JP3347430B2 - Color data collection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is used for digital processing of a color video signal. In particular, it relates to conversion of an analog composite television signal into a three primary color RGB digital signal.

[0002]

2. Description of the Related Art A case where an analog composite television signal expressing a color image by synthesizing a luminance signal Y and a color signal obtained by modulating a color difference signal or an IQ signal with subcarriers is processed by a digital processing device such as a microprocessor. In a general digital processing device, since a color image is represented by RGB signals of three primary colors, it is necessary to convert a composite signal into an RGB signal. That is, the analog composite television signal is converted into a three primary color RGB digital signal, which is stored in a memory and processed by a microprocessor.

[0003]

However, when the composite signal is R
Since there is an error between a decoder for converting to a GB signal and an A / D converter for converting an analog signal to a digital signal,
Conventionally, accurate data levels have not been obtained, and satisfactory measurement results have not been obtained. In particular, a decoder constituted by an analog circuit generally has a limit in accuracy depending on environmental conditions.

SUMMARY OF THE INVENTION The present invention solves the above problem and provides a color data collecting apparatus capable of correcting an analog error and converting an analog composite television signal into three primary color RGB digital signals with high accuracy. The purpose is to:

[0005]

SUMMARY OF THE INVENTION A color data collecting apparatus according to the present invention converts a color video signal represented by an analog signal different from the three primary color signals into an analog three primary color signal, and a signal converted by the decoder. An analog-to-digital converter for converting a three primary color signal into a digital three primary color signal is provided. Means for determining an error, and correcting the color level error of the digital three primary color signals obtained with respect to the input of the reference signal based on these errors, converting the corrected signal into a Y color difference signal, And change it again to 3
Means for obtaining a phase error by a decoder by converting to a primary color signal and comparing the levels thereof, and means for correcting a digital three primary color signal by using the color level error and the phase error. .

As an analog signal different from the three primary color signals, an analog composite television signal generally represented by combining a luminance signal and a color difference signal or a color signal obtained by subcarrier-modulating an IQ signal is used. Can also be used.

Black and white are suitable as colors for which color level errors are determined.

At least a part of the means for obtaining the error, the means for obtaining the phase error, and the means for correcting can be realized as a program of a microprocessor. Further, it can be realized by hardware.

[0009]

A reference signal is inputted in advance as an analog composite television signal, converted into RGB signals of three primary colors, and the conversion error is measured. For an actual video, the conversion data is corrected based on the measured conversion error. Thereby, highly accurate data can be obtained.

[0010]

FIG. 1 is a block diagram showing a color data collecting apparatus according to an embodiment of the present invention. In this embodiment, the apparatus converts a color video signal represented by a signal different from the three primary color signals, in this embodiment, an analog composite television signal into an analog signal.
A decoder 1 for converting the signals into primary color signals; and an analog / digital converter 2 for converting the three primary color signals converted by the decoder 1 into digital three primary color signals.
Video signal storage device 3 for storing digital three primary color signals
And an address controller 4 for controlling a storage address of the video signal storage device 3, a read-only memory 5, a random access memory 6, and a microprocessor 7 for processing data stored in the video signal storage device 3. Here, the features of this embodiment are as follows.
A read-only memory, a random access memory, and a microprocessor for obtaining an error of a color level between two colors of a digital three primary color signal obtained with respect to an input of a reference signal; The color level error of the digital three primary color signals obtained with respect to the input of the reference signal is corrected, the corrected signal is converted into a Y color difference signal to change the color phase, and is again converted into the three primary color signals. A means for determining the phase error by the decoder 1 by comparing the levels and a means for correcting the digital three primary color signals using the color level error and the phase error.

FIG. 2 is a flowchart simply showing the overall operation flow of the apparatus. This device first detects an error with respect to the input of the reference signal, and performs error correction on the signal under measurement based on the error.

FIG. 3 is a flowchart showing the flow of error detection. In response to the input of the reference signal, the obtained digital three primary color signals are stored in the video signal storage device 3, and the white level and black level errors of the RGB signals are detected from the signals. Subsequently, using the detected black level error and white level error, black level correction and white level correction are applied to cyan and magenta of the reference signal. Next, a phase error is detected using the RGB levels of cyan and magenta of the reference signal that has undergone black level correction and white level correction.

