In this image:
I want to find this rectangle with all contents(without those grid's lines)
I think the total of the pixels can help a little like:
img = Import["http://i.stack.imgur.com/lnd5w.png"]; data = Total[ImageData[ImageRotate[ColorNegate[img]]]]; Show[ImageRotate[img], ListLinePlot[data, PlotRange -> All, PlotStyle -> Red]]
And I have such images:
I have no idea to do this thing. Does anyone have an idea?