Specifically i'm trying to extract all the imagery possible from a vehicle Sat Nav SD card.
When viewed on a PC, I can see certain ico, bmp or jpg files which consist of splash screens or small vehicle icon, which is fine. However i'm wanting to extract similar screens to the ones attached (not the visual map data but the ones which have a generic image of the road and sky and direct you which lane to be in when exiting or entering a road)
I want these images (if possible) to draw or paint into them.
Whether they exist as an image hidden somewhere in the code or they are an algorithm generated based on the type of road and direction you are heading, I don't know.
I have tried with HEX editors, but can only work with text.
Is there such a thing as a "visual" HEX editor?
Thanks all!
Related
Noticed that images sometimes are sliced up in PDFs.
Steps:
insert an image with a high resoultion (3000x1800) into a .docx
use "Microsoft Print to PDF" option of Word to convert to PDF
extracting all images with pdfimages or pymupdf
Result:
Image is sliced horizontally into three images
Questions:
What exactly happens in the in the transition from .docx to pdf (or in generell in the process to pdf) that makes the converter slice it up into three images instead of one?
Do the individuell XObjects of the sliced images contain information which says that these three images belong to originally one?
How do I know how the images are sliced (horizontally / vertically) and what if originally there were two images inserted into the .docx file and both of them are sliced. Can you tell if slice x belongs to original image y or z?
So, as you have found out: because the code which generates the PDF choose to do so.
The technical reasons may be various - it could be that historically there were printers which would only have so much memory, and would need to get limiterd size-images when printing, and someone at some point when writing the PDF export code present in Microsoft Office choose to apply this limit.
Anyway, technically, as put in the comments, an image in a PDF file could be composed of unlimited smaller images collated together.
Now, the second part, and your actual question: to know whether images ibn a PDF file belong together in a single original image one would need a custom extractor tool to check the geometry of all images in the document and find out which images have no margins or boundaries with others - it would not be that hard to do for well behaved files (which we can't know if MS Office generated files are: there are ways to obfuscate image positioning by making it indirectly). The metadata in the image-parts may or may not contain information that would allow one to recompose the original image: it would be up to the code generating the PDF to include this metadata or not - but the geometry can't lie in this case: if the final document presents a single image visually, it is possible to detect that when fetching the images.
The question seems to be weird, but I need to ask this, since I am witnessing a quite interesting output when I compare text as image and graphics as image.
Ideally I am in process of identifying an tool, or algorithm to compare two pdfs, generate output which will highlight the difference between them.
There are possibilities in pdfs, which will have text as image format (legacy text on papers, are converted to pdfs).
and we are doing migration of those legacy pdfs, and finally we are comparing with legacy and converted pdf output.
I am evaluating couple of tools like Adobe dc pro, i-net pdfc and power pdf etc, for comparing two pdfs.
While evaluating, I am able to see graphic images are getting compared(not accurate either) on either side of the pdfs. Where as text as images are completely ignored, unanimously same results in all the tools.
But I am more interested in text as image, since we deal more of legacy text pdfs.
Below, is attached graphic image comparison result, where it could able to capture the differences between the images.
But when I compare text image, differences are not highlighted in the tool.
What I understand from this, text is not compared as image graphics, and tool is completely ignoring the comparison. I would like have clarification whether my assumption is correct.
Secondly, I would like to know how to compare text image in pdfs to generate the differences?.
I'm working for the company that is author of i-net PDFC so I'll answer your first question as well:
Your assumption is correct. i-net PDFC is able to compare images and shapes, but it cannot detect if some content completely changed it's meaning, e.G. a line shape that is used to draw a letter or in your case an image that has to be recognized as text. Recognizing ASCII art as image won't work for the same reason either. Such cases will always be detected as differences even though their visual appearance is similar.
On your second question: Using an OCR conversion tool for one or both documents is a common solution to this problem. A simple image comparison of the compared pages in unlikely to work due to the different font styles and line wrappings in the converted file.
Please note that most OCR applications will use the rendered page images for the recognition. This may lead to incorrect recognition results even if there are no images in the PDF file.
i-net Software is aware of this general issue and an OCR module is currently in development. It'll provide an option to apply the recognition solely to the images in the PDF files.