The above operation will be described in more detail. First, a 100% color bar signal, which is a reference signal, is input to the decoder 1, and the three primary color signals output from the decoder 1 in response to the input are converted from analog to digital. The video signal is converted into a digital signal by the device 2 and stored in the video signal storage device 3. The write address of the video signal storage device 3 is controlled by a synchronization signal from the address controller 4.

Subsequently, the microprocessor 7 reads the white, yellow, cyan, green, magenta, red, blue, and black signals from the video signal storage device 3 and sets the white R level to [R-WH].
T], White G level is [G-WHT], White B level is [B-WH]
T], yellow R level [R-YEL], yellow G level [G-YE
L], yellow B level is [B-YEL], and cyan R level is [R-
[CYN], cyan G level [G-CYN], cyan B level [B-CYN], green R level [R-GRN], green G level
[G-GRN], green B level is [B-GRN], magenta R level is [R-MGN], magenta G level is [G-MGN], magenta B level is [B-MGN], The red R level is [R-RED], the red G level is [G-RED], the red B level is [B-RED], the blue R level is [R-BLU], and the blue G level is [ G-BLU], blue B
The level is stored in the random access memory 6 as [B-BLU], the black R level is [R-BLK], the black G level is [G-BLK], and the black B level is [B-BLK].

Next, the microprocessor 7 calculates an error between the black level and the white level from the contents stored in the random access memory 6. If the reference black level handled by the digital processing device is [BLK-REF] and the black level errors of the RGB signals are Δ [R-BLK], Δ [G-BLK], and Δ [B-BLK], the black level The equation for detecting the error is as follows. <Error detection equation 1> Δ [R-BLK] = [BLK-REF] − [R-BLK] Δ [G-BLK] = [BLK-REF] − [G-BLK] Δ [B-BLK] = [ BLK-REF]-[B-BLK] For the white level error, the reference white level handled by the digital processing device is [WHT-REF], and the white level error of each of the RGB signals is Δ [R-WHT]. , Δ [G-WHT], Δ [B-
WHT], it is detected as follows: <Error detection equation 2> Δ [R-WHT] = ([R-WHT] − [R-BLK]) / ([WHT-REF] − [BLK-REF]) Δ [G-WHT] = ([G -WHT]-[G-BLK]) / ([WHT-REF]-[BLK-REF]) Δ [B-WHT] = ([B-WHT]-[B-BLK]) / ([WHT-REF ]-[BLK-REF]) Therefore, the collected RGB data [R], [G],
The correction formula for the black level and the white level for [B] is as follows. <Correction formula 1> [R] ^* = (([R] −Δ [R-BLK]) / Δ [R-WHT]) + [BLK-REF] [G] ^* = (([G] −Δ [ G-BLK]) / Δ [G-WHT]) + [BLK-REF] [B] ^* = (([B] −Δ [B-BLK]) / Δ [B-WHT]) + [BLK-REF ]

Next, the correction of the decoding phase error by the decoder 1 will be described. To detect the decoding phase error, first, the black level and white level of cyan and magenta of the data obtained from the reference signal are corrected according to the following equation. <Error detection equation 3> [R-CYN] ^* = (([R-CYN] −Δ [R-BLK]) / Δ [R-WHT]) + [BLK-REF] [G-CYN] ^* = ( ([G-CYN] −Δ [G-BLK]) / Δ [G-WHT]) + [BLK-REF] [B-CYN] ^* = (([B-CYN] −Δ [B-BLK]) / Δ [B-WHT]) + [BLK-REF] [R-MGN] ^* = (([R-MGN] −Δ [R-BLK]) / Δ [R-WHT]) + [BLK-REF] [G-MGN] ^* = (([G-MGN] −Δ [G-BLK]) / Δ [G-WHT]) + [BLK-REF] [B-MGN] ^* = (([[B-MGN] −Δ [B-BLK]) / Δ [B-WHT]) + [BLK-REF] Using the corrected cyan and magenta data,
The conversion from the RGB signal level to the Y color difference signal level is performed as follows. <Error detection formula 4> [Y-CYN] = 0.299 [R-CYN] ^* + 0.587 [G-CYN] ^* + 0.114 [B-CYN] ^* [CB-CYN] = 0.500 [R-CYN] ^* -0.419 [G-CYN] ^* -0.081 [B-CYN] ^* [CR-CYN] = 0.500 [B-CYN] ^* -0.169 [R-CYN] ^* -0.331 [G-CYN] ^* [Y-MGN] = 0.299 [R-MGN] ^* + 0.587 [G-MGN] ^* + 0.114 [B-MGN] ^* [CB-MGN] = 0.500 [R-MGN] ^* -0.419 [G-MGN] ^* -0.081 [B-MGN] ^* [CR-MGN] = 0.500 [B-MGN] ^* -0.169 [R-MGN] ^* -0.331 [G-MGN] ^* Let ΔPHS be the phase error from the case of normal decoding, and use cyan and magenta. The following conversion is performed for <Error detection formula 5> [Y-CYN] ^* = [Y-CYN] [CB-CYN] ^* = cos (ΔPHS) × [CB-CYN] + sin (ΔPHS) × [CR-CYN] [Y-MGN] ^* = [Y-MGN] [CB-MGN] ^* = cos (ΔPHS) × [CB-MGN] + sin (ΔPHS) × [CR-MGN] At this time, ΔPHS satisfying the following condition is calculated. <Error detection formula 6> [Y-MGN] ^* + 1.772 [CB-MGN] ^* = [Y-CYN] ^* + 1.772 [CB-CYN] ^{* The} ΔPHS obtained by this is calculated by [WHT-REF]. It will be a close value.

