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by fastmapper
Mon Aug 18, 2014 7:10 pm
Forum: Camera board
Topic: What is the Rolling Shutter Speed?
Replies: 12
Views: 5614

Re: What is the Rolling Shutter Speed?

In your earlier reply you said it doesn't have global shutter and now it doesn't have rolling shutter so what does it have? I think jamesh made a typo the Pi Camera is 100% rolling shutter from some of the video samples I've seen so far. Richard S. My understanding is that the OV5647 has both rolli...
by fastmapper
Tue Apr 15, 2014 3:11 am
Forum: Camera board
Topic: Can I use this sensor module with RPI
Replies: 41
Views: 15643

Re: Can I use this sensor module with RPI

More like if you require almost any ISP function you need to buy a supported camera, or you need to be looking at YUV sensors. Bayer sensors generally (someone's bound to find an exception) don't have things like AGC or AWB control loops on board, so those are run on GPU based on the statistics pro...
by fastmapper
Tue Mar 25, 2014 8:04 pm
Forum: Camera board
Topic: Can I use this sensor module with RPI
Replies: 41
Views: 15643

Re: Can I use this sensor module with RPI

Hi All, I am also working on interfacing an Aptina Mt9v011 with the Rpi. Haven't made much progress Without access to the source code on the GPU which houses the camera driver (there is a custom camera driver for each sensor), you will not make any progress. Not quite true. If you want to use a par...
by fastmapper
Wed Mar 19, 2014 2:19 pm
Forum: Camera board
Topic: new 2x2 bin mode and RAW output
Replies: 13
Views: 3626

Re: new 2x2 bin mode and RAW output

The SoC support 4 lane CSI-2 which has a huge bandwidth. BUT, the Raspi only has support for two lanes, and the Raspi camera is even slower than that, although it does use both lanes. If five megapixel images can be provided at 15 frames per second, then the image sensor is running as fast as it ca...
by fastmapper
Wed Mar 19, 2014 4:40 am
Forum: Camera board
Topic: new 2x2 bin mode and RAW output
Replies: 13
Views: 3626

Re: new 2x2 bin mode and RAW output

I don't know what the maximum operating speed of the CSI-2 interface hardware is, but I expect that the pixel output rate of the image sensor is limited to converting about 96 million pixels (from analog to digital) per second. This means that up to 15 five-megapixel frames can be produced in a seco...
by fastmapper
Wed Mar 19, 2014 2:28 am
Forum: Camera board
Topic: new 2x2 bin mode and RAW output
Replies: 13
Views: 3626

Re: new 2x2 bin mode and RAW output

My understanding is that the binning function simply adds nearby pixels of like color together and does not change the number of pixels produced. It is subsampling (decimation) that reduces the number of pixels. I believe that binning and subsampling can be selected independently. Of course, that me...
by fastmapper
Sun Jun 30, 2013 10:57 pm
Forum: Camera board
Topic: Capture raw image to memory buffer (C/C++)
Replies: 25
Views: 13548

Re: Capture raw image to memory buffer (C/C++)

Note in stills capture, the ISP has to change camera mode from preview (a video) mode to stills mode, it then needs to capture a frame, then go back to preview mode - that takes a fair while - a few frames at 30ms each. That setup each side of the actual capture is going to add up to around 100ms b...
by fastmapper
Fri Jun 28, 2013 4:25 pm
Forum: Camera board
Topic: CSI Camera, Car and Raspistill . Problems
Replies: 12
Views: 4880

Re: CSI Camera, Car and Raspistill . Problems

You are not really going to fix the problem with the non-straight lamppost. The sensor uses a rolling shutter, so this sort of effect is pretty inevitable. - its the time difference in the top to bottom scan that causes the problem. Hopefully I'll be able to take a look at the various exposure issu...
by fastmapper
Fri Jun 28, 2013 5:36 am
Forum: Camera board
Topic: Frame synchronisation
Replies: 82
Views: 35078

