Image Quality Video

[Curtis Cassel]

Imagequality should not be mistaken with image fidelity. Image fidelity refers to the ability of a process to render a given copy in a perceptually similar way to the original (without distortion or information loss), i.e., through a digitization or conversion process from analog media to digital image.

The image formation process is affected by several distortions between the moment in which the signals travel through to and reach the capture surface, and the device or mean in which signals are displayed. Although optical aberrations can cause great distortions in image quality, they are not part of the field of Image Quality Assessment. Optical aberrations caused by lenses belong to the optics area and not to the signal processing areas.

In an ideal model, there's no quality loss between the emission of the signal and the surface in which the signal is being captured on. For example, a digital image is formed by electromagnetic radiation or other waves as they pass through or reflect off objects. That information is then captured and converted into digital signals by an image sensor. The sensor, however, has nonidealities that limit its performance.

Image quality can be assessed using objective or subjective methods. In the objective method, image quality assessments are performed by different algorithms that analyze the distortions and degradations introduced in an image. Subjective image quality assessments are a method based on the way in which humans experience or perceive image quality. Objective and subjective methods of quality assessment don't necessarily correlate with each other. An algorithm might have a similar value for an image and its altered or degraded versions, while a subjective method might perceive a stark contrast in quality for the same image and its versions.

Subjective methods for image quality assessment belong to the larger area of psychophysics research, a field that studies the relationship between physical stimulus and human perceptions. A subjective IQA method will typically consist on applying mean opinion score techniques, where a number of viewers rate their opinions based on their perceptions of image quality. These opinions are afterwards mapped onto numerical values.

Since visual perception can be affected by environmental and viewing conditions, the International Telecommunication Union produced a set of recommendations for standardized testing methods for subjective image quality assessment.[4]

Image quality metrics can also be classified in terms of measuring only one specific type of degradation (e.g., blurring, blocking, or ringing), or taking into account all possible signal distortions, that is, multiple kinds of artifacts.[7]

I'm pretty sure it isn't. If they do compression it is probably lossless, meaning the removal of extraneous/duplicate data which doesn't affect the quality of the image at all. See:

[removed per the Community's Guidelines]

Dave

I put some photo's into Dropbox to share with a friend. I asked him if he was able to download a photo at original quality as it's important for us at a future stage to be able to send each other original sized images.

I'd like to also raise the issue of poor image quality when converting (right click -> convert to PDF with Nitro Pro) which is quite disappointing. I am hoping someone can assist with a fix. For me, this issue is with both version 13.49.2.993 and 13.50.4.1013.

Nitro PDF Pro uses the Nitro PDF Creator when printing and converting a document to PDF.

There is a settings in the Nitro PDF Creator where you can increase the quality of conversion. Please see the steps below:

1. On your Windows machine, go to Printers & Scanners.

2. Look for the Nitro PDF Creator, select it then click Manage

3. Click the Printing Preferences. Under Nitro PDF Creator tab, set the Conversion Quality to Print-Ready.

4. Click Apply then Ok to save the settings.

Thanks for the reply- I've followed your steps, but it didn't change the image quality. I also tried custom- changing the downsample (DPI) to 1200 from 96 (leaving the downsample type - bicubic; compression - automatic as I am not familiar with these options). This also did not change the image quality.

Thank you for sending the file for testing. I have made some changes in the DPI section, setting it to 'Keep original DPI' then saved it. After this, the workflow on right-clicking the file to convert to PDF looks good. Here are the steps I've taken:

1. Open Nitro Pro

2. Go to the Home tab.

3. Click the 'PDF' option in the Create option -> From File -> Settings.

4. On the settings prompt choose the 'Keep original DPI' option. As seen in the screenshot below.

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You can change the image display resolution to high. Or you can keep the image display resolution low in LO and just make the output image display resolution high. Lowering display resolution for viewports and images in LO helps keep the program snappy.

I have been using the photoshop express for years now, yesterday I noticed that when I save an image the quality is diminished & extremely fuzzy. I'm using HD photos and my Jpeg setting is at 100%. Has anyone else experienced this?

I suggest to save locally, without a cloud service feature enabled, just to avoid any unwanted file compression standards that may be enforced during the transmission of the file over a network medium (or the web).

Once I can confirm that my jpeg was saved locally in my device without loosing quality nor reduced in size, then I can deal about how to avoid loosing quality during file reduction or compression before is sent by email or to the cloud.

I am also having this issue. It feels recent to me. I hadn't noticed any loss of image quality even a couple of weeks ago, but today noticed got "unable to download content" error and have now noticed my photos are not appearing at full resolution.

I am using PS Express 23.8.0

To retrieve your app and device information, kindly go to your PsX settings - > then to Help Us Improve -> copy the details on the opened email from App Version down to Status, and send these details, including the video, to me via DM.

Hi - If you try it yourself you will see the issue. I entered a very legible map and as soon as it goes into ps express it basically becomes illegible. Very sad because I really enjoy the Color effects.

I use Mylio photos for organization and editing. However, I like the red-eye feature of PS. Mylio has great support. They get back to you right away, and they acutally send you videos of how to do it right. They don't expect the customer to make a video of how they might be doing it wrong!

Hi,

When I download my edited foto's from PS Express it looks like the quality is not lost, but the image size decreases. The original photo is for example 20mb, but when I edit it and download it from the app it becomes 8mb. I have done everything your colleague told me via chat (update the app, reinstalled the app and turned photo compression on Icloud off). JPEG Quality is on "very high".

Hi so my issue is that when I zoom in on a picture on my mac, the image is crystal clear quality and I can see the smallest details. I shoot both in RAW and in JPEG and both images come out with the same crystal clear quality. However, when I import photos into Lightroom CC and zoom in on the picture, its just very pixelated. I've been trying to find ways to fix it but im just lost at this point.

I have had a similar issue recently when importing 'large' Canon R5 RAW files. Regardless of wether or not the files are viewed directly from the memory card or if the files are first imported to my hard drive and then viewed with Lightroom the result is the same. So chosing which files are the best for improting into Lightroom is not possible as zooming in to check each image sharpnes will result in a hopless pixely image. I tried selecting 1:1 preview and the other sugestions above but the result is the same. My workround is to import all the files (if there are not too many) and then delete the ones I dont want before processing. Once the images are imported there is no pixely effect. If I have many RAW files to sort through then I have to pick the ones I want to keep first with Canon's DPP program which works fine. I am wondering if the problem is a Lightroom bug as I did not have this problem earlier when importing RAW files taken with a Canon 7D mark II and a Canon 5D mark IV, and Lightroom has been recently updated several times since then anyway. If anybody is still expeiencing the same issue, or really has fixed the same one as I am describing, it would be good the hear from you.

I'm having the same problem. It's my first time using lightroom, so I'm not sure if this is user error. I have a chromebook, so I have the Google Play version of the Lightroom App. I uploaded all of my photos directly from my SD card into the Lightroom App. I was planning on sorting through them in there as I don't have a good system for culling yet. And I noticed that even for the photos that are perfectly in focus and look great other places, are just pixally in LR. HELP?!

The first imported graph is

sin1.png (directly exported from gnuplot), whereas the second is sin2.png (a screenshot from my MacBook). These are the original pictures, you can see the result of importing them in the presentation.

The first image looks the same as the original (yes, the linked images are the originals) and actually looks fine to me as well. I agree with you that the second image is blurred, but the corresponding one in the ODP looks worse and quite pixelated to me, very similar to this: Why do images copied to Libre Office Writer look so pixelated? - Super User. I guess this has to do with the bug they mention? _bug.cgi?id=86675

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