Finding the boundary line

Hi , I have images which i need to process further for image rectification.. These images are from newspaper camera shots as given in the figure 70.jpg. To proceed further I needed to detect only the image and not the texts. So i rotated the image -90 degrees and applied contour propagation . BUt i got a result as shown in figure 1.jpg. I could not obtain the proper boundary line which is hampering my work..

I need to detect only image and the four corner coordinates of the image to proceed further. Please provide me information on what steps to take ?

Thanking you

Answer 1

[Image Analyst]

There are papers with algorithms on how to do that. Look here: http://www.visionbib.com/bibliography/contentschar.html#OCR,%20Document%20Analysis%20and%20Character%20Recognition%20Systems at this section:

23.2.2.2 Document Layout, Document Segmentation, Page Layout, Structure Analysis
    23.2.2.2.1 Page Segmentation, General Evaluations
    23.2.2.2.2 Find Text in Documents
    23.2.2.2.3 Text Detection, Find Text in General Scenes, Documents, Scene Text
    23.2.2.2.4 Recognize Text from Signs in General Scenes
    23.2.2.2.5 Find Text in Video Scenes
    23.2.2.2.6 Text vs. Non-Text Regions
    23.2.2.2.7 Separate Images and Graphics from Text
    23.2.2.2.8 Newspaper Structure Extraction
    23.2.2.2.9 Table Segmentation, Extract Tables or Forms, General
    23.2.2.2.10 Document Layout, Structure Analysis, Web Documents, Online Documents

Sections 23.2.2.2.6 and 23.2.2.2.7 look particularly relevant to your needs. Pick an algorithm and code it up (I don't have one in MATLAB code to give you, so you'll have to do it yourself).