Re: Frame synchronisation

pads on ov5747 NOT available on 24 pin connector: 15 PWDN 17 RESETB 28 PCLK 10 STROBE 11 FREX For the digital video port (DVP), the timing of the pixel data bits (D0 to D9) is related to PCLK. The VSYNC and HREF signals are present, so the only signal missing would be PCLK. I strongly suggest that ...
by fastmapper
Thu Jun 06, 2013 12:22 pm
Forum: Camera board
Topic: Variant characterizations of the camera module lens
Replies: 39
Views: 10310

Re: Variant characterizations of the camera module lens

rkinch wrote:could you at least look at my photo above, and at towolf's farther above, and compare to the lens you measured at f=3.6mm? Are they similarly featured with the spline edge? The 2.2mm OD bevel around the pupil? Do they look otherwise similar in proportions?
Here is a photo of my camera.
by fastmapper
Thu Jun 06, 2013 4:37 am
Forum: Camera board
Topic: Variant characterizations of the camera module lens
Replies: 39
Views: 10310

Re: Variant characterizations of the camera module lens

So I am waiting for fastmapper to confirm his 1.8mm pupil measurement, versus my 1.25mm. Please don't wait. I made a quick estimate of pupil diameter using a photo that was not as good as I would like and I only intended it to provide an upper bound. The measurements I made with any level of seriou...
by fastmapper
Tue Jun 04, 2013 10:47 pm
Forum: Camera board
Topic: Stock lens in the camera module 3.6mm f/2.9 [was: 4mm f/3.2]
Replies: 11
Views: 19847

Re: Stock lens in the camera module shown to be 4mm f/3.2

Shooting a full-resolution still (2592 x 1944 pixels) displays a field of view about 34.75 inches wide at 38 inches. How accurate do you believe your measurements were? I measured 48.8+/-0.1 inches horizontal cross range at 48.4+/-0.3 inches range. I also measured at 5 additional ranges up to 168.1...
by fastmapper
Mon May 27, 2013 3:00 pm
Forum: Camera board
Topic: Focal length and HFOV
Replies: 2
Views: 2172

Re: Focal length and HFOV

I have been trying to stitch some photographs together taken with the raspberry pi camera board. The software (hugin) requires some lens data as the image does not have any stored with it. It needs 2 of these 3 values Horizontal field of view (HFOV) Focal length Crop factor (aka focal length multip...
by fastmapper
Sun May 26, 2013 5:14 am
Forum: Camera board
Topic: RAW output information
Replies: 236
Views: 94688

Re: RAW output information

The pixel data is arranged in the file in rows, with 3268 bytes per row. With 2592 image pixels across on the sensor, and 5/4 bytes per pixel, you might expect only 3240 bytes per row, but there are 28 extra bytes at the end of each row which encode some other, unknown information. Some of that may...
by fastmapper
Sun May 26, 2013 4:24 am
Forum: Camera board
Topic: STICKY: Foundation (old) Camera Board information
Replies: 446
Views: 299543

Re: Foundation Camera Board information

fastmapper, want to take a stab at deriving aperture too? Sure. I presume that you are looking for an f-stop rating for the lens. It's hard to measure the physical diameter of the lens without taking it apart so I estimated the diameter of the front lens opening using a high resolution photograph o...
by fastmapper
Sat May 25, 2013 10:03 pm
Forum: Camera board
Topic: STICKY: Foundation (old) Camera Board information
Replies: 446
Views: 299543

Re: Foundation Camera Board information

Here is a focal length update. Now that the full field of view is available for still photos, I have repeated my estimation of focal length. To do this I took photos of a measuring tape at 6 different distances from the camera. I estimate that the focal length of my Raspberry Pi camera is 3.60+/-0.0...
by fastmapper
Sun May 19, 2013 7:20 am
Forum: Camera board
Topic: STICKY: Foundation (old) Camera Board information
Replies: 446
Views: 299543