Using the values thus obtained, the decoding phase error is corrected by the following correction formula. <Correction equation 2> [Y] = 0.299 [ R] * + 0.587 [G] * + 0.114 [B] * [CB] = 0.500 [R] * - 0.419 [G] * - 0.081 [B] * [CR] = 0.500 [B] ^* -0.169 [R] ^* -0.331 [G] ^* [Y] ^* = [Y] [CB] ^* = cos (ΔPHS) × [CB] + sin (ΔPHS) × [CR] [CR] ^* = Cos (ΔPHS) × [CR] −sin (ΔPHS) × [CB] [R] ^** = [Y] +1.402 [CR] ^* [G] ^** = [Y] −0.714 [CR] ^* −0.344 [CB] ^* [B] ^** = [Y] + 1.772 [CB] ^*

By correcting the RGB data stored in the video signal storage device 3 using the correction formulas 1 and 2 thus obtained, highly accurate data can be obtained.

In the above description, a 100% color bar signal is used as a reference signal. However, other signals can be similarly used as a reference signal by multiplying by a coefficient corresponding to the signal. Further, even when the input signal is other than the analog composite television signal, the present invention can be similarly implemented by using a conversion formula for converting the signal into an RGB signal. In that case, if the decoder can input such a signal and can input the three primary color RGB signals to the video signal storage device, the correction can be performed by changing the reference signal. Although it is necessary to change the above error detection formulas 5 and 6, colors other than cyan and magenta may be used for phase error detection.

[0020]

As described above, the color data collecting apparatus of the present invention converts an analog signal different from the three primary color signals, particularly an analog composite television signal, into the three primary color RGB signals with high precision.
It can be converted to a digital signal. Therefore,
There is a great effect as an input device for image processing using digital processing, for example, high-precision color correction.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a color data collecting apparatus according to an embodiment of the present invention.

FIG. 2 is a flowchart schematically showing a flow of an overall operation of the apparatus.

FIG. 3 is a flowchart illustrating a flow of error detection.

[Explanation of symbols]

 Reference Signs List 1 decoder 2 analog-to-digital converter 3 video signal storage device 4 address controller 5 read-only memory 6 random access memory 7 microprocessor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-157188 (JP, A) JP-A-2-302197 (JP, A) JP-A-5-137025 (JP, A) 121185 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 9/44-9/78 H04N 17/02

Claims (3)

(57) [Claims] A decoder for converting a color video signal represented by an analog signal different from the three primary color signals into an analog three primary color signal; and an analog / digital converter for converting the three primary color signals converted by the decoder into a digital three primary color signal. in the color data collection device that includes a digital converter, with the two colors of the digital three primary color signals obtained for an input of the reference signal including a plurality of color signal as a reference
Means for determining a color level error from each of the preset reference levels; and, based on these errors, a color level of the digital three primary color signals obtained with respect to the input of the reference signal. The error is corrected, and the corrected signal is used as an signal different from the three primary color signals.
Means for obtaining a phase error by the decoder by inversely converting to a analog signal and comparing with the reference signal; and means for correcting a digital primary color signal using the color level error and the phase error. A color data collection device, characterized in that: 2. An apparatus according to claim 1, wherein said analog signal different from said three primary color signals is an analog composite television signal represented by a luminance signal and a color difference signal. 3. The color data collection device according to claim 1, wherein said two colors are black and white.