference smaller between the dark and light parts. If you choose a bigger value, the effect makes the difference bigger.
Windows Form |
Windows forms version
MainForm.cs
using System; using System.Windows.Forms; using Ozeki.Camera; using Ozeki.Media; namespace ImageManipulation_WF { public partial class MainForm : Form { private ICamera _camera; private DrawingImageProvider _imageProvider; private MediaConnector _connector; private ImageManipulation _manipulation; private OzGammaCorrection _filter; public MainForm() { InitializeComponent(); _connector = new MediaConnector(); _imageProvider = new DrawingImageProvider(); // Create video viewer UI control // Bind the camera image to the UI control videoViewer.SetImageProvider(_imageProvider); _manipulation = new ImageManipulation(); _manipulation.Start(); _filter = new OzGammaCorrection(); } private void btn_Connect_Click(object sender, EventArgs e) { _camera = new WebCamera(); if (_camera == null) return; _connector.Connect(_camera.VideoChannel, _manipulation); _connector.Connect(_manipulation, _imageProvider); _camera.Start(); videoViewer.Start(); } private void btn_Add_Click(object sender, EventArgs e) { _manipulation.Add(_filter); } private void btn_Remove_Click(object sender, EventArgs e) { _manipulation.Remove(_filter); } private void factorTrack_Scroll(object sender, EventArgs e) { var trackBar = sender as TrackBar; if (trackBar != null) { var value = (double)(trackBar.Value) / 100; _filter.Gamma = value; lb_Level.Text = @"Gamma: " + value; } } } }
GUI
MainForm.cs
namespace ImageManipulation_WF { partial class MainForm { ////// Required designer variable. /// private System.ComponentModel.IContainer components = null; ////// Clean up any resources being used. /// /// true if managed resources should be disposed; otherwise, false. protected override void Dispose(bool disposing) { if (disposing && (components != null)) { components.Dispose(); } base.Dispose(disposing); } #region Windows Form Designer generated code ////// Required method for Designer support - do not modify /// the contents of this method with the code editor. /// private void InitializeComponent() { this.videoViewer = new Ozeki.Media.VideoViewerWF(); this.btn_Connect = new System.Windows.Forms.Button(); this.btn_Remove = new System.Windows.Forms.Button(); this.btn_Add = new System.Windows.Forms.Button(); this.lb_Level = new System.Windows.Forms.Label(); this.trackBar = new System.Windows.Forms.TrackBar(); ((System.ComponentModel.ISupportInitialize)(this.trackBar)).BeginInit(); this.SuspendLayout(); // // videoViewer // this.videoViewer.BackColor = System.Drawing.Color.Black; this.videoViewer.FlipMode = Ozeki.Media.FlipMode.None; this.videoViewer.FrameStretch = Ozeki.Media.FrameStretch.Uniform; this.videoViewer.FullScreenEnabled = true; this.videoViewer.Location = new System.Drawing.Point(12, 57); this.videoViewer.Name = "videoViewer"; this.videoViewer.RotateAngle = 0; this.videoViewer.Size = new System.Drawing.Size(471, 334); this.videoViewer.TabIndex = 0; this.videoViewer.Text = "videoViewerWF1"; // // btn_Connect // this.btn_Connect.Location = new System.Drawing.Point(12, 12); this.btn_Connect.Name = "btn_Connect"; this.btn_Connect.Size = new System.Drawing.Size(152, 26); this.btn_Connect.TabIndex = 14; this.btn_Connect.Text = "Connect to WebCamera"; this.btn_Connect.UseVisualStyleBackColor = true; this.btn_Connect.Click += new System.EventHandler(this.btn_Connect_Click); // // btn_Remove // this.btn_Remove.Location = new System.Drawing.Point(104, 475); this.btn_Remove.Name = "btn_Remove"; this.btn_Remove.Size = new System.Drawing.Size(75, 23); this.btn_Remove.TabIndex = 1; this.btn_Remove.Text = "Remove"; this.btn_Remove.UseVisualStyleBackColor = true; this.btn_Remove.Click += new System.EventHandler(this.btn_Remove_Click); // // btn_Add // this.btn_Add.Location = new System.Drawing.Point(23, 475); this.btn_Add.Name = "btn_Add"; this.btn_Add.Size = new System.Drawing.Size(75, 23); this.btn_Add.TabIndex = 0; this.btn_Add.Text = "Add"; this.btn_Add.UseVisualStyleBackColor = true; this.btn_Add.Click += new System.EventHandler(this.btn_Add_Click); // // lb_Level // this.lb_Level.AutoSize = true; this.lb_Level.Location = new System.Drawing.Point(20, 423); this.lb_Level.Name = "lb_Level"; this.lb_Level.Size = new System.Drawing.Size(46, 13); this.lb_Level.TabIndex = 15; this.lb_Level.Text = "Gamma:"; // // trackBar // this.trackBar.Location = new System.Drawing.Point(104, 423); this.trackBar.Maximum = 500; this.trackBar.Minimum = 1; this.trackBar.Name = "trackBar"; this.trackBar.Size = new System.Drawing.Size(379, 45); this.trackBar.TabIndex = 16; this.trackBar.Value = 100; this.trackBar.Scroll += new System.EventHandler(this.factorTrack_Scroll); // // MainForm // this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F); this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font; this.ClientSize = new System.Drawing.Size(498, 520); this.Controls.Add(this.trackBar); this.Controls.Add(this.lb_Level); this.Controls.Add(this.btn_Remove); this.Controls.Add(this.btn_Add); this.Controls.Add(this.btn_Connect); this.Controls.Add(this.videoViewer); this.Name = "MainForm"; this.Text = "Gamma correction"; ((System.ComponentModel.ISupportInitialize)(this.trackBar)).EndInit(); this.ResumeLayout(false); this.PerformLayout(); } #endregion private Ozeki.Media.VideoViewerWF videoViewer; private System.Windows.Forms.Button btn_Connect; private System.Windows.Forms.Button btn_Remove; private System.Windows.Forms.Button btn_Add; private System.Windows.Forms.Label lb_Level; private System.Windows.Forms.TrackBar trackBar; } }
Related Pages
Conclusion
With the help of this lecture you can successfully implement gamma correction with your C# camera application using the Ozeki Camera SDK.
FAQ
Below you can find the answers for the most frequently asked questions related to this topic:
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What kind of developer environment is needed?
- Microsoft Visual Studio 2010
- Microsoft .Net Framework 4.0
- Internet connection
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How can I get the URL of the camera?
You can get the URL from the producer of the camera.
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I have not managed to build the solution. How to solve it?
- Please set the Target framework property of the project to .NET 4.0.
- You should add the OzekiSDK.dll to the references of the solution.
- Please import the missing classes.
More information
- Introduction to image manipulation
- How to implement brightness filter in C#
- How to create channel filtering in C#
- How to create contrast correction in C#
- How to implement gamma correction in C#
- How to implement greyscale effect in C#
- How to implement histogram equalization in C#
- How to accomplish rotate filter in C#
- How to accomplish invert colors in C#
- How to accomplish jitter in C#
- How to create mirror effect in C#
- How to accomplish pixellate in C#
- How to implement rotate channels in C#
- How to implement hue modifier in C#
- How to implement salt and pepper noise in C#
- How to create saturation correction in C#
- How to create sepia effect in C#
- How to implement sharpen in C#
- How to implement simple posterization in C#
- How to create water wave in C#
- How to implement YCbCr in C#