Re: Foundation Camera Board information

Ah..ok...but this is exactly what you would expect then, right?? With only 1.25 mega pixels that are sensitive to (say) red on the physical sensor itself, you cannot expect to get more than that in independent pixels in the final image, no matter at which resolution, even 5 M (de-bayered = interpol...
by fastmapper
Sun May 19, 2013 4:37 am
Forum: Camera board
Topic: STICKY: Foundation (old) Camera Board information
Replies: 446
Views: 299543

Re: Foundation Camera Board information

Does this take into account the nature of the Bayer array? A 5 Mega pixel sensor has only 1.25M pixels that detect blue, 1.25M pixels that detect red, and 2.5 M pixels that detect green. So there can be no more than 1.25 M truly independent pixels in the de-bayered final image. Or am I missing some...
by fastmapper
Sun May 19, 2013 3:25 am
Forum: Camera board
Topic: STICKY: Foundation (old) Camera Board information
Replies: 446
Views: 299543

Re: Foundation Camera Board information

If we can get the raw Bayer form of the image, then there should be no image scaling. I'll see what happens when I try the related option of raspistill. That is a good idea. I would be very interested to see such a file with the embedded raw data, to try some experiments. I don't know if any raw da...
by fastmapper
Sat May 18, 2013 9:03 pm
Forum: Camera board
Topic: STICKY: Foundation (old) Camera Board information
Replies: 446
Views: 299543

Re: Foundation Camera Board information

If we can get the raw Bayer form of the image, then there should be no image scaling. I'll see what happens when I try the related option of raspistill. That is a good idea. I would be very interested to see such a file with the embedded raw data, to try some experiments. I don't know if any raw da...
by fastmapper
Fri May 17, 2013 11:34 pm
Forum: Camera board
Topic: STICKY: Foundation (old) Camera Board information
Replies: 446
Views: 299543

Re: Foundation Camera Board information

The focal length estimates I made presume that the image has not be scaled, so if there is a 1.8x scaling, that would imply a focal length closer to 3.6mm. I have also made some related physical measurements and I think the distance from the lens cover front to the focal plane is about 5.2mm. It wou...
by fastmapper
Fri May 17, 2013 9:18 pm
Forum: Camera board
Topic: STICKY: Foundation (old) Camera Board information
Replies: 446
Views: 299543

Re: Foundation Camera Board information

I have focal length estimation results. My Raspberry Pi camera was delivered yesterday. Today I setup my measuring tapes and took photos to estimate the camera focal length. I measured the scene width at 5 different distances from the camera and I got a consistent result. My estimate of the focal le...
by fastmapper
Sun Apr 07, 2013 10:18 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO Set / Clear Latency Problem
Replies: 7
Views: 2007

Re: GPIO Set / Clear Latency Problem

Here is what the BCM2835 ARM Peripherals document says: Accesses to the same peripheral will always arrive and return in-order. and It is not required to put a memory barrier instruction after each read or write access. Only at those places in the code where it is possible that a peripheral read or ...
by fastmapper
Sun Apr 07, 2013 2:35 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO Set / Clear Latency Problem
Replies: 7
Views: 2007

Re: GPIO Set / Clear Latency Problem

Since I'm reading the state of the pin within the Broadcom BCM2835, I suspect the wire length would be only a few microns. For the experiments I've done: what I'm reading is correct after two reads even if it is incorrect after one. I have checked the signal on an oscilloscope, but I cannot see when...
by fastmapper
Sun Apr 07, 2013 12:27 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO Set / Clear Latency Problem
Replies: 7
Views: 2007

GPIO Set / Clear Latency Problem

I've been trying to use the GPIO pins at high rates using assembly language. Through the course of development I have stumbled upon a problem reading and writing the GPIO pins. If I set or clear a GPIO pin, then read the state of the GPIO pins on the next assembly instruction, it generally but not a...

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