I am working on a Xamarin App compatible with all devices. I have a general question related to images. I am using Location Mark Image Icons to provide locations available on the Map. My issue is, Image has a white background which is also showing along with its background. I want to show only the Image.
Is this related to the designer to provide the image without background? Or as a developer, I can do something on it.
Xamarin.Forms doesn't delete your white background. What you need to do is following a small tutorial on how to use Adobe Photoshop for example and export your images as png, you might even consider which png type you need, there's 3 types of png:
png8
png24
png32
I won't be going deep in explaining each one of them, but you need to know that they all support transparency and could have a transparent background, however, you might notice some differences between them on the edges.
For example, png8 will give a small white border while png24 will not show that.
You can check this for example: https://helpx.adobe.com/photoshop-elements/using/optimizing-images-png-24-format.html
No, you can't do anything about it using Xamarin.Forms. You need to modify the image and remove the background (using Adobe Photoshop, etc.) and make sure to save it as .png.
If its simple white background you want to remove, You can utilise simple [MakeTransparent][1] method ofBitMap.
But this will remove all white coloured pixel. So IF your logo also contains white color, better you contact your designer.
I would like to loop through a sequence of images. I have tried using a Pivot control, but I don't like the blank space in between image transitions. I would prefer to use something that will animate between images smoothly. I also looked at the LoopingSelector control, but I can't seem to set the orientation to horizontal.
I'm assuming you're interested in a kind of image viewer like iOS offers, swiping right or left to navigate through the photos. If that's the case, I hate to say it but i think you're looking at building your own control.
I think to implement it properly these are the essential things you need to think about and address:
For performance' sake, load all the images you have into memorystream objects and store the binary data (you can get creative with this and only store the first 10-15 images, depending on how large the images are, doing this would enable your control to support thousands of images and still perform like a champ).
Once an image is about to be on-screen set the source of the image to the saved memorystream object that has the bytes loaded into it (this will minimize the work that the UI thread does, keeping the control performant and responsive)
Use Manipulation events to track the delta x of the motion someone uses when swiping left to right in order to actually perform the moving of the items
Move the images by changing their Canvas.Left property (you can go negative I think, otherwise just make your canvas the width of all the images you have combined)
Look up some of the available libraries to support momentum so you can have a natural smooth transition between images
I need to develop a desktop application which will
1.) have a list of the Different Application logos (Background Transparent) e.g. IE, FIREFOX, CHROME, PHOTOSHOP ETC.
2.) User will take a screenshot of desktop and save the image.
3.) Now my application need to search all the logos in the screenshot image and tell which all logos are present and where.
4.) I used OPENCV, it's working, but when user changes the desktop background & captures screenshot, it's not working as the transparent area of logo is getting the desktop background content.
Can somebody provide a solution or libraries open source, commercial to do this job.
This is easy to do using cross-correlation.
See my answer to this question.
Basically:
Start with desktop image and one template image for each icon
Apply edge detection (e.g. Sobel) to the desktop image and template images.
Throw away the original desktop image and templates, you won't need them anymore cause we'll be using the edge-detected images
For each template
Do template matching as you normally would
Threshold the maximum of the result. If it's above the threshold, you have a match at that position. Otherwise, no match.
If your icons are aligned in a grid on the desktop, you may be able to speed up your processing by only checking those specific grid positions.
EDIT
You can also save a lot of time by knowing which icons to search for. If you have access to the file system, then just look for *.lnk files (or any other extensions you may be interested in) in the directory that corresponds to the desktop (can't remember exactly what it is, but for Windows7 it's something like c:\users\misha\desktop). That will tell you what icons are there on the desktop. This will allow you to shorten your template candidate list before you go and do the template matching.
I like misha's answer and I think it should work for you. But it that doesn't work you could try replacing the transparant pixels in your reference logo with uniformly distributed random noise before trying the match. This will make the transparant pixels irrelevant for any matching computation because they will match just as bad no matter what there is on the desktop in those pixels.
I'm not familiar with the tools you're using, but I'm guessing you have to either:
a) Tell your program to ignore transparent pixels in the icon images during the comparison operation.
OR
b) Tell your program to treat transparent pixels in the icon images as "wildcards" which can be any color.