Remove Shadows and Denoise Your Color and B&W Scans

BP Mobile
4 min readOct 24, 2023

Hundreds of things can impact the quality of your scanned documents, from multiple types of image noise to uneven lighting and glare to shadows, stains, paper wrinkles, and show-throughs on the source page. At the end of the day, do we really care what all these artifacts are called and what causes them? We just want to remove them from our pictures and scans with as little time and effort as possible. If you’re on board with this, iScanner’s got great news for you. We’re happy to announce the release of our newest filter that allows you to denoise images and remove shadows, show-throughs, and other artifacts from scanned documents in one tap.

What Does Denoise Mean

Image denoising is a term used to describe a range of techniques and processes aimed at removing digital noise and unwanted artifacts from an image. Essentially, it involves the removal of visual information that lacks meaning to the viewer or a processing system, such as random color pixels, shadows, smudges, etc., while preserving the important details of the image.

Why Is It Important to Denoise Your Scans

There are three main reasons why you should denoise your scans.

  1. First of all, denoising gives them a tidier, more professional look.
  2. Second of all, denoised images are much easier to read, which makes it easier to focus on the actual content.
  3. Lastly and most importantly, noise and various artifacts create a serious problem for optical character recognition software. Shadows, stains, glare, creases, and show-throughs can cause OCR algorithms to misread the characters which can result in incorrect or incomplete extraction of data.

This is why most organizations will reject applications containing scanned images with low resolution or multiple visual artifacts. So even if you aren’t fussy about the overall look of your scans, there might be situations where it will be necessary to denoise them, and it’s always handy to have an easy-to-use tool that is always on hand.

Get the Best Possible Scan Quality Even in Tricky Conditions

Tricky conditions are unfortunately much more common than perfect ones. Therefore, the Clear filter is an invaluable tool if you need to scan a lot on the go. Here are several things it can help you with:

  • Glare and shadow removal — Natural light is great, but trying to scan something on a sunny day can be a real quest because glare and shadows are pretty much impossible to avoid. Save time with the Clear filter — just make a shot and the filter will remove shadows and glare.
  • See-Throughs Correction — See-throughs are a common issue with thin pages because the contents of the underlying page will inevitably show on the one you’re trying to scan. The Clear filter can take care of that too.
  • Smudges and Stains Removal — If your source document isn’t in a pristine condition, you can remove smudges and stains with just a tap.
  • Colored Pixel Noise Reduction — Pixelated images are very common if the picture was taken in insufficient lighting conditions. The Clear filter can identify random colored pixels responsible for visual noise and remove them, creating a much clearer, tidier picture.

What You’ll Like about the New Filter

  • It has a slider controller, so you can adjust the effect of the filter very easily.
  • You can see all the changes in real time — no need to save to see the result.
  • It can deal with color images as well as B&W ones. If you’ve tried to remove shadows from a color image, you probably know that it can be a real pain in the backside.
  • The filter can change the background color completely while preserving the original color of the text.
  • You can denoise not only the documents you’ve scanned with the app but also upload images from your camera roll, files, email, etc.
  • It’s super easy to use (as shown below).

How to Denoise Scans and Remove Shadows with the Clear Filter

The workflow is super straightforward:

1) Install the iScanner app.

2) Scan a page.

3) Underneath your scanned page, you’ll see all the filters — tap Clear.

4) Adjust the filter effects by moving the slider controller until you get the result you like.

5) Tap Done in the top right corner.

With uploaded documents, the process is a bit different but fairly simple as well:

  1. Upload the file to the iScanner app.
  2. Tap Adjust at the bottom of the screen.
  3. Next, tap Color, and you’ll enter the color filters menu.
  4. Now, tap Clear and Done once you’re happy with the result. All done.

If this sounds interesting and helpful to you, check out how the app can help you deblur unfocused images, correct perspective distortions and skewed text lines, and remove captured fingertips from scans. To see examples of how the new filter works, please visit this blog post.

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