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Camera Zoom

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  • #21
    Howdy, David!

    I do have several questions! I'm doing some work this morning and will post a few questions- in a new thread. The first thing I'd like to create a minimal template that demos displaying a camera.


    • #22
      Originally posted by Gary Beene View Post
      Howdy, David!

      I do have several questions! I'm doing some work this morning and will post a few questions- in a new thread. The first thing I'd like to create a minimal template that demos displaying a camera.
      Gary's "new thread" is here:


      • #23
        Stuart! What would I do without you! Thanks for posting the clarifications.


        • #24
          I've worked with optical zoom document cameras for a few years. They give the ultimate in zero-distortion zooms. Unfortunately, those cameras can be quite expensive, starting at $800 or so. The company Elmo had a $600 version that I really liked, but they quit making that model. A $200 optical camera would be a major success with the folks I deal with!

          I recently discovered another camera, the Solo8+ by HoverCam for about $400. Its non-optical zoom uses a proprietary method that is significantly better at zooming in on text than the simple window resizing code that I've posted in the Source code forum and in other posts.

          But, knowing that there are techniques to give much-better-than-window-resizing-of-text results keeps me on the search!

          It seems to me that Steve's earlier post ...

          Shoot your video at a higher resolution and you can zoom up to the resolution with no quality loss.
          ... applies to displaying content in windows that are smaller than the highest available resolution. In my case my window size is 1920x1080 and I want to zoom in from there. Cameras with 4K resolution do offer some lift there, but video frame sizes that large can slow down the frame rates the PC can deliver. Even so, that's a good tradeoff. Seeing something clearly is a high priority for my users.


          • #25
            The question was ...

            However, I'm not sure if the IAMCameraControl interface can be used to control a camera's optical zoom. I'd think so but I've not demonstrated it on a camera to know for sure. I hope to try it out later today and will post something on how the test goes.
            And the answer is ...

            Yes, the code that Pierre and I posted recently can use DirectShow to access a camera's optical zoom. At least, it works on the Elmo camera that I have.

            It also works on controlling the non-optical zoom of the HoverCam camera as well.

            it does NOT work on controlling zoom on my Logitech C920 webcam.

            I guess the answer is that the DirectShow Interface can access a camera's zoom but only if the camera drivers support the capability.


            • #26
              It sounds like it could be the AI technology that Topaz uses, but built in to the camera.
              "Not my circus, not my monkeys."


              • #27
                Howdy, Eric!

                Thanks very much for that link. From reading the material, it appears that the technology works best on static images. I didn't see "video" mentioned plus a few reviews implied slow speeds and the system requirements showed an i7 recommendation.

                I'll take a closer look to see if there's is any way to apply it to video. I sent the company a question, asking if a video version is available. I've also downloaded the trial to see how it works on a blurred text image. (3GB download ... that's huge!)


                • #28
                  It's amazing. Scary amazing. I think it must use FM*.

                  *F*****g Magic
                  "Not my circus, not my monkeys."


                  • #29
                    On images, you're right, it was quite amazing!

                    Unfortunately I gave it a try on some fuzzy text and the results were not good at all. I created "Zoomed Text" using simple window resizing and asked Topaz to improve the image. You can see that the results not very good. But compare that to the far right image returned by the HoverCam camera. HoverCam's ability to zoom in on text is pretty amazing.

                    I did send a question about text to Topax. We'll see what they have to say.

                    Click image for larger version

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                    • #30
                      There is a trick that the Sony video cameras I own use, when it gets to the end of its optical zoom, it then stretched the upper range by some form of digital technique and you really cannot tell the difference. Depending on the detail you want to transfer, the base frame size (1920x1080 or 4k) and the bitrate you can tolerate without noticeable pixelation AND the level of movement in the video (motor racing versus a person sitting and talking) you can probably optimise for what you are after by what you are doing with the data.

                      Now if you are only getting the data at 640x480, only display it at that size, you could go a bit bigger by sharpening the feed but that runs out of puff real fast. At the other end if it was getting fed to you at 4k or 8k, downsizing it should not be a big deal and you could set it at the native display size.
                      hutch at movsd dot com
                      The MASM Forum