About Image comparision of images taken from the webcam

Question

Hi My requirement is i connect a webcam to the system i will take photos using the webcam in the room for every fixed interval of time (like 1 hour or 2 hours) and i will compare the present image with previous image By doing so i have to find out that wheather light in the room is on or off Means i take on photo when the light is on and i take another photo when light is off and i compare both photos then result should come IMAGES ARE DIFFERENT IF i take two photos when light is on then result should have to come as IMAGES ARE SAME BUT Its not working i have taken two photos by keeping same paper in front off webcam with out any change those two photos are seems to be 100% similar and same but when i compared those two images pixel by pixel the result was IMAGES ARE DIFFERENT WHY LIKE THIS IS THERE ANY OTHER WAY TO COMPARE THOSE TWO IMAGES THAT COMPARISION MUST BE ON MAJOR CHANGES LIKE LIGHT IN THE ROOM NOT ON VERY MUNUTE CHANGES

Roei Bar · Answer

hey here is the howto compare images: private void button1_Click(object sender EventArgs e) { progressBar1.Visible = true; string img1_refimg2_ref; img1 = new Bitmap(fname1); img2 = new Bitmap(fname2); progressBar1.Maximum = img1.Width; if (img1.Width == img2.Width && img1.Height == img2.Height) { for (int i = 0; i { for (int j = 0; j { img1_ref = img1.GetPixel(i j).ToString(); img2_ref = img2.GetPixel(i j).ToString(); if (img1_ref != img2_ref) { count2++; flag = false; break; } count1++; } progressBar1.Value++; } if (flag == false) MessageBox.Show(Sorry Images are not same   + count2+  wrong pixels found); else MessageBox.Show( Images are same   + count1 +  same pixels found and  + count2 +  wrong pixels found); } else MessageBox.Show(can not compare this images); this.Dispose(); } dont forget to mark this as  Accepted Answer