9

I will try to explain with the simplest math terms possible. If you want to skip the math, jump to part II, if you want to get the short answer skip to Part III Part I Frequency of a signal means the number of occurrences of a repeating event per unit of time. So if the unit of time is seconds then frequency is measured with Herz: 1Hz = 1/s. So a signal ...


6

There are photoshop plugins around like imatag or digimarc, which offer this as a professional service. The software encrypts a bit of information in a bit pattern and then hides this pattern in your image numerous times. This will work ok as long as there is enough variation in the image, which usually is true for photographies. The information is somewhat ...


5

This seems to be a request for help with a class assignment, which is perfectly acceptable here. But rather than tell you which movement each photo may fit into, I'm going to try and help you better do the assignment yourself, okay? The way you've done it is putting the cart before the horse, so to speak. You've taken a few random images and now you wish to ...


4

What curves do photographers use when modifying the contrast of their photographic images?¹ The vast majority don't do their own curves programmatically, which seems to be what you are seeking. Instead, most start with a "canned" default curve, such as your example of y = a*x + b, applied by their chosen raw processing application, and then either ...


3

I'm not clear on your question. I note that a 55mm equivalent divided by a 3.19 crop factor suggests a 17mm lens. Pixels don't have sizes. Sensors have sizes, and pixels can be presented as pixels per inch as a function of your print or display. Pixels may even be referred to as having a size derived from how they are constructed from the sensors, but in ...


3

For anyone else wanting to do this I figured it out. First I got the color curve I wanted, and clicked the plus to "Save the current settings as named preset" Then next to the plus I pressed Manage presets -> export current settings to file Then I downloaded CurveBatch from here http://gimpfr.org/contrib_photolabo.php Then in GIMP I clicked edit->...


2

The end result of High Dynamic Range Imaging (HDRI) is not to produce an image with dynamic range as high as the scene it attempts to reproduce. We do not have display technology available that can do that. At least not practical ones. The aim of HDRI is to take a very high dynamic range scene and reproduce it in a way that we can see the very bright and ...


2

First, regardless of the particular dynamic range definition, calculating "anything vs zero" luminance is not useful, because then the ratio becomes infinite. Your: log2(max)-log2(0) is another way of saying: log(max/0) and we can't divide by zero (and log2(0) is undefined) So let's forget the 0 for now (zero means the image is not well exposed anyway ...


2

As pointed out in the comments, your illustration shows the image in the wrong place. The image is formed behind the lens. Moreover, the image is doubly inverted with regard to the actual object: If you put the pinhole at the origin (0, 0, 0), things are quite simple: no calculations are necessary, just a reflection about the origin. Suppose the film/sensor ...


2

Pixel sizes are anywhere from 1 to 10+ microns in size and the size and the way they are configured/positioned compared to one another determines their light-gathering abilities. Cramming too many pixels on to a sensor may make it sound like you have a high megapixel (millions of pixels) camera but it was misleading. Improvements in processors over the years ...


1

It seems that GIMP is not able to guess the appropriate compression settings for your photos and artificially boosts the "quality". Don't let the "Use quality settings from original image" option deceive you. Unless the original JPEG is saved by the same library (and in your case, it is not, because it was produced by the camera firmware) ...


1

A difference between the settings used by GIMP and your digital camera likely explains the change in file sizes you're seeing. By default, GIMP appears to export JPEGs with quality 97 without subsampling. Many older digital cameras may use quality settings around 80-90 with subsampling. Using the first photo I encountered on my computer, saving with Q=90 + 4:...


1

To work such a problem you need to know the dimensions of the imagining chip. Chips with 480 x 640 and labeled VGA resolution and typically they are CCD’s containing 0.3 megapixels. Typical is a chip measuring 6.6mm height by 8.8mm length. Now using trigonometry we can compute the focal length of a lens that delivers a horizontal angle of view of 60° and a ...


1

You can draw a right triangle from the center of the lens to the center of the sensor to the edge of the sensor. The angle at the lens is half the field of view. The leg opposite the angle is half the width of the sensor. The focal length is the other leg. You can find the focal length by trig. The two axes have inconsistent data, so will result in ...


1

The Nikon focus points map like this. What that means in terms of image pixel size IDK... a lot more than 1. FWIW, this is nothing like how the AF sensor/sensor lines actually look/work. The exif for a D850 image reads like this: AF Area Mode : Group Area Phase Detect AF : On (153-point) AF Points Used : E12 Primary AF Point : C12 Which means: Group ...


1

You'll want to take it to a professional retoucher or risk going through several students to achieve a finished product. They would likely use digital means, such as scanning the photo then using software like Photoshop to do the actual correction, because while physically retouching the photo is possible it's usually not preferred because of cost, time, and ...


1

A professional retoucher/restorer might be able to do it. I've got to admit it's probably beyond my abilities. The sky isn't too difficult to clean up, & getting rid of the small dings & scratches is time-consuming but not difficult [so I didn't do much of that except for the big one in the sky], but that stripe across the middle is tough. Maybe if ...


1

Depending on what you're focusing on (how close the subjects are from the cameras), you're experiencing the unavoidable effects of parallax due to capturing images from two different perspectives. In photography, perspective is the conceptual point of view of the camera — the actual position of the entrance pupil (apparent location of the iris or aperture) ...


1

On Windows 7 have used free batch converter Converseen to convert HEIC to JPG. Retains EXIF. http://converseen.fasterland.net/


1

I've just come across this (now almost) 9 year-old question. There is some good information in these answers, but many are quite old now, and none really answer the OP's original question: Can software auto-detect image focus? After reviewing the posts here, I found an application called Fast Raw Viewer that has at least a partial solution.


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