9 Replies Latest reply on Mar 23, 2018 9:53 AM by DanMadill

    hd-camera underexposed

    DanMadill

      I have compiled and run the hd-camera sample application supplied by Intel at sample-apps/hd-camera at master · intel-aero/sample-apps · GitHub to test the RGB HD camera (OV8858) on the Intel Aero (/dev/v4l/by-path/pci-0000:00:03.0-video-index2) but the images are very underexposed so the images are quite dark. RGB pixel values are in the 0-30 range out of 255 in a normally lit room. Shining a flashlight directly at the camera can yield an RGB pixel value of (255,255,255), so the range of pixel values are not being saturated. It looks very much like the default exposure settings are quite wrong, and standard V4L2 mechanisms for setting the exposure manually do not appear to have any effect.

       

      Does Intel have any examples akin to hd-camera that actually provide normally exposed camera images from the HD camera? The RealSense camera works very well and is properly exposed, as does the optical flow camera. We have been trying for some time to get the HD camera to work properly, and while we can get images from the camera, both with the examples supplied by Intel (hd-camera, capturev4l2) and with our own V4L2-based code, the exposure always appears to be far too low in all cases. I have pasted an example below. I included the overhead light so you can compare pixel values in the full spectrum of light to dark. Note that the room is well lit and the camera does not appear to adjust the exposure automatically (without a light in the image it's just dark). Do you not observe the same behavior from the hd-camera sample or capturev4l2 sample? The image was taken from our own software on the Intel Aero but the sample applications produce very similar results.

       

      Help would be greatly appreciated.

       

      Sincerely,

      Daniel Madill

        • 1. Re: hd-camera underexposed
          Intel Corporation
          This message was posted on behalf of Intel Corporation

          Hello, Daniel

          Thank you for your Interest in Intel products. 
          In order to help you further, I need you to answer a few questions first:
          What values did you choose for aperture and shutter speed?

          With the camera's automated settings, please take a picture of a white, black and 50% gray cardboard and send all three of them back to me to take a look. 
          With the exposure of the 50% gray please check where the information goes on the histogram and if the image is underexposed how much do you have to compensate to bring it to zero?


          Regards,
          Alexandra

          • 2. Re: hd-camera underexposed
            Intel Corporation
            This message was posted on behalf of Intel Corporation

            Hello, Daniel

            It seems that there are some limitations with the down facing camera.The engineering team is looking into it. We will let the community know as soon as we have an update.

            Regards,
            Alexandra

            • 3. Re: hd-camera underexposed
              DanMadill

              Hello Alexandra,

               

              The RGB camera I'm referring to is on a swivel mount and faces forward and down, as opposed to the greyscale optical flow camera which faces directly downward. I'm assuming we are talking about the same RGB camera but thought I should clarify just in case.

               

              Regards,

              Daniel

              • 4. Re: hd-camera underexposed
                DanMadill

                Hello Alexandra,

                 

                I have tried adjusting brightness, hue, sharpness, color effect, backlight compensation, contrast, saturation, gamma, white balance, gain, pan, roll, exposure, focus, tilt, zoom and iris settings in our own V4L2 application and none of them appear to do anything. The same application talking to the RealSense camera can change some of those settings, so I don't think it's a bug in the code. However, since you appear to be confident that the camera aperature and shutter speed can be set, do you have some sample code that sets these parameters of the camera? Also, I should note that the camera does not appear to automatically adjust any settings despite high and low-level light conditions.

                 

                Here is a picture of a white sheet of paper:

                Here is a picture of a black object:

                Here is a picture of a grey object (not guaranteed to be 50% grey I'm afraid):

                Finally, here is a picture in normal lighting of my hand:

                All camera settings are defaults. However, I can't seem to change any of the camera settings mentioned above via V4L2 on this camera anyways. Note that these images may show artifacts from JPEG compression because I compressed them but other than that they are very representative. Just as a point of comparison, here is a picture taken using the RealSense camera of my hand using the same application, same lighting conditions, same JPEG compression and default camera settings:

                 

                Regards,

                Daniel

                • 5. Re: hd-camera underexposed
                  Intel Corporation
                  This message was posted on behalf of Intel Corporation

                  Hello, Daniel

                  Thank you for your answer. It seems that for this camera also  is a known limitation and the engineering team is currently looking into it. As soon as we have additional information, we will update the thread.

                  Regards,
                  Alexandra

                  • 6. Re: hd-camera underexposed
                    DanMadill

                    Thank you, I look forward to an update.

                     

                    Regards,

                    Dan

                    • 7. Re: hd-camera underexposed
                      DanMadill

                      Any updates on this issue?

                       

                      Best regards,

                      Dan

                      • 8. Re: hd-camera underexposed
                        Intel Corporation
                        This message was posted on behalf of Intel Corporation

                        Hi Dan,

                        Unfortunately we have no update yet, the engineering team is still looking into it. 
                        We will let you know.

                        Regards,
                        Alexandra

                        • 9. Re: hd-camera underexposed
                          DanMadill

                          Thanks for responding Alexandra.

                           

                          Regards,

                          Dan