JPEG Recovery Editor (Available in Professional Version only) - Sample Page 2

If you have photos exhibited problem that similar to the below:

Sample 1: Color changed

Sample 2: Color changed, contents shifted and border wrapped to the left hand side of the photo

Then it is possible to recover them into the the below pictures:

Note: There is still minor color mismatch in the recovered picture.


Cause of the Picture Corrupted

JPEG is a highly compressed format. Every bit counts. A malfunction bit can cause great impact in JPEG.

In our samples, both of them only have 1 bit of data (out of millions of bits in the file) gone wrong. The originals can be downloaded below (All data in hexadecimal notation except those enclosed in brackets are in decimal):

  Sample 1 (Demo 4 in user manual) Sample 2 (Demo 5 in user manual)
Original Picture Download (1,356K) Download (347K)
Corrupted Picture Download (1,356K) Download (347K)

Difference

Offset: 5BC15 (375,829)
Original: 9A
Corrupted: 98
Offset: E41F (58,399)
Original: 4F
Corrupted: 4D
Recovered Picture Download (1,356K) Download (347K)
Defects in Recovered Picture Some pixels still corrupted near (352, 568) to (447, 575) Minor color mismatch

What are the impacts of a malfunction bit?

A common answer: it depends. Depending on the location of the bit, it may result in:

  • No impact at all, or
  • Minor or invisible defects in a few pixels that you won't notice, or
  • Color shift, or
  • Pixel shift, or
  • Both color and pixel shift, or
  • Normal graphics viewer cannot open the picture.

Again, an incorrect bit in JPEG is sufficient to corrupt the whole picture.

Why there is such 'malfunction bit'?

We don't know. But in case your pictures exhibit similar problem, very likely there are some bits in the picture having incorrect value.

We guess that such corruption might be found when the picture has been placed in the CD/DVD for a long time, transfer between media (e.g. between hard disk, memory card, imagetank, network, etc), stored in an old hard disk without access for some time, etc.

What JPEG Recovery Editor can help?

JPEG Recovery Editor cannot locate the malfunction bit(s). However, JPEG Recovery Editor provides a simple to use interface such that you can try repairing the picture hopefully into an acceptable version with minor defects and flaws using a few mouse clicks.

Why can't you locate and correct those malfunction bit'?

Even those we can track down the approximate location of the problem, we cannot exactly pinpoint the problem byte (not to mention the bit). The possible combinations of those bytes are too many to guess. The situation can be more complicated if there are more than 1 corrupted bits in the region. In addition, although there is corrupted bit, very often it does not violate JPEG encoding rules.

Why there may be defects and flaws?

Bear in mind that JPEG Recovery Editor repairs the corrupted picture; it cannot locate those problem bit(s) and correct them. While JPEG Recovery tries to reduce the defects and flaws to minimum, it cannot eliminate them completely. Thus, you must evaluate the result before making any purchase decision.

Defects and flaws will be more visible if your picture has:

  • Low resolution, or
  • Noise (e.g. shot in high ISO), or
  • Many different patterns

How can I avoid data corruption?

We don't expect there is data corruption. Data corruption in other files (e.g. Windows system files) can cause hazards.

The only way to tackle data corruption is to backup your data frequently. Make sure 'archival grade discs' are used if you use CD-R or DVD-R for data backup, and store the discs in an environment with controlled temperature and relative humidity mentioned by the disc manufacturers.

 

Important Note: The above demonstration images are for software testing and evaluation purposes. The author owns the copyright of the images, and you are not allowed to use them for other purpose without written consent from us.

 

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